Team PYREX built a planetary rover called Animus for the 2014 Robo-Ops competition. Animus features a rocker-bogie suspension system with six-wheel drive and four-wheel steering for navigating varied terrain. It is remotely operated via 4G internet connection. Components were selected through analytical and rapid prototyping methods. Key features include a rectangular aluminum chassis, fiberglass rocker-bogie legs, 3D printed tread wheels, 13 servos, 6 motors, sensors, and a lithium battery power supply. The team's goal was to complete objectives while establishing experience for future competitions.
Analysis and simulation of a rocker bogie exploration roverAnkush Mukherjee
This document summarizes a study analyzing and simulating a rocker-bogie exploration rover. Key points:
- Models of the mechanics and kinematics of the rocker-bogie rover configuration are presented to aid in design and control.
- An efficient method is outlined for solving the rover's inverse kinematics and performing quasi-static force analysis, accounting for factors like the manipulator, actuator limits, and wheel slip.
- A physical model is developed of the Lightweight Survivable Rover (LSR-1) rocker-bogie rover prototype. Experimental results confirm the validity of the models.
This document describes a rocker-bogie rover mechanism. It discusses how bogies were commonly used in tank tracks and truck trailers to distribute load but now prefer trailing arm suspensions. The rocker-bogie configuration allows planetary rovers to continue playing an important role in exploration by providing two different angles to the four joints of each bogie, allowing it to cross obstacles easily. Acrylic material and large, heavy-grip wheels powered by DC motors were used to fabricate and test a rocker-bogie model.
Simulation of eight wheeled rocker bogie suspension system usingIAEME Publication
This document summarizes a study that used MATLAB to simulate an eight-wheeled rocker bogie suspension system for a rover. The study involved modeling the rover system in SolidWorks, importing it into MATLAB using a SolidWorks translator tool, and simulating it moving in MATLAB. The simulation analyzed slippage of the wheels at different speeds and showed that slip decreases over time, and higher speeds result in more initial slip but less slip overall. The study concluded the simulation helped analyze the stress levels and motions of the rover components and confirmed the design could withstand loading.
The document discusses the design of a mobility system for a Mars rover. It aims to design a suitable mobility system and bracket to house motors. It describes different types of Mars rovers including wheeled, tracked, and elastic loop mobility systems (ELMS). It provides details on the design of the ELMS and bracket. It discusses how Mars rovers have continually improved with features like self-navigation, solar power, and scientific instruments to further exploration.
This document summarizes the market research and design process of a student team creating an advanced lunar rover. It discusses existing rover designs from NASA, including the Sojourner, Spirit, Athlete, and Curiosity rovers. These rovers informed the requirements for the new design, including flexibility to navigate different terrains, minimizing energy usage, and negotiating difficult surfaces. The document then covers the team's concept generation and selection of components, including wheels, suspension, power source, and materials. Design prototypes, calculations, and a management plan are also summarized to outline the comprehensive process undertaken to create a more advanced lunar rover design.
The document discusses the rocker-bogie suspension system, which was developed by NASA and JPL for use in space exploration rovers. It has since been used successfully on Mars rovers like Pathfinder, Spirit, Opportunity and Curiosity. The system allows rovers to climb over obstacles nearly twice the wheel diameter. It works by allowing independent wheel motion through linked rocker arms and bogies. The study aims to analyze if this system could benefit heavy loading vehicles on Earth by improving efficiency and reducing maintenance costs over conventional suspensions. It details the mechanics and modeling of the rocker-bogie system and shows how it allows stable, balanced motion over rough terrain at slower speeds.
The document describes the design and fabrication of a rocker bogie mechanism. It discusses:
1) The introduction of the rocker bogie suspension system used on Mars rovers and its ability to maintain contact over uneven terrain.
2) The objectives of the project to optimize speed while preventing flipping and increase cost effectiveness for exploration and other applications.
3) The related concepts of traction, stability, and mobility required for the rover to traverse rough terrain and obstacles.
Wheel diameter and RPM calculations are provided to design wheels that can achieve various speeds over different terrains. The requirements, applications, and future scope of the rocker bogie mechanism are also summarized.
This document describes the design and fabrication of a rocker bogie mechanism. It provides details on the components, working principle, advantages, and applications of the rocker bogie suspension system. The rocker bogie allows vehicles to traverse rugged terrain by lifting each wheel over obstacles independently. It has been used successfully on NASA Mars rovers due to its ability to distribute weight evenly and climb obstacles twice the wheel diameter. The document outlines the process followed to design, build, and test a rocker bogie mechanism model.
Analysis and simulation of a rocker bogie exploration roverAnkush Mukherjee
This document summarizes a study analyzing and simulating a rocker-bogie exploration rover. Key points:
- Models of the mechanics and kinematics of the rocker-bogie rover configuration are presented to aid in design and control.
- An efficient method is outlined for solving the rover's inverse kinematics and performing quasi-static force analysis, accounting for factors like the manipulator, actuator limits, and wheel slip.
- A physical model is developed of the Lightweight Survivable Rover (LSR-1) rocker-bogie rover prototype. Experimental results confirm the validity of the models.
This document describes a rocker-bogie rover mechanism. It discusses how bogies were commonly used in tank tracks and truck trailers to distribute load but now prefer trailing arm suspensions. The rocker-bogie configuration allows planetary rovers to continue playing an important role in exploration by providing two different angles to the four joints of each bogie, allowing it to cross obstacles easily. Acrylic material and large, heavy-grip wheels powered by DC motors were used to fabricate and test a rocker-bogie model.
Simulation of eight wheeled rocker bogie suspension system usingIAEME Publication
This document summarizes a study that used MATLAB to simulate an eight-wheeled rocker bogie suspension system for a rover. The study involved modeling the rover system in SolidWorks, importing it into MATLAB using a SolidWorks translator tool, and simulating it moving in MATLAB. The simulation analyzed slippage of the wheels at different speeds and showed that slip decreases over time, and higher speeds result in more initial slip but less slip overall. The study concluded the simulation helped analyze the stress levels and motions of the rover components and confirmed the design could withstand loading.
The document discusses the design of a mobility system for a Mars rover. It aims to design a suitable mobility system and bracket to house motors. It describes different types of Mars rovers including wheeled, tracked, and elastic loop mobility systems (ELMS). It provides details on the design of the ELMS and bracket. It discusses how Mars rovers have continually improved with features like self-navigation, solar power, and scientific instruments to further exploration.
This document summarizes the market research and design process of a student team creating an advanced lunar rover. It discusses existing rover designs from NASA, including the Sojourner, Spirit, Athlete, and Curiosity rovers. These rovers informed the requirements for the new design, including flexibility to navigate different terrains, minimizing energy usage, and negotiating difficult surfaces. The document then covers the team's concept generation and selection of components, including wheels, suspension, power source, and materials. Design prototypes, calculations, and a management plan are also summarized to outline the comprehensive process undertaken to create a more advanced lunar rover design.
The document discusses the rocker-bogie suspension system, which was developed by NASA and JPL for use in space exploration rovers. It has since been used successfully on Mars rovers like Pathfinder, Spirit, Opportunity and Curiosity. The system allows rovers to climb over obstacles nearly twice the wheel diameter. It works by allowing independent wheel motion through linked rocker arms and bogies. The study aims to analyze if this system could benefit heavy loading vehicles on Earth by improving efficiency and reducing maintenance costs over conventional suspensions. It details the mechanics and modeling of the rocker-bogie system and shows how it allows stable, balanced motion over rough terrain at slower speeds.
The document describes the design and fabrication of a rocker bogie mechanism. It discusses:
1) The introduction of the rocker bogie suspension system used on Mars rovers and its ability to maintain contact over uneven terrain.
2) The objectives of the project to optimize speed while preventing flipping and increase cost effectiveness for exploration and other applications.
3) The related concepts of traction, stability, and mobility required for the rover to traverse rough terrain and obstacles.
Wheel diameter and RPM calculations are provided to design wheels that can achieve various speeds over different terrains. The requirements, applications, and future scope of the rocker bogie mechanism are also summarized.
This document describes the design and fabrication of a rocker bogie mechanism. It provides details on the components, working principle, advantages, and applications of the rocker bogie suspension system. The rocker bogie allows vehicles to traverse rugged terrain by lifting each wheel over obstacles independently. It has been used successfully on NASA Mars rovers due to its ability to distribute weight evenly and climb obstacles twice the wheel diameter. The document outlines the process followed to design, build, and test a rocker bogie mechanism model.
Design and Fabrication of Wheel Chair using Rocker Bogie Mechanismijtsrd
Rocker bogie finds a vital role in determining the scientific analysis of objectives separated by many distance apart. The mobility design at present is quite a bit complex with many legs or wheels. The wheeled rover which is capable of driving over the rough terrain provided with high degree of mobility suspension system. The drive provided by the rocker bogie is simple and it mainly operated by the means of two motors. The motors are kept inside in order to make it more reliable and efficient. In overcoming the bumps in the natural terrain the wheels are operated simultaneously. By implementing this mechanism the vehicle can come through any obstacles it faces during the travel in the terrain. Arjun CP | Jithin Peter TK | C. Mohamed Meersa | Habeeb Rahman PP "Design and Fabrication of Wheel Chair using Rocker Bogie Mechanism" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd42537.pdf Paper URL: https://www.ijtsrd.comengineering/mechanical-engineering/42537/design-and-fabrication-of-wheel-chair-using-rocker-bogie-mechanism/arjun-cp
This document describes the design and fabrication of a rocker bogie mechanism. The rocker bogie system is a suspension used on Mars rovers to allow independent wheel movement over obstacles. The design includes two rocker arms that allow the left and right wheels to climb obstacles individually. Calculations are shown for tilt angle, wheel base, link lengths, and motor specifications. Components include shafts, links, wheels, bearings, and motors. The advantages of the rocker bogie system include its ability to climb obstacles twice the wheel diameter and distribute load evenly across independently moving wheels.
Design, Modification and Manufacturing of a Stair Climbing VehicleRaian Nur Islam
A ‘STAIR CLIMBING VEHICLE’ that is designed by following the mechanism of a Shrimp Rover Model of EPFL (Swiss Federal Institute of Technology Lausanne), Switzerland) described in this paper. This stair climbing vehicle is able to climb stairs, move on flat and rough surfaces. Here, we have detailed the designing and manufacturing of such kind of vehicle. Along with building a well-functioning prototype, experimental demonstration has been done with the final construction and the result recorded is very promising.
Check the link below to get the 3D CAD model of this project for FREE
https://grabcad.com/library/shrimp-rover-1
IRJET- Design and Fabrication of Rocker Bogie Mechanism using Solar EnergyIRJET Journal
1. The document describes the design and fabrication of a rocker bogie mechanism using solar energy. It discusses the history and design of various planetary rovers that use rocker bogie and other suspension systems.
2. The researchers designed a new rocker bogie mechanism with a double-lambda configuration that allows for higher speeds over rough terrain while maintaining obstacle clearance. They used structural synthesis methods to design and analyze the mechanism.
3. The rover is powered by solar energy through the use of a solar tracking system. It is intended to be a lower-cost alternative to existing rocker bogie rovers while improving traversal speed for exploration.
This document presents a mathematical model of a vehicle suspension that was developed as a midterm project. It includes:
1) A quarter-car model to simulate the bounce of one wheel over a pothole or bump.
2) A full-car model combining 4 quarter-car models to simulate the bounce of each tire.
3) An extension of the full-car model to simulate pitching of the vehicle body when encountering road variations.
4) Consideration of rolling of the vehicle body when taking turns. Non-linear springs are proposed to improve the model.
Quarter model of passive suspension system with simscapeabuamo
The document summarizes key aspects of vehicle suspension systems. It defines a suspension system as using springs and shock absorbers to connect wheels/axles to the vehicle chassis. Suspension systems serve to carry weight, maximize tire traction, provide stability and handling, and ensure passenger comfort by smoothing bumps. Springs absorb shock from bumps by converting it to potential energy, while shock absorbers dissipate shock without causing undue vehicle oscillation. Passive suspensions use traditional springs and dampers, while active suspensions constantly sense the road and adjust components like shock stiffness electronically. Simscape software can be used to model and simulate multi-domain physical systems like vehicle suspensions.
Design of Tank Simulator for Side-Mount Support Structure for a SpacecraftIRJET Journal
This document describes the design of a tank simulator for a side-mounted support structure for an Indian communications satellite (GSAT). The traditional design of mounting fuel tanks inside the central cylinder increases the satellite's length-to-diameter ratio and reduces stability. The new design moves the fuel tank to the sides of the satellite, connected via a side-mount structure. This includes a central ring, top/bottom plates, ribs, flex plates, struts, and brackets. Finite element analysis was conducted applying 8g loads horizontally and 18g vertically to simulate launch stresses. Stress and displacement results for all components were within allowable limits, validating the new tank simulator design.
STUDY & DESIGN OF FIRE DETECTING & FIRE EXTINGUISHING ROBOTIJARIIE JOURNAL
This document discusses the design of a fire detecting and extinguishing robot. It begins with an introduction to the need for such robots in hazardous firefighting situations. It then discusses various drive mechanisms that could be used, including wheel, track, Mecanum and holonomic drives. Design considerations for each are evaluated in a decision matrix. Wheel vs track designs are also compared. The document then covers motor selection based on the robot's weight, incline and acceleration needs. Finally, it discusses how IR sensors could be used to detect fires based on detecting reflected light intensity.
This document discusses mobile robot vehicles and provides several examples of different types of mobile robot platforms. It covers key concepts related to mobility including configuration space, task space, degrees of freedom, and actuation. Examples discussed include trains, hovercrafts, helicopters, fixed-wing aircraft, underwater robots, and cars. Each example describes the robot's configuration space, degrees of freedom, actuation, and task space. The document aims to explain the basic issues involved in programming robots to perform tasks by analyzing different types of mobile robot platforms and their mobility characteristics.
This document analyzes the suspension system of an automobile modeled as a two-degree-of-freedom spring-mass-damper system. Equations of motion were derived using Lagrange's equations and modeled in SIMULINK. Natural frequencies were found to be 5.1 rad/s and 6.5 rad/s. Increasing damping reduced bounce by 3x10-3 m to 1x10-3 m and pitch by 5x10-4 m to less than 1x10-4 m. MATLAB modal analysis verified results and natural frequencies were compared.
Mathematical Modeling and Simulation of Two Degree of Freedom Quarter Car Modelijsrd.com
The proposed study is to develop an active suspension system to increase the comfort for the passenger by reducing the body acceleration. The dynamic quarter car suspension system is considered for mathematical modelling and simulation is carried using MATLAB SIMULINK. The present suspension system is controlled by Proportional- Integral -Derivative controller. The system performance is analysed using the single speed bump road surface and the effectiveness is evaluated with active and passive controlled systems.
1. The document describes the design of a Mars rover vehicle for a competition to retrieve rocks and return them to a designated area while overcoming small obstacles.
2. The proposed design uses tank-style treads, a gripping mechanism, and an inclined rock receptacle. It will be powered by rechargeable batteries and controlled remotely.
3. The document provides details on the design concepts, requirements, proposed budget, and continuing areas of concern for the Mars rover vehicle.
The ROBO MAT is an autonomous mapping tool developed for General Atomics to measure deterioration in railgun bores. It uses four 3D-printed rollers attached to a chassis to traverse the bore length in under 30 minutes, avoiding heavy sludge buildup along corners. A Raspberry Pi controls motors that drive the bottom rollers and records data from a tracer wheel and camera, storing bore images on an SD card. While not tested in an actual railgun, it mapped a fabricated bore model effectively.
The document describes the design of a slider-crank leg mechanism for a mobile hopping robotic platform. The mechanism uses a slider-crank mechanism to convert continuous motor rotation into piston motion, which impacts the ground to generate hopping locomotion. A mechanical clutch trigger mechanism was developed to control the impact timing and maintain a constant transmission angle for repeated hopping. Dynamic analysis was performed to determine the optimal position of the clutch trigger mechanism to maximize hopping height. Experimental validation was conducted, and future work on a two degree-of-freedom leg design is proposed.
Design and Development of Passive Magnetic BearingIJMER
Passive Magnetic Bearings (PMB) are known for their non-contact and negligible friction
operations but these desirable characteristics of PMB can only be attained if proper designing of bearing
is carried out based on the applied load. To aid to the design of PMB, 3D Coulombian model to estimate
the load carrying capacity of magnetic bearings has been proposed. To exemplify the design procedure,
analyses of various configurations of magnetic bearings have been presented. To economize the magnetic
bearings, usage of easily available square magnets in stator made of aluminium has been proposed.
Finally, a case study has been included to illustrate the design of magnetic bearing.
The formula cars need high tire grip on racing challenge by reducing rolling displacement at corner or
double change lands. In this case study, the paper clarifies some issues related to suspension system with
inerter to reduce displacement and rolling angle under impact from road disturbance on Formula SAE
Car. We propose some new designs, which have an advance for suspension system by improving dynamics.
We optimize design of model based on the minimization of cost functions for roll dynamics, by reducing the
displacement transfer and the energy consumed by the inerter. Base on a passive suspension model that we
carried out quarter-car and half-car model for different parameters which show the benefit of the inerter.
The important advantage of the proposed solution is its integration a new mechanism, the inerter, this
system can increase advance in development and have effects on the vehicle dynamics in stability vehicle.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Simulation of an Active Suspension Using PID ControlSuzana Avila
The document simulates an active vehicle suspension using PID control. It builds a quarter car model and analyzes the controllability and observability. Numerical simulations show the active suspension with PID controller improves performance over the passive suspension by reducing displacement peaks and settling times for step, harmonic, and noise road profiles. The active suspension improves comfort but has higher manufacturing costs than passive suspensions.
Design, Analysis and Simulation of Double Wishbone Suspension System for Form...IRJET Journal
This document describes the design, analysis, and simulation of a double wishbone suspension system for a formula student racing vehicle. The authors first discuss the basic parameters and requirements for the suspension system. They then describe the detailed design of the knuckle, wishbones, and helical coil spring. Finite element analysis is conducted on these components using ANSYS to analyze stresses and deformations. Finally, dynamic simulation of the full suspension system is performed using ADAMS software to analyze how kinematic parameters like camber angle and roll steer change with wheel travel. The results of the simulation match the designed parameters and help validate the suspension system design.
Design and Fabrication of Wheel Chair using Rocker Bogie Mechanismijtsrd
Rocker bogie finds a vital role in determining the scientific analysis of objectives separated by many distance apart. The mobility design at present is quite a bit complex with many legs or wheels. The wheeled rover which is capable of driving over the rough terrain provided with high degree of mobility suspension system. The drive provided by the rocker bogie is simple and it mainly operated by the means of two motors. The motors are kept inside in order to make it more reliable and efficient. In overcoming the bumps in the natural terrain the wheels are operated simultaneously. By implementing this mechanism the vehicle can come through any obstacles it faces during the travel in the terrain. Arjun CP | Jithin Peter TK | C. Mohamed Meersa | Habeeb Rahman PP "Design and Fabrication of Wheel Chair using Rocker Bogie Mechanism" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd42537.pdf Paper URL: https://www.ijtsrd.comengineering/mechanical-engineering/42537/design-and-fabrication-of-wheel-chair-using-rocker-bogie-mechanism/arjun-cp
This document describes the design and fabrication of a rocker bogie mechanism. The rocker bogie system is a suspension used on Mars rovers to allow independent wheel movement over obstacles. The design includes two rocker arms that allow the left and right wheels to climb obstacles individually. Calculations are shown for tilt angle, wheel base, link lengths, and motor specifications. Components include shafts, links, wheels, bearings, and motors. The advantages of the rocker bogie system include its ability to climb obstacles twice the wheel diameter and distribute load evenly across independently moving wheels.
Design, Modification and Manufacturing of a Stair Climbing VehicleRaian Nur Islam
A ‘STAIR CLIMBING VEHICLE’ that is designed by following the mechanism of a Shrimp Rover Model of EPFL (Swiss Federal Institute of Technology Lausanne), Switzerland) described in this paper. This stair climbing vehicle is able to climb stairs, move on flat and rough surfaces. Here, we have detailed the designing and manufacturing of such kind of vehicle. Along with building a well-functioning prototype, experimental demonstration has been done with the final construction and the result recorded is very promising.
Check the link below to get the 3D CAD model of this project for FREE
https://grabcad.com/library/shrimp-rover-1
IRJET- Design and Fabrication of Rocker Bogie Mechanism using Solar EnergyIRJET Journal
1. The document describes the design and fabrication of a rocker bogie mechanism using solar energy. It discusses the history and design of various planetary rovers that use rocker bogie and other suspension systems.
2. The researchers designed a new rocker bogie mechanism with a double-lambda configuration that allows for higher speeds over rough terrain while maintaining obstacle clearance. They used structural synthesis methods to design and analyze the mechanism.
3. The rover is powered by solar energy through the use of a solar tracking system. It is intended to be a lower-cost alternative to existing rocker bogie rovers while improving traversal speed for exploration.
This document presents a mathematical model of a vehicle suspension that was developed as a midterm project. It includes:
1) A quarter-car model to simulate the bounce of one wheel over a pothole or bump.
2) A full-car model combining 4 quarter-car models to simulate the bounce of each tire.
3) An extension of the full-car model to simulate pitching of the vehicle body when encountering road variations.
4) Consideration of rolling of the vehicle body when taking turns. Non-linear springs are proposed to improve the model.
Quarter model of passive suspension system with simscapeabuamo
The document summarizes key aspects of vehicle suspension systems. It defines a suspension system as using springs and shock absorbers to connect wheels/axles to the vehicle chassis. Suspension systems serve to carry weight, maximize tire traction, provide stability and handling, and ensure passenger comfort by smoothing bumps. Springs absorb shock from bumps by converting it to potential energy, while shock absorbers dissipate shock without causing undue vehicle oscillation. Passive suspensions use traditional springs and dampers, while active suspensions constantly sense the road and adjust components like shock stiffness electronically. Simscape software can be used to model and simulate multi-domain physical systems like vehicle suspensions.
Design of Tank Simulator for Side-Mount Support Structure for a SpacecraftIRJET Journal
This document describes the design of a tank simulator for a side-mounted support structure for an Indian communications satellite (GSAT). The traditional design of mounting fuel tanks inside the central cylinder increases the satellite's length-to-diameter ratio and reduces stability. The new design moves the fuel tank to the sides of the satellite, connected via a side-mount structure. This includes a central ring, top/bottom plates, ribs, flex plates, struts, and brackets. Finite element analysis was conducted applying 8g loads horizontally and 18g vertically to simulate launch stresses. Stress and displacement results for all components were within allowable limits, validating the new tank simulator design.
STUDY & DESIGN OF FIRE DETECTING & FIRE EXTINGUISHING ROBOTIJARIIE JOURNAL
This document discusses the design of a fire detecting and extinguishing robot. It begins with an introduction to the need for such robots in hazardous firefighting situations. It then discusses various drive mechanisms that could be used, including wheel, track, Mecanum and holonomic drives. Design considerations for each are evaluated in a decision matrix. Wheel vs track designs are also compared. The document then covers motor selection based on the robot's weight, incline and acceleration needs. Finally, it discusses how IR sensors could be used to detect fires based on detecting reflected light intensity.
This document discusses mobile robot vehicles and provides several examples of different types of mobile robot platforms. It covers key concepts related to mobility including configuration space, task space, degrees of freedom, and actuation. Examples discussed include trains, hovercrafts, helicopters, fixed-wing aircraft, underwater robots, and cars. Each example describes the robot's configuration space, degrees of freedom, actuation, and task space. The document aims to explain the basic issues involved in programming robots to perform tasks by analyzing different types of mobile robot platforms and their mobility characteristics.
This document analyzes the suspension system of an automobile modeled as a two-degree-of-freedom spring-mass-damper system. Equations of motion were derived using Lagrange's equations and modeled in SIMULINK. Natural frequencies were found to be 5.1 rad/s and 6.5 rad/s. Increasing damping reduced bounce by 3x10-3 m to 1x10-3 m and pitch by 5x10-4 m to less than 1x10-4 m. MATLAB modal analysis verified results and natural frequencies were compared.
Mathematical Modeling and Simulation of Two Degree of Freedom Quarter Car Modelijsrd.com
The proposed study is to develop an active suspension system to increase the comfort for the passenger by reducing the body acceleration. The dynamic quarter car suspension system is considered for mathematical modelling and simulation is carried using MATLAB SIMULINK. The present suspension system is controlled by Proportional- Integral -Derivative controller. The system performance is analysed using the single speed bump road surface and the effectiveness is evaluated with active and passive controlled systems.
1. The document describes the design of a Mars rover vehicle for a competition to retrieve rocks and return them to a designated area while overcoming small obstacles.
2. The proposed design uses tank-style treads, a gripping mechanism, and an inclined rock receptacle. It will be powered by rechargeable batteries and controlled remotely.
3. The document provides details on the design concepts, requirements, proposed budget, and continuing areas of concern for the Mars rover vehicle.
The ROBO MAT is an autonomous mapping tool developed for General Atomics to measure deterioration in railgun bores. It uses four 3D-printed rollers attached to a chassis to traverse the bore length in under 30 minutes, avoiding heavy sludge buildup along corners. A Raspberry Pi controls motors that drive the bottom rollers and records data from a tracer wheel and camera, storing bore images on an SD card. While not tested in an actual railgun, it mapped a fabricated bore model effectively.
The document describes the design of a slider-crank leg mechanism for a mobile hopping robotic platform. The mechanism uses a slider-crank mechanism to convert continuous motor rotation into piston motion, which impacts the ground to generate hopping locomotion. A mechanical clutch trigger mechanism was developed to control the impact timing and maintain a constant transmission angle for repeated hopping. Dynamic analysis was performed to determine the optimal position of the clutch trigger mechanism to maximize hopping height. Experimental validation was conducted, and future work on a two degree-of-freedom leg design is proposed.
Design and Development of Passive Magnetic BearingIJMER
Passive Magnetic Bearings (PMB) are known for their non-contact and negligible friction
operations but these desirable characteristics of PMB can only be attained if proper designing of bearing
is carried out based on the applied load. To aid to the design of PMB, 3D Coulombian model to estimate
the load carrying capacity of magnetic bearings has been proposed. To exemplify the design procedure,
analyses of various configurations of magnetic bearings have been presented. To economize the magnetic
bearings, usage of easily available square magnets in stator made of aluminium has been proposed.
Finally, a case study has been included to illustrate the design of magnetic bearing.
The formula cars need high tire grip on racing challenge by reducing rolling displacement at corner or
double change lands. In this case study, the paper clarifies some issues related to suspension system with
inerter to reduce displacement and rolling angle under impact from road disturbance on Formula SAE
Car. We propose some new designs, which have an advance for suspension system by improving dynamics.
We optimize design of model based on the minimization of cost functions for roll dynamics, by reducing the
displacement transfer and the energy consumed by the inerter. Base on a passive suspension model that we
carried out quarter-car and half-car model for different parameters which show the benefit of the inerter.
The important advantage of the proposed solution is its integration a new mechanism, the inerter, this
system can increase advance in development and have effects on the vehicle dynamics in stability vehicle.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Simulation of an Active Suspension Using PID ControlSuzana Avila
The document simulates an active vehicle suspension using PID control. It builds a quarter car model and analyzes the controllability and observability. Numerical simulations show the active suspension with PID controller improves performance over the passive suspension by reducing displacement peaks and settling times for step, harmonic, and noise road profiles. The active suspension improves comfort but has higher manufacturing costs than passive suspensions.
Design, Analysis and Simulation of Double Wishbone Suspension System for Form...IRJET Journal
This document describes the design, analysis, and simulation of a double wishbone suspension system for a formula student racing vehicle. The authors first discuss the basic parameters and requirements for the suspension system. They then describe the detailed design of the knuckle, wishbones, and helical coil spring. Finite element analysis is conducted on these components using ANSYS to analyze stresses and deformations. Finally, dynamic simulation of the full suspension system is performed using ADAMS software to analyze how kinematic parameters like camber angle and roll steer change with wheel travel. The results of the simulation match the designed parameters and help validate the suspension system design.
Slideshare fisiologia instintos sexo y sexualidadannapri66
El documento define el instinto como las pautas o conductas hereditarias que permiten la reacción y adaptación de los animales y humanos ante situaciones que requieren respuesta rápida. Aunque más neutralizadas en los humanos, los instintos permiten la evolución y supervivencia de las especies al facilitar la adaptación a nuevas realidades. El instinto es común a toda una especie y no depende de la educación o estilo de vida individual.
Zapbuild Technology, is an Enterprise Business Solutions Provider. We can conceive, design, develop and implement an enterprise application of any magnitude and on any platform. We are globally accepted, as evidenced by the faith reposed by multiple clients.
Este documento describe varios modelos de toma de decisiones organizacional. Explica el modelo racional, el cual asume que los gerentes tienen toda la información y capacidad para tomar la mejor decisión. También describe las críticas a este modelo, como la incertidumbre y preferencias variables. Luego introduce el modelo de Carnegie, el cual reconoce las limitaciones de la información y el procesamiento racional. Finalmente, discute otros modelos como el incremental, el no estructurado y el del "bote de basura", los cuales reconocen aún más la incertidumbre y la política
This document contains trivia questions testing knowledge about generals from fiction, television shows like Game of Thrones and Futurama, board game characters, slogans, wrestlers, book introductions, science facts, and determining whether self-help books are real or made up. It features over 100 short multiple choice or fill-in-the-blank questions across various categories to test general knowledge.
Thabile Given Tshabalala is seeking employment and has over 10 years of experience in payroll, human resources, and customer service roles. She has a National Diploma in Internal Auditing from Vaal University of Technology and is computer literate in Microsoft Office programs. Her previous roles include working as a wages clerk for Rhodes Food Group, a Kronos operator for Edgars department store, and a service center operator and supervisor also at Edgars. She has strong communication, organization, and problem solving skills.
Este documento trata sobre el maltrato infantil. Explica que el maltrato puede ser físico o psíquico. Define el maltrato infantil y enumera siete tipos como el maltrato físico, abandono, maltrato emocional, abuso sexual, abandono emocional, síndrome de Münchhausen por poderes y maltrato institucional. También describe indicadores de maltrato en los niños y en los padres, así como efectos en los niños y formas de prevenir el maltrato.
This document provides information about Apex Group of Institutions in Rajasthan, India, which was established 50 years ago. It lists the names and positions of important people associated with Apex. It then provides brief descriptions and contact information for the various institutions that make up Apex, including engineering, management, and polytechnic colleges. It discusses programs and certifications offered to students to enhance their employability. Finally, it discusses the promising future of engineering in India and skills that will be important for future careers.
The National Western Stock Show is the world's largest livestock exhibition by animal count and largest carload and pen cattle show. It serves as a premier stock show, rodeo, and horse show and hosts year-round events in Denver. The mission is to serve producers and consumers by providing agricultural and medical scholarships. Stakeholders include directors, staff, exhibitors, donors, and local, national, and international communities. The marketing, livestock, and horse/rodeo departments use various media including websites, social media, radio, TV, and print advertising to promote the stock show. Analytics and reports track media success.
The Hidden Truth on instagram comment bot Revealedmuddledray5715
Instagram is working to ensure users only see authentic content from real accounts like Tony Hawk and Taylor Swift, rather than knock-offs. While premium filters and sponsorships are possible features, the focus is on high-quality brand advertisements that feel consistent with the Instagram experience and like content seen in magazines. Research found that Mondays at 5pm PST and leveraging other social networks are optimal times and strategies for gaining followers and engagement on Instagram posts. However, a portion of new followers may be inactive or fake accounts.
This story is about how Ananse the spider man outwits the Sky God, Nyame, to obtain all of the stories on Earth. Nyame tells Ananse he can have the stories if he captures Osebo the leopard, Mmboro the hornets, and Mmoatia the fairy. Through clever tricks, Ananse is able to capture all three creatures. He presents them to Nyame, who is so impressed he gives Ananse the golden box of stories. From that day on, all stories were called "Spider Stories" and belonged to Ananse.
Design and Optimization of Double Wishbone Suspension System for ATVsIRJET Journal
This document discusses the design and optimization of a double wishbone suspension system for all-terrain vehicles (ATVs). It aims to minimize weight and cost while improving performance. CAD software was used to model the geometry, which was then simulated in ADAMS and analyzed in ANSYS for stress and deformation. The optimized design improved suspension parameters like camber angle, caster angle, king pin inclination and scrub radius. It also reduced roll steer compared to the original design. The optimized double wishbone suspension is suitable for installing on ATVs as well as other vehicles.
IRJET- Dynamic Analysis of the Front and Rear Suspension System of an All...IRJET Journal
This document describes the design and analysis of the front and rear suspension systems for an all-terrain vehicle (ATV). It discusses using a double wishbone suspension in the front for steering control and an H-arm suspension in the rear for load bearing capacity and control of camber and toe. The design process considers factors like geometry, material selection, force analysis, and damper and spring selection and tuning. The goals of the suspension design are to provide maximum traction, control, comfort, and stability over rough terrain.
IRJET- Experimental Analysis of Passive/Active Suspension SystemIRJET Journal
This document presents an experimental analysis comparing the performance of passive and active suspension systems using a quarter car model. A quarter car model with two degrees of freedom was created using masses, springs, and dampers to simulate the sprung and unsprung components of a vehicle. Experimental tests were conducted using this physical model, with and without active control via a PID controller. The results showed that with active control, displacements were reduced to 600-900 μm and accelerations were reduced to 1-3 m/s2, compared to 5-10 mm and 14-20 m/s2 respectively for the passive system. Graphs of the experimental data further demonstrated that the active suspension provided better vibration isolation than the passive system. In
IRJET - Review of Suspension System for a Race CarIRJET Journal
This document reviews suspension systems for race cars. It summarizes 15 previous research papers on race car suspension design. The key findings are that double wishbone suspension systems are best for race cars to maintain optimal wheel contact and handling. Simulation software can be used to optimize suspension geometry and components to reduce weight while ensuring strength. Forces extracted from dynamic simulations can then be applied to components in static analysis to evaluate stress and durability. An optimized suspension design starts with kinematic analysis, applies loads from modeling, and uses results to validate component design.
Design,Analysis & Fabrication of suspension of all terrain vehicleZubair Ahmed
This document provides an overview of suspension systems for vehicles, including definitions of key terms. It focuses on designing the suspension system for an all-terrain BAJA vehicle. The document discusses dependent and independent suspension systems. For the BAJA vehicle, an independent suspension was selected. The design process involved selecting components, geometry, and simulation to optimize ride, handling, and other factors. Detailed design of front and rear suspension components is described, including wishbones, uprights, wheel hubs, stub axles, trailing arms, and more. Steering system design is also discussed.
IRJET- Design and Analysis of Chassis for Solar Electric VehicleIRJET Journal
The document discusses the design and analysis of a chassis for a solar electric vehicle. It begins with an introduction to solar vehicles and then describes the challenges in developing an effective solar car chassis, namely maximizing strength while minimizing weight. It then outlines the various types of chassis frames that were considered for the vehicle, including ladder, backbone, and monocoque frames. The design process is discussed, including considerations for ergonomics, dimensions based on a standardized anthropometric model, and using triangulation to increase torsional stiffness. A CAD model was generated and an analysis was performed using ANSYS software to simulate front, side, rear impacts and torsion. The final designed chassis was optimized for increased stiffness and strength.
IRJET- Design and Fabrication of Multi Legged RobotIRJET Journal
1. Students designed and fabricated an eight-legged walking robot based on the Klann linkage mechanism to test new walking algorithms.
2. The Klann mechanism converts rotary motion of a crank into linear movement of the leg, simulating an animal's gait. Two linkages are coupled 180 degrees out of phase to allow the robot to walk.
3. An analysis of the robot and leg mechanisms was performed using ANSYS software to evaluate stresses, deformations, and fatigue over time. The results provide data to optimize the robot's design qualities and walking performance.
This document describes the design, analysis, and performance evaluation of a mechanical gyrator vehicle. A mechanical gyrator is a three-wheeled vehicle with two large outer wheels and an inner frame that can oscillate. The document outlines the subsystems of the gyrator such as the wheels, chassis, transmission, seat, and electrical system. It discusses the material selection, modeling, and analysis done to optimize the design. The goal was to develop an efficient personal transportation vehicle for disabled individuals that is stable, easy to operate, and has a low turning radius.
Design, analysis and performance evaluation of a mechanical gyratorIjrdt Journal
The project focuses on the development of an efficient and safe system for navigation for disabled people. Such a system should enable the user to control with minimum effort and should be stable in all practical situations. A gyrator is neither a motorcycle nor a four wheeler. It is a vehicle made up of an inner frame which is encompassed and supported by two large coaxially aligned wheels. The inner frame is supported by a common axle as a result, is free to oscillate back and forth relative to outer wheels. The inherent instability has limited its potential as a commercially available vehicle. But by reducing this oscillation to an optimum value by incorporating internal braking, we could make a very stable navigation system. In order to achieve motion, a shift in the centre of gravity of the inner frame is required. Two independent electric motors provide the driving torque to gearbox which drives the large outer wheels. This unique design gives the vehicle a clear advantage over conventional 4wheeled and 2wheeled vehicles as it has zero turning radius. Key word:- Inflation Pressure, Pressure switch ,Pressure guage, Solenoid control valve, DC Compressor.
Finite Element Analysis and Topography Optimization of Lower Arm of Double Wi...IJERA Editor
The suspension system is one of the most important components of vehicle, which directly affects the safety, performance, noise level and style of it. The vehicle suspension system is responsible for driving comfort and safety as the suspension carries the vehicle-body and transmits all forces between body and road. Structure optimization techniques under static load conditions have been widely used in automotive industry for lightweight and performance improvement of modern cars. However, these static load conditions could not represent all the severe situations of automobile parts which subjected to complex loads varying with time, especially for lower control arm of front suspension. This paper deals with Finite Element Analysis of the Lower arm suspension of double wishbone suspension which consist the stress optimization under static loadings. Lower arm suspension has been modeled using Unigraphics .In first stage of analysis area of maximum stress was identified. These analysis were carried using Altair Hyperworks and solver used is Abacus. In order to reduce stresses and to improve structural strength Topography optimization approach is carried out in Hyperworks in which a design region for a given part is defined and a pattern of shape variable-based reinforcements within that region is generated to increase Stiffness.
IRJET- Review on Rover with Rocker-Bogie Linkage Mounted with Ultrasonic Sens...IRJET Journal
This document describes a rover designed with a rocker-bogie linkage suspension system and equipped with an ultrasonic sensor and Bluetooth module powered by solar energy. The rocker-bogie system, inspired by NASA designs, allows the six-wheeled rover to traverse uneven terrain by keeping all wheels in contact with the ground. An Arduino board controls the motors and ultrasonic sensor for navigation via commands from a Bluetooth module. The goal is to create an affordable rover capable of moving across multiple terrains using an efficient suspension system.
Designing FSEV suspension system in Lotus Suspension Analysis SHARKIRJET Journal
The document discusses the design of the suspension system for a Formula-style race car using Lotus Suspension Analysis SHARK software. The goal was to increase stiffness and reduce spring travel to improve handling. Both the front and rear suspension geometries were redesigned and optimized. The rear suspension was changed significantly due to engine replacement altering weight distribution. The new designs showed reduced spring travel, improved roll stability, and increased but controlled bump steer to boost driver confidence.
Design and Development of H-Frame with Lateral Link Suspension for an All Ter...IRJET Journal
This document describes the design and development of a rear suspension system for an all-terrain vehicle (ATV) using an H-frame with a lateral link. The suspension components were modeled, analyzed using FEA software to calculate stresses, and tested. The H-frame with lateral link suspension provides better handling, lateral load capacity, and camber control. Component stresses from FEA were within safety factors. Testing showed the suspension responded well to rough terrain without failures over 450km.
Chassis 2002 01-3300 design, analysis and testing of a formula sae car chassisELKINMAURICIOGONZALE
This document summarizes the design, analysis, and testing of a Formula SAE car chassis. It discusses key concepts in frame design including load paths, deformation modes, and stiffness targets. A spring model is developed to determine frame and chassis torsional stiffness targets relative to suspension components. Finite element analysis is used to analyze frame concepts. Experimental techniques like strain gauges and whole-car tests are used to validate designs and determine actual stiffness.
Design & Analysis of Rail Wheel FailureIRJET Journal
This document discusses the design and analysis of rail wheel failures. It begins with an introduction to the increasing speeds and loads on trains leading to more fatigue failures in wheels. A literature review covers previous research on factors that influence rolling contact fatigue crack initiation in wheels. The study focuses on modeling a train wheel and axle in CAD software and analyzing it in FEM software to determine stresses and temperatures under loading. Forces on the wheel are calculated and the model is meshed and solved. Results show maximum displacement of 0.0769mm and von Mises stress of 1330MPa. The conclusion discusses developing a multiaxial fatigue life prediction model to study parameters affecting wheel fatigue damage.
This document analyzes the double wishbone suspension system used in sedan vehicles. It discusses how using low profile tires can increase hub rotation during braking due to the coupled nature of castor and longitudinal stiffness in a traditional double wishbone design. The objectives are to decouple castor and longitudinal stiffness, reduce castor trail loss and hub rotation when braking, while maintaining the suspension geometry kinematics. A potential solution of moving the longitudinal elastic center vertically down from the wheel center to the ground plane is proposed to be analyzed using multibody dynamics software.
The document summarizes the design of the suspension system for a formula student race car. It describes the design procedure and considerations, which included kinematic and dynamic analysis to optimize wheel alignment and spring specifications. Key steps involved deciding geometry and dimensions through iterative modeling and simulation. Results showed minimal changes in camber, caster and toe angles during wheel travel. Spring stiffness and damping ratio were validated through additional roll analysis. The designed system aims to provide stable handling and absorb vibrations during high-speed racing.
1. The document describes the design of an automobile gearbox holding device to safely remove and replace gearboxes during maintenance.
2. Currently, mechanics use dangerous methods involving multiple men lying under vehicles to support heavy gearboxes by hand, risking injury.
3. The proposed design uses a linked mechanism with a support plate, power screw, brackets, and links to lift and lower the gearbox. Rotating the power screw causes the support plate to move up and down.
4. Calculations were done to design the plate, screw, and links to withstand the required loads while keeping stresses below safe limits. The design aims to minimize risks for mechanics and be reliable, efficient, and cost-effective.
IRJET - Design, Simulation and Analysis of Double Wishbone Suspension Sys...IRJET Journal
This document describes the design, simulation, and analysis of a double wishbone suspension system for an all-terrain vehicle (ATV). The authors designed the suspension system using CATIA V5 software, analyzing components using ANSYS, and simulating the full system in MSC Adams. An optimized roll center geometry was determined which limited changes in camber and toe angles during wheel travel. Materials including mild steel and aluminum were selected for components like the knuckle and hub based on strength requirements. The suspension system was designed to provide 3 inches of bump and rebound travel while maintaining vehicle stability during cornering.
Design & Development of Formula Student ChassisIRJET Journal
The document describes the design process for a Formula Student chassis. It discusses how the team used Solidworks to design a spaceframe chassis with AISI 4130 steel tubes. Key steps included:
1. Defining suspension hardpoints and the vehicle envelope based on driver ergonomics and positioning components.
2. Using software to sketch tubes and ensure proper triangulation at nodes for structural rigidity.
3. Adding tertiary tubes and performing analysis in ANSYS to optimize stiffness.
Ergonomic testing with drivers ensured the optimal seating position for visibility and controls. Manufacturing jigs and fixtures were designed to aid in precise tube notching and welding of the chassis.
Similar to VT PYREX RoboOps 2014 Final Report (20)
1. Team PYREX
2014 Robo-Ops Final Technical Report
Virginia Tech
460 Old Turner St
Blacksburg, VA 24060
Undergraduate Team Members Faculty Advisor
Tom Corona Dr. Kevin Shinpaugh
Chris Gumm Adjunct Faculty, Aerospace and Ocean Engineering – Virginia Tech
Kevin Hummel Director, I.T and Services – Virginia Bioinformatics Institute
Nick Socky
Jason Duane
Jimmy Congleton
Joe Haslem
Matt Canavra
2. 1
Chapter 1: Background and Motivation
Virginia Tech will be entering Animus, the nickname of the team’s rover, into the 2014
RASC-AL Exploration Robo-Ops Competition. Built and developed by eight undergraduate
students under the guidance of the Aerospace Department, Animus is designed to function as a
tele-operated rover in a planetary simulated environment. Animus’s systems were designed with a
primary focus to swiftly and effectively traverse the varying terrain of the course. As the
University’s first entry into the competition, PYREX (PlanetarY Rover EXploration) hopes to
prove Animus’s capabilities in completing the objectives outlined in the competition’s guidelines
as well as establish the groundwork for future teams to compete. Along with developing this rover,
PYREX has actively networked with companies to sponsor Virginia Tech in Animus’s
development as well as working with the local community in public outreach programs to promote
further interest in the project.
Chapter 2: Description of System Components
Animus features a rocker-bogie suspension system with four wheeled steering and six
wheeled drive. Although challenging to manufacture, this design has proven to have benefits that
outweigh the time investment needed to form such a complex structure. The rocker-bogie
suspension and drivetrain components increase the chance for the rover to have all six wheels in
contact with a terrain at a given moment, ensuring minimal wheel slip.
Having a rover capable of navigating complex terrain is complimented by a user-friendly
control system. Onboard Animus are two Verizon hotspots that provide a 4G internet connection
to an onboard computer. A UDP connection then allows the operator in Blacksburg to control three
cameras, all rover drive functionality, a five degree of freedom (DOF) manipulating arm, and
access to various sensors.
When selecting these components, it was necessary to ensure the correct decision was made
to achieve our goals. Initially, an analytical hierarchy process (AHP) was used to numerically rank
criteria based on different alternatives to attain an unbiased result. However, in a complex group
environment pressured by time, a rapid prototyping approach was adapted. This method utilized
computer aided design (CAD) and preliminary calculations, followed by initial prototyping, and
then iterative refinement until a final product was realized. With the support of subdivision and
team leaders, this process proved to be very efficient while still being reinforced by numerical
data. The products of PYREX’s decisions are detailed below:
Description of Chassis and Suspension Mechanisms. The rover’s chassis takes the form
of a simple rectangular shape. A rectangular frame maximizes platform area for mounting
components and it is simple to manufacture. The final chassis can be seen in Figure 1. It is mainly
comprised of 6061 Aluminum ¾ inch square tubing and G10-FR4 fiberglass brackets. Using these
two materials allowed the team to quickly fabricate and test different configurations to find optimal
dimensions and fastening techniques.
The chassis in Figure 1 weighs 2.0 kg and provides the blank platform to build the rover
around. The frame is 0.838 meters long, 0.457 meters wide, and .114 meters high. These
3. 2
dimensions give the rover room for mounting components and remain within the maximum size
limits. The frame is held together by brackets and screws allowing parts to be interchanged.
Figure 1 – Final Rover Frame. A detailed CAD of the blank rover chassis. This provided the
rover with a large area that could easily be fitted with all the necessary systems and components.
The rover utilizes a six wheeled rocker-bogie system. The rocker-bogie configuration can
be seen in Figure 2. The advantages to using this system are that the rover is able to maintain
contact between all of its wheels and the ground while maneuvering over obstacles. Distributing
the weight and drive torque to six wheels instead of four, gives the rover greater traction and
stability.
Figure 2 - Completed CAD model of rover chassis and suspension system. There are 2.38 mm
thick FR4-G10 fiberglass sheets mounted on the deck of the rover’s frame, to allow for easy
mounting. The differential bar is located on the top of the assembly, and turning motors are seen
at the ends of the suspension system.
The rocker-bogie legs are comprised of ¾ inch thick G10-FR4 fiberglass. Figure 3
highlights the fabrication process of rocker-bogie legs. This material has a lower density than
aluminum, and as such a lower yield strength.
Electronic Deck
Turning Servo
Differential Bar
Rocker- Bogie
Suspension
4. 3
(3.1) (3.2) (3.3)
Figure 3 – Construction of Suspension Pieces. Above highlights some of the work involved in
perfecting a suspension arm. Four individual pieces were crafted for use on the rover, plus a spare
bogie arm.
After assembling the rocker-bogie suspension to the frame, some degree of torsional
bending was bowing the wheels outwards. This bowing is known as camber gain, and is caused
by the flexibility in the fiberglass arms and from a large kingpin offset between the longitudinal
centers of the wheel and the suspension. To counter camber gain, a slight toe-in adjustment was
given to the front steering wheels and a front sway bar was added to the rover. Rigidity through
the suspension system was achieved by the use of a differential bar. The solid ¼ inch thick 6061
Aluminum differential bar can also be seen in Figure 2 above. To minimize the stress on this bar,
ridged body dynamics were used to investigate areas throughout the suspension system that could
be modified.
The triangle shown in Figure 4 is created from the main axel, differential bar, and the top
of the suspension system. This triangle plays a very important part on the overall rigidity of the
system. If all other dimensions are kept the same, varying the height, H, in Figure 4 also varies
the angle θ. As the value of θ increases and becomes close to 90°, the forces required to keep the
rover system rigid become exponentially increased. The optimal angle of θ would be 45°, as this
would evenly distribute the forces between all components in the suspension system. Due to the
rover’s height restriction limits, an angle of 45° was not possible. The maximum angle θ that was
obtained while staying below the height restrictions was 69°.
5. 4
Figure 4 – Side view of rocker bogie suspension system. The distance H is the relationship
between the height of the main axel and the height of the differential bar. This distance plays a
key role in determining the overall rigidity of the rover system.
Design of Wheels for Optimal Traction. It was necessary to research vehicle dynamics
and terramechanics theories to derive a proper wheel for Animus. Thankfully, Virginia Tech offers
a class on land vehicle dynamics, and has professors such as Dr. Saied Taheri and Dr. Mehdi
Ahmadian (both leaders in vehicle and tire systems) available for support. The equations and
branching theories behind wheel terramechanics are quite indepth, and will not be covered in the
scope of this report. For more information, see reference [1]
. Instead, this section gives a brief
overview of the basic physics involved in wheel design and terramechanics.
Terramechanics, or the interaction between a soil and a tire can be modeled as a rigid case
or an elastic case. For the purpose of this design, a rigid wheel case was used. This assumes no tire
deflection, and no pneumatic inflation pressure within the tire. A rigid wheel will sink into a soil
to some degree, have a certain slip velocity, deform the soil to some amount, and have a resistive
self-aligning force in the lateral and longitudinal wheel direction. This is largely based on the
contact patch the wheel makes with the soil, and the load on each individual wheel. The contact
patch dimension is a function of wheel radius and width, so it was necessary to select a size that
met desired weight constraints, vehicle speed, and various other limiting size factors.
A MatLab program was developed that allowed a user to change tire dimensions, loading
force, and terrain properties (ranging from firm to soft soil) in order to optimize a wheel design.
The parameters used for the soil properties can be found in reference [1]
. Below is a Figure that
depicts the sinkage of a wheel based on the contact angle.
Figure 5 - Representation of interaction between a rigid wheel and soil interface. It should be
noted in this figure that the velocity V is to the right, angular velocity w is clockwise, Zr is the
wheel sinkage, and the wheel is in contact with the soil from points C to A [1]
. P(θ) is the pressure
distribution and S(θ) is the shear displacement distribution.
6. 5
After itervatily running the Matlab program under different inputs, it was found that an
20.32 cm diamter wheel at 12.7 cm wide would prove to have the most tractive benefits under all
soils. Knowing the degree of wheel sinkage for this case and assuming a slip percentage of 3%
(used as a standard amount of wheel slip [2]
), another Matlab progam was made to derive the
neeeded lug height and thickeness. There is a relationship between the tread spacing and lug height,
which was found to meet our needs at a spacing of 16.68˚. To simplfy this model, Animus uses
twenty-two repeating tread patterns at a lug height of 8.89 mm and a sidewall thickness of 3.81
mm. A simple curved tread pattern was used to clear debris easily while providing enough resitance
to travel through sand.
Further calculations used the known wheel properties to derive the required torque for
steering and driving up a hill of 33 percent grade, through sand, and at a desired operation velocity
of 1.5 meters per second. It was found that the motors would need a total drive torque of 10.2 N.m
at 143.3 RPM, and the steering motors would need a total of torque of 4.8 N.m. The use of six
wheels also shows benefits here by splitting the needed torque for each motor six ways instead of
four.
Knowing the desired wheel properties, construction could begin. A G10-FR4 fiberglass
wheel hub was used to provide rigidity and remove unceaccary weight casused by metal. A similar
8 in. fiberglass wheel shell was used which would later have tread applied on the outer surface.
Figure 6 below shows the final wheel design after performing a finite element analysis and initial
prototyping.
Figure 6 – Final Wheel Design Without Tread. Above shows the second generation wheel
design without tread applied yet. The motors are mounted and there is a waterproof connector
attached to the leads from the motor.
Next was to apply the desired tread pattern to the tire. A two-part urethane rubber mix was
selected for the tread design as it can be molded to any shape. The rubber featured a shore hardness
of 70A – the same as a typical tire tread. This would ensure the treads have the same flexing
qualities and frictional coefficients as a normal automotive tire. Below shows the construction
process of the tire tread.
7. 6
(7.1) (7.2) (7.3) (7.4)
Figure 7 – Rover Tread Construction Process. Above shows the essential steps in creating a
wheel. Figure 7.1 shows each mold block section being CNC’d, Figure 7.2 shows a completed
mold box, Figure 7.3 shows one of the first molds being removed from the box, and Figure 7.4
depicts one side of the rover’s tread completed.
The process of creating a tread took roughly nineteen hours per wheel (allowing the rubber
to cure). This technique results in a durable wheel that can be changed to whichever tread pattern
is needed.
Description of On-board Electronics. The electrical subsystem of the rover distributes
power to all of the actuating and moving parts of the rover. This system includes the motors, motor
controllers, servos, servo controller, on board computer, all sensors, cameras, power supply,
wiring, shielding, and weather proofing.
Sensors on board the rover allow the operator to analyze real-time data during the
competition. Major sensors include a voltage sensor, a current sensor, an accelerometer, and a GPS
unit. A voltage sensor in parallel with the battery pack determines the battery capacity by directly
correlating the voltage reading to the amount of charge left. The current sensor, a CS-100A, is a
Hall Effect current sensor for DC current flow and it will be used to measure specific currents
throughout the system such as between the voltage bar and the Printed Circuit Board (PCB), and
between the voltage bar and the drive motors. The GPS, a 10 Hz 66 Channel GPS from Adafruit,
will be used as an interface to let the driver know where the rover is on the course, as well as online
viewers. The accelerometer, an ADXL345, will be used to see what type of accelerations the rover
is experiencing during the competition. The rover has three cameras on board: one on the mast to
gain a heading for the rover, one on the arm to focus on a target rock, and one of the front of the
rover to act as a color sensor. The camera on the mast, which is elevated 50.8 cm above the rover,
has pan and tilt capabilities. The mast camera is a Logitech C920 HD Pro Webcam with HD 1080p
video at 30 fps. It also has a wide 78 degree diagonal field of view. The large viewing arrow and
high quality video feed the operator get a better picture of where the rover can safely navigate, as
well as look for rocks. These cameras will be powered by the onboard computer via USB.
Apart from the sensor system, the drive and manipulation system consists of thirteen servos
and six motors. The six motors are BLWRPG24V-4200-R24 series brushless DC planetary gear
8. 7
motors from Anaheim Automation. They supply a max torque of 24.78 Nm, with a rated speed of
the output shaft at 175 rpm. Each of the six motors is controlled by six DC motor drivers. The
driver selected was the MDC100-040101. These motors where selected from preliminary terra-
mechanics calculations with a desired total torque of 10.2 N-m at 143.3 RPM
The servos selected for turning were also the same servos selected for the arm
manipulation. The HS-5685MH servo is a standard ratio servo with a maximum rotation of 180
degrees. The rover electrical system, including the turning and arm manipulation has a total of 7
HS-5685 MH servos. The additional servos on the used with the arm manipulation system and the
claw are the HS-5585MS for wrist rotation, HS-5565 MS for more wrist motion and HS-7954SH
for the claw itself. The additional two servos that will be used on the rover system are pan and tilt
servos on the mast. They are both Hitec HS-311 servos.
Estimating a segment of time, the duty cycle, to which each electrical component will be
active during a one-hour run time, then applying it to the electrical properties, the required power
for that component can be calculated and used in the electrical budget. An electrical budget was
used to see how much power the rover would need to run for a one hour time period and then used
to find an appropriate on-board power supply. Table 1 is a simplified electrical budget based on
each electrical subsystem. The total energy required to run the rover for one hour is 185.36 Wh.
The battery is a K2B24V10E lithium iron phosphate battery (LiFeP04) with a capacity of 9.6 Ah
and a DC voltage of 25.6 V. A LiFeP04 battery was chosen as it is cheaper, has a faster discharge
rate, and has negligible mass gains over a lithium ion battery. With three batteries in parallel, the
onboard power supply will produce 692.2 Wh, allowing the rover to operate for 3.72 hours.
Along with the power supply and the electrical components, proper wiring and shielding
needs to be done to protect the electrical system from failure. With the K2B24V10E batteries, the
electrical system could expect current spikes from the motors drawing high levels of current to
increase the torque. To accommodate for potential high current spikes, as well as high voltage,
specific gauge wire was used. Using the American Wire Gauge (AWG) chart based on the possible
current spikes, wire gauge was able to be chosen for different sections of the electrical system. For
the wire coming directly off the battery, 6-gauge wire was selected based on the AWG chart. A 60
amp inline fuse was also placed here as a safety feature.
For each of the motors and four turning servos, a large connector is used to allow for motor
and servo removal in case of failure. Along with the connector as part of the wire harness, an
aluminum wire braided sheath will be used to protect important electrical components from
electromagnetic interference and radio frequency interference. Because the braided sheath is metal,
it has to be grounded. A plastic wire loom was placed around the sheaths to provide weather
protection as well as to keep the wire harness organized.
The last part of the electrical system is the use of the Printed Circuit Boards (PCBs). There
are two, two layer, 3x4 inch boards sandwiched on top of each other with the lower board
interfacing directly with the Arduino, and the upper board interfacing with the power supply and
all the servo connections. PCBs were used to add a simplified central hub to save space and
condense the amount of wiring needed on the design. Not only does the PCB interface directly
with the Arduino and servos, but it also is where all of the different sensors are located. Another
important electrical component being used on the PCB is the DC-DC converter. The DC-DC
converter takes the 25.6 volt power supply and regulates it to the 5 volt power supply that all of
the sensors and servos use on the PCB. A continuity test showed that the PCB has all of the proper
connections, and the PCB has now be integrated into the rover’s electrical system.
9. 8
Section Number of Electronics Total Energy Consumed (Wh)
BLDC Planetary motors 6 180.91
Turning Servos 4 1.04
Manipulation System 6 2.26
Additional Servos 3 0.49
Sensors/Other 5 0.66
Total: 24 185.36
Required (Wh) 185.36
Available (Wh) 691.20
Safety Margin (Wh) 505.84
Life Comparison 3.72
Table 1 – System Electrical Budget. Table 1 is the condensed electrical budget used for the rover
electrical design. It incorporates the rover’s brushless DC (BLDC) motors, servos, and any other
additional electrical components that require power. A life comparison is the equivalent run time
in hours.
Implemented Manipulator System. The manipulation system of the rover is an important
system for the success of the rover mission because a large part of the competition is having the
capability to pick up various rocks on the course. The rocks that the rover must pick up range from
2 cm to 8 cm in diameter and masses ranging from 20 grams to 150 grams. The entire manipulation
system on the rover is comprised of six servos: a rotating base servo, shoulder servo, elbow servo,
wrist servo, wrist rotation servo, and claw servo. The constructed arm is shown below in Figure 8.
Figure 8 – Rock Manipulating Arm. The system shown above has a total of five degrees
of freedom. The five degrees of freedom will allow for a wide range of locations to pick up rocks
from and it makes it easier for the operator to do so. Each of the servos has a rotational freedom
of 180 degrees.
10. 9
To be able to pick up rocks, the servos used in the manipulation system must be able to
apply a specific amount of torque to operate and move with the rock. Because the arm has to lift a
maximum of 150 grams, preliminary torque calculations should be done to find a servo that will
work. Equation 1 below represents a simple static torque required to move a mass on the end of a
beams.
∑ 𝑇 = 0 = 𝑚 ∙ 𝑔 ∙ 𝐿 − 𝑇 (1)
In equation 1, T represents the torque, L represents the moment arm to which the force is
applied, and the m∙g represents the force that is applied on the end of the moment arm. The highest
torque scenario is when the arm is fully extended. This is because if m∙g is constant and L is
maximized, then the torque will be highest. There will be a different moment arm at each joint and
different lifting mass, resulting in different calculated torques at each servo.
Using this simple static equation, the required worst case scenario moment can be
calculated at every joint of the manipulation system. The most torque the entire system will see
will be at the shoulder. The shoulder torque T can now be calculated and it should be lower than it
was initially calculated. From testing and further calculations it was determined that a counter
weight should be used to help with the torques on the servo. With a counter weight of 725.5 +/-
1.0 g, and a moment arm length of 70.0 +/- 5 mm the maximum shoulder torque is 4.08 +/- 0.13
N.m. This worst case torque can be used to select the proper servos for the manipulation system.
It should be noted that these calculations have a factor of safety of two built in to allow for dynamic
angular accelerations within the manipulation system.
User Interface and Programming Background. The user requires a way to communicate
with and control the components on the rover. The software system needs to meet minimum
requirements that include streaming video from the rover, allow input from an operator, and
communicate data between rover and operator.
The operator subsystem is the point of interaction for the user. The operator uses a Dell
XPS laptop running Ubuntu 12.05, but the program can run on any debian-based Linux system.
This program was written in a Linux environment and features a graphical user interface (GUI) to
display information to the user. The GUI can select between different video feeds, shows a digital
projection of the arm and wheel position, and shows sensor information. The GUI can be seen
below in Figure 9.
11. 10
Figure 9 –Graphical User Interface for Blacksburg Operator. Above is the GUI that the
operator will have available during the competition. The operator will also be able to check GPS
location, battery capacity, and have access to quick debugging features such as wheel tare (if
misaligned).
The best method of control input for the GUI is through an Xbox controller, which can
control drive actions, arm manipulations, and video pan/tilt features. The user also has the option
of using predefined arm manipulator macros that are designed to save time for the user and
eliminate dangerous movements when near the rover frame when collecting a rock.
The rover has a laptop that will be running its own custom program. The onboard laptop is
a Lenovo Y580 running the Ubuntu operating system. The rover program was designed using C++
and shell scripts that were designed to communicate data with the operator, pass data to the
Arduino, maintain systems status, and stream video.
The Arduino is used to communicate commands to individual hardware components as
well as receive data from sensors on board. The Arduino controls servo positions and motor speed
as well as their direction. It receives data from GPS, current and voltage sensors, and an
accelerometer. This data is sent back to the rover computer over serial and can then be passed to
the operator.
The Arduino reads commands byte by byte as characters. Each data packet starts with a
“*”, and each individual block ends with a “/”. The first block of each command is the identifier
and corresponds to its type. The blocks following the identifier contain data to be used for a given
type. The program will attempt 10 reads before continuing. Each type corresponds to its function.
This could be setting a servo angle, or controlling the drive system. At the end of each main
function, updates are called on each servo. The update uses an open loop proportional-integral type
controller and interpolates points between a servos current position and final position, creating
smooth movements for all servos.
Methods of Communication Between Rover and Operator. The communication system is
designed to allow control of the rover from any location that has internet access. In this system,
the operator acts as the server and the rover acts as the client. Data can be transmitted in both
directions between the operator and rover. The design is used to minimize latency and bandwidth
of connection. The rover will be connected to a cellular network by two 4G Verizon hotspots and
the operator will be connected by Ethernet to Virginia Tech's network.
12. 11
This system needs a communication protocol that is low in latency because our data is time
sensitive. The UDP Protocol was chosen due to the fact that is does not require delivery
confirmation, which can increase latency by at least two times. This protocol does not have any
methods for checking dropped packets or knowing if the intended recipient ever received the data.
If the rover has dropped or failed to send packets, they are not resent and the rover simply moves
on to the next packet.
Both the rover and operator are running are on dynamic IP addresses. To establish a static
link the rover can be used to locate the operator, an outside service need to be used. The operator
will be using a free Dynamic DNS service called Duck DNS. This service allows you link a web
address, such as www.sitename.com to an IP address. The operator will automatically update the
service with its current IP address. The service will then reroute any connection to
rover.duckdns.org, to the operator. This is the address that Animus will attempt to establish a
connection with the operator. Once the operator has received an initial signal from Animus, it will
bind its address and commands can be sent back and forth.
Chapter 3: List of Technical Specifications
The Table below gives a list of key specifications.
Mass 35.2 Kg
Dimensions (LxWxH) 98.5 cm x 72.0 cm x 46.5 cm
Rated Payload 18.14 Kg
Maximum Speed 2.24 m/s
Maximum Obstacle
Size
Suspension Travel: 24 cm
Clearance: 26 cm
Operating Time 3.7 Hr
Drive Power 25.93 Nm at 175 RPM
Drawbar Pull 19.23 kg
Battery
25.6 VDC, 9.6 Ah
K2B24V10 Lithium Iron Phosphate (3)
On-Board Computer Lenovo IdeaPad Y580 20994KU
Communications
Interface
4G Verizon Hotspot (2)
Software Linux-Ubuntu 12.04
Table 2 - Technical Specifications. Animus’s key specifications are detailed above. Drawbar
pull is the amount of tractive force in the horizontal direction from rest. Operating time may vary
depending on environment.
13. 12
Chapter 4: Testing Strategies Used to Determine Rover Performance
A series of tests were performed with the rover after visual inspection of the terrain features
at the Johnson Space Center (JSC). To replicate the uneven terrain at JSC, a nearby construction
site was selected for testing. This site featured sand, gravel, and rock obstacles ranging from 3 cm
to 20 cm in diameter. The location also offered a slopes ranging from 20 of 34 percent grade. The
pitch and rock diameter were incrementally increased until the rover failed to navigate the obstacle
successfully three times in a row. Currently, Animus is capable of climbing a 30 percent grade hill
consisting of a packed dirt/rock mix. An endurance test was also performed on site where the rover
was operated in normal conditions (all rover functions active, limited heavy stress scenarios) until
the batteries were depleted. From this test, a run time of 3.7 hours was achieved.
A friction test was also performed to gather coefficient of friction data for different terrains.
This data will be useful for future teams so they can derive wheel forces with higher precision, and
will be used for analyzing how much traction the tread will have during the competition. During
these tests a spare tread was laid down and a mass was rested on top of it. At one end a force gage
was attached. A diagram of this can be seen in Figure 10 with forces labeled. The static and kinetic
friction coefficients were determined by using basic statics equations based on time, distance,
mass, and spring scale measurements.
Figure 10 –Coefficient of friction test free body diagram. Above shows the free body diagram
used to derive the equation’s necessary to find the static and kinetic coefficients of friction. After
solving these equations, a set of unknown parameters can be measured during testing.
The soil used for testing was a mix of 2 cm gravel and loose dirt. This test will be repeated
for other terrains such as sand, grass, and different density soil mixtures during May 20th
to May
31st
to understand the frictional capabilities of the urethane rubber on different soils. Tests have
shown the rubber to have a static coefficient of friction of .81 ± .031 and a kinetic coefficient of
friction of .74 ± .038 for the 2 cm gravel and loose dirt case.
Chapter 5: Competition Strategies
The decision was made early on that the best way to achieve success during the competition
was to focus on the higher valued objectives and to regulate the available time carefully. Above
everything else, the team wanted to be sure that Animus could obtain the 25 points acquired by
picking up a single rock in each area and the 15 points for ending back at the Mars Hill. To ensure
that Animus can succeed in completing these objectives, the team will lean on Animus’s strengths.
14. 13
Animus is capable of easily traversing uneven ground and large rocks by utilizing its
rocker-bogie system accompanied with carefully designed wheels. It is expected that Animus will
be able to collect multiple rocks in each area. The driver will focus on collecting the more easily
obtainable rocks, as opposed to the higher risk rocks, due to time considerations. The team hopes
that the speed of Animus will make up for the lack of focus placed on obtaining higher point value
rocks.
Chapter 6: Distribution of Funds and Current Budget
The work conducted and progress made on this rover has been possible due to the generous
funds and donations made from a variety of sources. The team began with an initial fund of $2,000
provided by the Aerospace Department at Virginia Tech, and allowed the team to begin work
immediately, before receiving the main funding. Figure 11 shows the distribution of all acquired
funds for this project. Approximately one-third of the money used to build the rover was provided
from sources outside the competition.
Figure 11 – Breakdown of Income and Donations. Above shows how PYREX was funded for
the 2014 Robo-Ops Competition.
Fifteen percent of funding has been from our sponsors who have collectively allowed the
team to save over $2,200 in essential parts and equipment. Additionally, $595 was given by the
Student Engineering Council (SEC) at Virginia Tech, and over $200 was raised through a bake
sale.
With the current budget that was made available over the duration of this project,
approximately 53% of funds were used to purchase the structural components for the rover, 23%
was utilized for electrical and communications equipment, 20% was used for all the fees associated
with travelling to the competition, and the remaining 4% was used for additional tools and
miscellaneous items needed for the development of the rover.
NASA
67%
Aerospace Dept
13%
SEC
4% Bake Sale
1%
Cell-Con
9%
General
Cable
5%
ServoCity
1%
Other
15%
15. 14
Chapter 7: Public Outreach and Stakeholder Engagement
The competition focuses on both how well the rover performs and how well teams can
reach out to the community. For the competition, 10% of the final score was based on how well
the team could reach out to the public and make lasting impressions in the local community. To
reach out to fans of the project, both Facebook and Blogger were used to provide team updates.
The Facebook page, www.facebook.com/VTRover2014, was used to build up a fan base and
provide short updates about the progress of the systems. Currently 428 fans are following the
teams updates on Facebook. Blogger, vtrobo-ops.blogger.com, was used to provide more detailed
updates and thanks our major contributors. The team posted between one and two articles per
week. Since the blogs launch, over 1,840 page views were recorded, with 435 page views in April
alone.
The team sought out to find lasting relationships with companies, specifically companies
that have stock invested in rover applications. Public stakeholders provided the team advanced
technology for a discounted price to promote scientific advancement. Originally, the team sent
out brochures to many companies with the idea of finding stakeholders. The companies that were
the most inspired by the team were those that had an interest in the product. Outside of the
competition and the University, Cell-con, ServoCity, and General Cable were major contributors.
Cell-con, a leading manufacturer of energy solutions in aerospace and general applications,
donated approximately $1,300 of Lithium Iron Phosphate batteries and a charging station. General
Cable donated $675 of cable for the team to test and wire all of our low voltage components.
ServoCity, an online retailer for many electrical components, gave the team a student discount of
approximately $125 on servos used in the arm and turning servos. These companies were very
helpful in completing the rover, and PYREX is glad to have made lasting connections with the
companies for future teams to use.
References
[1] Wong, J.Y. Terramechanics and Off-Road Vehicle Engineering. Butlerworth-Heinmann,
2009. Print.
[2]
Ahmadian, M., “Class Notes, Spring 2014,” CRN #14813 ME 4534, Mechanical
Engineering, Virginia Tech.