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Pick and place Line following robot report

Download report on pick and place line following report.the robot is made by using LM324,L293d and microcontroller 8051/52.

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Pick and place Line following robot report

  1. 1. LINE FOLLOWING PICK AND PLACE ROBOT A Project submitted in partial fulfillment of the requirements for the award of the degree of B.Tech in ELECTRONICS AND INSTRUMENTATION By YASH KUMAR YADAV (1009032059) VINOD KUMAR (1009032058) PRADEEP KUMAR (1009032037) ELECTRONICS AND INSTRUMENTATION IEC COLLEGE OF ENGINEERING & TECHNOLOGY GREATER NOIDA MAY 2014 1
  2. 2. DECLARATION We, hereby declare that this submission is our own work and that, to the best of our knowledge and belief, it contains no material previously published or written by another person nor material which to a substantial extent has been accepted for the award of any other degree or diploma of the university or other institute of higher learning, except where due acknowledgement has been made in the text. 1. Signature.................................................... Name YASH KUMAR YADAV Roll No 1009032059 Date ................................................... 2. Signature.................................................... Name VINOD KUMAR Roll No 1009032058 Date ................................................... 3. Signature................................................... Name PRADEEP KUMAR Roll No. 1009032037 Date ................................................... MR.SATISH JAISWAL MR. R.P. SINGH Guide Head of the Department Project Viva-voce held on _____________________________ Internal Examiner External Examiner 2
  3. 3. ABSTRACT Mankind has always strived to give life like qualities to its artifacts in an attempt to find substitutes for himself to carry out his orders and also to work in a hostile environment. The popular concept of a robot is of a machine that looks and works like a human being. The industry is moving from current state of automation to Robotization, to increase productivity and to deliver uniform quality. The industrial robots of today may not look the least bit like a human being although all the research is directed to provide more and more anthropomorphic and humanlike features and super-human capabilities in these. One type of robot commonly used in industry is a robotic manipulator or simply a robotic arm. It is an open or closed kinematic chain of rigid links interconnected by movable joints. In some configurations, links can be considered to correspond to human anatomy as waist, upper arm and forearm with joint at shoulder and elbow. At end of arm a wrist joint connects end effectors which may be a tool and its fixture or a gripper or any other device to work. Here how a pick and place Line following robot can be designed for a workstation where loading and packing of lead batteries is been presented. All the various problems and obstructions for the loading process has been deeply analyzed and been taken into consideration while designing the pick and place line following robot. 3
  4. 4. ACKNOWLEDGEMENT It gives us a great sense of pleasure to present the report of the B. Tech Project undertaken during. Tech. Final Year. We owe special debt of gratitude to Project In charge Mr. Satish Jaiswal, Department of Electronics & Instrumentation Engineering, IEC College of engineering & technology, Greater Noida for his constant support and guidance throughout the course of our work. His sincerity, thoroughness and perseverance have been a constant source of inspiration for us. It is only his cognizant efforts that our endeavours have seen light of the day. We also take the opportunity to acknowledge the contribution of Professor R.P. Singh Head, Department of Electronics & Instrumentation Engineering, IEC College of Engineering, Greater Noida for his full support and assistance during the development of the project. We also do not like to miss the opportunity to acknowledge the contribution of all faculty members of the department for their kind assistance and cooperation during the development of our project. Last but not the least, we acknowledge our friends for their contribution in the completion of the project. 4
  9. 9. CHAPTER -1 1.1 INTRODUCTION TO LINE FOLLING ROBOT A line follower robot is basically a robot designed to follow a ‘line’ or path already predetermined by the user. This line or path may be as simple as a physical white line on the floor or as complex path marking schemes e.g. embedded lines, magnetic markers and laser guide markers. In order to detect these specific markers or ‘lines’, various sensing schemes can be employed. These schemes may vary from simple low cost line sensing circuit to expansive vision systems. The choice of these schemes would be dependent upon the sensing accuracy and flexibility required. From the industrial point of view, line following robot has been implemented in semi to fully autonomous plants. In this environment, these robots functions as materials carrier to deliver products from one manufacturing point to another where rail, conveyor and gantry solutions are not possible. Apart from line following capabilities, these robots should also have the capability to navigate junctions and decide on which junction to turn and which junction ignore. This would require the robot to have 90 degree turn and also junction counting capabilities. To add on to the complexity of the problem, sensor positioning also plays a role in optimizing the robots performance for the tasks mentioned earlier. Line-following robots with pick- and- placement capabilities are commonly used in manufacturing plants. These move on a specified path to pick the components from specified locations and place them on desired locations. Basically, a line-following robot is a self-operating robot that detects and follows a line drawn on the floor. The path to be taken is indicated by a white line on a black surface. The control system used must sense the line and man oeuvre the robot to stay on course while constantly correcting the wrong moves using feedback mechanism, thus forming a simple yet effective closed- loop system. Industrial robots are found in a variety of locations including the automobile and manufacturing industries. Robots cut and shape fabricated parts, assemble machinery 9
  10. 10. and inspect manufactured parts. Some types of jobs robots do: load bricks, die cast, drill, fasten, forge, make glass, grind, heat treat, load/unload machines, machine parts, handle parts, measure, monitor radiation, run nuts, sort parts, clean parts, profile objects, perform quality control, rivet, sand blast, change tools and weld. Outside the manufacturing world robots perform other important jobs. They can be found in hazardous duty service, CAD/CAM design and prototyping, maintenance jobs, fighting fires, medical applications, military warfare and on the farm. 1.2 TYPES OF ROBOTS AS PER APPLICATIONS Nowadays, robots do a lot of different tasks in many fields. And this number of jobs entrusted to robots is growing steadily. That's why one of the best ways how to divide robots into types is a division by their application. 1.2.1 INDUSTRIAL ROBOTS: Robots today are being utilized in a wide variety of industrial applications. Any job that involves repetitiveness, accuracy, endurance, speed, and reliability can be done much better by robots, which is why many industrial jobs that used to be done by humans are increasingly being done by robots. 1.2.2 MOBILE ROBOTS: Also known as Automated Guided Vehicles, or AGVs, these are used for transporting material over large sized places like hospitals, container ports, and warehouses, using wires or markers placed in the floor, or lasers, or vision, to sense the environment they operate in. An advanced form of the AGV is the SGV, or the Self Guided Vehicle, like PatrolBot Gofer, Tug, and Specie-Minder, which can be taught to autonomously navigate within a space. 1.2.3 AGRICULTURE ROBOTS: Although the idea of robots planting seeds, ploughing fields, and gathering the harvest may 10 FIG 1.1 INDUSTRIAL ROBOT FIG 1.2 AGRICULTURAL ROBOT FIG 1.3 TELE ROBOT
  11. 11. seem straight out of a futuristic science fiction book, nevertheless there are several robots in the experimental stages of being used for agricultural purposes, such as robots that can pick apples. 1.2.4 TELEROBOTS: These robots are used in places that are hazardous to humans, or are inaccessible or far away. A human operator located at a distance from a Tele robot controls its action, which was accomplished with the arm of the space shuttle. Telerobots are also useful in nuclear power plants where they, instead of humans, can handle hazardous material or undertake operations potentially harmful for humans. 1.2.5 SERVICE ROBOTS: The Japanese are in the forefront in these types of robots. Essentially, this category comprises of any robot that is used outside an industrial facility, although they can be sub-divided into two main types of robots: one, robots used for professional jobs, and the second, robots used for personal use. Amongst the former type are the above mentioned robots used for military use, and then there are robots that are used for underwater jobs, or robots used for cleaning hazardous waste, like. HUMANOID ROBOT : A humanoid robot is a robot with its body shape built to resemble that of the human body. A humanoid design might be for resemble humans functional purposes, such as interacting with human tools and environments, for experimental purposes, such as the study of bipedal locomotion, or for other purposes. In general, humanoid robots have a torso, a head, two arms, and two legs, though some forms of humanoid robots may model only part of the body, for example, from the waist up. Some humanoid robots may also have heads designed to replicate human facial features such as eyes and mouths. Androids are humanoid robots built to aesthetically. 11
  12. 12. Figure 1…A humanoid robot 12
  13. 13. 1.3 PROJECT AIM AND OBJECTIVE: The aim of this project is design an autonomous robot with complete system allow the robot wander about its environment and to interact with certain object that its encounter. In order to achieve the aim of this project, several objectives are needed to be complete. 13 1.4 IMPORTANCE OF WORK: In this scenario, the industry having a problem by human life in some hazardous duty service. Robot can work in environments so hazardous that an unprotected human would quickly die 1.5 SCOPE OF PROJECT: Industrial automation, equipment and goods carrier, tour guide in museum, deliver the mail in office building, delivers medication in the hospital, can be used in place of crane in various lifting and carriage application.
  14. 14. 1.6 INTRODUCTION TO EMBEDDED SYSTEMS An embedded system is a system which is going to do a predefined specified task is the embedded system and is even defined as combination of both software and hardware. A general-purpose definition of embedded systems is that they are devices used to control, monitor or assist the operation of equipment, machinery or plant. "Embedded" reflects the fact that they are an integral part of the system. At the other extreme a general-purpose computer may be used to control the operation of a large complex processing plant, and its presence will be obvious. All embedded systems are including computers or microprocessors. Some of these computers are however very simple systems as compared with a personal computer. The simplest devices consist of a single microprocessor (often called a "chip”), which may itself be packaged with other chips in a hybrid system or Application Specific Integrated Circuit (ASIC). Its input comes from a detector or sensor and its output goes to a switch or activator which (for example) may start or stop the operation of a machine. Figure: 1.4 Block diagram of Embedded System 14 Embedded System Software Hardware o ALP o C o VB Etc., o Processor o Peripherals o memory
  15. 15. Embedded consist of both software and hardware: Memory: It is used to store data or address. Peripherals: These are the external devices connected Processor: It is an IC which is used to perform some task 15 Applications of embedded systems Manufacturing and process control Construction industry Transport Buildings and premises Domestic service Communications Office systems and mobile equipment Banking, finance and commercial Medical diagnostics, monitoring and life support Testing, monitoring and diagnostic systems
  16. 16. CHAPTER – 2 HARDWARE DISCRIPTION 2.1 AT89S52 MICROCONTROLLERS: The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 4K bytes of programmable Flash memory and erasable read only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry- standard MCS-51 instruction set and pin out. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications. 16 2.2 PIN CONFIGURATIONS: FIGURE 2.1 PIN DIAGRAM AT89S52
  17. 17. FIGURE2.2AT89S52 IC 17 2.2.1 Standard Features:  4K bytes of Flash,  128* 8 bits of internal RAM,  32 programmable I/O lines,  Full static operation: 0Hz to 24 MHz  Three level program memory Lock  two 16-bit timer/counters,  a six-vector two-level interrupt architecture, 2.2.2 PIN DESCRIPTION VCC Supply voltage. Port 0 Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as
  18. 18. high impedance inputs. Port 0 can also be configured to be the multiplexed low order address/data bus during accesses to external program and data memory. In this mode, P0 has internal pull ups. Port 0 also receives the code bytes during Flash programming and outputs the code bytes during program verification. External pull ups are required during program verification. 18 Port 1 Port 1 is an 8-bit bidirectional I/O port with internal pull ups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pull ups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pull ups. Port 1 also receives the low-order address bytes during Flash programming. Port 2 Port 2 is an 8-bit bidirectional I/O port with internal pull ups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pull ups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pull ups. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal pull-ups when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register. Port 2 also receives the high-order address bits and some control signals during Flash programming and verification. Port 3 Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (IIL) because of the pull-ups.
  19. 19. Port 3 also serves the functions of various special features of the AT89S52, as shown in the following table. Port 3 receives some control signals for Flash Programming. Table: 2.1 port 3 alternate functions 19 RST Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device. ALE/PROG Address Latch Enable (ALE) is an output pulse for latching the low byte of the address during accesses to external memory. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory. If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. PSEN Program Store Enable (PSEN) is the read strobe to external program memory. When the AT89S52 is executing code from external program memory, PSEN is activated
  20. 20. twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory. 20 EA/VPP External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit. XTAL2 Output from the inverting oscillator amplifier. 2.2.3 CRYSTAL OSILLATOR A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency. This frequency is commonly used to keep track of time (as in quartz wristwatches), to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. The most common type of piezoelectric resonator used is the quartz crystal, so oscillator circuits incorporating them became known as crystal oscillators, but other piezoelectric materials including polycrystalline ceramics are used in similar circuits. Quartz crystals are manufactured for frequencies from a few tens of kilohertz to hundreds of megahertz. More than two billion crystals are manufactured annually. Most are used for consumer devices such as wristwatches, clocks, radios, computers, and cell phones. Quartz crystals are also found inside test and measurement equipment, such as counters, signal generators, and oscilloscopes.
  21. 21. A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. Almost any object made of an elastic material could be used like a crystal, with appropriate transducers, since all objects have natural resonant frequencies of vibration. For example, steel is very elastic and has a high speed of sound. It was often used in mechanical filters before quartz. The resonant frequency depends on size, shape, elasticity, and the speed of sound in the material. High-frequency crystals are typically cut in the shape of a simple, rectangular plate. Low-frequency crystals, such as those used in digital watches, are typically cut in the shape of a tuning fork. For applications not needing very precise timing, a low-cost ceramic resonator is often used in place of a quartz crystal. When a crystal of quartz is properly cut and mounted, it can be made to distort in an electric field by applying a voltage to an electrode near or on the crystal. This property is known as electrostriction or inverse piezoelectricity. When the field is removed, the quartz will generate an electric field as it returns to its previous shape, and this can generate a voltage. The result is that a quartz crystal behaves like a circuit composed of an inductor, capacitor and resistor, with a precise resonant frequency. Quartz has the further advantage that its elastic constants and its size change in such a way that the frequency dependence on temperature can be very low. The specific characteristics will depend on the mode of vibration and the angle at which the quartz is cut (relative to its crystallographic axes). Therefore, the resonant frequency of the plate, which depends on its size, will not change much, either. This means that a quartz clock, filter or oscillator will remain accurate. For critical applications the quartz oscillator is mounted in a temperature-controlled container, called a crystal oven, and can also be mounted on shock absorbers to prevent perturbation by external mechanical vibrations. 21
  22. 22. Figure 2.3diagram of typical crystal oscillator generating a frequency of 11.0592 22 MHz 2.2.4 CERAMIC CAPACITOR: A ceramic capacitor is a fixed value capacitor in which ceramic material acts as the dielectric. It is constructed of two or more alternating layers of ceramic and a metal layer acting as the electrode The composition of the ceramic material defines the electrical behavior and therefore applications. Ceramic capacitors are divided into two application classes:  Class 1 ceramic capacitors offer high stability and low losses for resonant circuit applications.  Class 2 ceramic capacitors offer high volume efficiency for buffer, by-pass and coupling applications. Ceramic capacitors, especially the multilayer style (MLCC), are the most produced and used capacitors in electronic equipment that incorporate approximately one trillion pieces (1000 billion pieces) per year. Ceramic capacitors of special shapes and styles are used as capacitors for RFI/ MFI suppression, as feed-through capacitors and in larger dimensions as power capacitors for transmitter
  23. 23. 23 2.2.5 Pull-up resister: Pull up resister are used in electronic logic circuits to ensure that inputs to logic systems settle at expected logic levels if external devices are disconnected or high impedance is introduced. They may also be used at the interface between two different types of logic devices, possibly operating at different power supply voltages When the switch is open the voltage of the gate input is pulled up to the level of Vin. When the switch is closed, the input voltage at the gate goes to ground. A pull-up resistor weakly "pulls" the voltage of the wire it is connected to towards its voltage source level when the other components on the line are inactive. When all other connections on the line are inactive, they are high-impedance and act like they are disconnected. Since the other components act as though they are disconnected, the circuit acts as though it is disconnected, and the pull-up resistor brings the wire up to the high logic circuits When another component on the line goes active, it will override the high logic level set by the pull-up resistor. The pull-up resistor ensures that the wire is at a defined logic level even if no active devices are connected to it. A pull-down resistor works in the same way but is connected to ground. It holds the logic signal near zero volts when no other active device is connected. . Figure 2.4 pull up resister
  24. 24. ELECTROLYTIC CAPACITOR: electrolytic capacitor is a capacitor that uses an electrolytic (an ionic conducting liquid) as one of its plates to achieve a larger capacitance per unit volume than other types. The large capacitance of electrolytic capacitors makes them particularly suitable for passing or bypassing low-frequency signals and storing large amounts of energy. They are widely used in power supply and interconnecting stages of amplifiers at audio frequencies. An electrolytic capacitor will generally have higher leakage current than a comparable (dry) capacitor, and may have significant limitations in its operating temperature range, parasitic resistance and inductance, and the stability and accuracy of its capacitance value. FIGURE 2…. A Electrolytic capacitor 2.2.7 BASES OF IC : IC sockets are generally for preventing damage to IC's from soldering and while testing multiple circuits. These are made from Black Thermoplastic and tin-plated alloy contacts. One end is notched to aid in identification. They can be mounted end to end to suit longer IC's 24
  25. 25. Figure 2.5base of 8 pin 2.2.8 RESISTOR: These do exactly what they say, they resist the flow of electron. These are necessary for several reasons. They control how much current goes down to each wire. They control the power uses. They can control voltages (since current, resistance) The last point is important as it is the basis of Ohm's law, V=IR. Voltage = Current x Resistance. For example, suppose you take a resistor and connect the two ends of a battery with it. You know that your battery is 9V (or whatever) and you know the resistor is 3Kohm (determined by the color stripes on the resistor), so 9V divided by 3Kohm is .003amps (3 milliamps). So why is this information useful? Well now that you know the current, you can determine other useful things such as power. P=IV. You will notice that if you increase resistance, you decrease current. If you decrease current, you decrease power use. Put a 1ohm resistor between the battery and it will get so hot it could burn because of the power use. Use a 100Kohm resistor and almost no power at all will be used. Figure 2.6 Resistor 25 2.2.9 VOLTAGE REGULATOR
  26. 26. Figure 2.7 voltage regulator ic 7805 A voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. It may use an electromechanical mechanism, or passive or active electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages. There are two types of regulator are they. 26  Positive Voltage Series (78xx) and  Negative Voltage Series (79xx) 78xx: ’78’ indicate the positive series and ‘xx’indicates the voltage rating. Suppose 7805 produces the maximum 5V.’05’indicates the regulator output is 5V. 79xx: ’78’ indicate the negative series and ‘xx’indicates the voltage rating. Suppose 7905 produces the maximum -5V.’05’indicates the regulator output is -5V.
  27. 27. These regulators consists the three pins there are 27 Pin1: It is used for input pin. Pin2: This is ground pin for regulator Pin3: It is used for output pin. Through this pin we get the output. 2.2.10 IR SENSORS An Infra-Red sensor detects Infra-Red light/white light from a particular object/line and then converts light energy to electrical energy. An IR sensor pair consists of an emitter and a detector. The emitter is blue in color and the detector can be grey, black or white in color. figure 2.8 IR sensor 2.2.11 IR EMITTER An infra-red emitter is a Light Emitting Diode (LED) made from Gallium Arsenide. It detects IR energy at a wavelength of 880nm and emits the same. The infrared phototransistor acts as a transistor with the base voltage determined by the amount of light hitting the transistor. Hence it acts as a variable current source. Greater amount of IR light cause greater currents to flow through the collector-emitter leads. The variable current traveling through the resistor causes a voltage drop in the pull-up resistor. This voltage is measured as the output of the device. 2.2.12 IR DTECTOR
  28. 28. An infra-red detector is a photo detector. It detects IR energy emitted by the emitter and converts it into electrical energy. The main principle involved in the conversion of light energy to electrical energy is PHOTOELECTRIC EFFECT. IR sensor circuit to detect a black line on white background: 28 Fig: 2.9. IR sensor circuit The output is taken at negative terminal of IR detector. The output can be taken to a microcontroller either to its ADC (Analog to Digital Converter) or LM 339 can be used as a comparator. 2.2.13 LM 324 FEATURES:  Wide gain bandwidth : 1.3MHZ input common-mode voltage range  Includes ground .large voltage gain: 100DB .very low supply current/amplify : 375ma low input bias current : 20NA low input offset voltage : 5mv max.  Low input offset current : 2NA wide power supply range :  Single supply : +3v to +30v  Dual supplies : ±1.5v to ±15v  It is a comparator ic DESCRIPTION These circuits consist of four independent, high gain, internally frequency compensated operational amplifiers .They operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the
  29. 29. low power supply current drain is independent of the magnitude of the power supply voltage. Fig:2.10. pin configuration top view 16 8 1 2 15 L_IN2 R_IN1 LM-RM+ L2 9 3D INPUT LINES 7 9 10 3 14 6 11 4 5 12 13 GND 29 2.2.14 L293D( H-BRIDGE): LM+ OUTPUT FOR MOTOR1 OUTPUT FOR MOTOR2 RM- Figure 2.11 PIN DIAGRAM OF L293D IC VCC1 - LOGIC SUPPLY= 5V L_IN1 L_EN R_IN2 R_EN Motor are arrange in a fashion called H bridge. H bridge is an electronics circuits which enables a voltage to be applied across the load in either direction. It allow a
  30. 30. circuit full control, that is an H bridge, a microcontroller logic chip, or remote control can electronically command the motor to go forward ,reverse and brake An H-bridge is an electronic circuit which enables DC electric motors to be run forwards or backwards. These circuits are often used in robotics. H-bridges are available as integrated circuits, or can be built from discrete components. 30 Figure 2.12 circuit diagram of H bridge The two basic states of a H-bridge. The term "H-bridge" is derived from the typical graphical representation of such a circuit. An H-bridge is built with four switches (solid-state or mechanical). When the switches S1 and S4 (according to the first figure) are closed (and S2 and S3 are open) a positive voltage will be applied across the motor. By opening S1 and S4 switches and closing S2 and S3 switches, this voltage is reversed, allowing reverse operation of the motor. Using the nomenclature above, the switches S1 and S2 should never be closed at the same time, as this would cause a short circuit on the input voltage source. The same applies to the switches S3 and S4. This condition is known as shoot-through. 2.2. 13.1 OPERATION The H-Bridge arrangement is generally used to reverse the polarity of the motor, but can also be used to 'brake' the motor, where the motor comes to a sudden stop, as the motors terminals are shorted, or to let the motor 'free run' to a stop, as the motor is effectively disconnected from the circuit. The following table summarizes operation.
  31. 31. 31 S1 S2 S3 S4 Result 1 0 0 1 Motor moves right 0 1 1 0 Motor moves left 0 0 0 0 Motor free runs 0 1 0 1 Motor brakes Table: 2.2 H-bridge switch operation 2. 2.13.2 H-BRIDGE DRIVER The switching property of this H-Bridge can be replaced by a Transistor or a Relay or A Mosfet or even by an IC. Here we are replacing this with an IC named L293D as the driver whose description is as given below. The Device is a monolithic integrated high voltage, high current four channel driver designed to accept standard DTL or TTL logic levels and drive inductive loads as and switching power transistors. To simplify use as two bridges each pair of channels is equipped with an enable input. A separate supply input is provided for the logic, allowing operation at a lower voltage and internal clamp diodes are included. This device is suitable for use in switching applications at frequencies up to 5 kHz. The L293D is assembled in a 16 lead plastic package which has 4 center pins connected together and used for heat sinking The L293D is assembled in a 20 lead surface mount which has 8 center pins connected together and used for heat sinking. 2. 13.3 FEATURES  600mA OUTPUT CURRENT CAPABILITY
  32. 32.  PER CHANNEL  1.2A PEAK OUTPUT CURRENT (non repetitive)  ENABLE FACILITY  OVERTEMPERATURE PROTECTION  LOGICAL "0" INPUT VOLTAGE UP TO 1.5 V  (HIGH NOISE IMMUNITY)  INTERNAL CLAMP DIODES 32 BLOCK DIAGRAM: Figure 2.13block diagram of LM293D 2.2. 14 DC MOTORS: These are very commonly used in robotics. DC motors can rotate in both directions depending upon the polarity of current through the motor. These motors have free running torque and current ideally zero. These motors have high speed which can be reduced with the help of gears and traded off for torque. Speed Control of DC motors is done through Pulse Width Modulation techniques, i.e. sending the current in intermittent bursts. PWM can be generated by 555 timer IC with adjusted duty cycle. Varying current through the motor varies the torque.
  33. 33. FIGURE 2.14(DC MOTOR  GRIPPER ARM: The gripper module is state of the art robotic arm which can be used in various 'pick and place' kind of robots. It works on DC Motor (9 to 12V DC).  Change in rotation direction of the DC Motor, generates Jaw Open & Close 33 Action.  The DC motor can be easily be controlled with the help of DPDT Switch (manual mode) or with the help of any micro controller along with L293D Motor Driver module.  FIGURE3…Gripper orthogonal view, main view
  34. 34.  LIFTER ASSEMBLY: It is made from laser cut Metal and acrylic. There is a worm gear and spur gear assembly which is attached with a DC motor (9 to 10 volt) to provide torque so that gripper can pick and lift the load. 34  Figure 3…..Lifter assembly LIFTER PARTS: • Gripper assembly Plates. • Fiber Grippers-2nos. • 45 RPM Motor-1nos. • Worm Gear-1nos. • Spur Gear-2nos. • Different Screws and nuts.
  35. 35. Worm drive: Worm drive is a gear arrangement in which a worm (which is a gear in the form of a screw) meshes with a worm gear (which is similar in appearance to a spur gear, and is also called a worm wheel). The terminology is often confused by imprecise use of the term worm gear to refer to the worm, the as a worm gear, or the worm drive unit. Like other gear arrangements, a worm drive can reduce rotational speed or allow higher torque to be transmitted. The image shows a section of a gear box with a worm gear being driven by a worm. A worm is an example of a screw, one of the six simple machines. Figure: 3.12 worm drive arrangement 35
  36. 36. (a) (b) Figure 3.125 (a) Spur gear (b) Worm gear, (Made by acrylic fiber) TRACK WHEEL: Track wheel is a circular wheel with rubber grip fastened on DC motor shaft by screw. Track wheel provide help in movement of robot in any direction. Figure 3.125 Track wheel 36
  37. 37. CHASSIS: A chassis consists of an internal framework that supports a man-made object in its construction and use. It is analogous to an animal's skeleton. An example of a chassis is the under part of a motor vehicle, consisting of the frame (on which the body is mounted). Here metallic chassis is used. FIGURE 3.212 A metallic chassis POWER SUPPLY: To provide energy to DC motors for movement of robot A Battery of DC (6 volt to 12 V, 4.5A) is being used. Figure 3.225 Battery 37
  39. 39. 39 3. WORKING PROCEDURE 3.1 WORKING Robotics is an interesting subject to discuss about and in this advanced world Robots are becoming a part of our life. In this project we are going to discuss about a robot which is capable of following a line without the help of any external source. The Embedded Line following robot uses four motors to control rear wheels and the single front wheel is free. It has 2-infrared sensors on the bottom for detection of white tracking tape. When the middle sensor detects the black color, this sensor output is given to the comparator LM324. The output of comparator compares this sensor output with a reference voltage and gives an output. The output of comparator will be low when it receives an input from the sensor  When a sensor is on the black line it reads 0 and when it is on the bright surface read 1. and sensor module gives the value to controller to generate control signal according to programmer  When both right and left sensors are on bright surface (read 1) then both couple of motor move.  When left sensor comes in black (for white line tracer) region then left motor stops while right motor continue to move so that left turn takes place and robot returns on black line.  When right sensor comes in black region then right motor stops while left motor continue to move so that right turn takes place and robot returns on black line.  By correcting the path robot move to destination.  When both sensors comes on black surface simultaneously (read 0) than both motor stop.
  40. 40.  When both sensor read 0 simultaneously and both wheel motor stops than immediately motor for right and left movement of lifter arm start moving for some definite time duration using Timer of controller.  After movement of left- right motor of lifter the motor for lifting and gripping move one by one for some definite time duration defined in program using timer of controller.  The lifter and gripper arm have various gear arrangement, so that after movement of each motor of arm one by one the arm pick an object or work piece softly.  After movement of gripper motor, all the motor of arm starts moving in reverse direction of previous movement, one by one.  After picking an object by gripper and lifter arm, either left or right wheel motor starts moving until the robot reverts his path and both sensor comes on bright surface after crossing a black surface between.  After reversing the path robot move by correcting path and reach to destination  At destination both sensors read 0 simultaneously, so that previous process is repeated and the object is now placed by same movement of motor.  The robot revert its path and repeats the pick and place process again and again 40 continuously. 3.2 ADVANTAGES  Robot movement is automatic.  Fit and Forget system.  Used for long distance applications.  Defense applications.  Used in home, industrial automation.  Cost effective.
  41. 41. 41  Simplicity of building 3.3 DISADVANTAGES  LFR follows a black line about 1 or 2 inches in width on a white surface.  LFR are simple robots with an additional sensors placed on them.  Needs a path to run either white or black since the IR rays should reflectfrom the particular path.  Slow speed and instability on different line thickness or hard angles. 3.4 APPLICATIONS:  Guidance system for industrial robots moving on shop floor etc.  Industrial applications.  Home applications.
  42. 42. CHAPTER 4 42 4. SOFTWARE TOOLS 4.1 KEIL SOFTWARE: Keil compiler is software used where the machine language code is written and compiled. After compilation, the machine source code is converted into hex code which is to be dumped into the microcontroller for further processing. Keil compiler also supports C language code. #include<reg51.h> sbit m1=P0^0; sbit m2=P0^1; sbit m3=P0^2; sbit m4=P0^3; sbit m5=P0^4; sbit m6=P0^5; sbit m7=P0^6; sbit m8=P0^7; sbit ma=P3^6; sbit mb=P3^7; sbit sens1=P1^0; sbit sens2=P1^1; void delay(int); void main() { m1=0;
  43. 43. 43 m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=0; ma=0; mb=0; sens1=1; sens2=1; while(1) { while((sens1==1)&&(sens2==0)) { m1=1; m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=0; ma=0;
  44. 44. 44 mb=0; } while((sens1==0)&&(sens2==1)) { m1=0; m2=0; m3=1; m4=0; m5=0; m6=0; m7=0; m8=0; ma=0; mb=0; } while((sens1==1)&&(sens2==1)) { m1=1; m2=0; m3=1; m4=0; m5=0; m6=0; m7=0;
  45. 45. 45 m8=0; ma=0; mb=0; } while((sens1==0)&&(sens2==0)) { m1=0; m2=0; m3=0; m4=0; m5=1; m6=0; m7=0; m8=0; ma=0; mb=0; delay(500); m1=0; m2=0; m3=0; m4=0; m5=0; m6=0; m7=1;
  46. 46. 46 m8=0; ma=0; mb=0; delay(500); m1=0; m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=0; ma=1; mb=0; delay(500); m1=0; m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=0; ma=0;
  47. 47. 47 mb=0; m1=0; m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=0; ma=0; mb=1; delay(500); m1=0; m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=0; ma=0; mb=0;
  48. 48. 48 m1=0; m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=1; delay(500); m1=0; m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=0; m1=0; m2=0; m3=0; m4=0; m7=0; m8=0;
  49. 49. 49 m5=0; m6=1; delay(500); m1=0; m2=0; m3=0; m4=0; m7=0; m8=0; m5=0; m6=0; m1=1; m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=0; while(sens1==0); while(sens1==1); while(sens1==0);
  50. 50. 50 delay(20); m1=0; m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=0; } } } void delay(int x) { int y,z; for(y=0;y<x;y++) for(z=0;z<1275;z++);
  51. 51. 51 } 4.4 RESULT The objective of the line following robot is to follow a line on its given path which is obtained for which it uses IR sensors which detects the line and sends the information to LM324 comparator and then to H bridge which controls the working of the wheel’s. Microcontroller controls the other operations.
  52. 52. 52 4.2 SAFETY REQUIREMENTS The various safety requirements which were considered while designing the robot are decided as follows: 1. The Robot should not be programmed such that it should damage the Battery while holding it in its gripper. 2. Correct holding position should be set as if it not set then while movement of the Robot it may drop the Lead Batteries which can arise a Hazardous situation in the industry. 3. The Robot should be interfaced properly with the sensors been placed near the Belt conveyor so as to know when the belt conveyor is to be stopped or to be started to move the batteries ahead. 4. Load carrying capacity should be maintained as it should be always more than the default load which is to be shifted.
  53. 53. CONCLUSION AND FUTURE SCOPE 53 CONCLUSION: In this project we have studied and implemented a Line Following Robot using a Microcontroller for blind people. The programming and interfacing of microcontroller has been mastered during the implementation. FUTURE SCOPE:  Smarter versions of line followers are used to deliver mails within office building and deliver medications in a hospital.  This technology has been suggested for running buses and other mass transit systems and may end up as a part of autonomous cars navigating the freeway.  Used in heavy machinery industry  Used where high load and risky operation going on  Use in place of the crane
  54. 54. REFERENCES :  www.avrfreaks.com,Microcontrollers,Atmel  septiembre-2001. www.atmel.com  The 8051 Microcontroller and Embedded Systems Using Assembly and C By Muhammad Ali Mazidi, Janice Gillispie Mazidi & Ro linD. McKinley  Atmel Corp. Makers of the AVR 54 microcontroller  www.atmel.com  www.electronic projects.com  www.howstuffworks.com  Electrikindia.  EMBEDDED SYSTEM BY RAJ KAMAL
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