1. Car
Suspensions:

2. • Definition:
Suspension system: a mechanical system of springs and shock
absorbers that connect the wheels and axles to the chassis of a
wheeled vehicle
• The Function of suspension system:
- to carry the static weight of the vehicle.
- to maximize the friction between the tires and the road surface.
- to provide steering stability with good handling (minimize body
roll).
- to ensure the comfort of the passengers (ability to smooth out a
bumpy road).

3.  The Function of Spring: to absorb shock energy from road bump
and convert it into potential energy of spring
 The Function of Shock Absorber: to dissipate shock energy from
road bump without causing undue oscillation in the vehicle.

4.  Passive suspension:
Traditional springs and dampers are referred to as passive suspensions

5. Active suspensions:
active suspension works by constantly sensing changes in the road
surface and feeding that information, via the ECU, to the outlying
components. These components then act upon the system to modify
its character, adjusting shock stiffness, spring rate and the like, to
improve ride performance, drivability, responsiveness, etc.

6.  Simscape™ extends Simulink® with tools for modeling and simulating
multidomain physical systems, such as those with mechanical,
hydraulic, and electrical components.
Simscape can be used for a variety of automotive, aerospace,
defense, and industrial-equipment applications
 With Simscape you build a model of a system just as you would
assemble a physical system.
This approach lets you describe the physical structure of a system
rather than the underlying mathematics.
From your model, which closely resembles a schematic, Simscape
automatically constructs equations that characterize the behavior of the
system. These equations
are integrated with the rest of the Simulink model.

7. Problem(1)
Forced vibration
Equation Of Motion:
f(t)=Kx+Rx'+Mx''

9. Signal I/p Mass Displacement

10. Equation Of Motion:
K(x-y)+R(x‘-y‘)+Mx'‘=0

12. Signal I/p Mass Displacement

13. Model parameters are:
Mse-seat and driver mass (90 kg)
Ms-is the quarter of the vehicle sprung mass
(250kg)
Mu-is the quarter of the vehicle unsprung mass
(40kg)
Bs-Damping ratio of the vehicle suspension
(2000Ns/m)
Bse-Damping ratio of the seat suspension
(3000Ns/m)
Kt=Tire stiffness (125000N/m)
Ks-vehicle susspension stiffness (28000N/m)
Kse-seat suspension spring stiffness (8000N/m)

14. Equation of motion for drive and seat mass
is:
Equation of motion for sprung mass is:

17. Signal I/p , Zse Zs,Zu

18. Thank you