Question

PLEASE READ CAREFULLY TASK GIVEN BELOW AND ANSWERS THE QUESTIONS WHICH BEEN ASKED A vehicle suspension system can be modelled by the block diagram shown in Figure 1 below: Body mas:s 12 er of s cmicen G, Roac rgut Figure 1: Block diogrom of vehicle suspension system In this block diagram, the variation in the road surface height r as the vehicle moves is the input to the system. The tyre is modelled by the spring and dashpot (damping) system with spring constant Ke and damping coefficient Cr respectively and this results in the displacement of the wheel (x), represented by the mass m. The wheel's displacement acts as an input to the suspension system, modelled by the spring and dashpot with spring constant k, and damping coefficient C, respectively and this results in the displacement (y) of the body, represented by the mass m2. when the car is at rest, it is taken that r-o, x- 0 and y = O. (Note: m2 is normally a quarter of the vehicle mass since it is assumed the weight is distributed evenly between the 4 wheels. This system is composed of two mass-spring damper systems 'stacked one on top of the other. We shall first consider the behaviour of a single sub-system and then later attempt to combine these to find the overall system behaviour. Consider the simple mass-spring damper system shown in Figure 2 below: Mlass Spring Dampr Figure 2: A single mass-spring-domper system In Figure 2: . x is the position of input body/surface, with its rest position given byx 0 .The mass m represents the mass : The height of mass m above its reference level is called y. The reference level is chosen such that when system is at rest, y o.

Answer 1