Consider the two-degree-of-freedom quarter-car model shown in Figure 5.34, in which the force f, applied between the car body and the wheel–tire–axle assembly, is controlled by feedback and represents the active components of the suspension system. Assume that
f = 20568x1 − 30493x2 −12781+ 31892. Build a block diagram of the feedback control system, where the quarter-car model is constructed using Simscape blocks and the controller is constructed using Simulink blocks. Find the displacement responses x1(t) and x2(t) if initially x1 = –0.05 m and x2 = –0.05 m. Ignore the displacement input z(t). What are the system responses x1(t) and x2(t) without control?