Abstract
The full car 7-D.O.F. with the optimal active suspension system is utilized to evaluate the vehicle dynamic performance by various controllers. The optimal controller includes the integral action for the suspension deflection. The integral control action considerably improves attitude motion because the rolling motion at cornering maneuver and the pitching motion at braking maneuver are reduced. In addition, the integral action for the suspension deflection results in the zero steady state deflection in response to static body forces and ramp road input. The dynamic characteristics of the suspension control system are evaluated in terms of time domain and frequency domain. The simulations in time domain demonstrate the advantage of integral action and frequency characteristic curves show the degree of decrease in ride comfort due to integral action. As the derivative controller is added the active suspension system with integral action, the potential of derivative control is showed through the performance of the car travelling on the bump.