| The study reported in this thesis deals with developing an active suspension of passenger cars taking into consideration the driver input. Both of the vertical motion control and the lateral motion control of the vehicle are investigated. For the vertical motion control of the vehicle, the Linear Quadratic Optimal Preview Control method is used for increasing the ride comfort and road holding as well as reducing the power consumption of the control system.; For the lateral motion control of the vehicle, a driver-vehicle-controller closed system is considered. A driver is modeled using the fuzzy logic technique. A seven-degrees-of-freedom nonlinear vehicle model is used in which the lateral stiffness of the tire depends on the vertical load at the wheel. To decrease the side slip and roll of the vehicle and consequently increase its stability, two roll control methods are considered: the first controls roll moment distribution between the front and rear suspensions and the second controls the counteracting moment to cancel out the roll moment developed by the lateral acceleration.; The evaluations of the developed controllers are carried out for both the open loop and the closed loop system. The simulation shows that the controller which causes the vehicle maneuver to be enhanced in the open loop system does not guarantee the enhancement of the vehicle maneuver in the closed loop system. Therefore, tuning of the controller in the closed loop system is recommended, since the closed loop system assessment of the vehicle correlates much better with the subjective assessment by the drivers than the handling data of the open loop system of the vehicle. |
