Semi-active suspension control system design for vibration reduction of passenger's body based on lissajous figure of damping force

In recent years, it is reported that passenger's dynamics and vibration characteristics to the multidirectional vibration at sitting position are different from a driver. However, there are few researches about a suspension control which considers these dynamics of human body characteristics and sitting position. In this paper, new semi-active suspension control method is developed to reduce passenger's vibration and motion. Firstly, a vehicle and passenger model including the dynamics of human body and sitting position is constructed. Second, the robust control system design method which uses the vertical acceleration of a passenger's head to one of the amounts of evaluation function is proposed. In order to control the jerk which is generated by changing of a damping coefficient rapidly, the robust controller is designed based on Lissajous figure of damping force. From the result, it was confirmed that in nearly the resonance frequency of vertical direction of a passenger's head (vertical direction), the proposed control method is effective in reducing a passenger's vibration better than the general control method which uses a vartical acceleration of the vehicle body as the evaluation function.