Design of Static Output Feedback Active Suspension Controllers with Quarter-Car Model for Motion Sickness Mitigation

This paper presents a method to design a static output feedback active suspension controller with a quarter-car model for motion sickness mitigation. To mitigate motion sickness in a vehicle, it has been known that the vertical acceleration and pitch rate of a sprung mass should be reduced over the frequency range from 0.8 to 8 Hz. For this purpose, a half-car model has been used with linear quadratic optimal control for controller design because it can describe the pitch motion of a sprung mass. However, a controller design procedure with the half-car model is relatively more complex than the quarter-car one. To cope with this problem, a quarter-car model is used for controller design in this paper. The half-car model consists of two quarter-car models. Based on this fact, a controller designed with a quarter-car model can be applied to the front and rear suspensions in the half-car one. To avoid the full-state feedback in a real vehicle, a static output feedback structure is selected. To find the gains of the controllers for the quarter-car models in the front and rear suspensions, linear quadratic optimal control and a simulation-based optimization method are applied. To validate the proposed method, the controllers designed with the quarter-car and half-car models are simulated on a vehicle simulation package. From the simulation results, it is shown that the static output feedback active suspension controller designed with the quarter-car model is quite effective for motion sickness mitigation.