Preview Control with Virtual Disturbance for Active Suspension Systems

This paper presents a method to design a preview controller with virtual disturbance and an active suspension system for ride comfort improvement and motion sickness mitigation. Quarter-car and half-car models are selected as the vehicle model. With those models, an LQ optimal preview controller is designed in the discrete-time domain. In the controller, feedback controllers are designed with LQ static output feedback (SOF) control. In real driving environments, it is hard to exactly measure a bump profile, which causes performance deterioration. To cope with difficulties and uncertainties in measuring a real bump, a virtual disturbance is used instead of a real bump. In the LQ optimal preview controller, the virtual disturbance, used for the feedforward control, is optimized with a simulation-based optimization method. To show the effectiveness of the proposed method, a simulation is performed on a vehicle simulation package. The simulation results show that the LQ SOF controller decreases the vertical acceleration and pitch rate of the sprung mass by 28% and 66%, respectively, whereas the preview controllers with the optimized virtual disturbance yield reductions of 41% and 84%, respectively. Those results demonstrate that the proposed preview controller with the optimized virtual disturbance can effectively enhance ride comfort and mitigate motion sickness.