Improving suspension control by an optimal control component and disturbance compensation

The paper presents an optimal control component to enhance the comfort achieveable by an existing reference model based controller. The basic controller concept controls a hybrid suspension system by emulating a timevarying damping and stiffness between wheel and chassis, resulting in significant improvements in comfort and safety compared to a passive suspension. It is extended by an optimal control strategy to increase its performance when passing single excitations critical for suspension deflection. The optimal control component uses offline calculated optimal control solutions for the actual vehicle states to react at an early stage of the compression movement leading to a smoother and lower chassis acceleration when passing critical excitations. The presented additional disturbance compensation uses information about the road excitation to beneficially influence the wheel movement. The feedforward filter influences the wheel dynamics such that a significant reduction of wheel load deviations is reached while additionally reducing chassis acceleration.