Abstract
This paper presents a sliding mode controller for semi-active suspension systems. The structure of the proposed controller is basically designed by applying the integral sliding mode control theory, which consists of two control laws. One of them is a state feedback law to realize an ideal closed-loop dynamics such as a sky-hook suspension without disturbances. Another one is a discontinuous control law to induce a sliding mode for rejecting the disturbances. It is shown that not only the discontinuous control mentioned above but also the passivity constraint induces a high frequency vibration known as chattering. That is, the passivity constraint brings about a discontinuous control signal naturally. Then, in order to reduce the chattering, it is attempted to smooth the passivity constraint by using a continuous function as is done in a relay control. Numerical simulation results illustrate the effectiveness of the proposed control strategy.
