Adaptive control of an MR mount for vibration attenuation

In this paper, an MR mount with flow mode operation is studied for vibration suppression subject to base excitations. Recently, magneto-rheological (MR) fluid has become a popular material for actuator use. There are some good properties associated with MR fluid such as the reversible, controllable, and continuous change of rheological characteristics upon application of magnetic field. However, the dynamic equation of MR mount is highly nonlinear, hence making the controller design an extremely difficult task. This paper aims to develop a semi-active control technique for suppressing vibration of an MR mount subject to its base disturbances. The adaptive control scheme is employed for vibration attenuation. Function approximation technique is used here to represent the unknown system dynamics including the external disturbance in some finite linear combination of the orthogonal basis. The dynamics of MR mount system can thus be proved to be a stable first order filter driven by function approximation errors. Moreover, the adaptive update law can be obtained by using the Lyapunov stability theory. The well-known skyhook control scheme and a controller with constant applied magnetic field are to be compared with the proposed adaptive controller for semi-active vibration control of the MR mount.