Hysteretic behavior is inherently encountered in many application devices that usually involve magnetic, ferroelectric, and mechanical systems. Smart materials such as magnetorheological (MR) ™uids, electrorheological (ER) ™uids, piezoceramics (PZTs), and shape memory alloys (SMAs) have recently been adopted as actuators for various active and semi-active control systems. These smart materials also exhibit nonlinear hysteretic responses, which have an adverse effect on actuator performance within control systems. Due to the increasing demand for superior control performance, nonlinear hysteresis models [1, 2] and robust feedback control schemes [3] have been intensively investigated by many researchers to improve or compensate for the hysteretic actuator behavior of smart materials.