Compensation of Parameter-dependent Complex Hysteretic Actuator Nonlinearities In Smart Material Systems

In many mechatronic applications actuators which are based on active materials are found and thus show a strong complex hysteretic output-input characteristic. A typical example is the hysteresis in actuators based on magnetostrictive materials. Unfortunately, especially in this case the hysteretic characteristic depends on a second input parameter, the mechanical stress in the material, which affects strongly the form of the hysteretic curves. In the best case these undesired effects lead to a reduced system perfomance and in the worst case to an unpredictable behavior of the superior control unit. Therefore, it is useful and effective to linearize these nonlinearities by a compensator which is also able to consider the dependence of the output on the second input. For this purpose this study describes the design of a compensator for parameter-dependent complex hysteretic nonlinearities which are based on a new so-called threshold-discrete formulation of the Preisach hysteresis operator. Finally, some experimental results are presented, which document the capability of the method for practical applications.