Robust and high precision control using piezoelectric actuator circuit and integral continuous sliding mode control design

While piezoelectric actuators have been widely used in vibration suppression and high precision controls, their intrinsic nonlinearity such as hysteresis, if not considered in control design, may deteriorate the system performance. In this research, a new methodology is proposed for the high-precision and robust control using piezoelectric actuator with hysteresis compensation. This methodology is featured by the introduction of a resistance/inductance circuit connected to the piezoelectric actuator to form an actuator network and a new integral continuous sliding mode control (ICSMC) algorithm. In addition to the well-known increased passive damping and active control authority, the main advantage of the actuator network in this particular study is that the charge and/or current in the piezoelectric actuator now become independent state variables that can be directly measured and fed back. Not only can this actuator network configuration improve the hysteresis characterization, the control design can also be greatly simplified. With the introduction of the RL shunt circuit, two dynamic subsystems (the mechanical structure and the electrical circuit) are formed. With these two coupled dynamic subsystems as basis, we then develop an ICSMC scheme which combines the advantages of conventional continuous sliding mode control and integral variable structure control. Different from the inverse cancellation of hysteresis behavior which might not be reliable due to the measurement noise, a direct piezoelectric hysteresis compensation is achieved using this control strategy. Detailed analysis and case studies demonstrate that this new methodology can lead to improved precision for both tracking control and vibration attenuation, enhanced control robustness, and smoother control action.