Modeling and control of hysteresis in piezoceramic actuators
Stacked piezoceramic actuators utilize the piezoelectric effect to transform electrical charge into mechanical stress. Due to their relatively small mass and high stiffness, the natural frequency of piezoceramic actuators can reach on the order of several kilohertz. With such a high bandwidth and their nanometer resolution, piezoceramic actuators are often selected by designers for many precision engineering applications. The open loop control accuracy of piezoceramic actuators is, however, limited by their nonlinear hysteresis behavior and drift. The major thrust of this dissertation is to reveal the nature of the hysteresis nonlinearity, to develop a generalized mathematical model for describing the nonlinear hysteresis, and to design a real-time control scheme to improve the tracking performance and control accuracy of piezoceramic actuators.^ The analysis shows that nonlocal memory and the unsymmetrical behaviors of hysteresis loop in piezoceramic actuators are major obstacles to the most of the analytical and numerical model currently used for modeling the hysteresis nonlinearity of piezoceramic actuators. However, the generalized Preisach model, which was used originally to describe the magnetic hysteresis, can work with these hysteresis characteristics. Thus, a numerical generalized Preisach model is then developed with some modifications to describe the hysteresis nonlinearity of piezoceramic actuators. The developed model was tested for different kinds of input signals which include sinusoidal, triangular and arbitrary signals. The results show that the model can predict both the major and minor hysteresis output with high accuracy. A tracking control approach that combines a feed-forward loop with a PID feedback controller was, thereby, designed and tested. Comparisons were made among four different kinds of control approaches. The experiments on a stacked piezoceramic actuator show that by adding a hysteresis, the tracking performance is significantly improved.^ The second part of the dissertation discusses a genetic hysteresis nonlinearity--backlash. A mathematical model based on the particular behavior of the backlash nonlinearity is developed. The predictions of the backlash output has been verified in simulations by using two types of signals. A tracking control scheme is proposed based on the backlash model. The results show that when incorporating the model, the backlash effect can be completely eliminated. ^
Engineering, Electronics and Electrical|Engineering, Mechanical
"Modeling and control of hysteresis in piezoceramic actuators"
Dissertations and Master's Theses (Campus Access).