Optimal Design And Experimental Research On Piezoelectric Actuators With Flexure Hinges

Once the vibration of large space structures occurs, it is hard to attenuate in a short time, due to its large scale, low frequency, and small damping. This thesis presents a new type of piezoelectric actuator that is suitable for the vibration control of space cable-net structures. The main work is as follows.Firstly, the displacement characteristics of piezoelectric ceramic block and piezoelectric stack are studied on the basis of the first kind of piezoelectric equation, and the electrical equivalent model of piezoelectric stack is established. The transmission principles of several kinds of flexure hinge mechanisms are analyzed, as well as their corresponding theoretical amplification factor. The rotation flexibility of flexure hinge is deduced by using material mechanics method. Secondly, a micro-displacement amplifying element is designed in three-dimensional space. By its parameterized finite element model in conjugation with genetic algorithm, taking the structural dimensions as design variables, and taking the stress constraint and dimension constraint into consideration, the optimized amplifying coefficient of displacement is obtained through MATLAB in combination with ANSYS. Thirdly, on the basis of the analysis of the Preisach hysteresis model, a neural network method is applied to describe the Preisach model, and two kinds of improved postprocessing method are proposed: the optimal selection method and the weighted average method. The validity of these two methods is verified by numerical examples. Afterwards, the linear dynamic model of the piezoelectric actuator is proposed. Finally, the dynamic input-output characteristics of the piezoelectric actuator are studied experimentally, as a result the hysteresis loop of the piezoelectric stack is obtained. The vibration control of an elastic beam with the piezoelectric actuator is carried out. The results show that the design of the piezoelectric actuator has good output performance.In this thesis, the design of a piezoelectric actuator with amplifying element and its optimization is studied, including its dynamic output characteristics. The results show that the actuator is suitable for the vibration control of space cable-net structures.