Model-based optimization for structure dimension and driving signal of a stick-slip piezoelectric actuator

The main idea of this paper is to optimize the dimension of a flexible mechanism and the driving signal of a stick-slip piezoelectric actuator. First, a dynamic model is built for predicting the performance of a stick-slip piezoelectric actuator. And the genetic algorithm is used to search for the optimal parameters of the flexible mechanism model, namely the equivalent stiffness and mass that can bring the best performance, then the dimension of flexible mechanism can be calculated. Second, the function of friction work during the operation of a stick-slip piezoelectric actuator is derived, and the rising edge of the normal sawtooth driving signal is optimized through minimizing the friction work that wastes energy. After optimization work, a stick-slip piezoelectric actuator prototype with optimized flexible mechanism is manufactured. Besides, two additional flexible mechanisms with different dimension are also manufactured for contrast experiments. Then, experiments are carried out to test the performance of the prototype with varied driving frequency, driving voltage, vertical load and lateral load. The results of experiments show the optimized flexible mechanism can provide maximum velocity and largest driving force, and the rectified driving signal can enhance the velocity performance for 20.56% and 29.48% than the normal sawtooth driving signal under 100 Hz and 1000 Hz.