Driving Technology Of Piezoelectric Ceramic Actuators

Piezoelectric ceramic actuators, which have been widely used in precision positioning, micro electronic mechanical systems (MEMS), nano-technology, nano bio-engineering, are one kind of new-type micro-displacement devices. The driving power for piezoelectric ceramic actuators is the key component of the piezoelectric actuator based micro-displacement systems and directly determines the performance of the piezoelectric actuator, such as precision, stability, and the dynamic charactericstics. In order to increase the displacement and force of the piezoelectric ceramic actuators, the piezoelectric ceramic stacks are usually used, which let the piezoelectric ceramic actuators present high reactive impendence and make it difficult to design the corresponding driving powers. Up to now, almost domestic driving powers for piezoelectric ceramic actuators are developed for static application and the dynamic performance are poor, which has limited the applications of the piezoelectric ceramic actuators in the vibration isolation and the rapid precision positioning.In this dissertation, aiming at the strong capacitive impedance of piezoelectric actuators, the principles and systems to improve the dynamic performance of the piezoelectric ceramic actuators through increasing the output peak current and the output power of the driving power are explored. Based on the error-amplified principle, the method that enlarges the range of the voltage output of the dynamic power supply for piezoelectric ceramic actuators through using a high-voltage operational amplifier in series with the power booster unit, as well as the method that improves the peak value of the power output through paralleling multi power booster units, are proposed and realized. Moreover, the driving power for piezoelectric ceramic actuators is digitalized using digital signal processor (DSP) and electronic design automation (EDA) technology.The major research works completed in this dissertation include:(1) Based on the error-amplified principle, the method that enlarges the range of the voltage output of the dynamic power supply through using a high-voltage operational amplifier in series with the power booster unit, as well as the method that improves the peak value of the power output through paralleling multi power booster units, are proposed and analyzed. The principle of the driving power proposed in this dissertation is verified through the simulation results in OrCAD, which also is used to determine the parameters of the electric circuit and predict the performance of the driving power.(2) Based on the principle of the driving power for the piezoelectric ceramic actuators proposed in this dissertation, the driving power is developed and tested. The experimental testing results indicated that the developed driving power not only can deliver the dynamic power of 270W with the output current of 0.8A, but also possesses good static performance, for example, the resolution is 20mV, the linearity is better than 99.9%, and the ripple voltage is less than 10mV.(3) The overall design of the digital system of the driving power based on DSP TMS320F2812, as well as the principles of all subsystems including the hardware design (A/D, D/A, USB, LCD, and so on) and the software design, are studied.(4) In addition, a following style driving power for piezoelectric ceramic actuators is also explored in this dissertation. The simulation and experimental testing results on the developed driving power indicated that the following style driving power possesses the relatively low accuracy and large power consumption in static state although the stability is good and the structure is simplied. The comparation between the experimental testing results of the two driving powers developed in this dissertation, the error-amplified driving power is superior to the following style driving power.(5) The driving power has been used to constitute the driving system of the six degree-of-freedom (DOF) vibration isolation and positioning platform based on piezoelectric ceramic actuators and the prototype of six-DOF vibration isolation and positioning system based on Stewart platform is developed.The research works in this dissertation provide a novel method for developing the driving powers for piezoelectric ceramic actuators.