| Electric proportional valve is an important component in the electric system. It can transfer electronic power to mechanical power, and amplify it at the same time. The performance of electric proportional valve will affect the capability of the whole electric system. A new type Proportional driven by piezoelectric actuator is designed in this paper. The improved performance of existing electric proportional valve is desired. With the rapid development of piezoelectric ceramic, the capability of piezoelectric actuator was improved greatly in recent years. In modern society it has been used in a large area. Its advantages of short response time, large displacement, little volume, and simple structure are very suitable to fill the requirements of electric proportional valve. So, the plan that using new valve actuator based on PMA (piezoelectric multilayer actuator) instead of the traditional proportional valve is designed. The thesis consists of several parts; the details are described as follows: 1. The basic principle of piezoelectric ceramic and piezoelectric actuator Discuss the basic principle of piezoelectric ceramic and kinds of piezoelectric actuator for rationally design the driver of valve. It supplied theoretical dependence to the selection of piezoelectric multilayer actuator and the design of valve driver. 2. Design and Performance test of Piezoelectric Valve's Actuator According to the large displacement and high frequency of the driver requested by valve and the characteristics of piezoelectric multilayer actuator's structure, the driver of proportional valve is designed based on PMA. The characteristics of Voltage-displacement, Creep, Hysteresis Curves are tested circling the prestressed force to PMA, as well as the Impedance Characteristics and Frequency response. The prestressed 100N force is selected to add to actuator of proportional valve. Its largest displacement is 46.2μm, Hysteresis Curves <5%, bandwidth is 800Hz. It is obvious that the performance of driver can fill the request of valve. Its successful design builds the base of debugging electric proportional valve. 3. Design of test and control system The test and control system of Piezoelectric Electric proportional valve is design in this chapter according to the requested work characteristic of electric proportional valve. Computing control system with stability and rapid response is set up to fill with the demanded control precision and various conditions in debugging piezoelectric proportional valve. Develop the test and control system of electric proportional valve based on the industrial control computer. The system is aimed at the characteristics of piezoelectric valve. The results of experiments show that the system can satisfy the requirement of control, measuring and debugging to proportional valve. 4. Test and Research on Proportional driven by piezoelectric actuator First, introduce the structure and working principle of traditional Electric proportional valve. Describe the idea of design and principle of piezoelectric valve. At last, under the control of the piezoelectric valve, the atmospheric pressure jar can achieve exact orientation of itself, and also can cooperate with the sensor of pressure to achieve the given load. It is proved that the possibility of translating the actuator of traditional valve to piezoelectric driver. Establish the basement of further research on piezoelectric valve. At the same time, the jar can achieve exact orientation under the given pressure and load. Establish the basement of further research on the new type of the... |
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