Research On Double-nozzle Electro-hydraulic Servovalve Driven By Piezoelectric Actuator

Electro-hydraulic Servovalve is an important component in the electro-hydraulicsystem. It can transfer electronic power to mechanical power, and amplify it at thesame time. The performance of electro-hydraulic servovalve will affect thecapability of the whole electro-hydraulic system. A new type Double-nozzleElectro-hydraulic Servovalve driven by piezoelectric actuator is designed in thispaper. The improved performance of existing electro-hydraulic servovalve isdesired.With the rapid development of piezoelectric ceramic, the capability ofpiezoelectric actuator was improved greatly in recent years. In modern society ithas been used in a large area. Its advantages of short response time, largedisplacement, little volume, and simple structure are very suitable to fill therequirements of electro-hydraulic servovalve. So, the plan that using newservovalve actuator based on PMA (piezoelectric multilayer actuator) instead ofthe traditional torque motor is designed. The thesis consists of several parts; thedetails are described as follows:1. The basic principle of piezoelectric ceramic and piezoelectric actuatorDiscuss the basic principle of piezoelectric ceramic and kinds of piezoelectricactuator for rationally design the driver of servovalve. It supplied theoreticaldependence to the selection of piezoelectric multilayer actuator and the design ofservovalve driver.? IV ?吉林大学硕士学位论文2. Design and Performance test of Piezoelectric Servovalve's actuatorAccording to the large displacement and high frequency of the driver requested byservovalve and the characteristics of piezoelectric multilayer actuator's structure,the driver of servovalve is designed based on PMA.The characteristics of Voltage-displacement, Creep, Hysteresis Curves are testedcircling the prestressed force to PMA, as well as the Impedance Characteristicsand Frequency response.The prestressed 100N force is selected to add to actuator of servovalve. Its largestdisplacement is 46.2μm, Hysteresis Curves <5%, bandwidth is 800Hz. It isobvious that the performance of driver can fill the request of servovalve. Itssuccessful design builds the base of debugging electro-hydraulic servovalve.3. Design of test and control systemThe test and control system of Piezoelectric Electro-hydraulic Servovalve isdesign in this chapter according to the requested work characteristic ofelectro-hydraulic servovalve.Computing control system with stability and rapid response is set up to fill withthe demanded control precision and various conditions in debugging piezoelectricservovalve. Develop the test and control system of electro-hydraulic servovalvebased on the industrial control computer.The system is aimed at the characteristics of piezoelectric servovalve. The resultsof experiments show that the system can satisfy the requirement of control,measuring and debugging to servovalve.4. Test and Research on Double-nozzle Electro-hydraulic Servovalve drivenby piezoelectric actuator ? V ?摘　　　　要First, introduce the structure and working principle of traditionalElectro-hydraulic Servovalve. Describe the idea of design and principle ofpiezoelectric servovalve.Then, interpret the classic structure and elements of nozzle-flapper amplifier;debugging the driver and prestressed driving oil-way of Double-nozzleElectro-hydraulic Servovalve. Introduce the key role of debugging.At last, measure the static performance and dynamic performance of piezoelectricservovalve. The static performance mainly includes flow characteristic andpressure characteristic. The dynamic performance includes amplitude-frequencycharacteristic.It is proved that the possibility of translating the actuator of traditional servovalveto piezoelectric driver. Establish the basement of further research on piezoelectricservovalve.5. ConclusionsThe main content and conclusions as following, 1. Look f...