1、 中文 3450 字 附二 : 外文翻译 High Precise Control Method for a New Type of Piezoelectric Electro hydraulic Servo Valve Abstract： A new type of piezoelectric electro-hydraulic servo valve system was proposed And then multilayer piezoelectric actuator based on new piezoelectric ceramic material was used as th
2、e electricity-machine converter of the proposed piezoelectric electro-hydraulic servo valve. The proposed piezoelectric electro -hydraulic servo valve has ascendant performance compared with conventional ones.But the system is of high nonlinearity and uncertainty, it cannot achieve favorable control
3、 performance by conventional control method To develop an efficient way to control piezoelectric electro hydraulic servo valve system A high precise fuzzy control method with hysteresis nonlinear model in feedforward loop was proposed. The control method is separated into two parts： a feedforward lo
4、op with Preisach hysteresis nonlinear model and a feedback loop with high-precise fuzzy contro1. Experimental results show that the hysteresis loop and the maximum output hysteresis by the PID control method are 4.22 and 2 11 pm, respectively； the hysteresis loop and the maximum output hysteresis by
5、 the proposed control method respectively are 0 74 and 0 37m， respectively； the maximum tracking error by the PID control method for sine wave reference signal is about 5 02 , the maximum tracking error by the proposed control method for sine wave reference sign al is about 0 85 contro1 Key words： p
6、iezoelectric electro hydraulic servo valve； hysteresis nonlinearity； Preisach model； fuzzy control 1 Introduction Electro hydraulic servo system is widely applied in industrial domain nowadays for example robot drive， machine building, architectural engineering The electro-hydraulic servo valve is t
7、he kernel of the electro-hydraulic servo system,and its performance has decisive effect Of the whole system The conventional drive mode of electro hydraulic servo valve has lower resolution and narrower work band width， which restricts the applications of the electro-hydraulic servo valve The propos
8、ed piezoelectric electro-hydraulic servo valve adopts multilayer piezoelectric actuator as electricity-machine converter. This Hew type of piezoelectric electro-hydraulic servo valve has better dynamic performance than that of conventional ones At present， with the research and the development of ne
9、w-type actuator based on new type materials, it is possible to make the new electricity-machine converter with high frequency. New materials include piezoelectric ceramic materials, magnetostrjctive materials, shape memory alloys Thereinto, multilayer piezoelectric actuators based on new piezoelectr
10、ic ceramic materials have many merits such as small cubage， high resolution， high frequency and large drive force Hence， they are widely used in the micro-position device of machine tools and other precision machines 1-6 However, they also have many shortcomings， for example， hysteresis nonlinearity
11、 model in feedforward loop was proposed 2 Work principle and characteristic of new-type of piezoelectric 第 页 1 electro-hydraulic Valve Because the pulling force capacity of multilayer piezoelectric actuator is very poor, it cannot make the slide valve of the electro, hydraulic servo valve bidirectio
12、nallv move. Two multilayer piezoelectric actuators were adopted to solve this problem 7-8. The shortcoming of this method is high cost and system is difficult to contro1. Utilizing the restoring force of a leaf spring， one multilayer piezoelectric actuator can realize bidirectional movement of the s
13、lide valve in this paper. W hen the voltage imposed on multilayer piezoelectric actuator 1s increased， multilayer piezoelectric actuator will elongate and drive the slide valve to move towards the left， which makes the leaf spring deform On the contrary, when the voltage imposed on multilayer piezoe
14、lectric actuator is reduced， multilayer piezoelectric actuator will be shortened and then drive the slide valve move towards the right by the action of the restoring force of the leaf spring. The structure of new type of piezoelectric electro hydraulic servo valve is shown in Fig 1 The input-output
15、characteristic of the new type of piezoelectric electro-hydraulic servo valve system indicates that it has hysteresis nonlinearity with nonloca1 memory(see Fig 2). At any reachable point L (Ua ， Ya)in input-output diagram， the number of alternative curve that describes the future path of hysteresis
16、nonlinearity with nonloca1 memory is infinite. Namely, the future output of the system depends not only on the current output Ya and future input， but also on the past history of input values extremum. Hence, the output response of new type of piezoelectric electro-hydraulic servo valve to an applie
17、d input voltage becomes unpredictable. In the system， there exist other nonlinearities such as force of friction and work dead zone of valve, furthermore， damping coefficient and oil temperature are also changed with time The nonlinearity and uncertainty have seriously effects on the position precis
18、ion. To improve the performance of the new type of piezoelectric electro-hydraulic servo valve system, a valid control method is needed 3 Control algorithm At present, conventional PID controller is widely applied in industrial control domain because of its simple control structure, easy design and
19、inexpensive cost However, conventional PID controller is difficult to achieve good control performance in the new type of piezoelectric electro, hydraulic servo valve system because the control object has high nonlinearity and uncertainty Fuzzy controller shows good results in the case of controllin
20、g high nonlinear systems. However, conventional fuzzy controller is essentially a kind of nonlinear PD controller, there exists steady state error, which cannot meet the demand of high precise of the system In this paper, a high-precise fuzzy control algorithm with Preisach 第 页 2 hysteresis nonlinea
21、r model in feedforward loop was proposed The block diagram of the combined controlis shown in Fig 3 The control system is composed of a feedforward loop based on Preisach model and a feedback loop of high precise fuzzy controller Ul( is the output of feedforward loop based on Preisach mode1 As a lin
22、ear term, it is selected from a Preisach function table based on the given position value U2( is the output of the high precise fuzzy controller The sum U(t) of feedforward control voltage f and feedback control voltage U2(t) ， as ultimate control voltage， is acted on new type piezoelectric electro-
23、hydraulic servo valve. 3 1 Feedforward loop based on Preisach model The open loop response of the new type piezoelectric electro-hydraulic servo valve system under an arbitrary and non-cyclic input signal is shown in Fig 2 This phenomenon appears as hysteresis nonlinearity with nonlocal memory, whic
24、h can be predicted by Preisachmode1 The numerical form of Preisach model can be written as foliows： ddtuutf S )(),()( (1) Eqn.(1) can be used to calculate the response of the new type of piezoelectric electro-hydraulic servo valve subject to a known arbitrary input voltage sequence A series of first
25、 order functions kkr of the new type of piezoelectric electro-hydraulic servo valve are experimentally determined The procedure is as follows The space between zero and saturation voltage Us is divided into n equipartitions, and the voltage of every equantpoint is kUs n， where k=-0， 1， 2， n Voltage
26、is applied from zero to every equant point kUs n， and then decreased to zero In this process，the position output values of the new type of piezoelectric electro-hydraulic servo valve are recorded at every equant point between zero and saturation voltage Us， therewith， kkr and the Preisach function table are obtained(see Fig 4)，
