Piezoelectric electro-hydraulic servo valve and control method thereof

Abstract

The invention provides a piezoelectric electro-hydraulic servo valve and a control method thereof. The pre-stage pressure of the servo valve is controlled through a piezoelectric driving scheme, so that the displacement and the output flow of a main valve element of the servo valve are controlled. The piezoelectric electro-hydraulic servo valve comprises a piezoelectric driving device, a controller, an LVDT displacement detection device, a fixed baffle, a throttler and a valve element; the LVDT displacement detection device acquires a valve element displacement signal and sends the valve element displacement signal to the controller; the controller receives an input signal of the servo valve and the valve element displacement signal and outputs a control signal; the piezoelectric driving device receives the control signal, controls the electro-hydraulic servo valve to generate a controllable pre-stage pressure, and generates an acting force for driving the valve element; and the fixedbaffle and the piezoelectric driving device form a variable throttling hole. According to the invention, by the piezoelectric driving scheme, a brand-new electro-hydraulic servo valve variable throttling scheme is formed; a complete control strategy of the servo valve is completed through an electric closed loop; and the piezoelectric electro-hydraulic servo valve has the advantages of pollution resistance, convenience in mounting and adjustment and reliable performance.

Description

technical field [0001] The invention relates to the field of piezoelectric servo drive, in particular to a piezoelectric electro-hydraulic servo valve and a control method thereof. Background technique [0002] The electro-hydraulic servo valve with torque motor spray gear structure has the advantages of small size, light weight, high control precision, and fast response. It is a classic electro-hydraulic servo valve structure, and its structural form has basically no substance in the past few decades. However, there are still some problems that are difficult to solve for the torque motor electro-hydraulic servo valve: (1) The torque motor servo valve has a complex structure and is difficult to develop. The processing precision of the parts of the torque motor electro-hydraulic servo valve is high, and the parts need to be precisely matched and matched. (2) Self-excited oscillation problem of servo valve. There are many elastic structures in the torque motor servo valve. U...

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Problems solved by technology

(2) Self-excited oscillation problem of servo valve

There are many elastic structures in the torque motor servo valve. Under the comprehensive action of elastic elements such as magnetic springs, spring tubes, feedback rods, and oil source pulsation, the problem of howling of torque motor electro-hydraulic servo valves has always been a problem in the debugging and use of electro-hydraulic servo valves. intractable problems in

(3) Bottleneck of torque motor output capacity

However, on the one hand, the torque motor is greatly affected by hysteresis. In order to limit the nonlinearity, the displacement of the armature is limited; on the other hand, when the electromagnetic torque coefficient of the torque motor increases, the magnetic spring stiffness also increases accordingly. performance, it is necessary to increase the stiffness of the spring tube accordingly, so that the important single point of failure control point of the servo mechanism - the spring tube works under harsher conditions, reducing the stability and reliability of the servo valve

[0003] At present, the structure of the traditional torque motor electro-hydraulic servo is complicated, and the output capacity of the torque motor is limited. The structure of the traditional electro-hydraulic servo valve has lasted for decades. It is urgent to use the existing technology to improve and develop the traditional electro-hydraulic servo valve.

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