Hydraulic cylinder position control system and control method based on bidirectional pressure inputting adjustment

Abstract

The invention discloses a hydraulic cylinder position control system and control method based on bidirectional pressure inputting adjustment. The system involves a hydraulic cylinder, two symmetrically-arranged servo driving devices, a displacement sensor and a motion control unit used for distributing output, wherein the two servo driving devices are connected to an inlet and an outlet of the hydraulic cylinder respectively, the displacement sensor is connected with a piston of the hydraulic cylinder to obtain displacement information, the displacement sensor is connected with the motion control unit, and the motion control unit is connected with the two servo driving devices to form a closed-loop control loop. According to the control system and the control method, the responsiveness isvery high, the speed control range is wide, the controllability of the piston is good, the position can be bidirectionally adjusted at any speed and load, position deviation is eliminated, regenerative energy recovery can be carried out through direct current parallel connection, and energy is further saved.

Description

technical field [0001] The invention relates to the technical field of hydraulic control, in particular to a hydraulic cylinder position control system and control method based on two-way feed pressure regulation. Background technique [0002] Hydraulics is a transmission technology that is widely used in industry, especially in the field of linear motion. It is widely used in metal forming, rubber and plastic machinery, heavy machine tools and other fields due to its superior performance such as heavy load, smoothness, impact resistance, durability and reliability. [0003] In terms of position control performance of linear motion, traditional hydraulic transmission technology has great defects and limitations: [0004] First of all, in terms of fixed-point positioning technology, the traditional method is to slow down before reaching the target position, and then withstand the mechanical stopper at a low speed, or cut off the flow to stop after reaching the target position...

AI Technical Summary

Problems solved by technology

[0003] In terms of position control performance of linear motion, traditional hydraulic transmission technology has great defects and limitations:

[0004] First of all, in terms of fixed-point positioning technology, the traditional method is to slow down before reaching the target position, and then withstand the mechanical stopper at a low speed, or cut off the flow to stop after reaching the target position, which has the following defects: 1. Use the mechanical stopper to stop the hydraulic cylinder movement, then It can only stay at one position and the impact noise needs to be controlled. 2. Cut off the flow of the hydraulic pump after reaching the target position. Since the braking torque cannot be provided, the load of the hydraulic pump actually stops, which will be affected by various working factors As a result, the stop position is uncontrollable. 3. Using high-low speed position control, the system must retain a long low-speed movement distance, and the positioning time is long;

[0005] In addition, in terms of position closed-loop control, the following methods have certain disadvantages: 1. The directional valve is used to switch the forward and reverse directions of the oil pump. Since the switching time of the directional valve is very slow, the control accuracy and responsiveness are extremely poor. 2. Servo valves are used to dynamically adjust the ratio of the flow in and out of the cylinder to realize two-way flow control and position control of the cylinder, but the cost of the equipment is high and large-scale machinery cannot be used. The rotation pushes the forward and reverse movement of the oil pump, but the hydraulic circuit must be closed, and the oil pump, motor and other components cannot be used in other hydraulic circuits, and it is difficult to achieve complete symmetry and closure of the hydraulic circuit. The responsiveness and accuracy of position control at speed are relatively low

[0006] Therefore, high-precision, high-response linear position control basically cannot apply hydraulic technology, and uses mechanical transmission methods such as screw, synchronous belt, and pinion-rack, but large-scale, heavy-duty, and harsh-environment motion control is also the above-mentioned machinery Drives are difficult to implement or expensive, and there are gaps in technology and application requirements in this regard

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