Hydraulic actuator and its method for implementing position control and position feedback

Abstract

The invention discloses a hydraulic actuator. The hydraulic actuator comprises a hydraulic cylinder assembly, a hydraulic system and a local closed-loop control system, wherein the hydraulic cylinder assembly comprises a single-action oil cylinder, a displacement sensor, an upper ear ring and a lower ear ring; the upper ear ring is in threaded connection with a piston; the displacement sensor is arranged on a lower end cover; a measuring rod of the displacement sensor passes through the lower end cover, and extends into the piston; a magnetic ring of the displacement sensor is arranged on the end part of the piston; the piston drives the magnetic ring to move in a way of extending and retracting; the specific position of the magnetic ring is sensed through a waveguide tube in the measuring rod, so that the absolute position of the piston is detected; the hydraulic system comprises a motor, a pump, two leakage-free reversing valves and a pressure sensor, and is used for providing hydraulic power for a hydraulic cylinder and controlling the flow; the closed-loop control system comprises a main circuit module, a power supply module, a sensor module group and a microprocessor module. The hydraulic actuator has the advantages of high positioning accuracy and low cost, accurate source changing, scanning, tracking and position keeping of the oil cylinder can be realized, and continuous and stable control of the actuator during low-speed running can be ensured.

Description

technical field [0001] The invention relates to a telescopic mechanism capable of positioning control and position feedback and a method for realizing positioning control and position feedback, in particular to a hydraulic actuator and a method for realizing positioning control and position feedback. Background technique [0002] A hydraulic actuator is a telescopic mechanism that can be used for positioning control and position feedback. It is widely used in hydraulic jack systems. An existing hydraulic actuator (application publication number is CN103307059A) is realized by direct oil supply from an oil pump. The telescopic cylinder of the actuator; and the oil pump has the minimum stable speed characteristic. At present, the stable minimum flow rate of domestic and foreign oil pumps reaches 1 / 8 of the maximum flow rate, which is very good, that is to say, the stable minimum speed of the actuator of the above patent It is 1 / 8 of the maximum speed, and if it needs to be low...

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Problems solved by technology

[0002] A hydraulic actuator is a telescopic mechanism that can be used for positioning control and position feedback. It is currently widely used in hydraulic jack systems. An existing hydraulic actuator (application publication number is CN103307059A) is realized by direct oil supply from an oil pump. The telescopic cylinder of the actuator; and the oil pump has the minimum stable speed characteristic. At present, the stable minimum flow rate of domestic and foreign oil pumps reaches 1 / 8 of the maximum flow rate. It is 1 / 8 of the maximum speed, and if it needs to be lower, there will be a dead zone. The actual working condition needs 0-1.6mm / s. If the maximum speed is used as the benchmark design, then the speed is lower than 0.2mm / s, and only intermittent oil supply can be used mode, the operation cannot be continuous, the real-time tracking and positioning accuracy are low, and it is difficult to meet the requirements of actual working conditions; at the same time, the above patent uses PLC control, which is large in size and high in cost. For projects requiring thousands of hydraulic actuators, the total cost too high

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