Control system and method for flexible docking of movable beam of hydraulic press and leveling system

Abstract

The invention relates to a control system and method for flexible docking of a movable beam of a hydraulic machine and a leveling system. Input the command signal with the same difference to the proportional servo valve of the leveling cylinder to control the circular fall of the leveling cylinder and collect the displacement of the leveling cylinder and the pressure of the rodless chamber, and record the corresponding command signal; use the neural network algorithm to carry out model identification on the collected data , get the flow model of the valve port of the leveling cylinder control valve, and calculate the feedforward value of the speed valve port of each leveling cylinder; then, collect the position information of the movable beam and the four leveling cylinders in real time, and calculate the position information of each leveling cylinder according to the displacement difference Control the opening of the valve port, and at the same time, the displacement deviation compensation module of the four leveling cylinders adjusts and compensates the valve ports of the control valves of each cylinder; after docking, use the sliding mode controller to perform pressure tracking control on the rodless cavity of the four leveling cylinders . The invention adopts the coordinated control of the main cylinder and the leveling system and the coordinated control method of four cylinders, can realize the flexible docking of the movable beam and the hydraulic leveling system, and has strong engineering adaptability.

Description

technical field [0001] The invention relates to the technical field of hydraulic presses, in particular to a control system and method for flexible docking of movable beams of hydraulic presses and leveling systems. Background technique [0002] The hydraulic press is a machine that uses Pascal's principle, uses liquid as the working medium, and uses static pressure to transmit power to work, so that the movable beam moves up and down. As an important large-scale equipment in the manufacturing and processing industry, hydraulic presses play a vital role in the forming of large parts. In order to obtain products with good molding quality and high processing precision, the high-performance hydraulic press should have the advantages of short pressing cycle, high control precision of the movable beam, and stable operation of the hydraulic system. At present, large-tonnage hydraulic presses mostly adopt a three-beam and four-column frame structure. The movable beam in the middle...

AI Technical Summary

Problems solved by technology

[0004] (1) The docking speed of the movable beam and the four-cylinder leveling system cannot be effectively matched

That is, due to the large inertia of the movable beam, when the two collide with each other with a large speed difference, the pressure shock of the rodless cavity of the four leveling cylinders will be relatively large, causing mechanical vibration and noise. The long-term high-frequency pressure shock will be extremely The service life of the compressor and key hydraulic valves is greatly shortened; in addition, at the moment of rigid collision, the movable beam is subjected to the abrupt upward resistance exerted by the leveling cylinder on the movable beam, which makes the movable beam have a sudden change in speed or even stops at the docking point, which is not conducive to Subsequent billet pressing and leveling control will ultimately affect the molding accuracy of the product

[0005] (2) The leveling system cannot adapt to the initial horizontal deviation of the four corners when the movable beam is docked

That is, before docking, the four leveling cylinders of the leveling system can ensure a certain level of accuracy when performing closed-loop position control at the waiting position. Due to the impact of the movable beam, there is a certain initial level deviation when it is docked. When docked, the movable beam will rigidly collide with the four leveling cylinders in sequence, causing the initial leveling error of the leveling system, which is not conducive to the subsequent synchronous control of the four cylinders.

[0006] (3) After the rigid collision between the movable beam and the leveling cylinder, the pressure PID control of the rodless cavity of the leveling cylinder has poor anti-interference ability and long adjustment time

After the movable beam is docked with the leveling cylinder, the pressure in the rodless chamber of the leveling cylinder suddenly increases and shakes. In order to make the leveling cylinder close to the movable beam and stabilize the pressure, PID pressure control is used for the rodless chamber of the leveling cylinder. However, the PID control adjusts Long time, sensitive to coupling interference, and limited effect on stabilizing pressure, which is not conducive to the leveling control of the subsequent four cylinders

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