A Compensation Method for Low-Frequency Interference in Electro-hydraulic Position Servo System of Valve-controlled Cylinder

Abstract

The invention discloses a valve-controlled cylinder electro-hydraulic position servo system low-frequency interference compensation method. The valve-controlled cylinder electro-hydraulic position servo system low-frequency interference compensation method comprises the steps that a position command signal r is input; a pressure difference signal p of two cavities of a hydraulic cylinder and an acceleration signal a of a piston rod of the hydraulic cylinder are used as input signals of a disturbing force calculation module to obtain the disturbing force F; the disturbance compensation signal x2 is calculated; the position command signal r is used for subtracting the a displacement signal c of the piston rod of the hydraulic cylinder, and the difference between the position command signal rand the displacement signal c are used as input signals of a proportional plus integral controller; an output signal x1 of the proportional plus integral controller is added to a disturbance compensation signal x2 to obtain a drive signal x of a servo valve, and the drive signal x is input to a valve-controlled cylinder system to drive the hydraulic cylinder and the load to generate the corresponding movement. According to the valve-controlled cylinder electro-hydraulic position servo system low-frequency interference compensation method, the fluctuation of the amplitude-frequency characteristic of closed loop transfer function of system location within the 6-7hz band can be reduced to within 3dB, and control precision of the system is significantly enhanced. The valve-controlled cylinderelectro-hydraulic position servo system low-frequency interference compensation method is easy to realize by computer numerical control.

Description

technical field [0001] The invention relates to an electro-hydraulic position servo system in the mechanical field, in particular to a low-frequency interference compensation method for a valve-controlled cylinder electro-hydraulic position servo system. Background technique [0002] The design of the traditional valve-controlled cylinder electro-hydraulic position servo system assumes that the system has a rigid foundation, and the hydraulic cylinder and the load are rigidly connected. However, for systems with heavy loads, the above assumptions are not valid. The foundation of the system has elasticity, and there is also a flexible connection between the hydraulic cylinder and the load. Affected by the basic elasticity and the flexible connection between the hydraulic cylinder and the load, the amplitude-frequency characteristic of the closed-loop transfer function of the system position is prone to large fluctuations in the low frequency band, which greatly reduces the co...

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Problems solved by technology

Affected by the basic elasticity and the flexible connection between the hydraulic cylinder and the load, the amplitude-frequency characteristic of the closed-loop transfer function of the system position is prone to large fluctuations in the low frequency band, which greatly reduces the control accuracy of the valve-controlled cylinder position servo system

[0003] The analysis shows that when the traditional control method is adopted, affected by the interference of the foundation elasticity and the flexible connection between the hydraulic cylinder and the load, the amplitude-frequency characteristics of the closed-loop transfer function of the system position fluctuate by about 20dB in the 6-7Hz frequency band, which seriously affects the given Determine the reproduction accuracy of the signal in this frequency band

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