A Control Method of Asymmetric Electro-hydraulic Proportional System Based on Model Transformation

Abstract

The invention discloses a control method for an asymmetric electric-hydraulic proportional system based on model transferring. By converting a transfer function, an asymmetric mathematical model of the asymmetric electric-hydraulic proportional system is converted into a symmetric system model, the symmetry of a load flow model is achieved, and when a unified controller is adopted, responses of forward and reverse motions are identical; by means of signal conversion, the load flow model of the asymmetric system is established, and the purposes of transfer function converting and model converting are achieved, and a new established system model serves as a symmetric load flow model. The achieving method comprises the steps that a reference signal symmetrical to a proportional valve is given, after a signal is converted, a new input signal of the proportional valve is obtained, and proportional valve is controlled to work, so that load flows of the asymmetric electric-hydraulic proportional system in a proportional valve linear region in the forward motion and the reverse motion is identical; by means of the method, an asymmetric effect is eliminated by an asymmetric factor of the system through mathematical conversion, and the identical response of the asymmetric electric-hydraulic proportional system is achieved simply and intelligently.

Description

technical field [0001] The invention belongs to the technical field of machinery and electronics, and relates to a control method of an asymmetric electro-hydraulic proportional system based on model conversion. Background technique [0002] The hydraulic control system of the 125MN extrusion press adopts the control form of "pilot valve combined with throttle valve", which is essentially a valve-controlled cylinder hydraulic system. When the speed of the movable beam is too large, the opening height of the throttle valve is reduced. When the speed becomes smaller, increase the opening of the throttle valve spool, the system schematic diagram is as follows figure 1 shown. [0003] The field application shows that the characteristics of the throttle valve spool in the two directions of opening and closing are different. The opening process of the spool is very slow, the closing speed is very fast, and the dynamic characteristics are asymmetrical, mainly manifested in stabili...

AI Technical Summary

Problems solved by technology

However, their common features are that the theory is more complex, there are more parameter adjustments, the design and maintenance are difficult, and the requirements for engineering and technical personnel are high.

And because the control program is more complicated and the real-time performance is poor, it is difficult to be widely used in the industrial field

[0005] According to the above analysis, the existing asymmetric control strategy cannot meet the field practical requirements in terms of manufacturing cost, complex working conditions and stability.

Images