Online fault detection, estimation and location method of valve-controlled cylinder electro-hydraulic servo system

Abstract

The invention discloses online fault detection, estimation and location method of a valve-controlled cylinder electro-hydraulic servo system. The method comprises the following steps: 1) performing nonlinear modeling of the system; 2) identifying normal parameters of the system; 3) substituting the data of normal operation of the system acquired in the step 2) into a nonlinear state equation of the system in the step 1), to obtain a normal system parameter matrix and an expression of the nonlinear state equation of the system; 4) acquiring relevant input / output parameters of the system in realtime; 5) performing fault detection and estimation under varying load; 6) making a robust fault decision; 7) if no fault exists in the step 6), returning to the step 4); if a fault exists, starting afault vector estimation module in a fault detection observer in the step 5); and 8) performing fault isolation and location. The method disclosed by the invention has the following beneficial effects: real-time monitoring on the operation state of the system can be performed in the case of unknown time-varying external load, nonlinearity and uncertain parameters in the valve-controlled cylinder system, so as to reduce economic loss.

Description

technical field [0001] The invention relates to the field of fault diagnosis of an electro-hydraulic servo system, in particular to an online fault detection, estimation and positioning method of a valve-controlled cylinder electro-hydraulic servo system. Background technique [0002] The electro-hydraulic servo system is a feedback control system composed of an electric signal processing device and a hydraulic power mechanism. It is widely used in industrial Manufacturing, transportation, engineering machinery and other fields. Among them, the valve-controlled cylinder electro-hydraulic servo system is a common and widely used system. Its working principle is mainly to control the oil in and out of the hydraulic cylinder through a servo valve or a proportional valve, thereby controlling the position and speed of the cylinder piston, etc., such as The valve-controlled cylinder electro-hydraulic servo system is used for the control of aircraft and ship steering gear, the pos...

AI Technical Summary

Problems solved by technology

The above methods have their own advantages and disadvantages. In recent years, many fault methods based on model and data-driven fusion have emerged. However, they are mainly aimed at the situation where the external load is constant and the load is known or measurable.

Based on the complexity of the actual working conditions, the operating parameters of the system and the external load force are often not constant but time-varying, and it is difficult to obtain accurately. Under this unknown time-varying load, even under normal conditions, the system output pressure, The flow rate is not a fixed value, but fluctuates up and down, sometimes with a large fluctuation range, so the fault form of the system is easily confused with the normal form, and it is difficult to distinguish

In addition, there are many inherent nonlinear factors in the valve-controlled cylinder electro-hydraulic servo system, such as the nonlinear relationship between pressure and flow. challenge

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