Adaptive fault-tolerant control for electro-hydraulic servo actuator based on multiple unmodeled dynamics estimation and compensation

基于多种未建模动态估计与补偿的电液舵机自适应容错控制

¹ School of Automation, Northwestern Polytechnical University, Xi'an 710072, China
² AVIC Jincheng Nanjing Engineering Institute of Aircraft System, Nanjing 211106, China

Received: 25 April 2022

Abstract

The internal leakage fault-tolerant control problem of the electro-hydraulic servo actuator under the influence of multiple unmodeled dynamics is investigated in this paper, and an adaptive fault-tolerant control scheme based on unmodeled dynamics estimation and compensation is proposed. The model of the actuator is divided into two subsystems, which extended-state observers are respectively constructed to estimate the matched and mismatched unmodeled dynamics. Combined with the estimation results of the unmodeled dynamics, an adaptive fault-tolerant controller is designed by using the backstepping method. In which a controller reconfiguration mechanism based on internal leakage fault parameter online adaptation is used to accommodate the fault, and a feedforward compensation strategy is used to suppress the influence of unmodeled dynamics. Semi-physical simulation test of the proposed scheme is conducted under serious cylinder internal leakage. The test result shows that when the maximum internal leakage flow reaches 10.53 L/min, accounting for about 56.77% of the load flow, at the moment the opening of the servovalve is close to the maximum and the proposed scheme can still achieve high-precision position tracking control, where the maximum position tracking errors of fault transient and post-fault steady state are both limited within ±1.5% of the given position.

摘要

针对多种未建模动态影响下的电液舵机内泄漏故障容错控制问题, 提出一种基于未建模动态估计与补偿的自适应容错控制方法。将舵机模型划分为2个子系统, 分别设计扩展状态观测器估计匹配及非匹配未建模动态。结合未建模动态估计结果, 基于反步法设计自适应容错控制器。利用基于内泄漏故障参数自适应更新的控制器重配置调节故障影响, 采用前馈补偿方式抑制未建模动态影响。对所提方法进行严重内泄漏条件下的半物理仿真试验, 结果表明: 当作动筒最大内泄漏流量达到10.53 L/min, 即约占伺服阀最大负载流量的56.77%时, 伺服阀开口接近最大, 所提方法仍可实现高精度的位置跟踪控制, 故障暂态及故障后稳态的最大位置跟踪误差均可控制在给定的±1.5%以内。