Adaptive fault tolerant control for hydraulic actuators

Abstract

Sudden or incipient faults can lead to a degradation in plant performance, impairment of important functions and eventual loss of safety. Thus, the diagnosis and accommodation of incipient faults in dynamical systems is important to meet performance and reliability requirements. This paper outlines a fault tolerant control algorithm for a hydraulic actuator with a faulty piston seal. An experimental setup capable of simulating different kinds of faults observed in hydraulic systems is constructed. A detailed nonlinear model of the experimental setup is developed and validated. A robust nonlinear control strategy is developed for position control of the actuator. A nonlinear stochastic parameter estimation algorithm is also developed and its effectiveness in estimating leakage faults is demonstrated. The nonlinear control strategy is then improved upon by adapting based on the online fault estimate. The experimental results demonstrate the effectiveness of the adaptive fault tolerant control strategy by maintaining a position tracking error below .2mm compared to simple robust control for which the error increases to .5mm as the fault size increases.

Adaptive Robust Fault-Tolerant Synchronization Control for a Dual Redundant Hydraulic Actuation System with Common-Mode Fault

“…However, most research focuses on the FTC problems for single-channel hydraulic actuator (SHA). The existing design methods include quantitative feedback theory (QFT) [6,7], adaptive robust control (ARC) [8][9][10], and intelligent control [11]. Among them, [7][8][9][10][11] belong to the AFTC method, which needs to employ real-time fault detection and diagnosis (FDD) module to provide up to date information about the true status of a system [12].…”

“…The existing design methods include quantitative feedback theory (QFT) [6,7], adaptive robust control (ARC) [8][9][10], and intelligent control [11]. Among them, [7][8][9][10][11] belong to the AFTC method, which needs to employ real-time fault detection and diagnosis (FDD) module to provide up to date information about the true status of a system [12]. The FDD methods in [7][8][9][10][11] include neural network [7], adaptive robust observer [8], parameter adaptive methodology [9], and stochastic filtering theory [10,11].…”

Disturbance-Estimation Based Adaptive Backstepping Fault-Tolerant Synchronization Control for a Dual Redundant Hydraulic Actuation System With Internal Leakage Faults

“…However, to the best of the authors' knowledge, research on FTC problem for HAs especially for RHAS subject to internal leakage faults is still very limited. In [14], an FTC algorithm based on stochastic parameter estimation was presented for an HA with internal leakage fault. In [15], an adaptive robust FTC scheme based on faulty parameter adaption was proposed for a single-rod HA.…”

“…Among these methods, the schemes [16]- [18] are linear control strategies without consideration of disturbances and it should be noted that a high position tracking accuracy cannot be achieved with a linear controller due to the high nonlinearity of the HA [19]. Furthermore, the nonlinear controllers in [14], [15] have neglected the matched disturbances in actuators.…”

Experimental Study of Sensor Fault-Tolerant Control for an Electro-Hydraulic Actuator Based on a Robust Nonlinear Observer

“…Therefore, it is essential to construct advanced fault detection and isolation (FDI) and fault-tolerant control (FTC) techniques for augmenting the system to ensure the safety, reliability, and sustainability of the systems. The benefits of FDI or simply fault diagnosis (FD) and FTC techniques for industrial systems have been recognized [5][6][7][8][9][10][11]. The FD algorithm primarily consists of making a binary decision between fault and no fault.…”