Reconfigurable control design with integration of a reference governor and reliability indicators

Abstract

A new approach to manage actuator redundancy in the presence of faults is proposed based on reliability indicators and a reference governor. The aim is to preserve the health of the actuators and the availability of the system both in the nominal behavior and in the presence of actuator faults. The use of reference governor control allocation is a solution to distribute the control efforts among a redundant set of actuators. In a degraded situation, a reconfigured control allocation strategy is proposed based on on-line re-estimation of the actuator reliability. A benefit of incorporating reliability indicators into over-actuated control system design is the smart management of the redundant actuators and improvement of the system safety. Moreover, when the fault is severe, an adaptation approach using the reference governor is proposed. The reference governor unit is a reference-offset governor based on a discrete-time predictive control strategy. The idea is to modify the reference according to the system constraints, which become stricter after the occurrence of an actuator fault. The proposed approach is illustrated with a flight control application.

Joint maintenance and controller reconfiguration policy for a gradually deteriorating control system

“…In Weber et al (2012a), the failure of an actuator is modeled with a lifetime distribution whereas in Lefebvre (1996) a stochastic process is used. In any case, the successive hitting times of degradation thresholds L 1 , L 2 and L f are then random while in FTCS literature an arbitrary date is often chosen when a faulty situation occurs Casavola (2006).…”

A modeling framework for deteriorating control system and predictive maintenance of actuators

“…In general, required performance is obtained by expending high actuator energy with no-control on the actuator lifetime. Only some research has already investigated this problem and give partial answers [4][5][6][7][8]: the degradation of the actuator is modeled by a loss of effectiveness to fully implement the control input but this kind of degradation is (i) independent on the control law, (ii) independent on any kind of physical degradation process, (iii) governed by deterministic fault occurrence dates. So it is difficult to use this type of model to take into account random usage or operational condition variations in the future.…”

Robust Adaptive Observer based on Multi wheeled Mobile Robot Cooperation Algorithm

“…Diverse FDI methods have been reported in the literature such as: generating redundancy in the case of physical redundancy between sensors or parity space formulation. After FDI block [11], Fault tolerant control systems are needed in order to maintain the performance objectives [12], or if that turns out to be impossible, to assign achievable objectives so as to avoid catastrophic failures [13]. Since the process used in this work is from the family of mobile robot, it is better to refer to some researches that are interested by both diagnosis term [14,15] and robotic theme [16].…”