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

Abstract

This paper tackles with the maintenance decision-making of gradually deteriorating control systems. The main feature of these systems is their ability within a closedloop to drive actuators in order to set the controlled process in a given state.Usually, the literature deals with the diagnosis of faults of a control system and the means for recovering system performances after their appearance. The controller reconfiguration is one of these means. The root cause of a fault is rarely argued nor its occurrence time. Before designing maintenance policies, this paper proposes a stochastic modeling framework of a degrading control system focusing on the actuator deterioration. It is assumed a close relationship between the controller setting, the actuator deterioration and finally its faulty situations. These latter are related to given degradation thresholds. Due to the stochastic nature of the deterioration, the corresponding hitting times are thus random. The obtained models allow to assess the conditional reliability of the actuator and then the prognosis of its residual useful life namely the RUL. This RUL is finally used to achieve two maintenance policies based upon the reconfiguration of the controller considered as a new maintenance action.Prepared using sagej.cls

Review of Post-Prognostics Decision-Making in Prognostics and Health Management

“…Langeron et al (Langeron, Grall, & Barros, 2017), presented an approach that defines operational decision-making by changing the matrix Q and R of the LQR controller and scheduling the maintenance actions based on the RUL of the system. This approach was tested on a DC motor by varying its speed and planning the replacement of its bearing.…”

A root location-based framework for degradation modeling of dynamic systems with predictive maintenance perspective

“…The question arising is how to choose or to combine these features in order to estimate the system health. In previous works, 3,18 the authors show that it may be tricky to combine these features for emerging an indicator representative of system health. Here, instead of dealing with these features wondering which of them best describe the loss of performance, this paper focuses on the location of the complex conjugate roots s 1 , 2 in complex plane.…”

“…Based upon the predicted faults, a Monte-Carlo algorithm is used to forecast the probability that the system falls into forbidden states in future. Langeron et al 3,4 study a drilling unit facing a set of observable faults in a closed-loop feedback structure. These latter are correlated to the degradation of an actuator assumed to be the critical component.…”

Deterioration estimation for predicting and controlling RUL of a friction drive system

“…The information on the predicted RUL is not only necessary to verify whether the mission goal can be accomplished, but it is also important to aid in online decision-making activities such as fault mitigation, control reconfiguration [4,5,6], mission replanning [7,8][9] and eventually maintenance operations. Mission replanning can be implemented using for example load-sharing mechanisms at different levels [10], i.e between components within a multi-component system or between equipments within a fleet, whereas control reconfiguration can be achieved by a suitable modification of desired control-loop references for the operation of a component or an item, as stated in [11]. However, eventually, both problems of mission replanning and controller reconfiguration can be considered as a RUL control problem formulated as a multi-objective optimization problem.…”

“…To this aim, it is first necessary to build a model that links the control inputs of the considered system both to its performance level and to its deterioration behavior, which are often two antagonistic processes. In [11,12], it is assumed that the control input is seen as a source of stress deteriorating the actuator. This assumption is in general accepted by engineers in several applications.…”