Feedback Control System with Stochastically Deteriorating Actuator: Remaining Useful Life Assessment
Proceedings of the 19th IFAC World Congress
Feedback control system performance can be decreasing during its operation because of the components' wear or degradation. To deal with such loss of efficiency, a research aspect of dependability concerns fault-tolerant control (FTC) strategies which give the feedback control system the ability to overcome faults. In this way, the RUL (remaining useful life) becomes valuable information which can be integrated in controller design in efforts to find a satisfactory trade-off between control system performances and components' lifetime. The main aim of this paper is twofold. On one hand, it proposes an integrated model which jointly describes the state of the feedback control system and the actuators degradation. On the other hand, a probabilistic model-based framework is presented in order to assess the RUL of the deteriorating feedback system. No special monitoring device is used to observe the health status of actuator, thus the measurements of closed system response are considered as the only available health information. The RUL is computed by a two-step technique. First, the system state regarding the available observations is estimated on-line by using the Particle Filter method. Then, the reliability of the system is computed with a classical Monte Carlo method. In order to illustrate this approach, a well-known simulated double-tank level control system is used.