Predicting remaining useful life of degraded control systems considering three-source factors

As industrial control systems are operating in the long run, the performance of their components will inevitably degenerate, which might ultimately lead to the systems failure. Compared with the single-component systems, the output of control systems may remain satisfactory tracking on the reference output due to the distinctive structure of closed-loop feedback, even if the structural parameters of internal components degenerate. This will result in the inner degradation difficult to detect, showing a characteristic of hidden degradation. In the existing literatures, there are scarce researches on the remaining useful lifetime (RUL) prediction of control systems, which consider the hidden degradation process under the closed-loop feedback control. In this paper, a prediction method of RUL based on analytic model is proposed for a class of deterministic closed-loop control systems only considering actuator degenerating. In addition, there are more factors that affect the reliability of control systems than the single-component systems. This paper considers three-source factors: control constraint, degradation model and random disturbance, which have direct or indirect effects on the systems reliability. Then, the factors are respectively abstracted into a corresponding parameter in the system model for conveniently discussing their specific influence on the results of RUL prediction. The simulation results of stabilization loop control system in inertial platform indicate that the corresponding RUL prediction method is effective and feasible.