IJCAS

This paper focuses on the velocity tracking control problem of high-speed trains (HSTs), in the presence of unpredictable partial loss of actuator effectiveness faults, actuator output magnitude and rate saturations, unknown time-varying model parameters, as well as the unmeasurable additional resistance. An augmented plant of train longitudinal dynamical system is constructed to restrict the actuator dynamics and facilitate the development of the control law. A train fault-tolerant velocity tracking control algorithm is designed by combining the dynamic surface control (DSC) technique, adaptive control technology and auxiliary system. Within the proposed controller, the auxiliary signal is introduced to compensate for the influence of actuator output magnitude saturation; Adaptive technology is adopted to estimate the unknown nominal values of train model parameters, the upper bound of the change of actuator output due to actuator faults and the lumped system uncertainties composed of model parameter uncertainties and additional resistance; The adopted DSC approach is applied to avoid the derivative of virtual control signal, which simplifies the controller. The stability of the closed-loop system is analyzed based on Lyapunov stability theory, and good performance of the presented controller is verified by simulation results.

Keywords: Adaptive dynamic surface control, fault-tolerant tracking control, high-speed trains, magnitude and rate saturations.