Research On Fault Diagnosis And Fault - Tolerant Control Of Electromechanical Servo System Based On Sliding Mode

With the background of Natural Science Foundation of China, the paper has researched online fault detection and fault tolerant control of mechatronics hydraulic servo system based on analytical redundancy, as the following aspects show:(1) Established mathematical model containing additive fault description. The failure of motor and electro-hydraulic servo system is various, impacting on system control performance differently, for the convenience of research, represent these common faults as a unified form, establish a unified mechatronics hydraulic servo system model containing additive fault description.(2) Fault detection based on state estimation/reconstruction. Treat the motor and electro-hydraulic servo system as research subject, for the system unmodeled dynamics, parameter perturbation, failures and other problems, design robust adaptive observer combined with robust filtering techniques and adaptive technology design. Reconstructing the state and adaptiving system parameter on the basis of weakening the impact of uncertain non-linearities. Use state reconstruction error to determine whether the system is a failure, give the upper bound of adaptive parameter theoretically, avoiding the blindness of artificial upper bound. Meanwhile, It can detect what errors that the system occurs according to the adaptive error of adaptive parameters.(3) Additive fault detection based on disturbance estimate. For additive fault of system, design sliding mode disturbance observer to observe additive fault level and analyze the error, guaranteeing the accuracy of observations theoretically. At the same time, provide fault information for subsequent fault tolerant control strategy.(4) Active fault tolerant control for occurred additive fault. According to fault detection results, combining with additive fault observation information, design a series of active fault tolerance control strategy based on sliding mode. Estimating additive fault level and model uncertainty of electro-mechanical and electro-hydraulic servo system by sliding mode observer, compensate them in the active fault tolerance controller to weaken or eliminate chattering of sliding mode control. Meanwhile, introducing observer sliding surface into controller sliding surface to construct a new controller sliding surface to ensure good dynamic performance of controller. Then, to enhance the convergence of system control error, propose continuous sliding mode active fault tolerance control strategy with tracking error finite time convergence.(5) Carrying on MATLAB/Simulink simulation, Simulink and AMESim co-simulation and experiment with noise in the system model and under model uncertainties and other various conditions. Establishing more realistic model, verify effectiveness of fault tolerance strategies and reliability of detection strategies from various aspects and conditions.