The Research On Nonlinear System Based Multi Models Intellectual Active Fault-tolerant Control Methods

Tow active fault-tolerant control method based on multi-model including the possible system fault statuses is proposed aiming at nonlinear systems and some simulations are done on its validity and robustness with the precondition that some data about the systems are known. The main research work on it is done as follows:1) For the problems which based on the multi model active fault-tolerant control system, adopt the PID control to deal with the unstable tuning and the disability of optimal control, rise the multi model predict active fault-tolerant control based on the BP neural network and make the best use of the characters of the predictive control which need the low precision of model, good robustness and best dynamic characteristic. The approach is validated by simulations.2) According to the PID parametric tuning, adopt the BP neural network which exists the problem of the low speed and easy to convergence to local minimum, and the low speed of on-line reconfiguration control law of the fault model which lacks the precondition in the model bank, use the RBF-NN to replace the BP-NN. Form the internal central of RBF tuning PID parametric, to make the model bank exist not only all the NN model in every condition, but also the control parametric. And improve the quickness of fault-tolerant, at the same time lay the basis on the on-line learn and make up in the model bank when the new faults lacking in precondition happen. The approach is validated by simulations and it is validated to linear system likewise.3) There is some brief analysis on the performance of the RBF-PID FTC system and some simulations on systems which contain some uncertainty due to the environment in the thesis. The simulations indicate the FTC systems have some robustness in the condition of a limited disturbance and small faults, which means that the supervision does not have false judge and false controller reconfiguration and the controller itself has some robustness.