The Research On Adaptive Compositive Control For Nonlinear System

With the in-depth improvement of technology, the conventional linear control theory can not meet the request of higher satisfied dynamic performance of nonlinear servo control systems. Recently, many researchers applied themselves to nonlinear control theory and its applications and acquired many significant results. However, for nonlinear systems, despite of several special occasions, there is no a kind of feasible general method and each control method is only applicable to solve some class of problem. Thus, the main research of this paper is to seek a valid integrated control technique which takes advantages of multi control methods. In general, the control purpose is to make the output track the reference input preferably with the high dynamic, static and strong robust performance by exerting control on the nonlinear plant.Firstly, by weakening the strict suppose for its application, the conventional backstepping control method is extended to general backstepping control method. Then based on the original model and the normal model of system, the robust problem is solved by introducing a kind of Neural Network adaptive online compensation law which is easily to implement in practice. Moreover, based on the normal model of system, good dynamic performance is acquired by adding the nonlinear smooth trajectory filter (STF) feedforward.Secondly, aiming at the Lyapunov stability problem for MIMO nonlinear systems and considering general reference input i.e. its steady value are generated by some natural stable exosystem, the conditional servocompensator and slide mode stabilizer are designed based on internal model theory. Furthermore, the non-modeling nonlinear parts of system are compensated by introducing Neural Network adaptive online compensator and the dynamic performance of system is greatly improved by adding the nonlinear smooth trajectory filter strategy.Lastly, in this paper, considering the permanent magnet synchronous motor (PMSM) as the controlled plant, the proposed two feedback-feedforward integrated control methods are applied to implement the position servo control for PMSM. And the validity and effectiveness of the nonlinear control strategies are verified through the simulations and the practical DSP experiments.