Research On Some Sliding Mode Variable Structure Control Stategies Of Robot Uncertainties

Because of the dynamics characteristics with time-varying, strong coupling and non-linear, the rubust control of robot system received great attention in theoretical research and engineering at all times. When the robot model is exactly known, because of the system can be influenced by uncertainties such as external disturbance and payload change. Thus, it is essential for CTC to be improved. Considering the uncertainties of robot system, Sliding Mode Variable Structure Control(VSC) is applied to robot control more widely for its sliding mode is fully adaptive to nterference and perturbations. with the advantage easy control ,decoupled, order reduction. But its chatting is harmful, so the elimination of chatting is highly significant.Firstly, the dissertation gives a brief description about the developing situation and control theory of robot, and then the models of robot and mathematics knlwledge are introlduced in detail. Researched on the uncertain parameters and structures of robotic model in the trajectory tracking some effective control strategies are presented. Firstly, based on saturated function, a adaptived sliding mode control schem is proposed, and then RBF neural network is introduced to design a neural network sliding mode control strategies. Its main idea is that two combined controllers aim at nominal model and practical plant of the robot system separately. The status feedback controller was designed for nominal model, the compensatory sliding mode controller is designed for practical plant. Radial Basic Function Neural Network(RBFNN) was used to adaptively learn the unknown bounds of system uncertainties. So as to make the control smoothed and bounded with the ruburst. Besides, a new dynamic sliding mode control law based on Backstepping is presented for trajectory tracking control of robot manipulator. New switch function based on Backstepping method is designed to transfer discontinuity to derivativeness of the control law, which can be eliminate the chatterings of control base on controller and Robot Manipulator themselves. So that better control effection can be obtained.