Dynamic Model Building And Fuzzy Variable Structure Control For Two-degree-of-freedom Parallel Manipulator

Along with the more development of science and technology, the more parallel mechanisms are applied to robots field. Because the characteristic of parallel robots is closed loop, they are different to series-wound robots, and the control methods of parallel robots are attended by people. The paper bases on the two-degree-of-freedom planar parallel robot, studies the sliding mode variable structure control method with adjusting the change of torque based on fuzzy rules.The paper applies Vector method to analysis inverse kinematics for the 2-degree-of-freedom robot, and takes use of Principle of Virtual Work to build dynamics equations respectively. Provides based control model for this control method.The biggest excellence of variable structure control method is that the sliding mode is completely adaptive to the interference and perturbation of system. Once the states of system come into the movement of sliding mode, they will converge to control target quickly. The fetal disadvantage of this method is that the acquirement of movement of sliding mode is along with high frequent flutter. It is aroused by the discontinuous switch character in essence of the sliding mode variable structure control method. So expect that can attain to the purpose of weakening flutter and responding quickly by connecting fuzzy control method to variable structure control method. Design a variable structure controller by making use of exponential adience law. The application of exponential adience law is not only make sure that the system can satisfy approach condition forever, but also make sure that the system can exist sliding mode. Combine variable structure control and fuzzy control, form a fuzzy sliding mode variable structure controller which can respond quickly by adjusting the change of torque which make use of fuzzy rules.Make use of MATLAB languages, simulate the model by giving two reference import signals, acquires angle trajectory error and angular velocity error for two master arms and the trajectory of the sliding mode. Analysis the influence of the parameters for system. Compare the simulation results of the fuzzy variable structural controller to that of the common variable structural controller. Check out the feasibility of this project and the validity of the fuzzy sliding mode variable structure control method.