Trajectory Tracking Control Design For A Class Of Robot Systems

Robot technology has been widely applied in engineering and many other fields. The developments of the robot technology become a core of the information technology, control technology and the system integration technology. Therefore, the study of robot control is of great significance both in theoretical research and engineering application. In this thesis, the research object is the 2 DOF Robot, which was manufactured by Quanser Company of Canada. According to the designed trajectory, the controller operates the ends of the four bar linkage, which is connected to the DC motor. The control goal is to track the designed trajectory at the two-dimensional plane. The main contributions of this thesis are as follows:(1) The kinematic equations of the 2 DOF Robot are established. The transfer function from the input voltage to the output load angle of the DC motor is established on the basis of its operating principle. The establishment of the model lay the foundation for the next works.(2) Based on the structural model of the robot system, we design a PID controller, and the parameters of this PID controller are optimized by the genetic algorithm. On the other hand, because the parameters of the traditional PID controller are invariant, it cannot possess perfect performance when the parameters of the plant change. Thus, we design a nonlinear PID controller, of which the parameters are optimized by the genetic algorithm.(3) Considering the factor of the coupling and nonlinearity of the system and the inaccuracy of the model established in the simulation, we design a fuzzy controller. Because the membership functions and the control rules of the conventional fuzzy controller are fixed, we design a multi-fuzzy soft switching controller. Then, to solve the problem that the residual error of the system cannot be eliminated by the fuzzy controller, we design a switching controller with multiple fuzzy controllers and a nonlinear PID.(4) By utilizing the result above, we build a hardware platform of the 2 DOF Robot. Then, the designed controller is applied on this platform. The designed trajectory can be tracked well by the four bar linkage. The simulation demonstrates the feasibility and effectiveness of the proposed design method.Finally, the results of the dissertation are summarized and further research topics are pointed out.