Research On Motion Control Of SMT Mounter

Motion control is one of the key technologies for SMT mounter. In fact, SMT mount-header is a robot has four joints, and belongs to transport robot. Most commercial robot system currently equipped with conventional PID controllers due to their simplicity in structure and ease of design. Using PID control, however, it is difficult to achieve a desired position and velocity control performance since the dynamic equations of a mechanical manipulator are tightly coupled, highly nonlinear and uncertain. With the development of modern control theories, more and more intelligent control methods are applied to solving this problem. Up to now, neural network technology has been applied widely in the uncertain and nonlinear system. PID control combined with neural network, its advantage is kept, and the robust and anti-disturbance performance of the system is enhanced. In this thesis, a discussion of conventional PID control and neural network PID control in the motion control was presented, and a good control system for the rigidity robot manipulator was proposed.According to the character of motion control and the operation demand of SMT mount-header, a dynamic model of the motion control system, which based on direct current servo-motor, was established, the value and the cause of the error for single-joint and multi-joint position controller adopted conventional method were analyzed, the results were proved by simulation. To overcome the deterioration of the performance under uncertainty and disturbance, a new intelligent hybrid control scheme for the manipulator was presented, which is PID—Neural networks control, The result of simulation demonstrates the effectiveness and robustness of the new controller. Finally, a distributed control system for SMT mounter was proposed, then hardware and software design based on MCS51 microprocessor of single-joint controller was compeleted.