Study Of Mounter Motion Control System

Surface Mount Technology ( SMT ) prevails in the today's electronic manufacturing in dustry. Among the equipments that constitute a SMT assembly line,placement machine is the most important one,and which is also common in electronics manufacturing industry.Most of all, Motion control is one of the key technologies for SMT mounter. In fact, placement machine 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 case of design. Using PID control only, 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.So,it's time to use some new methods and techniques to modify the original programs.In this article,we elaborate on the placement machine's motion control systems and establish the motion control systems of mount-header.Firstly, in base of describing the placement machine motion control system's hardware work platform,a motion control system for SMT mounter is proposed.In addition,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, is established, the value and the cause of the error for single joint and multi joint position controller adopted conventional method are analyzed.Finally,due to the traditional PID algorithm's low precision position control in the placement machine motion control systems,we find a modified PID algorithm, which is speed and acceleration feed forward arithmetic.We also introduce some methods of parameter moderating and use one of it to achieve the PID parameter tuning.Through tradition and improved PID algorithm for system simulation,we obtain a pefect result that placement machine motion control system can achieve high precision movement.