High-precision Positioning Control Of Linear Motor In IC Defect Detection

High-speed and high-precision motion control is one of the key technologies in the manufacturing of electronics equipment. With the decreasing of the size of the chip and increasing of the productivity, the demanding of the acceleration, speed and positioning accuracy of the packaging equipment were required more and more higher, which gives a great challenge to the design of motion controller.This dissertation described the principles, history and classification of the linear motor and control technology firstly, and then introduced the main control strategies of the recent permanent magnet synchronous motor, as well as the control strategy which was adopted in this dissertation. Secondly, the installment of the IC defect detection platform was presented, as well as the composition of the XY linear motor control system. Thirdly, a basic mathematical model was established by using the dynamic characteristics of linear motor, and then the parameters of the X, Y-axis were identified by using Frequency Response Method, whose accuracy and application value were also studied.A repetitive learning control algorithm was introduced in the fourth chapter, which increased the precision of position control gradually. Since the XY positioning stage moved repeatedly, this dissertation adjusted the trajectory command by adopting repetitive learning control algorithm (Iterative Learning Control - ILC) in the adjacent movement cycles, while the controller used cascading structure, whose structure and parameters unchanged in the motion process. The platform suppress the interference by using cascade controller, whose speed loop and position loop adopted PI controller and P controller, respectively. Combined with the trajectory of point to point, fast point-to-point movement was achieved by using A - type ILC trajectory commands, which compensated for the load inertia and interference effects, in order to make the platform tracking the motion trajectory. This method named trajectory adjustment control algorithms, which is usually applied to the equipments which does not allow users to modify the controller structure, but can modify the controller parameters and expectations of the trajectory. Therefore, it has the potential of a wide range of practical applications.