Printed Circuit Board Optical Inspection Positioning Platform System Design And Its Application

Automatic optical inspection technology is widely used in circuit board quality inspection. Positioning platform as a key equipment of optical detection technology, its positioning precision and speed directly affect the accuracy of the circuit board and the efficiency of operations. Hence, there is an urgent need to develop the positioning platform with high speed and high precision. So the positioning platform system with high speed and high precision is designed for automatic optical inspection in this paper. The main contents of this paper are as follows.Firstly, the overall design for the hardware system of positioning platform is completed, a positioning platform prototype is built under laboratory conditions. A permanent magnet synchronous motor is used to drive the ball screw, achieving the motion axis linear motion. Linear grating ruler is the position feedback measurement device, closed loop control system of servo control system is constructed.Secondly, motion axis model of positioning platform is established. The common algorithm of positioning control used in industry is analyzed. Using compound control algorithm which is composed of feed-forward control algorithm and PID feedback control algorithm to complete the positioning control of platform. The simulation models are built for simulation with MATLAB/Simulink, and the simulation results that with and without compound control algorithm are obtained, and verify that the control effect of control algorithm.Thirdly, the compound control algorithm which is composed of feed-forward control algorithm and PID feedback control algorithm, is applied to the ACR9000 controller, by adjusting the control parameters, making it meet the stability and dynamic performance indicator of servo control system, reached the design request of the platform which achieve the positioning precision with high speed.Fourthly, the software system is developed based on the dynamic link library and VC++6.0, including many modules,such as the modules of movement testing, PCB board location hole inspection and positioning and communication and so on.Finally, the experimental test of positioning precision verifies the performance indicators of the platform. Then the platform prototype is applied to the positioning experiment of the PCB board location hole, the results further show that the positioning platform is designed in this thesis can meet the positioning requirements of automatic optical inspection system.The simulation experiments and practical experiments show that the position--ing platform designed in this thesis is up to standard, and meet the requirement of automatic optical inspection..