基于机器视觉与PLC的三轴转台闭环控制方法

Closed-loop Control of Three-axle Table Based on Image Recognition and PLC Control

针对点胶工序中需要消除点胶机工作原点与PCB板定位误差的问题,对视觉系统、三轴转台的结构设计与控制系统设计进行研究分析,提出一种通过机器视觉获得电路板相对于工作台原点的位移和转角偏差,利用PLC对三轴工作台进行运动控制补偿偏差,并通过视觉实时监控位移和转角实现位置闭环控制的方法。编写上位机软件与PLC控制程序,设计搭建一种补偿电路板定位误差的三轴转台及控制电路。对系统机电联调测试,测试结果表明该方案可有效的解决工件定位误差的问题。

Aiming at the problem of the PCB has a relative deviation from the origin point of dispenser in the process of dispensing SMD components on PCB,it is need to align the working origin of the dispenser and the positioning point of the PCB before dispensing.The control program,structure design and control method of three-axis turntable are studied.A method is proposed to obtain the deviations of the PCB relative to the origin of the turntable through image recognition,and then use PLC to control the motion of the turntable to compensate the deviations.Closed-loop control is realized through real-time monitoring.A method is introduced of communication between host computer and PLC,the host computer software and PLC programs are wrote,the structure and control circuit of three-axis turntable are designed.The test results show that by using image recognition technology to control the motion of the three-axis turntable in a closed loop,the workpiece on the turntable can be accurately corrected and positioned.