Research On EtherCAT Bus Integration Technology Of Machine Vision

The integration of machine vision technology on smart CNC machines is very common,such as the workpiece surface quality detection,tool wear detection and whether the fixture has chips.However,in situations where visual data information needs to be transmitted back to the CNC system to form a closed-loop precise control,the uncertainty in the transmission of data between the vision system and the motion control system often becomes a bottleneck in the improvement of the precision of the intelligent control.Based on the high real-time performance of the EtherCAT bus and the simple advantages of the communication link,a technology of bus-integrated vision system is proposed,which has a clear relationship between vision and motion control systems,and can better solve some practical problems in the field of intelligent applications.The research contents of this paper are as follows:Through the summary and comparative analysis of existing industrial ethernet,vision system function development methods and integration technologies,the theoretical feasibility and advantages of bus integration vision technology are pointed out.And proposed the use of EtherCAT bus integrated vision system and control system of the overall program and the use of scripted programming vision module and the problem of real-time pointing to the target as the verification scheme of the technology.According to the overall scheme of bus-integrated vision technology,the EtherCAT communication program was designed from the three aspects of initialization,cyclic process data and state machine processing.At the same time,in order to ensure stable and reliable communication between the visual module and the slave,this paper adopts a communication method based on the “handshake” sign and packaging,and designs a packaged data analysis program.According to the functional requirements of the verification scheme,the visual aspects of the visual module calibration and identification process were analyzed and designed.Through scripted programming,the target was accurately captured;in addition to the implementation of the common functional block,a dynamic compensation function block is designed for the problem of the output position behind the position where the vision module captures the image due to the communication,transmission delay,and master scan cycle.It has improved lack of laser pointing delay.Finally,an experimental platform is built for the research results of this paper.The performance of bus-integrated vision technology is verified and analyzed from the aspects of communication,dynamic compensation and real-time.The experiment shows that the visual integration technology based on EtherCAT bus is accurate without loss of frame.The dynamic compensation weakens the problem of control output lag,and the relationship between the vision system and the motion control system is deterministic,and the real-time performance is good,completing the design goal.