Research Of Embedded Control System For Inverter Resistance Spot Welding

In recent years, the advanced manufacturing technology of our country is becomingmore and more precise and intelligent, which leads to more pressing demands on theintelligence control of resistance spot welding. There are many problems in the products ofresistance spot welding power source which are list as follows. Firstly, many of them used8-bit microcontroller as the core of the control system, which data processing capacity couldnot meet the requirements of real-time performance and control precision. Secondly, thecontrol algorithm is too simple and the contol system has no openness, adaptability andextensibility. Thirdly, the design of human-computer interface is not humanized, which makesthe operation more difficult. Lastly, most products could not realize the networkcommunication function and it is difficult for them to work efficiently in massive application.This paper has designed the dual-core architecture inverter resistance spot welding powersource control system which is based on DSP and ARM. DSP is responsible for theinformation detection and real-time control of the welding process. During the process ofwelding, DSP samples the current and voltage of the main circuit by sensors and createsPWM pulse output after every PID calculation to realize the closed loop control. Linux, aportable operating system, has been applied to undertake the tasks of data management andcommunication. Human-computer interface has been designed by using the graphicalinterface software called QT/Embedded. The communication between DSP and ARM iscompleted through SPI interface and the one between ARM and computer is based onModbus/TCP protocol. After being connected to the network, several control systems canrealize centralized management.As the result shows, the control system is stable and reliable, and has acquired higherprecision and rapider response. Its human-computer interface is more humanized and thewelding samples have good quality and satisfy the process requirements. What is more, itsnetwork communication feature makes great contribution to the massive application ofinverter resistance spot welding.