Study Of Robotic Intelligent Control System For Aluminum Alloy Pulsed MIG Welding Process

In resent years, lightweight has become a core problem for development of means of transportation such as automobile and high speed train, so more and more aluminum alloy welding structures have been widely applied to vehicle. In order to adapt to this tend, some key problems of automatized, intelligent and information welding production for aluminum alloy structure were studied in this paper.Development of numerically controlled (NC) robotic positioner is of vital importance to the design of welding flexible manufacturing center (WFMC) of arc-welding robot. The control system has taken 2-aixs servo motor control card as its core and used a two-mode controller that based on Fuzz and PID control method as its position controller. In the tow-mode controller, the outputs of Fuzz and PID acted on object at the same time, but weights of the Fuzz and PID were differing from value of error. This structure avoided concussion effectively when from one controller switch to other controller. The tow-mode controller has realized precise control over position of welding positioner. This paper has made a detail theoretical analysis of the constitution design and real-time controlled software and brought up the design and fulfillment method of multi-task real-time control software of high precisely and numerically controlled welding positioner. Three teaching devices which are teaching-box, joy-stick and computer keyboard are fulfilled with industry control computer and single-chip, and a set of control command system of NC welding positioner is also designed, including program command, track description command and I/O communicating command. Good results obtained in practice.Real-time sensing and control of weld pool dynamics are important techniques to ensure expected weld quality because there are many uncertain effects especially during aluminum alloy welding process. A vision sensing system for taking and processing the image of MIG welding pool of aluminum alloy has been setup in this paper. Clear images of the MIG welding pool are obtained by using the technology of narrow band filter, which used to overcome the influence of strong arc light. The aluminum alloy's characteristic of the MIG welding pool is analyzed. A corresponding image-processing algorithm has been developed to acquire characteristic parameters of the weld pool in real time. In order to overcome the disadvantages of traditional welding pool image processing method, the morphological operators is used to process the aluminum alloy MIG welding pool. This method can effectively wipe off noise and 'cathode pulverization' area in image. The morphological operator is used to process the aluminum alloy MIG welding pool. By using the result of the image processing, a simulation model of the welding system is prepared to make a digital controller. The welding pool width model of dynamic process in Aluminum Alloy pulsed MIG welding is identified by least square method. The input of the model is welding wire speed, base current, welding speed and pulse duty ratio respectively, and the output is beam width of welding pool. The order of these factors influence on welding pool width is analyzed. Based on Fuzzy controller and expert system (ES), real-time control of dynamic weld pool for topside weld width during robotic-pulsedMIG process has been realized in this study. Welding pulse duty ratio and wire-feed speed are controlled to get the desired bead width. The experiments show that the real-time and precision requirements for detecting and control of weld pool changes and bead width of aluminum alloy pulsed MIG welding process could be satisfied by developed image processing and control algorithm on the established systems.With the development of technology of Ethernet, how to apply it to industry filed is a very important problem. The author utilize the embedded gateway combining with MCU controlling system to fulfill the welding machine connection with Ethernet, which could integrate the welding machine with company information system based on Ethernet and TCP/IP completely, and which could make possible of remote management during the welding production and remote diagnosis of welding machine faults via Ethernet. And the author, utilizing SQL SERVER software, design the Net-welding machine managing system, construct the welding standard database and welding process supervision database based on web. The whole system could fulfill the maintenance of welding criterion database, the remote supervision of welding machine parameters and the remote setup of welding criterion and management based on Network..