Sensing and Digital Control of Weld Pool in Pulsed MIG Welding

A basic visual robot is proposed for sensing and controlling the weld pool shape. It has been difficult to observe the weld pool with a TV camera, since the arc light is too strong. The authors tried to make periodically the current low enough to watch clearly the weld pool with CCD (Charge Coupled Device) camera without after image. The weld pool is recognized by taking advantage of the feature on the brightness of the weld pool and its outskirts. A personal computer calculates the weld pool width and area in real time. The authors study the transient response of the wled pool width and area. The wedling current is determined to get a desired response of the weld pool. It is shown how to determine the digital controller characteristic. Small variations of system parameter during operation caused by the change in the base metal thickness, heat conductivity, temperature rise are allowed while the prescribed control performance is maintained. Experiments demonstrate the good controllability of the adjustable weld pool formation with the digital controller.rights: 社団法人溶接学会rights: 本文データは学協会の許諾に基づきCiNiiから複製したものであるrelation: IsVersionOf: http://ci.nii.ac.jp/naid/110003379835