Research On The Control System Of Submerged Arc Welding With Changeable External Characteristics

In welding field, control for the process of submerged arc welding is an important subject. Because of the nonlinear of arc and complex disturbances in field conditions, it's difficult to control and meet the requirements. For the low adaptability and robustness of existing controllers, this paper analyzes the weld process of submerged arc welding and has a research on the control methods. The main contents of this paper are:An analysis is conducted on the submerged arc welding process. First, a detail study is given to every module of submerged arc welding process. Then, the model of the submerged arc welding is obtained based on the mathematical model of these sub-modules. And the changeable external characteristic of submerged arc welding system which contains two subsystems is studied. The two subsystems are the submerged arc welding system with constant wire feed speed and the one with variable wire feed speed are construed.Linearization of the non-linear submerged arc welding models is carried. First, the common meatheads of linearization are analyzed and the accurate feedback linearization based on differential geometry is chosen. According to this meathead, the non-linear model of submerged arc welding is converted to linear model.The sliding model controller for submerged arc welding is designed. First, the theory of sliding model control is studied. Then, the sliding model controller is planed for the linear model, which is converted from the submerged arc welding with variable wire feed speed. And then, the simulation models are set up on the platform of the MATLAB. The results show that the designed controller can commendably achieve the requirement. In the case of disturbance, the length of arc recovers quickly.The control system on submerged arc welding with changeable characteristics is realized. First, the main circuit of arc welding power is studied and designed. The control circuit and wire feed system are also analyzed. Then, the software charts are shown and the arithmetic of sliding mode control is realized.