Gao Yanfeng

Predictive fuzzy control for a mobile welding robot seam tracking

For the curved weld seam tracking problem of wheeled welding mobile robot used in shipbuilding and large spherical tank welding, predictive fuzzy control method was proposed in this paper. To overcome the disadvantage of rotational arc sensor can not detect the next seam position, the algorithm employed weighted least square fitting method to predict the weld seam next position and used linearization model to predict the robot next orientation and position. In addition, fuzzy control was adopted to deal with nonlinear characteristic of the system. The main advantages of this predictive fuzzy controller include small tracking error, small robot orientation delay angle, and the availability of a linearized predictive model that reduce the computing complexity, and the highly tracking quality. In experiments, we applied this control method to tracking curved fillet weld seams and compared with a traditional fuzzy controller. The experiment results demonstrated that the feasibility and advantages of this predictive fuzzy control on the curve weld seam tracking.

Stable tracking control of autonomous welding mobile robots based on kinematics model

This paper proposes a stable tracking control law for mobile platform and welding torch of Autonomous Welding Mobile Robot used in shipbuilding and large spherical tank welding. Stability of the law is proved through the use of a Liapunov function. Not only the moving and rotating velocity of the robot is controlled, but also the moving velocity of the cross slider is controlled. In the simulation, we analyze the effects of different control parameters in line tracking problem. And the tracking response in circle-line tracking problem is also presented. It is shown that the output responses represent non-oscillatory property and effectiveness of the tracking law.