Seam tracking control for weld cladding of boiler tubes in thermal power plants

Welding distortions, assembly errors, and deviation correction between the welding torch and weld beads play a significant role in the automatic welding system of the boiler tube wall cladding. As a result, this paper proposes a seam tracking system comprised of two parts: a contact displacement sensor for data acquisition and an adaptive neuro-fuzzy inference system (ANFIS) controller along with the backpropagation (BP) algorithm for controlling the position and posture of the welding torch. The results showed that the proposed ANFIS controller achieves a faster rise time of up to 0.06 s, settling time of about 0.1 s, overshooting up to 1.5%, and amplitude stability with the lowest training error up to 2 × 10−4 mm. In contrast, the fuzzy logic controller achieves a rise time of up to 0.075 s, a settling time of around 0.3 s, and a 0.5% overshoot. Also, the proportional–integral–derivative (PID) controller executes a lower rise time of up to 0.035 s, a settling time of about 0.25 s, and an overshoot of up to 9.34%. According to the results, the ANFIS controller performs better than the PID and fuzzy logic controllers. Thus, the proposed system offers a much-improved functionality in terms of flexibility, consistency, and cladding layer surface finish of the treated components. It fully meets the requirements of the welding torch control motion for seam tracking. It can also be used to create automatic seam tracking systems for other types of surface treatment.