Active Vibration Avoidance Method for Variable Speed Welding in Robotic Friction Stir Welding Based on Constant Heat Input

• Published in: Materials Vol. 17; no. 11; p. 2593
• Main Authors: Zong, Guanchen, Kang, Cunfeng, Chen, Shujun
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 28.05.2024; MDPI
• Subjects: Active control; Alloys; Analysis; Avoidance; Control methods; Dynamic models; End effectors; Equilibrium equations; Friction stir welding; Industrial robots; Mechanical properties; Methods; Optimization; Robotics; Robotics industry; Robots; Sensors; Shipbuilding industry; Simulation methods; Systems stability; Vibration; Vibration analysis; Welding; China; robot dynamics; modal analysis; vibration analysis; vibration feedback; RFSW
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17112593

Robotic Friction Stir Welding (RFSW) technology integrates the advantages of friction stir welding and industrial robots, finding extensive applications and research in aerospace, shipbuilding, and new energy vehicles. However, the high-speed rotational process of friction stir welding combined with the low stiffness characteristics of serial industrial robots inevitably introduces vibrations during the welding process. This paper investigates the vibration patterns and impacts during the RFSW process and proposes an active vibration avoidance control method for variable speed welding based on constant heat input. This method utilizes a vibration feedback strategy that adjusts the spindle speed actively if the end-effector’s vibration exceeds a threshold, thereby avoiding the modal frequencies of the robot at its current pose. Concurrently, it calculates and adjusts the welding speed of the robot according to the thermal equilibrium equation to maintain constant heat input. A simplified dynamic model of the RFSW robot was established, and the feasibility of this method was validated through simulation experiments. This study fills the gap in vibration analysis of RFSW and provides new insights into control strategies and process optimization for robotic friction stir welding.