1. Key Lab for Robot and Welding Automation of Jiangxi Province, Mechanical and Electrical Engineering School; Nanchang University; Nanchang 330031 China
2. Department of Mechanical Engineering, College of Engineering; University of Kentucky; Lexington KY 40506 USA
3. State Key Laboratory of Advanced Welding and Joining; Harbin Institute of Technology; Harbin 150001 China