Papers by Author: Lin Wu

Abstract: Welding seam tracking precision is a key factor influencing welding quality for master-slave robot remote welding system. However, it does not satisfy the welding requirement due to significant noises. To eliminate the influence of noises upon the seam tracking precision and improve the seam tracking precision, a master-slave robot remote welding system was built and Kalman filtering (KF) was applied to the seam tracking process. The experimental results show that the KF eliminated the influence of noises upon the seam tracking precision and improved the seam tracking precision.

Abstract: 10mm-5A06 aluminum alloy was butt-welded in a single pass by the plasma-gas metal arc (plasma-MIG) welding procedure, the joints were subjected to X-ray inspection, the microstructure and mechanical performance of weld were also studied. The results indicate that plasma-MIG welding is superior to regular conventional MIG welding on the aspects of reducing weld porosity, increasing joint quality and improving deposition efficiency. Good weld joint with less porosity and excellent mechanical properties is obtained, which can reach as 92.62% tensile strength and 85.12% elongation percentage as base metal. Dimples in which the precipitated phase is the solid solution based on Al3Mg2 are observed in fracture scanning electron micrograph and the fracture mode is ductile rupture. α-Al and Al3Mg2 ,α-Al and eutectic structure are observed respectively in fusion area and in weld zone. The wire feed rate and melting rate can come to 14.5m/min and 80g/min respectively for the 1.6mm welding wire by the plasma-MIG welding process on the premise that the tensile strength of the joints meet the requirements.

Abstract: This paper presents a generic design and implementation of a telerobotic system application for the remote welding of unstructured and hazardous environment. The objective is to establish a remote welding telerobotic system that is flexibility to carry out welding seam tracing and welding remotely. According to the difference of welding task and environment, this paper presents human machine cooperative control strategies that integrate sensor and model-based computer assistance. The human operator decision and control commands participate into every control level of the teleoperation system. The specific control modes have been presented to integrate into human machine interface (HMI).

Abstract: In the near twenty years, with the rapid increase of Chinese economy, Chinese welding technology developed very fast. In 2003, the annual output of steel in China has reached 230 megatons and above 40 percent was manufactured by welding process. The main welding engineering projects include: the Three Gorges power station, bridges over the Changjiang River, high pressure heavy-duty chemical container, pipeline project of transferring natural gas from West to East and manned spacecraft etc. Meanwhile, Chinese annual output of welding materials exceeds 1,200 kilotons, welding equipments exceed 200,000 sets and the welding automation rate reached 40 percent. The State Key Laboratory of Advanced Welding Production Technology in Harbin Institute of Technology is the only welding laboratory of national level in China. It is the base of applied fundamental research and high quality welding technicians training. It has completed many projects of welding technology development and some significant applied engineering tasks. Every year, about 15-20 Doctors, 40-50 Masters and 70-100 Bachelors graduate from the Laboratory. Also, it is opened to the whole world.