Prof. Xinjun LIU

Tsinghua University, China

Topic

Key Technology Innovation and Application of Robots

Abstract

    Recent years, robots number has been increased dramatically in China. However, the market share of domestic robot is not high, no more than 10 percent. So, the key technology innovation is very important for the developing of domestic robots.
    As the key point, the presentation will introduce three key issues, i.e. type synthesis, performance evaluation and dimension optimization of the design for a parallel mechanism. A type synthesis method based on Grassmann line geometry and line-graph will be presented. Some parallel mechanisms that are designed with the method will be shown. Performance of a parallel mechanism depends on not only dimension but pose as well, and there is no global stability. Since the LCI which is used in some papers has no definite physical significance and it cannot effectively evaluate the performance of a parallel mechanism, a performance index LTI is proposed to evaluate the motion/force transmissibility. The LTI is frame free and has definite physical significance. By using the index, performance comparison between different types of parallel mechanisms is possible. Parameter size determines the performance of a mechanism. It can change from 0 to infinite and parameter can be in different dimensions. The key problem of dimension optimization is revealing the relationship between an index and parameters. So, in this presentation, a performance chart and optimum region based optimization method is introduced. The method has some advantages, such as an index corresponding to one chart, optimization with multiple indices being impossible, the solution selection being flexible. Finally, the innovation and application for three types of robots will be introduced. They are the high-speed parallel robot and its system, the mobile machining robot, and the multi-function moving robot.

Biography

    Dr. Liu is a full professor with tenure in Department of Mechanical Engineering at Tsinghua University, Beijing, China. He is the "Cheung Kong" Chair Professor of Ministry of Education of the People's Republic of China, and the winner of National Outstanding Youth Fund of China. Prof. Xin-Jun Liu received his Ph.D. degree in Mechanical Design and Theory from Yanshan University, Qinhuangdao, China, in 1999, the M.S. and B.S. degrees in Machine Design and Manufacture and Mechanics from Northeast Heavy Machinery Institute in 1994 and 1995, respectively. He was a Visiting Researcher at Seoul National University, Seoul, Korea in 2002-2003. He was the Alexander von Humboldt (AvH) Research Fellow at University of Stuttgart in Germany from 2004 to 2005. He was the visiting professor with Prof. Ilian Bonev in Department of Automated Manufacturing Engineering at École de technologie supérieure, Canada from July to August, 2006. He was the visiting professor with Prof. Dr. Reimund Neugebauer at Fraunhofer Institute for Machine Tools and Forming Technology, Germany, in August of 2007. Prof. Liu has published over 140 papers in refereed journals and refereed conference proceedings, 46 authorized patents, and two books. His research interests include parallel mechanisms, parallel kinematic machines, machining robots, moving robots, and roboticized equipments. He is now the associate editor of international journal “Mechanism and Machine Theory”, a member of the editorial board of “Frontiers of Mechanical Engineering”, and the director of Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control, Tsinghua University.