Abstract:When a robot operates at high speed,the deflection of its end-effector due to joint elasticity will affect the tracking precision of the robot.Redundant robots with elastic joints are considered study objects in this paper. The effects of redundancy resolution on joint elastic deflection of robots are researched. First,a redundancy resolution method called constant weight factor method is proposed by using joint elastic deflection as a performance index. And then based on this method,two improved methods, variable weight factor method and exchange method ,are presented further.The former uses a variable weight factor to automatically adjust angular acceleration′s influence on general objective function; the latter uses a threshold function to realize the exchange between two different resolution methods. At the same time, a necessary condition for the two improved methods to obtain optimal solutions is also given.Finally, a planar 3R redundant robot is used to make a simulation research, and comparisons among the three methods are also made .Study results show that the two improved methods have a good global characteristic.
1 Liegeois A.Automatic Supervisiory Control of the Configuration and Behavior of Multibody Mechanisms.IEEE Trans Syst Man Cyber n,1977,7:88~91 2 Yoshikawa T.Analysis and Control of Robot Man ipulators with Redundancy.The First International Symp,on Robotics Research,1984:735~747 3 Hollerb ach J M,Suh K C.Redundancy Resolution of Manipulator Through Torque Optimization.IEEE J of Robotics and Automation,1987,3:308~316 4 Kazerounian K,Nedungadi A.An Alternative Method for Minimization of the Driving Forces in Redundant Manipulators.Proc of IEEE Int Conf Robotics and Automation,1987:1701~1706 5 赵京.冗余度机器手的一种新的控制策略.机器人,1993,15:40~43 6 Berger R M,Elemaraghy H A.Feedback Linearization Control of Flexible Joint Robots.Robotics & Computer-integrated Manufacturing,1993,9:239~246 7 Pfeffer L E,Khatib O,Hake J.Joint Torque Sensory Feedback in the Control of a PUMA Manipulator.IEEE Journal of Robotics Automation,1989,RA-5,:418~425 8 Spong M W.Modeling and Control of Elastic Joint Robots.Trans A SM E J Dyna Syst Meas Contr,1987,109:310~319 9 Jankowski K P,V an Brussel H.Inverse Dynamics Task Control of Flexible Joint Robots-Ⅰ.Mech Mach Theory,1993,28:741~749 10 Korayem M H,Basu A.Dynamic Load Carrying Capacity of Robotic Manipulators with Joint Elasticity Imposing Accuracy Constrain ts.R obot ics and Autonomous Systems,1994,13:219~229 11 Ghosal A,Desa S.Dynamical Resolution of Redundancy for Robot Manipulators Trans.AS M E J Mechanical Design,1993,115:589~598 12 Chan T F,Dubey R V.A Weighted Least-norm Solution Based Scheme for A voiding Joint Limits for Red undant Manipulators.IEEE Int Conf on Robotics and Automation,1993:395~402 13 赵京.冗余度机器手的一种新的控制策略.机器人,1993,15:40~43 14 赵京.冗余度机械手逆运动学问题的次优准则混合法.机械科学与技术,1996,6(64) 15 Jankowski K P,V an Brussel H.In verse Dynamics Task Control of Flexible Joint Robots-Ⅰ.Mech Mach Theory,1993,28:741~749 16 Spong M W.Modeling and Control of Elastic Joint Robots.Trans ASM E J Dyna Syst Meas Contr,1987,109:310~319