An Experimental Robot Load Identification Method for Industrial Application

In this paper, we discuss a new experimental robot load identification method that is used in industry. The method is based on periodic robot excitation and the maximum likelihood estimation of the parameters, techniques adopted from Swevers et al. (1997 IEEE Transactions on Robotics and Automation 13(5):730—740). This method provides: (1) accurate estimates of the robot load inertial parameters; and (2) accurate actuator torque predictions. These are both essential for the acceptance of the results in an industrial environment. The key element to the success of this method is the comprehensiveness of the applied model, which includes, besides the dynamics resulting from the robot load and motor inertia, the coupling between the actuator torques, the mechanical losses in the motors and the efficiency of the transmissions. Accurate estimates of the robot link and motor inertial parameters, which can be considered identical for all robots of the same type, are obtained from separate experiments (see Swevers et al.), and used as a priori knowledge for the robot load identification. We present experimental results on a KUKA industrial robot equipped with a calibrated test load.

[1]  Christopher G. Atkeson,et al.  Estimation of Inertial Parameters of Manipulator Loads and Links , 1986 .

[2]  Rik Pintelon,et al.  Identification of Linear Systems: A Practical Guideline to Accurate Modeling , 1991 .

[3]  Michael W. Walker,et al.  Basis sets for manipulator inertial parameters , 1989, Proceedings, 1989 International Conference on Robotics and Automation.

[4]  Koichi Osuka,et al.  Base parameters of manipulator dynamic models , 1990, IEEE Trans. Robotics Autom..

[5]  Ralf Koeppe,et al.  Advances in Robotics: The DLR Experience , 1999, Int. J. Robotics Res..

[6]  Krzysztof Kozlowski,et al.  Experimental Identification of Robot and Load Dynamics , 1996 .

[7]  Jan Swevers,et al.  An integrated friction model structure with improved presliding behavior for accurate friction compensation , 1998, IEEE Trans. Autom. Control..

[8]  Josef Hölzl.  Modellierung, Identifikation und Simulation der Dynamik von Industrierobotern , 1993 .

[9]  Wisama Khalil,et al.  Direct calculation of minimum set of inertial parameters of serial robots , 1990, IEEE Trans. Robotics Autom..

[10]  Krzysztof Kozłowski,et al.  Modelling and Identification in Robotics , 1998 .

[11]  Wisama Khalil,et al.  Identification of the dynamic parameters of a closed loop robot , 1995, Proceedings of 1995 IEEE International Conference on Robotics and Automation.

[12]  Jean-Claude Samin,et al.  Minimal Parametrization of Robot Dynamic Models , 1994 .

[13]  Jean-Claude Samin,et al.  Linearity of Multibody Systems with Respect to Barycentric Parameters: Dynamics and Identification Models Obtained by Symbolic Generation , 1989 .

[14]  Brian Armstrong,et al.  On Finding Exciting Trajectories for Identification Experiments Involving Systems with Nonlinear Dynamics , 1989, Int. J. Robotics Res..

[15]  M. Gautier.  Numerical calculation of the base inertial parameters of robots , 1991, J. Field Robotics.

[16]  Mark W. Spong,et al.  Robot dynamics and control , 1989 .

[17]  Fouad Bennis,et al.  Comments on "Direct calculation of minimum set of inertial parameters of serial robots" , 1994, IEEE Trans. Robotics Autom..

[18]  Jean-Claude Samin,et al.  Minimal dynamic characterization of tree-like multibody systems , 1996 .

[19]  George A. Bekey,et al.  Identification of robot dynamics , 1986, Proceedings. 1986 IEEE International Conference on Robotics and Automation.

[20]  Maxime Gautier,et al.  New criteria of exciting trajectories for robot identification , 1993, [1993] Proceedings IEEE International Conference on Robotics and Automation.

[21]  Yoshisada Murotsu,et al.  Parameter identification of unknown object handled by free-flying space robot , 1994 .

[22]  J. Wittenburg,et al.  Dynamics of systems of rigid bodies , 1977 .

[23]  Phillip J. McKerrow,et al.  Introduction to robotics , 1991 .

[24]  Jan Swevers,et al.  Optimal robot excitation and identification , 1997, IEEE Trans. Robotics Autom..

[25]  Roger Fletcher,et al.  Practical methods of optimization; (2nd ed.) , 1987 .

[26]  Vincent Hayward,et al.  A New Computational Structure For Real-Time Dynamics , 1992 .

[27]  Wei Huo.  New formulas for complete determining base parameters of robots , 1995, Proceedings of 1995 IEEE International Conference on Robotics and Automation.

[28]  M. Gautier,et al.  Exciting Trajectories for the Identification of Base Inertial Parameters of Robots , 1991, [1991] Proceedings of the 30th IEEE Conference on Decision and Control.