Estimation of Inertial Parameters of Manipulator Loads and Links

Abstract

The inertial parameters of manipulator rigid-body loads and links have been automatically estimated as a result of gen eral movement. The Newton-Euler equations have been recast to relate linearly the measured joint forces or torques via acceleration-dependent coefficients to the inertial parame ters, which have then been estimated by least squares. Load estimation was implemented on a PUMA 600 robot equipped with an R TI FS-B wrist force-torque sensor and on the MIT Serial Link Direct Drive Arm equipped with a Barry Wright Company Astek wrist force-torque sensor. Good estimates were obtained for load mass and center of mass, and the forces and torques due to movement of the load could be pre dicted accurately. The load moments of inertia were more difficult to estimate. Link estimation was implemented on the MIT Serial Link Direct Drive Arm. A good match was ob tained between joint torques predicted from the estimated parameters and the joint torques estimated from motor cur rents. The match actually proved superior to predicted torques based on link inertial parameters derived by CAD modeling. Restrictions on the identifiability of link inertial parameters due to restricted sensing and movement near the base have been addressed. Implications of estimation accu racy for manipulator dynamics and control have been consid ered.

Get full access to this article

View all access options for this article.

References

An, C.H. , Atkeson, C.G. , and Hollerbach, J.M. 1985 (Dec. 11-13, Fort Lauderdale ). Estimation of inertial parameters of rigid-body links of manipulators. Proc. 24th IEEE Conf. Decision and Contr., pp. 990-995.

Asada, H. , and Youcef-Toumi, K. 1984. Analysis and design of a direct-drive arm with a five-bar-link parallel drive mechanism. ASME J. Dyn. Sys., Meas., Contr. 106:225- 230.

Asada, H. , Youcef-Toumi, K. , and Lim, S.K. 1984 (Dec. 12-14, Las Vegas). Joint torque measurement of a direct-drive arm. Proc. 23rd IEEE Conf. Decision and Contr., pp. 1332-1337.

Atkeson, C.G. , An, C.H. , and Hollerbach, J.M. 1985a (October 7-11, Gouvieux [ Chantilly], France). Estimation of inertial parameters of manipulator loads and links. Preprints of 3rd Int. Symp. Robotics Res., pp. 32-39.

Atkeson, C.G. , An, C.H. , and Hollerbach, J.M. 1985b (Dec. 11-13, Fort Lauderdale ). Rigid-body load identification for manipulators. Proc. 24th Conf. Decision and Contr., pp. 996-1002.

Coiffet, P. 1983. Robot technology: interaction with the environment , vol. 2. Englewood Cliffs, N.J.: Prentice-Hall.

Gelb, A. , ed. 1974. Applied optimal estimation. Cambridge: MIT Press .

Gilbert, E.G. , and Ha, I.J. 1984. An approach to nonlinear feedback control with applications to robotics. IEEE Trans. Sys., Man, Cyber. SMC-14:879-884.

Golub, G.H. , and Van Loan, C.F. 1983. Matrix computations. Baltimore : Johns Hopkins University Press.

10.

Hollerbach, J.M. , and Sahar, G. 1983. Wrist-partitioned inverse kinematic accelerations and manipulator dynamics. Int. J. Robotics Res. 2(4):61-76.

11.

Lawson, C.L. , and Hanson, R.J. 1974. Solving least-squares problems. Englewood Cliffs, N.J.: Prentice-Hall.

12.

Lee, K. 1983 (Dec.). Shape optimization of assemblies using geometric properties. Ph.D. thesis, Massachusetts Institute of Technology , Mechanical Engineering Department.

13.

Ljung, L. , and Soderstrom, T. 1983. Theory and practice of recursive identification . Cambridge: MIT Press.

14.

Luh, J.Y.S. , Walker, M.W. , and Paul, R.P. 1980a. On-line computational scheme for mechanical manipulators . J. Dyn. Sys., Meas., Contr. 102:69-76.

15.

Luh, J.Y.S. , Walker, M.W. , and Paul, R.P. 1980b. Resolved-acceleration control of mechanical manipulators . IEEE Trans. Auto. Contr. AC-25:468-474.

16.

Marquardt, D.W. , and Snee, R.D. 1975. Ridge regression in practice. Amer. Statistician 29:3-20.

17.

Mathlab Group. 1983. MACSYMA Reference Manual. Version 10. Cambridge, Mass.: Massachusetts Institute of Technology, Laboratory for Computer Science.

18.

Mayeda, H. , Osuka, K. , and Kangawa, A. 1984 (July 2-6, Budapest). A new identification method for serial manipulator arms. Preprints IFAC 9th World Congress, Vol. VI, pp. 74-79.

19.

Mukerjee, A. 1984 (Nov., Cambridge, Mass.). Adaptation in biological sensory-motor systems: a model for robotic control . Proc. SPIE Conf. on Intelligent Robots and Computer Vision, Vol. 521. Cambridge, Mass.

20.

Mukerjee, A. , and Ballard, D.H. 1985 (Mar. 25-28, St. Louis). Self-calibration in robot manipulators. Proc. IEEE Conf. Robotics and Automation pp. 1050-1057.

21.

Neuman, C.P. , and Khosia, P.K. 1985 (May 29-31, New Haven). Identification of robot dynamics: an application of recursive estimation. Proc. 4th Yale Workshop on Applications of Adaptive Sys. Theory , pp. 42-49.

22.

Olsen, H.B. , and Bekey, G.A. 1985 (Mar. 25-28, St. Louis). Identification of parameters in models of robots with rotary joints. Proc. IEEE Conf. Robotics and Automation, pp. 1045-1050.

23.

Paul, R.P. 1981. Robot manipulators: mathematics, programming, and control . Cambridge: MIT Press.

24.

Samson, C. 1983 (Dec. 14-16, San Antonio). Robust nonlinear control of robotic manipulators. Proc. 22nd IEEE Conf. Decision and Contr.

25.

Slotine, J.-J.E. 1985. The robust control of robot manipulators. Int. J. Robotics Res. 4(2):49-64.

26.

Spong, M.W. , Thorp, J.S. , and Kleinwaks, J.M. 1984 (Dec. 12-14, Las Vegas). The control of robot manipulators with bounded input. Part II: robustness and disturbance rejection. Proc. 23rd IEEE Conf. Decision and Contr ., pp. 1047-1052.

27.

Symon, K.R. 1971. Mechanics. Reading, Mass.: Addison-Wesley.

28.

Whitney, D.E. , Lozinski, C.A. , and Rourke, J.M. 1984. Industrial robot calibration method and results. CSDL-P-1879 Cambridge, Mass.: Charles Stark Draper Laboratory.