Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-25T04:42:20.139Z Has data issue: false hasContentIssue false

Accuracy improvement: Modeling of elastic deflections

Published online by Cambridge University Press:  09 March 2009

Junjie Yao
Affiliation:
Department of Production Engineering, Chalmers University of Technology, S-412 96 Gothenburg (Sweden)

Summary

Actual positions of industrial robot end-effectors differ from those commanded off-line. Consequently, it is then difficult for robots to fulfill certain tasks, such as automated assembly sequences or tasks where high performance accuracy is required. This paper shows that the accuracy of robot performance can be improved by introducing deviation matrices which are functions of many possible error sources. As a first approach, an experiment was carried out where structural elastic deflections, one of the many error sources, of a robot ASEA Irb 6/2 were taken into account. The experiment showed that using the improved model, the positioning accuracy of an ASEA Irb 6/2 robot carrying a weight of 5.6kg was improved from 2.5mm to 0.25mm and the orientation accuracy was improved from 0·45° to 0·3°.

Type
Article
Copyright
Copyright © Cambridge University Press 1991

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1.Kafrissen, E., Industrial robots and Robotics (Reston Publishing Company, Inc., Reston, Virginia, 1984).Google Scholar
2.Yao, J.J.Solution of Absolute Positions and Orientations of a Robot End-Effector by RemodelingJ. Robotics and Autonomous Systems 5, 191195 (1989).CrossRefGoogle Scholar
3.Yao, J.J. On improving Robot Positioning Accuracy (Thesis for Licentiate Degree, Chalmers University of Technology, Gothenburg, Sweden, 1989).Google Scholar
4.Day, C.P.Robot Accuracy Issues and Methods of ImprovementSME Robotics Today 1, No. 1, 19 (1988).Google Scholar
5.Ramsli, E., Industrial Robot – Performance Criteria and Testing Methods (Ph.D Dissertation, the Norwegian Institute of Technology, Trondheim, Norway, 1988).Google Scholar
6.Koren, Y., Robotics for Engineers (McGraw-Hill, New York, 1985).Google Scholar
7.Whitney, D.E., Lozinski, C.A. & Rourke, J.M.Industrial Robot Forward Calibration Method and ResultsJ. Dynamic Systems, Measurement, and Control, Trans. ASME 108, 18 (1986).Google Scholar
8.Everett, L.J., Oriels, M. & Mooring, B.W. “Kinematic Modeling for Robot Calibration” Proc. of IEEE International Conference on Robotics and Automation183189 (1987).Google Scholar
9.Bowes, W.H., Russell, L.T. & Suter, G.T.Mechanics of Engineering Materials (John Wiley & Sons, Inc., New York, 1984).Google Scholar
10.Craig, J., Introduction to Robotics: Mechanics & Control (Addison Wesley Publishing Company, Reading, MA, 1986).Google Scholar
11.Paul, R.P.Robot Manipulators: Mathematics, Programming, and Control (The MIT Press, Cambridge, Massachusetts, 1981).Google Scholar
12.Andersson, S., Tre Projekt Utförda av Maskinelement HK 1987–88 (in Swedish) (Department of Machine Elements, KTH, Sweden, 1988).Google Scholar