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Compliance Control of a 6-tink Electro-Hydraulic Manipulator

6축 전기 유압 매니퓰레이터의 컴플라이언스 제어

  • 안경관 (울산대학교 기계자동차공학과) ;
  • 표성만 (울산대학교 기계자동차공학과)
  • Published : 2004.01.01

Abstract

An electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is quite difficult to obtain stable control performance. We have applied a disturbance estimation and compensation type robust control to all the axes in a 6-link electro-hydraulic manipulator. It was confirmed that the performance of trajectory tracking and attitude regulating was greatly improved by the disturbance observer. For autonomous assembly tasks, it is said that compliance control is one of the most popular methods in contact task. We have proposed a compliance control based on the position control by a disturbance observer for our manipulator system. To realize more stable contact work, the states in the compliance loop are feedbacked, where not only displacement but also the velocity and acceleration are considered. We have also applied this compliance control to the Peg-in-Hole insertion task and proposed new methods of (1)rotating of the end-effector periodically in order to reduce the friction force, (2)random searching for the center of a hole and (3)trajectory modification to reduce the impact force. As a result of these new methods, it could be experimentally confirmed that the Peg-in-Hole insertion task with a clearance of 0.007 [mm] could be achieved.

References

  1. S. Yokota, M. Mitsuhashi, T. Toratani and T. Yamamoto, 'Control of electro-hydraulic manipulators for electric distributed power line tasks using a distribance observer', Journal of Japan Hydraulics & Pneumatics Society, vol. 25, no. 6, pp. 746-752, 1994 https://doi.org/10.5739/jfps1970.25.746
  2. T. Yamamoto, S. Yokota and Y. Tamura, 'Control of electro-hydraulic manipulators for overhead distribution line work', Journal of Japan Hydraulics & Pneumatics Society, vol. 26, no. 7, pp. 896-902, 1995 https://doi.org/10.5739/jfps1970.26.896
  3. S.Y okota, J. Shinogara, K. K. Ahn and T. Yamamoto, 'Compliance control of a 3-link electro-hydraulic manipulator', Journal of Japan Hydraulics & Pneumatics Society, vol.29, no.1, pp. 23-29, 1998
  4. N. Hogan, 'Impedance control: an approach to manipulation part2 - implementation', Trans. of ASME, Journal of DSMC, vol.107, pp. 8-16, 1985
  5. Whitney, 'Quasi-static assembly of compliantly supported rigid parts', Trans. of ASME, Journal of DSMC, vol. 104, pp. 66-77, 1982