Abstract
A planar three degree-of-freedom parallel manipulator has been extensively studied as the fundamental example of general parallel manipulators. It is proven from previous work (Kim, et. al., 1996) that when three identical joint compliances are attached to the three base joints of the mechanism in its symmetric configurations, this mechanism possesses a completely decoupled compliance characteristic at the object space, which is the important operational requirement for an RCC device. In this work, we are concerned with the adjustability of the output compliance matrix of this mechanism, by employing redundancy on either joint compliances or on actuators. Two approaches are suggested to achieve this purpose. In the first approach, the stiffness modulation is achieved through purely redundant passive springs or decoupled feedback stiffness gains. In the second approach, stiffness modulation is achieved through antagonistic actuation of the system actuators. General stiffness models are derived for both cases. Based on these stiffness models, stiffness modulation algorithms are formulated. The capability of actively adjustable stiffness will be very effective in several robotic applications.
Similar content being viewed by others
References
Brussel, H. V., Thielemans, H. and Simons, J., 1986, “Further Developments of the Active Adaptive Compliant Wrist (AACW) for Robot Assembly,”Proc. Int’l Symp. on Industrial Robots, SME, pp. 377–384.
Cutkosky, M. R. and Kao, I., 1989, “Computing and Controlling the Compliance of a Robotic Hand,”IEEE Transaction. of Robotics and Automation, Vol. 5, No. 2, pp. 151–165.
Freeman, R. A. and Tesar, D., 1988, “Dynamic Modeling of Serial and Parallel Mechanisms/ Robotic Systems, Part I-Methodology, Part II Applications,”Proceedings of 20th ASME Mechanisms Conference, Orlando, FL.
Kang, H. J., Yi, B. J., Cho, W. and Freeman, R. A., 1990, “Constraint-embedding Approaches for General Closed-Chain System Dynamics in Terms of A Minimum Coordinate Set,”Proc. of 1990 ASME Mechanism/Design Conf., DE Vol. 24, pp. 125–132.
Kim, W. K., Lee, J. Y. and Yi, B. J., 1996, “RCC Characteristics of Planar/Spherical 3 Degree of-Freedom Parallel Mechanisms with Joint Compliances,”’96 IROS, Osaka, Japan.
Kim, W. K., Lee, J. Y. and Yi, B. J., 1996, “Analysis of a Planar 3 Degree-of-Freedom Adjustable Compliance Mechanism,”KSME Journal, Vol. 10, No. 3.
McCallion, H., Alexander, K. V. and Pham. D T., 1980, “Aid for Automatic Assembly,”1st Int’ l Conf. on Assembly Automation, pp. 313–323.
Peshkin, M. A., 1990, “Programmed Compliance for Error Corrective Assembly,”IEEE Trans. on Robotics and Automation, Vol. 6, No. 4, pp. 474–482.
Whitney, D. E., 1986, “Remote Center Compliance,” inEncyclopedia of Robotics System and Control,” Vol. 2, pp. 1316–1324, edited by J. J. Diponio and Y. Hasegawa, published by Industrial Training Corporation.
Yi, B. J. and Freeman, R. A., 1993, “Geometric Analysis of Antagonistic Stiffness in Redundantly Actuated Parallel Mechanisms,”Journal of Robotic Systems, Vol. 10, No. 5, pp. 581–603.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kim, WK., Lee, JY. & Yi, B.J. Analysis for a planar 3 degree-of-freedom parallel mechanism with actively adjustable stiffness characteristics. KSME International Journal 11, 408–418 (1997). https://doi.org/10.1007/BF02945079
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02945079