Planar Manipulator with Mechanically Adjustable Joint Compliance
Hiroaki Seki, Yoshitsugu Kamiya, and Masatoshi Hikizu
School of Mechanical Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
A novel robot joint with mechanically adjustable compliance is presented. It utilizes a leaf spring and the joint compliance can be adjusted by rotating this spring, i.e., changing its bending direction. A joint actuatormoves an armlink via a connection that consists of a hollow cylinder and a leaf spring. This mechanism is compact to be installed in a joint and it can change the joint stiffness rapidly and stably. A planar manipulator using this joint mechanism is proposed for the contact or constraint tasks. Since four joints are necessary to obtain arbitrary stiffnesses and an arbitrary position of the end-effector in plane motion, a four DOF (degrees of freedom) manipulator with mechanically adjustable joint compliance is developed.
-  M. H. Ang and G. B. Andeen, “Specifying and Achieving Passive Compliance Based on Manipulator Structure,” IEEE Trans. Robotics and Automation, Vol.11, No.4, pp. 504-515, 1995.
-  G. A. Medrano-Cerda, C. J. Bowler, and D. G. Caldwell, “Adaptive Position control of Antagonistic Pneumatic Muscle Actuators,” Proc. of 1995 IEEE/RSJ Int. Conf. on Intelligent Robots and Systems, pp. 378-383, 1995.
-  D. Hyun, H. S. Yang, J. Park, and Y. Shim, “Variable stiffness mechanism for human-friendly robots,” Mechanism and Machine Theory, Vol.45, pp. 880-897, 2010.
-  R. Ghorbani and Q. Wu, “Adjustable stiffness artificial tendons: Conceptual design and energetics study in bipedal walking robots,” Mechanism and Machine Theory, Vol.44, pp. 140-161, 2009.
-  G. Tonietti, R. Schiavi, and A. Bicchi, “Design and Control of a Variable Stiffness Actuator for Safe and Fast Physical Human/Robot Interaction,” Proc. of 2005 IEEE Int. Conf. on Robotics and Automation, pp. 526-531, 2005.
-  R. V. Ham et al., “MACCEPA, the mechanically adjustable compliance and controllable equilibrium position actuator: Design and implementation in a biped robot,” Robotics and Autonomous Systems, Vol.55, pp. 761-768, 2007.
-  J. Oda, A. Wang, and N. Matsumoto, “Trial Formation of Variable-Stiffness Spring and Its Application to Displacement Control Problems,” J. of Japan Society of Mechanical Engineers Series C, Vol.59, pp. 2526-2531, 1993. (in Japanese)
-  T. Morita and S. Sugano, “Development of One-D.O.F. Robot Arm equipped with Mechanical Impedance Adjuster,” Proc. of 1995 IEEE/RSJ Int. Conf. on Intelligent Robots and Systems, pp. 407-412, 1995.
-  H. Seki et al., “Development of A Robot Joint Mechanism with Variable Compliance by Rotating A Leaf Spring,” Proc. of 2000 Japan-USA Flexible Automation Conf., CDROM, 2000.
-  M. Kaneko et al., “Direct Compliance Control of Manipulator Arms. Basic Concept and Application Examples,” Proc. of Symp. on Robot Control’88, 1988.