Analyzing achievable stiffness control bounds of robotic hands with coupled finger joints

The mechanical design of robotic hands has been converging towards low-inertia, tendon-driven strategies. As tendon driven robotic fingers are serial chain systems, routing strategies with compliant tendons lead to multi-articular coupling between the degrees of freedom. We propose a generalized analysis of such serial chain linkages with coupled passive joint stiffnesses. We analyze the effect of such coupling on maximum achievable stiffness control boundaries while maintaining passivity at the actuators by analytically deriving the boundaries. We believe that we can use this information to form mechanical design guidelines for intelligently selecting arrangements of compliance elements (mechanical springs) and transmission strategies, i.e. tendon routing and pulley radii, to provide intrinsic stability and customizable controller stiffness limits for high performance manipulation in robotic hands.

[1]  Alin Albu-Schäffer,et al.  The DLR hand arm system , 2011, 2011 IEEE International Conference on Robotics and Automation.

[2]  Alin Albu-Schäffer,et al.  Soft robotics: what Cartesian stiffness can obtain with passively compliant, uncoupled joints? , 2004, 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) (IEEE Cat. No.04CH37566).

[3]  Prashant Rao,et al.  Effect of Parallel Compliance on Stability of Robotic Hands With Series Elastic Actuators , 2015, HRI 2015.

[4]  Hiroaki Kobayashi,et al.  On Tendon-Driven Robotic Mechanisms with Redundant Tendons , 1998, Int. J. Robotics Res..

[5]  Martin Buss,et al.  Compliant actuation of rehabilitation robots , 2008, IEEE Robotics & Automation Magazine.

[6]  Nikolaos G. Tsagarakis,et al.  On the role of robot configuration in Cartesian stiffness control , 2015, 2015 IEEE International Conference on Robotics and Automation (ICRA).

[7]  E. Yaz.  Linear Matrix Inequalities In System And Control Theory , 1998, Proceedings of the IEEE.

[8]  André Seyfarth,et al.  A comparison of parallel- and series elastic elements in an actuator for mimicking human ankle joint in walking and running , 2012, 2012 IEEE International Conference on Robotics and Automation.

[9]  Robert Platt,et al.  Applied joint-space torque and stiffness control of tendon-driven fingers , 2010, 2010 10th IEEE-RAS International Conference on Humanoid Robots.

[10]  Manuel G. Catalano,et al.  Variable impedance actuators: A review , 2013, Robotics Auton. Syst..

[11]  Myron A. Diftler,et al.  The Robonaut 2 hand - designed to do work with tools , 2012, 2012 IEEE International Conference on Robotics and Automation.

[12]  H. Liu,et al.  DSP&FPGA-based joint impedance controller for DLR/HIT II dexterous robot hand , 2009, 2009 IEEE/ASME International Conference on Advanced Intelligent Mechatronics.

[13]  Neville Hogan,et al.  Impedance Control: An Approach to Manipulation , 1984, 1984 American Control Conference.

[14]  Robert D. Howe,et al.  The Highly Adaptive SDM Hand: Design and Performance Evaluation , 2010, Int. J. Robotics Res..

[15]  Robert O. Ambrose,et al.  Robonaut 2 - The first humanoid robot in space , 2011, 2011 IEEE International Conference on Robotics and Automation.

[16]  Antonio Bicchi,et al.  Hands for dexterous manipulation and robust grasping: a difficult road toward simplicity , 2000, IEEE Trans. Robotics Autom..

[17]  Gianluca Palli,et al.  Development of UB Hand 3: Early Results , 2005, Proceedings of the 2005 IEEE International Conference on Robotics and Automation.

[18]  Antonio Bicchi,et al.  Toward soft robots you can depend on , 2008, IEEE Robotics & Automation Magazine.

[19]  O. Boubaker,et al.  Stiffness and Impedance Control Using Lyapunov Theory for Robot-Aided Rehabilitation , 2012, Int. J. Soc. Robotics.

[20]  Prashant Rao,et al.  Compliance in parallel to actuators for improving stability of robotic hands during grasping and manipulation , 2015, Int. J. Robotics Res..

[21]  Matthew M. Williamson,et al.  Series elastic actuators , 1995, Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots.

[22]  Roland Siegwart,et al.  The hand of the DLR Hand Arm System: Designed for interaction , 2012, Int. J. Robotics Res..

[23]  Neville Hogan,et al.  Impedance Control: An Approach to Manipulation: Part I—Theory , 1985 .

[24]  Hong Liu,et al.  The HIT/DLR dexterous hand: work in progress , 2003, 2003 IEEE International Conference on Robotics and Automation (Cat. No.03CH37422).