Antagonistic Impedance Control for Pneumatically Actuated Robot Joints

This letter presents a novel joint torque-based impedance controller for antagonistically driven flexible joints actuated by pneumatic cylinders and compares it with the current state of the art. The work targets on transferring soft-robotics control concepts from classical motor-gear-torque sensor setups to pneumatic systems, with the goal of achieving similar performance levels in comparison to this well established technology. A detailed flexible joint model is derived that incorporates the pneumatic and mechanical dynamics of the proposed antagonistic design. This model is used for analyzing model-based control approaches, which in turn are based on reduced order dynamics. The tendon-based joint level impedance controller enables the simultaneous adjustment of closed-loop stiffness and damping. The proposed scheme shows good simulation results for both, position tracking and compliance performance, respectively. Experimentally, an angular position tracking of 7 Hz could be achieved. Also, stable rigid contacts could be established at considerable impact speed.

[1]  Thomas Wimböck.  Controllers for Compliant Two-Handed Dexterous Manipulation , 2013 .

[2]  Jeffrey K. Uhlmann,et al.  Unscented filtering and nonlinear estimation , 2004, Proceedings of the IEEE.

[3]  Behzad Taheri,et al.  Force and Stiffness Backstepping-Sliding Mode Controller for Pneumatic Cylinders , 2014, IEEE/ASME Transactions on Mechatronics.

[4]  Xiangrong Shen,et al.  Simultaneous Force and Stiffness Control of a Pneumatic Actuator , 2007 .

[5]  Toshiro Noritsugu,et al.  Application of rubber artificial muscle manipulator as a rehabilitation robot , 1996, Proceedings 5th IEEE International Workshop on Robot and Human Communication. RO-MAN'96 TSUKUBA.

[6]  Yildirim Hurmuzlu,et al.  A High Performance Pneumatic Force Actuator System: Part II—Nonlinear Controller Design , 2000 .

[7]  Oussama Khatib,et al.  Air muscle controller design in the distributed macro-mini (DM2) actuation approach , 2007, 2007 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[8]  John J. Craig,et al.  A systematic method of hybrid position/force control of a manipulator , 1979, COMPSAC.

[9]  Jun Morimoto,et al.  Torque and variable stiffness control for antagonistically driven pneumatic muscle actuators via a stable force feedback controller , 2015, 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS).

[10]  Richard M. Murray,et al.  A Mathematical Introduction to Robotic Manipulation , 1994 .

[11]  Brian Birge,et al.  PSOt - a particle swarm optimization toolbox for use with Matlab , 2003, Proceedings of the 2003 IEEE Swarm Intelligence Symposium. SIS'03 (Cat. No.03EX706).

[12]  Yildirim Hurmuzlu,et al.  A High Performance Pneumatic Force Actuator System: Part I—Nonlinear Mathematical Model , 2000 .

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

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

[15]  Emanuel Todorov,et al.  Design and analysis of an artificial finger joint for anthropomorphic robotic hands , 2011, 2011 IEEE International Conference on Robotics and Automation.

[16]  Farid Najafi,et al.  Stability and performance of pneumatic actuators in impedance control , 2014, J. Syst. Control. Eng..

[17]  J. Salisbury,et al.  Active stiffness control of a manipulator in cartesian coordinates , 1980, 1980 19th IEEE Conference on Decision and Control including the Symposium on Adaptive Processes.

[18]  Daniel E. Whitney,et al.  Quasi-Static Assembly of Compliantly Supported Rigid Parts , 1982 .

[19]  Yong Zhu,et al.  Impedance Control of a Pneumatic Actuator for Contact Tasks , 2005, Proceedings of the 2005 IEEE International Conference on Robotics and Automation.

[20]  M. James,et al.  The generalised inverse , 1978, The Mathematical Gazette.

[21]  Nikolaos G. Tsagarakis,et al.  Antagonistically actuated compliant joint: Torque and stiffness control , 2010, 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[22]  Christian Ott,et al.  Cartesian Impedance Control of Redundant and Flexible-Joint Robots , 2008, Springer Tracts in Advanced Robotics.

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

[24]  Gianluca Palli,et al.  Modeling, Identification, and Control of Tendon-Based Actuation Systems , 2012, IEEE Transactions on Robotics.