Compliance control for stabilizing the humanoid on the changing slope based on terrain inclination estimation

This paper presents a stabilization framework integrated with the estimation of the terrain inclination to balance a humanoid on the changing slope as an extension to our previous study. In this paper, the estimation of the terrain inclination is improved for walking in place on an inclination-varying slope. A passivity based admittance control utilizes the force/torque sensing in feet to actively regulate the impedance at the center of mass to stabilize the robot. The logic-based inclination estimation algorithm uses the feet to probe the terrain and deals with the under-actuation. The equilibrium set-point in the admittance control is regulated based on the detected inclination. The effectiveness of the control framework is validated on the humanoid robot COMAN and demonstrated by estimating the terrain inclination, coping with the under-actuation phase, adapting to the slope with changing inclination during both standing and walking. Experimental data are analyzed and discussed, and the future work is suggested.

[1]  Gerd Hirzinger,et al.  Posture and balance control for biped robots based on contact force optimization , 2011, 2011 11th IEEE-RAS International Conference on Humanoid Robots.

[2]  Atsuo Takanishi,et al.  Walking Control Method of Biped Locomotors on Inclined Plane , 2005, Proceedings of the 2005 IEEE International Conference on Robotics and Automation.

[3]  L. Nashner,et al.  The organization of human postural movements: A formal basis and experimental synthesis , 1985, Behavioral and Brain Sciences.

[4]  F E Zajac,et al.  Ankle and hip postural strategies defined by joint torques. , 1999, Gait & posture.

[5]  Gordon Cheng,et al.  Full-Body Compliant Human–Humanoid Interaction: Balancing in the Presence of Unknown External Forces , 2007, IEEE Transactions on Robotics.

[6]  Benjamin J. Stephens.  Integral control of humanoid balance , 2007, 2007 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[7]  Atsuo Takanishi,et al.  Landing Pattern Modification Method with Predictive Attitude and Compliance Control to Deal with Uneven Terrain , 2006, 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[8]  Nikolaos G. Tsagarakis,et al.  Stabilizing humanoids on slopes using terrain inclination estimation , 2013, 2013 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[9]  Neville Hogan,et al.  Stable execution of contact tasks using impedance control , 1987, Proceedings. 1987 IEEE International Conference on Robotics and Automation.

[10]  Dragomir N. Nenchev,et al.  Ankle and hip strategies for balance recovery of a biped subjected to an impact , 2008, Robotica.

[11]  Alin Albu-Schäffer,et al.  A passivity based Cartesian impedance controller for flexible joint robots - part I: torque feedback and gravity compensation , 2004, IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004.

[12]  Alin Albu-Schäffer,et al.  Development of a biped robot with torque controlled joints , 2010, 2010 10th IEEE-RAS International Conference on Humanoid Robots.

[13]  Twan Koolen,et al.  Capturability-based analysis and control of legged locomotion, Part 1: Theory and application to three simple gait models , 2011, Int. J. Robotics Res..

[14]  Nikolaos G. Tsagarakis,et al.  The design of the lower body of the compliant humanoid robot “cCub” , 2011, 2011 IEEE International Conference on Robotics and Automation.

[15]  Alin Albu-Schäffer,et al.  A passivity based Cartesian impedance controller for flexible joint robots - part II: full state feedback, impedance design and experiments , 2004, IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004.

[16]  Gordon Cheng,et al.  Passivity-Based Full-Body Force Control for Humanoids and Application to Dynamic Balancing and Locomotion , 2006, 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[17]  Twan Koolen,et al.  Capturability-based analysis and control of legged locomotion, Part 2: Application to M2V2, a lower-body humanoid , 2012, Int. J. Robotics Res..

[18]  Nikolaos G. Tsagarakis,et al.  COMpliant huMANoid COMAN: Optimal joint stiffness tuning for modal frequency control , 2013, 2013 IEEE International Conference on Robotics and Automation.

[19]  Nikolaos G. Tsagarakis,et al.  Walking pattern generation for a humanoid robot with compliant joints , 2013, Auton. Robots.

[20]  Christopher G. Atkeson,et al.  Dynamic Balance Force Control for compliant humanoid robots , 2010, 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[21]  Jun-Ho Oh,et al.  Walking Control Algorithm of Biped Humanoid Robot on Uneven and Inclined Floor , 2007, J. Intell. Robotic Syst..

[22]  Christopher G. Atkeson,et al.  Push Recovery by stepping for humanoid robots with force controlled joints , 2010, 2010 10th IEEE-RAS International Conference on Humanoid Robots.

[23]  Nikolaos G. Tsagarakis,et al.  A passivity based admittance control for stabilizing the compliant humanoid COMAN , 2012, 2012 12th IEEE-RAS International Conference on Humanoid Robots (Humanoids 2012).