Contact Force/Torque Control Based on Viscoelastic Model for Stable Bipedal Walking on Indefinite Uneven Terrain

Humanoid robots are being designed to perform tasks currently carried out by human workers in industry, manufacturing, service, and disaster assistance. To this end, the humanoid robot should be able to walk stably across many types of terrain. However, when traversing a complex unknown environment, it is difficult to realize accurate terrain perception immediately through large data collected by the sensor system, leading to a difference between planned foot landing positions and actual foot landing positions. As a result, an unexpected contact force/torque may affect the stability of the robot. This paper adopts active contact perception instead of terrain perception and proposes a contact force/torque control method based on the viscoelastic model to address this problem. In addition, we design a body stability controller based on tracking the trajectories of the virtual repellent point (VRP) and the divergent component of motion (DCM) to restrain the disturbance caused by the unexpected contact force/torque. Simulations and experiments on the BHR-6P humanoid robot platform demonstrate the proposed contact force/torque control method for walking on indefinite uneven terrain. Note to Practitioners—This paper presents a contact force/torque controller based on a viscoelastic model, which unifies contact perception and adaptive reaction. Using the viscoelastic model, we get the relationship between the end position/posture and the first-order differential of the contact force/torque, from which a state equation can be established and used to design a state feedback controller. Combining with body stabilization, we adopt this controller to modify the trajectory of both landing and support feet simultaneously for humanoid robots to realize stable bipedal walking on indefinite uneven terrain, which is validated in both simulations and experiments on the BHR-6P humanoid robot. In addition, this method can be employed for other robots or equipment when the contact force/torque control is needed; e.g., industry manipulators and quadruped robots.

[1]  Christian Ott,et al.  Unified Impedance and Admittance Control , 2010, 2010 IEEE International Conference on Robotics and Automation.

[2]  Qiang Huang,et al.  Disturbance Rejection for Biped Walking Using Zero-Moment Point Variation Based on Body Acceleration , 2019, IEEE Transactions on Industrial Informatics.

[3]  Russ Tedrake,et al.  Planning robust walking motion on uneven terrain via convex optimization , 2016, 2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids).

[4]  Kazuhito Yokoi,et al.  Biped walking pattern generation by using preview control of zero-moment point , 2003, 2003 IEEE International Conference on Robotics and Automation (Cat. No.03CH37422).

[5]  Alin Albu-Schäffer,et al.  Three-dimensional bipedal walking control using Divergent Component of Motion , 2013, 2013 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[6]  Ye Zhao,et al.  A three dimensional foot placement planner for locomotion in very rough terrains , 2012, 2012 12th IEEE-RAS International Conference on Humanoid Robots (Humanoids 2012).

[7]  Martin Buss,et al.  Online motion planning over uneven terrain with walking primitives and regression , 2016, 2016 IEEE International Conference on Robotics and Automation (ICRA).

[8]  Xinyu Wu,et al.  Individualized Gait Pattern Generation for Sharing Lower Limb Exoskeleton Robot , 2018, IEEE Transactions on Automation Science and Engineering.

[9]  Masayuki Inaba,et al.  Online walking pattern generation for push recovery and minimum delay to commanded change of direction and speed , 2012, 2012 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[10]  Jong-Hwan Kim,et al.  3-D Command State-Based Modifiable Bipedal Walking on Uneven Terrain , 2013, IEEE/ASME Transactions on Mechatronics.

[11]  Kazuhito Yokoi,et al.  Biped walking stabilization based on linear inverted pendulum tracking , 2010, 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[12]  R. Stein,et al.  Predictions and ecperimental tests of a visco-elastic muscle model using elastic and inertial loads , 2004, Biological Cybernetics.

[13]  Daniel D. Lee,et al.  Heel and toe lifting walk controller for traversing uneven terrain , 2015, 2015 IEEE-RAS 15th International Conference on Humanoid Robots (Humanoids).

[14]  Masayuki Inaba,et al.  Autonomous 3D walking system for a humanoid robot based on visual step recognition and 3D foot step planner , 2005, Proceedings of the 2005 IEEE International Conference on Robotics and Automation.

[15]  Jessy W. Grizzle,et al.  Supervised learning for stabilizing underactuated bipedal robot locomotion, with outdoor experiments on the wave field , 2017, 2017 IEEE International Conference on Robotics and Automation (ICRA).

[16]  Kazuhito Yokoi,et al.  Planning walking patterns for a biped robot , 2001, IEEE Trans. Robotics Autom..

[17]  Yuan F. Zheng,et al.  Trajectory generation for dynamic walking in a humanoid over uneven terrain using a 3D-actuated Dual-SLIP model , 2015, 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS).

[18]  Alin Albu-Schäffer,et al.  Bipedal walking control based on Capture Point dynamics , 2011, 2011 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[19]  Qiang Huang,et al.  Gait Planning of Omnidirectional Walk on Inclined Ground for Biped Robots , 2016, IEEE Transactions on Systems, Man, and Cybernetics: Systems.

[20]  David E. Orin,et al.  Terrain-Blind Humanoid Walking Based on a 3-D Actuated Dual-SLIP Model , 2016, IEEE Robotics and Automation Letters.

[21]  Kazuhito Yokoi,et al.  Balance control based on Capture Point error compensation for biped walking on uneven terrain , 2012, 2012 12th IEEE-RAS International Conference on Humanoid Robots (Humanoids 2012).

[22]  Gora Chand Nandi,et al.  Design of Vector Field for Different Subphases of Gait and Regeneration of Gait Pattern , 2018, IEEE Transactions on Automation Science and Engineering.

[23]  Benjamin J. Stephens,et al.  Push Recovery Control for Force-Controlled Humanoid Robots , 2011 .

[24]  Qiang Huang,et al.  Bioinspired Control of Walking With Toe-Off, Heel-Strike, and Disturbance Rejection for a Biped Robot , 2017, IEEE Transactions on Industrial Electronics.

[25]  Ken Chen,et al.  Parametric Walking Patterns and Optimum Atlases for Underactuated Biped Robots , 2006, 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[26]  Sergey V. Drakunov,et al.  Capture Point: A Step toward Humanoid Push Recovery , 2006, 2006 6th IEEE-RAS International Conference on Humanoid Robots.

[27]  Jong Hyeon Park,et al.  Foot and Body Control of Biped Robots to Walk on Irregularly Protruded Uneven Surfaces , 2009, IEEE Transactions on Systems, Man, and Cybernetics, Part B (Cybernetics).

[28]  Atsuo Kawamura,et al.  The Development of Biped Robot MARI-3 for Fast Walking and Running , 2006, 2006 6th IEEE-RAS International Conference on Humanoid Robots.

[29]  Ren C. Luo,et al.  Impedance and Force Compliant Control for Bipedal Robot Walking on Uneven Terrain , 2015, 2015 IEEE International Conference on Systems, Man, and Cybernetics.

[30]  Jerome Le Ny,et al.  A Motion Planning Strategy for the Active Vision-Based Mapping of Ground-Level Structures , 2018, IEEE Transactions on Automation Science and Engineering.

[31]  Atsuo Kawamura,et al.  Robust and high-mobility walking control for uneven terrain without zero-moment-point feedback , 2017, 2017 IEEE International Conference on Industrial Technology (ICIT).

[32]  Qiang Huang,et al.  Sensory reflex control for humanoid walking , 2005, IEEE Transactions on Robotics.

[33]  Soonwook Hwang,et al.  Balancing of humanoid robot using contact force/moment control by task-oriented whole body control framework , 2016, Auton. Robots.

[34]  Ren C. Luo,et al.  Biped Walking Trajectory Generator Based on Three-Mass With Angular Momentum Model Using Model Predictive Control , 2016, IEEE Transactions on Industrial Electronics.