A Predictive Momentum-Based Whole-Body Torque Controller: Theory and Simulations for the iCub Stepping

When balancing, a humanoid robot can be easily subjected to unexpected disturbances like external pushes. In these circumstances, reactive movements as steps become a necessary requirement in order to avoid potentially harmful falling states. In this paper we conceive a Model Predictive Controller which determines a desired set of contact wrenches by predicting the future evolution of the robot, while taking into account constraints switching in case of steps. The control inputs computed by this strategy, namely the desired contact wrenches, are directly obtained on the robot through a modification of the momentum-based whole-body torque controller currently implemented on iCub. The proposed approach is validated through simulations in a stepping scenario, revealing high robustness and reliability when executing a recovery strategy.

[1]  Alexander Herzog,et al.  Trajectory generation for multi-contact momentum control , 2015, 2015 IEEE-RAS 15th International Conference on Humanoid Robots (Humanoids).

[2]  Andrei Herdt,et al.  Online Walking Motion Generation with Automatic Footstep Placement , 2010, Adv. Robotics.

[3]  Sven Behnke,et al.  Balanced Walking with Capture Steps , 2014, RoboCup.

[4]  Nathan van de Wouw,et al.  Tracking Control for Hybrid Systems With State-Triggered Jumps , 2013, IEEE Transactions on Automatic Control.

[5]  G. Nicolao,et al.  Stability and Robustness of Nonlinear Receding Horizon Control , 2000 .

[6]  Andrew Howard,et al.  Design and use paradigms for Gazebo, an open-source multi-robot simulator , 2004, 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) (IEEE Cat. No.04CH37566).

[7]  Abderrahmane Kheddar,et al.  Multi-contact walking pattern generation based on model preview control of 3D COM accelerations , 2016, 2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids).

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

[9]  Daniele Pucci,et al.  Highly dynamic balancing via force control , 2016, 2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids).

[10]  Kazuhito Yokoi,et al.  The 3D linear inverted pendulum mode: a simple modeling for a biped walking pattern generation , 2001, Proceedings 2001 IEEE/RSJ International Conference on Intelligent Robots and Systems. Expanding the Societal Role of Robotics in the the Next Millennium (Cat. No.01CH37180).

[11]  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..

[12]  Daniele Pucci,et al.  iCub Whole-Body Control through Force Regulation on Rigid Non-Coplanar Contacts , 2015, Front. Robot. AI.

[13]  Pierre-Brice Wieber,et al.  Stabilization of the Capture Point Dynamics for Bipedal Walking Based on Model Predictive Control , 2012, SyRoCo.

[14]  John Lygeros,et al.  Hybrid Systems: Modeling, Analysis and Control , 2008 .

[15]  H. Michalska,et al.  Receding horizon control of nonlinear systems , 1988, Proceedings of the 28th IEEE Conference on Decision and Control,.

[16]  Henk Nijmeijer,et al.  On optimal trajectory tracking for mechanical systems with unilateral constraints , 2015, 2015 54th IEEE Conference on Decision and Control (CDC).

[17]  David Q. Mayne,et al.  Constrained model predictive control: Stability and optimality , 2000, Autom..

[18]  Russ Tedrake,et al.  Whole-body motion planning with centroidal dynamics and full kinematics , 2014, 2014 IEEE-RAS International Conference on Humanoid Robots.

[19]  B. Schutter,et al.  On hybrid systems and closed-loop MPC systems , 2001, Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228).

[20]  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.

[21]  John T. Betts,et al.  Practical Methods for Optimal Control and Estimation Using Nonlinear Programming , 2009 .

[22]  Francesco Nori,et al.  Torque-controlled stepping-strategy push recovery: Design and implementation on the iCub humanoid robot , 2016, 2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids).

[23]  Giulio Sandini,et al.  The RobotCub project -- an open framework for research in embodied cognition , 2006 .

[24]  Alexander Herzog,et al.  A Convex Model of Momentum Dynamics for Multi-Contact Motion Generation , 2016, ArXiv.

[25]  Nicolas Mansard,et al.  Whole-body motion integrating the capture point in the operational space inverse dynamics control , 2014, 2014 IEEE-RAS International Conference on Humanoid Robots.

[26]  Gabriele Nava,et al.  Stability analysis and design of momentum-based controllers for humanoid robots , 2016, 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS).

[27]  Pierre-Brice Wieber,et al.  Online walking gait generation with adaptive foot positioning through Linear Model Predictive control , 2008, 2008 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[28]  Pierre-Brice Wieber,et al.  Trajectory Free Linear Model Predictive Control for Stable Walking in the Presence of Strong Perturbations , 2006, 2006 6th IEEE-RAS International Conference on Humanoid Robots.

[29]  Bruno Siciliano,et al.  Control Problems in Robotics and Automation , 1998 .

[30]  Christopher G. Atkeson,et al.  Robust dynamic walking using online foot step optimization , 2016, 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS).

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

[32]  Olivier Stasse,et al.  A versatile and efficient pattern generator for generalized legged locomotion , 2016, 2016 IEEE International Conference on Robotics and Automation (ICRA).

[33]  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).

[34]  Nikolaos G. Tsagarakis,et al.  Yarp Based Plugins for Gazebo Simulator , 2014, MESAS.

[35]  Daniele Pucci,et al.  A Whole-Body Software Abstraction Layer for Control Design of Free-Floating Mechanical Systems , 2017, 2017 First IEEE International Conference on Robotic Computing (IRC).

[36]  Alberto Bemporad,et al.  Stabilizing Model Predictive Control of Hybrid Systems , 2006, IEEE Transactions on Automatic Control.