Unilateral Ground Contact Force Regulations in Thruster-Assisted Legged Locomotion

In this paper, we study the regulation of the Ground Contact Forces (GRF) in thruster-assisted legged locomotion. We will employ Reference Governors (RGs) for enforcing GRF constraints in Harpy model which is a bipedal robot that is being developed at Northeastern University. optimization-based methods and whole body control are widely used for enforcing the no-slip constraints in legged locomotion which can be very computationally expensive. In contrast, RGs can enforce these constraints by manipulating joint reference trajectories using Lyapunov stability arguments which can be computed much faster. The addition of the thrusters in our model allows to manipulate the gait parameters and the GRF without sacrificing the locomotion stability.

[1]  I. Kanellakopoulos,et al.  Backstepping to passivity: recursive design of adaptive systems , 1992, [1992] Proceedings of the 31st IEEE Conference on Decision and Control.

[2]  Twan Koolen,et al.  The Yobotics-IHMC Lower Body Humanoid Robot , 2009, 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[3]  Eduardo Sontag.  A Lyapunov-Like Characterization of Asymptotic Controllability , 1983, SIAM Journal on Control and Optimization.

[4]  Kenichi Ogawa,et al.  Honda humanoid robots development , 2007, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[5]  Nader Jalili,et al.  Performance satisfaction in Midget, a thruster-assisted bipedal robot , 2020, 2020 American Control Conference (ACC).

[6]  Jessy W. Grizzle,et al.  Feedback Control of a Cassie Bipedal Robot: Walking, Standing, and Riding a Segway , 2018, 2019 American Control Conference (ACC).

[7]  Pravin Dangol,et al.  Feedback design for Harpy: a test bed to inspect thruster-assisted legged locomotion , 2020, Defense + Commercial Sensing.

[8]  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).

[9]  H. Benjamin Brown,et al.  Experiments in Balance with a 3D One-Legged Hopping Machine , 1984 .

[10]  Hyun K. Kim,et al.  Biped humanoid robot Mahru III , 2007, 2007 7th IEEE-RAS International Conference on Humanoid Robots.

[11]  Oussama Khatib,et al.  A whole-body control framework for humanoids operating in human environments , 2006, Proceedings 2006 IEEE International Conference on Robotics and Automation, 2006. ICRA 2006..

[12]  Emanuele Garone,et al.  Explicit Reference Governor for Constrained Nonlinear Systems , 2016, IEEE Transactions on Automatic Control.

[13]  Ilya V. Kolmanovsky,et al.  Nonlinear tracking control in the presence of state and control constraints: a generalized reference governor , 2002, Autom..

[14]  Ilya Kolmanovsky,et al.  Nonlinear control of discrete-time linear systems with state and control constraints: a reference governor with global convergence properties , 1994, Proceedings of 1994 33rd IEEE Conference on Decision and Control.

[15]  Aaron D. Ames,et al.  3D dynamic walking with underactuated humanoid robots: A direct collocation framework for optimizing hybrid zero dynamics , 2016, 2016 IEEE International Conference on Robotics and Automation (ICRA).

[16]  Christopher G. Atkeson,et al.  Optimization based full body control for the atlas robot , 2014, 2014 IEEE-RAS International Conference on Humanoid Robots.

[17]  Pravin Dangol,et al.  Towards thruster-assisted bipedal locomotion for enhanced efficiency and robustness , 2020, IFAC-PapersOnLine.

[18]  S. Bhat,et al.  Continuous finite-time stabilization of the translational and rotational double integrators , 1998, IEEE Trans. Autom. Control..

[19]  Koushil Sreenath,et al.  Torque Saturation in Bipedal Robotic Walking Through Control Lyapunov Function-Based Quadratic Programs , 2013, IEEE Access.

[20]  Alberto Bemporad,et al.  Reference governor for constrained nonlinear systems , 1998, IEEE Trans. Autom. Control..

[21]  Kevin Blankespoor,et al.  BigDog, the Rough-Terrain Quadruped Robot , 2008 .