3D limit cycle walking of musculoskeletal humanoid robot with flat feet

Most of traditional biped walkers based on passive dynamic walking have arc feet and locked ankle joints. In this paper, we propose the method to substitute the arc feet with flat feet. We hypothesize that the shape of the arc feet corresponds to a circular roll-over shape (ROS), which is a shape of a trajectory of center of pressure in the shank-fixed frame. Firstly, we show that ankle joints driven by flexible muscles antagonistically can generate a circular ROS by simple simulation and real robot experiments. Radius of the ROS can be controlled by tension of the muscles. Then, we demonstrate stable 3D limit cycle walking by a biped robot with flat feet using the proposed ROS controlling method. We also investigate its behavior and stability when extra load is added to the robot and verified that the stability of the robot is maintained by keeping the ROS. The results suggest that the ROS can be a stability measure for limit cycle walkers to realize adaptive walking.

[1]  Kenichi Narioka,et al.  Designing Synergistic Walking of a Whole-Body Humanoid Driven by Pneumatic Artificial Muscles: An Empirical Study , 2008, Adv. Robotics.

[2]  Tad McGeer,et al.  Passive Dynamic Walking , 1990, Int. J. Robotics Res..

[3]  D. Childress,et al.  Effects of shoe heel height on biologic rollover characteristics during walking. , 2004, Journal of rehabilitation research and development.

[4]  Garth Zeglin,et al.  Ankle springs instead of arc-shaped feet for passive dynamic walkers , 2006, 2006 6th IEEE-RAS International Conference on Humanoid Robots.

[5]  Kenichi Narioka,et al.  Synergistic 3D limit cycle walking of an anthropomorphic biped robot , 2007, 2007 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[6]  Martijn Wisse,et al.  Three additions to passive dynamic walking; actuation, an upper body, and 3D stability , 2004, 4th IEEE/RAS International Conference on Humanoid Robots, 2004..

[7]  Martijn Wisse,et al.  Design and Construction of MIKE; a 2-D Autonomous Biped Based on Passive Dynamic Walking , 2006 .

[8]  Andy Ruina,et al.  A Bipedal Walking Robot with Efficient and Human-Like Gait , 2005, Proceedings of the 2005 IEEE International Conference on Robotics and Automation.

[9]  Zhiwei Luo,et al.  On Energy-Efficient and High-Speed Dynamic Biped Locomotion with Semicircular Feet , 2006, 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[10]  Minoru Asada,et al.  Walking stabilization of biped with pneumatic actuators against terrain changes , 2005, 2005 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[11]  Andrew H Hansen,et al.  Roll-over shapes of human locomotor systems: effects of walking speed. , 2004, Clinical biomechanics.