Can an Underactuated Leg with a Passive Spring at the Knee Achieve a Ballistic Step ?

In this paper, we present a control scheme aimed at moving an underactuated double pendulum simulating a leg. The system is actuated at the hip and includes a spring at the knee. It interacts with the ground, which is in fact a treadmill, through a telescopic foot made of a linear spring and a damper. The control scheme is different in the 2 phases, swing and stance, and a repetitive step is achieved by switching between these two controls. The paper describes the system, the used models and the control algorithms. It presents also experimental results of the approach.

[1]  N.H. McClamroch,et al.  Nonlinear control of a class of underactuated systems , 1996, Proceedings of 35th IEEE Conference on Decision and Control.

[2]  B. Espiau.  On the Mass Center of Articulated Chains , 1998 .

[3]  Jerry E. Pratt,et al.  Virtual model control of a bipedal walking robot , 1997, Proceedings of International Conference on Robotics and Automation.

[4]  Atsuo Takanishi,et al.  Development of a biped walking robot having antagonistic driven joints using nonlinear spring mechanism , 1997, Proceedings of International Conference on Robotics and Automation.

[5]  R. McN. Alexander,et al.  Three Uses for Springs in Legged Locomotion , 1990, Int. J. Robotics Res..

[6]  Ronan Boulic,et al.  On the Computation and Control of the Mass Center of Articulated Chains , 1998 .

[7]  Richard Quint van der Linde,et al.  Active Leg Compliance for Passive Walking , 1998, ICRA.

[8]  Bernard Espiau,et al.  Limit Cycles in a Passive Compass Gait Biped and Passivity-Mimicking Control Laws , 1997, Auton. Robots.

[9]  Yangsheng Xu,et al.  Experimental study of an underactuated manipulator , 1995, Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots.

[10]  Matthew M. Williamson,et al.  Series elastic actuators , 1995, Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots.

[11]  Ronald S. Fearing,et al.  Sliding and hopping gaits for the underactuated Acrobot , 1998, IEEE Trans. Robotics Autom..

[12]  T. McMahon,et al.  Ballistic walking: an improved model , 1980 .

[13]  Mark W. Spong,et al.  Swing up control of the acrobot using partial feedback linearization , 1994 .

[14]  R. Mattone,et al.  Control of underactuated mechanical systems: application to the planar 2R robot , 1996, Proceedings of 35th IEEE Conference on Decision and Control.

[15]  Yangsheng Xu,et al.  A dynamic coupling index for underactuated manipulators , 1995, J. Field Robotics.

[16]  Fumihito Arai,et al.  Swing and locomotion control for a two-link brachiation robot , 1994 .