Affiliation:
1. Robotics and Motion Laboratory,Department of Mechanical Engineering,The University of Texas at San Antonio,One UTSA Circle,San Antonio, TX 78249
Abstract
Abstract
In this paper, we demonstrate the application of a discrete control Lyapunov function (DCLF) for exponential orbital stabilization of the simplest walking model supplemented with an actuator between the legs. The Lyapunov function is defined as the square of the difference between the actual and nominal velocity of the unactuated stance leg at the midstance position (stance leg is normal to the ramp). The foot placement is controlled to ensure an exponential decay in the Lyapunov function. In essence, DCLF does foot placement control to regulate the midstance walking velocity between successive steps. The DCLF is able to enlarge the basin of attraction by an order of magnitude and to increase the average number of steps to failure by 2 orders of magnitude over passive dynamic walking. We compare DCLF with a one-step dead-beat controller (full correction of disturbance in a single step) and find that both controllers have similar robustness. The one-step dead-beat controller provides the fastest convergence to the limit cycle while using least amount of energy per unit step. However, the one-step dead-beat controller is more sensitive to modeling errors. We also compare the DCLF with an eigenvalue-based controller for the same rate of convergence. Both controllers yield identical robustness but the DCLF is more energy-efficient and requires lower maximum torque. Our results suggest that the DCLF controller with moderate rate of convergence provides good compromise between robustness, energy-efficiency, and sensitivity to modeling errors.
Funder
Division of Information and Intelligent Systems
Reference30 articles.
1. Passive Dynamic Walking;Int. J. Rob. Res.,1990
2. Owaki, D., Koyama, M., Yamaguchi, S., Kubo, S., and Ishiguro, A., 2010, “A Two-Dimensional Passive Dynamic Running Biped With Knees,” International Conference on Robotics and Automation (ICRA), Anchorage, AK, May 3–7, pp. 5237–5242.10.1109/ROBOT.2010.5509166
3. A Statically-Unstable Passive Hopper: Design Evolution;ASME J. Mech. Rob.,2017
4. Basin of Attraction of the Simplest Walking Model,2001
5. A Disturbance Rejection Measure for Limit Cycle Walkers: The Gait Sensitivity Norm;IEEE Trans. Rob.,2007
Cited by
9 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献