Minimal feedback to a rhythm generator improves the robustness to slope variations of a compass biped.
In recent years there has been a growing interest in the field of dynamic walking and bio-inspired robots. However, while walking and running on a flat surface have been studied extensively, walking dynamically over terrains with varying slope remains a challenge. Previously we developed an open loop controller based on a central pattern generator (CPG). The controller applied predefined torque patterns to a compass-gait biped, and achieved stable gaits over a limited range of slopes. In this work, this range is greatly extended by applying a once per cycle feedback to the CPG controller. The terrain's slope is measured and used to modify both the CPG frequency and the torque amplitude once per step. A multi-objective optimization algorithm was used to tune the controller parameters for a simulated CB model. The resulting controller successfully traverses terrains with slopes ranging from +7° to -8°, comparable to most slopes found in human constructed environments. Gait stability was verified by computing the linearized Poincaré Map both numerically and analytically.
Jonathan Spitz, Alexandrina Evstrachin and Miriam Zacksenhouse are with the Sensory-Motor Integration Laboratory, Faculty of Mechanical Engineering, TechnionIsrael's Institute of Technology, Haifa 32000, Israel.
Jonathan
J
Spitz
Alexandrina
A
Evstrachin
Miriam
M
Zacksenhouse
D001683:Biological Clocks / Q000502:physiology; D032701:Biomimetics / Q000379:methods*; D063226:Central Pattern Generators / Q000502:physiology*; D003198:Computer Simulation; D017076:Computer-Aided Design; D025461:Feedback, Physiological / Q000502:physiology; D005684:Gait / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000502:physiology; D008959:Models, Neurological; D012371:Robotics / Q000379:methods*; D065854:Spatial Navigation / Q000502:physiology*