Bipedal Robot Running: Human-like Actuation Timing Using Fast and Slow Adaptations

We have been developing human-sized biped robots based on passive dynamic mechanisms. In human locomotion, the muscles activate at the same rate relative to the gait cycle during running. To achieve adaptive running for robots, such characteristics should be reproduced to yield the desired effect. In this study, we designed a central pattern generator (CPG) involving fast and slow adaptation to achieve human-like running using a simple spring-mass model and our developed bipedal robot, which is equipped with actuators that imitate the human musculoskeletal system. Our results demonstrate that fast and slow adaptations can reproduce human-like running with a constant rate of muscle firing relative to the gait cycle. Furthermore, the results suggest that the CPG contributes to the adjustment of the muscle activation timing in human running.