Walking animals demonstrate impressive self-organized locomotion and adaptation to body property changes by skillfully manipulating their complicated and redundant musculoskeletal systems. Adaptive interlimb coordination plays a crucial role in this achievement. It has been identified that interlimb coordination is generated through dynamical interactions between the neural system, musculoskeletal system, and environment. Based on this principle, two classical interlimb coordination mechanisms (continuous phase modulation and phase resetting) have been proposed independently. These mechanisms use decoupled central pattern generators (CPGs) with sensory feedback, such as ground reaction forces (GRFs), to generate robot locomotion autonomously without predefining it (i.e., self-organized locomotion). A comparative study was conducted on the two mechanisms under decoupled CPG-based control implemented on a quadruped robot in simulation. Their characteristics were compared by observing their CPG phase convergence processes at different control parameter values. Additionally, the mechanisms were investigated when the robot faced various unexpected situations, such as noisy feedback, leg motor damage, and carrying a load. The comparative study reveals that the phase modulation and resetting mechanisms demonstrate satisfactory performance when they are subjected to symmetric and asymmetric GRF distributions, respectively. This work also suggests a strategy for the appropriate selection of adaptive interlimb coordination mechanisms under different conditions and for the optimal setting of their control parameter values to enhance their control performance.
Bibliografisk noteFunding Information:
We gratefully acknowledged the financial support of NSFC-DFG Collaborative Research Program (Grant no. 51861135306, PM, project Co-PI), the NUAA research fund (Grant no. 1005-YQRO7001, PM, Project PI), the National Natural Science Foundation of China (Grant no. 51435008 to ZD), and Chinese Government Scholarship (Grant no. CSC201906830012 to TS). The authors would like to also thank Weijia Zong, Yan Li, and Potiwat Ngamkajornwiwat for their comments.
© Copyright © 2021 Sun, Xiong, Dai, Owaki and Manoonpong.