Abstract
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.
Highlights
Walking animals demonstrate impressive self-organized locomotion and adaptation to body property changes by skillfully manipulating their complicated and redundant musculoskeletal systems (Taga et al, 1991; Dickinson et al, 2000; Der and Martius, 2012; Grabowska et al, 2012)
To realize self-organized locomotion and adaptation on artificial legged systems, many adaptive robot control schemes based on distributed abstract central pattern generators (CPGs) incorporating ground reaction force (GRF) feedback have been proposed (Kimura et al, 2007; Owaki et al, 2013; Barikhan et al, 2014; Ambe et al, 2018; Fukui et al, 2019)
We focused on the autonomous phase regulation of decoupled CPGs modulated by the phase modulation (PM) and phase resetting (PR), resulting in quadruped self-organized locomotion
Summary
Walking animals demonstrate impressive self-organized locomotion and adaptation to body property changes by skillfully manipulating their complicated and redundant musculoskeletal systems (Taga et al, 1991; Dickinson et al, 2000; Der and Martius, 2012; Grabowska et al, 2012). Investigations of various aspects of adaptive interlimb coordination mechanisms have attracted significant attention in various research fields To demonstrates these mechanisms, biologists have proposed some neurological principles, such as central pattern generators (CPGs) (Marder and Bucher, 2001), reflex chains (Grillner, 1975), and sensory feedback (Grillner, 2003; Rossignol et al, 2006), through biological experiments. To realize self-organized locomotion and adaptation on artificial legged systems, many adaptive robot control schemes based on distributed abstract CPGs incorporating ground reaction force (GRF) feedback have been proposed (Kimura et al, 2007; Owaki et al, 2013; Barikhan et al, 2014; Ambe et al, 2018; Fukui et al, 2019). The GRF feedback is exploited to modulate the phase relationships of the CPGs under two main strategies: (continuous) phase modulation (PM) and (discrete) phase resetting (PR)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
