To control highly-dynamic compliant motions such as running or hopping, vertebrates rely on reflexes and Central Pattern Generators (CPGs) as core strategies. However, decoding how much each strategy contributes to the control and how they are adjusted under different conditions is still a major challenge. To help solve this question, the present paper provides a comprehensive comparison of reflexes, CPGs and a commonly used combination of the two applied to a biomimetic robot. It leverages recent findings indicating that in mammals both control principles act within a low-dimensional control submanifold. This substantially reduces the search space of parameters and enables the quantifiable comparison of the different control strategies. The chosen metrics are motion stability and energy efficiency, both key aspects for the evolution of the central nervous system. We find that neither for stability nor energy efficiency it is favorable to apply the state-of-the-art approach of a continuously feedback-adapted CPG. In both aspects, a pure reflex is more effective, but the pure CPG allows easy signal alteration when needed. Additionally, the hardware experiments clearly show that the shape of a control signal has a strong influence on energy efficiency, while previous research usually only focused on frequency alignment. Both findings suggest that currently used methods to combine the advantages of reflexes and CPGs can be improved. In future research, possible combinations of the control strategies should be reconsidered, specifically including the modulation of the control signal's shape. For this endeavor, the presented setup provides a valuable benchmark framework to enable the quantitative comparison of different bioinspired control principles.


    Access

    Download


    Export, share and cite



    Title :

    Adapting Highly-Dynamic Compliant Movements to Changing Environments: A Benchmark Comparison of Reflex- vs. CPG-Based Control Strategies



    Published in:

    Publication date :

    2021-12-01



    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




    Adapting space plans to changing times.

    Becker, H. S. | NTRS | 1969



    Adapting Control Methods for Autonomous Exploration of Unknown Environments

    Mutz, D. / Chein, S. / Engelhardt, B. | NTRS | 2000


    Safe Reinforcement Learning Benchmark Environments for Aerospace Control Systems

    Ravaioli, Umberto J. / Cunningham, James / McCarroll, John et al. | IEEE | 2022


    Highly compliant active clinging mechanism

    Saravia, Walter / Udrea, Bogdan | IEEE | 2016