Bend and flex: Passive flexibility or active control in a quadruped animat


Muscle and tendon elasticity enables animals to interact with their environment softly, reducing ground impact force and increasing efficiency of locomotion. Traditional rigid body robots remain the commercially viable option, but incorporating flexibility can harness the benefits exhibited by natural organisms. In this paper, we examine how the addition of passive flexibility impacts performance and locomotive efficiency in a quadruped animat. Results show that the addition of flexibility in the spine and lower limbs of a quadruped animat significantly increases the distance traveled compared to a fully rigid-body animat. However, replacing these passively flexibile joints with actively controlled joints results in the farthest traveling individuals while maintaining similar efficiency. It appears that increases in DOF and joint configuration are the drivers of performance increases rather than passive flexibility.


Computer Science

Document Type

Conference Proceeding



Animats, Evolutionary robotics, Morphology, Passive flexibility

Publication Date


Journal Title

GECCO 2018 Companion - Proceedings of the 2018 Genetic and Evolutionary Computation Conference Companion