Locomotor sub-functions for design and control of locomotion

In this study we focus on bio-inspired legged locomotion concepts. A primary goal of comparative biomechanics is to understand the fundamental physics of locomotion within an evolutionary context. Such an understanding of legged locmotion results in a transition from copying nature to borrowing strategies for interacting with the physical world in design and control of bio-inspired legged robots or robotic assistive devices. Inspired from nature, legged locomotion can be composed of three locomotion sub-functions which are intrinsically interrelated: Stance: redirecting the center of mass by exerting forces on the ground. Swing: cycling the legs between ground contacts. Balance: maintaining body posture. With these three sub-functions, one can understand, design and control legged locomotion with formulating them in simpler separated tasks. Coordination between locomotion subfunctions in a harmonized manner looks as an additional problem which is absent while considering legged locomotion as one (more complex) problem. However, Biological locomotors show that appropriate design and control of each subfunction prevents suffering from complex coordination step.