Formation of gait patterns by passive mechanism emulating the musculoskeletal system of quadrupeds

Abstract

Four-legged animals are walking by switching the gait pattern such as walk, trot and gallop depending on speed of locomotion so as to minimize energy consumption. This is similar to that in the multi-degree-of-freedom vibration system, natural vibration mode has a frequency at which maximum efficiency (natural frequency). Authors thought that the natural vibration of the musculoskeletal system was related to the switching of the gait. Therefore, we examined the gait is switched corresponding on road surface speed by fabricating the apparatus of passive mechanism that simulates the musculoskeletal system. First authors examine the mechanism can form bent motion of one leg of the horse by self‐Excited vibration by the power from a road surface In three-link mechanism of a leg of forward deviation of neutral axis and disturbance formed leg motion only let contact road surface. Next authors examine the separation of the natural frequency of the shoulder waist to realize the gait of four passiveness mechanism. Shoulder waist which did a spring support position inward can separate natural frequency of trot and gallop Finally authors examine the gait pattern is switched corresponding road surface speed forms it just to let four leg passiveness mechanism ground a road surface. Four-legged passive mechanism of body, shoulder waist and three-link mechanism is formed the gait only let contact road surface.