To make galloping available as a high-speed gait of quadrupedal robots, this dissertation addresses the mechanics of galloping and the design of legged robots for rapid locomotion. A simple method of measuring an animal's geometric and inertial properties is used to develop reasonable model parameters for the animal. An impulsive model of galloping is extended to all dynamic quadrupedal gaits to show that with equal stride frequencies, galloping requires smaller vertical oscillations of the mass center than trotting does at high speeds. In contrast, spring-mass models of both gaits indicate that trotting is accomplished with smaller vertical oscillations and/or lower stride frequencies at lower speeds. In conjunction, these two results suggest that animals transition from a trot to a gallop in order to minimize their stride frequencies without experiencing large vertical displacements.; For a quadruped robot to gallop in an energy-efficient manner, it must be designed to exhibit this same behavior at high speeds. The generalized inertia ellipsoid is presented as visualization tool for comparing leg designs in terms of impact losses and energy required for leg return. Kinetostatic analysis of effective stiffness is introduced as a means of establishing leg geometry in order to match the leg stiffness of animals. This method is implemented in the design of an articulated, prototype leg which stores elastic energy in mechanical extension springs during its return phase and releases that energy as thrust during stance. Experimental results with this leg indicate that it has the performance capabilities to be used in a quadruped galloping machine.
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