A three degree of freedom leg design, and implementation in a bipedal robot

Reducing the number of actuators in a robot is advantageous for reducing the complexity, cost, and weight of the robot. However, it usually results in a reduction in functionality for the robot. In this paper, we present a design for the legs of a bipedal robot which uses only three actuators per leg, and yet is still capable of dexterous three dimensional motion. Each leg comprises two four-bar linkages, with one motor for each four bar linkage, and one motor for applying twist to the leg, to enable turning. We show that a free standing bipedal robot constructed with two of these legs is capable of walking, turning, and various other motions.