A Cam-Controlled, Single Actuator-Driven Leg Mechanism for Legged Vehicles

Leg design is crucial to the performance of a legged vehicle. To achieve good walking efficiency, a leg should be able to generate a horizontal straight line by a single actuator in the walking phase. In the return phase, additional actuator(s) is used to lift and place the foot. In this paper, a study of a cam-controlled, single-actuator-driven leg is presented. It does not require additional actuator for the return motion. In addition, the legs are driven by continuous, constant speed rotary input and they move in a constant speed. Therefore, it is conceivable that the legged vehicle can be driven by a traditional rotary engine. The cam curve is designed to have connectivity of third derivative (jerk). The driving torque is analyzed. The gait and stability related to such leg mechanism are discussed. This leg mechanism has the potential to be the leg of a practical and affordable walking machine.