A locking, unactuated knee is added to the Scout II quadruped robot and trotting gaits are studied. The mechanical design of the knee is presented, trotting algorithms are discussed, and a control approach for a robotic leg with an unactuated knee is developed. A model of a single leg is used to determine appropriate leg trajectory parameters and initial conditions to achieve trots. The single leg system and the complete robot are simulated. Experimental implementation of single leg control and quadruped trotting on Scout II are presented.

A simple mechanical design for quadrupedal locomotion, termed SCOUT, is proposed, featuring only one degree of freedom per leg. The paper demonstrates experimentally that our first prototype SCOUT-1 is capable of walking, turning, and climbing over a step, despite its mechanical simplicity. The underlying principle is dynamic operation, based on controlled momentum transfer. Simulations show successful walking, stair climbing and running.