Preliminary Experiments with an Actively Tuned Passive Dynamic Running Robot

: This paper describes experiments with an electrically actuated one legged hopping robot, the ARL Monopod. While a spring-mass system, comprised of the leg spring and the body mass has previously provided the basic \passive dynamic" vertical motion, we have now added a spring in series with the hip actuator to use the same passive dynamic principle for the leg swing motion. This paper validates our previously proposed hip actuation controller, which actively tunes the leg swing motion during running to remain close to its passive dynamic response, and at the same time maintains balance and controls the robot's desired forward speed. Experimental data of stable running at 1m=s show a 75% reduction in hip actuation energy during ight, and a mechanical energy expenditure for the complete robot of only 64W. The resulting speci c resistance of the robot reduces to 0:36 at 1m=s, which is about half the previously reported result for the robot without hip spring.

• Type: Conference
• Year: 1997
• Where: ISER
• Authors: Mojtaba Ahmadi, Martin Buehler
• Keywords: Hip Actuation, Hip Actuation Controller, ISER 1997, Leg Swing Motion, Robotics