The AMP-Foot 2.1 : Actuator Design, Control and Experiments with a Transfemoral Amputee.

The Ankle Mimicking Prosthetic (AMP-) Foot 2 is a new energy ef?cient, powered transtibial prosthesis mimicking intact ankle behaviour.

The focus behind the author's research enables the use of a low power actuator which stores energy in springs during the complete stance phase. At push-off, this energy can be released providing hereby propulsion forces and torques to the amputee.

Thanks to the use of the so-called 'catapult'-actuator, the size and weight of the drive can be decreased compared to state- of-the-art powered prosthesis, while still providing the full power necessary for walking.

In this article, the authors present a detailed description of the 'catapult'-actuator followed by a comparison with existing actuator technology in powered prosthetic feet with regard to torque and power requirements.

The implication on the actuator's design will then be outlined. Further, a description of the control strategy behind the AMP-Foot 2.0 and 2.1 will be given.

In the last section of the article, the actuation principle and control are illustrated by experimental validation with a transfemoral amputee.

Conclusions and future work will complete the paper.