This article discusses the design and testing of a powered ankle prosthesis. This new prosthesis mimics nonamputee (normal) ankle moments during the stance phase of gait through the use of an optimized spring loaded four-bar mechanism. A prototype prosthesis based on the optimization was designed, fabricated, and tested. The experimental results achieved 93.3% of the simulated theoretical ankle moment giving substantial evidence that this approach is a viable in designing powered ankle prostheses.

This paper outlines the design and testing of a powered ankle prosthesis, which utilizes a four-bar mechanism in conjunction with a spring and motor that mimics nonamputee (normal) ankle moments. This approach would enable transtibial (below the knee) amputees to walk at a normal speed with minimal energy input. The design takes into account the energy supplied by the wearer required to achieve many of the desired characteristics of a normal gait. A proof-of-concept prototype prosthesis was designed, optimized, fabricated, and tested with the purpose of demonstrating its ability to match crucial ankle moments during the stance phase of gait. Testing of this prosthesis proved crucial in determining the prosthesis’ capabilities and in evaluating this approach.

Abstract. In light of technological advances, researchers have lost sight of robotic grippers/end effectors design intent. In a semi-structured environment the biomimetic approach is impractical due to the high complexity of the mechanism and control algorithms. Current industrial grippers are robust, but lack the flexibility that allows for in hand manipulation. The authors believe that underactuated grippers provide the best approach to allow for in hand manipulation along with being rugged enough for an industrial setting. Thinking of the robotic gripper and the robotic arm as one system (as opposed to two separate subsystems), one is capable of using the degrees of freedom of the robot in conjunction with that of the gripper to provide the desired motion profile without the complexity of running two subsystems. This paper will outline where recent grippers have failed and will introduce a new design paradigm for grippers along with several underactuated gripper ideas.