Variable-mechanical-impedance artificial legs

摘要

In one aspect, the invention provides methods and apparatus facilitating an adjustable-stiffness prosthesis or orthosis (including approximations to arbitrarily definable non-linear spring functions). Spring rates may be varied under no-load conditions during a walking gate cycle to minimize power consumption. In another aspect, the invention provides methods and apparatus for outputting positive power from a prosthesis or orthosis, facilitating high-performance artificial limbs. In one embodiment of the invention, the positive power is transferred from a functioning muscle to the prosthesis or orthosis, which mimics or assists a non-functioning or impaired muscle. In another embodiment of the invention, the positive power comes from an on-board power source in the prosthesis or orthosis.

主权项

1. A biarticular prosthetic or orthotic leg comprising:
a support member connected at its upper end to an above-knee segment, said support member configured to rotate with respect to said above-knee segment to define a knee joint; a foot member including a rearwardly extending heel portion and a forwardly, extending toe portion to make periodic bearing contact with ground, said foot member operably connected to a lower end of said support member and configured to rotate relative to said support member to define an ankle joint; an anterior spring connected to the above-knee segment and to the support member, the anterior spring displaced from the knee joint and configured to store energy when said support member rotates about said knee joint to move said foot member rearwardly with respect to said above-knee segment and configured to release energy to rotate said support member about said knee joint; a biarticular posterior spring connected to the above-knee segment and to the heel portion of the foot member, the posterior spring displaced from the knee joint and configured to store energy when said support member is rotated in an extension movement about said knee joint and configured to release energy to rotate said foot member about said ankle joint to increase bearing force applied to the ground by said toe portion during powered ankle plantarflexion and to impart lifting force against the ground; and an anterior clutch connected in series with the anterior spring, the anterior clutch to engage the anterior spring at select engagement times when said support member rotates about said knee joint.