Do Adaptable Sockets Improve Military Performance?

For the static socket configuration, both the microprocessor control and user control are disabled, and the panels are positioned in their flush configuration to create the user's as-prescribed socket shape.

Sockets are configured for user control by disabling automated control and enabling push buttons on the side of the socket to adjust socket size. Each button push effects a socket size change of approximately 0.3% volume. An upper button effects a socket size increase, and a lower button a socket size decrease. The buttons are countersunk so reduce risk of accidental pushes, and they do not function unless the user is stationary. An additional button push will not be executed until motor motion from the prior push has been completed. If a button is continuously held then the motor will continue moving until the button is released. Limits are set on cable length to ensure that sockets sizes threatening to the user's residual limb (too tight) are avoided. The push buttons effect inner-loop control that operates completely within the mechanism, achieving high-resolution adjustment of cable length with minimal error.

"A strategy for automatically controlling the size of the socket during walking to compensate for unknown changes in limb volume will be used. The controller is essentially a regulator that continuously measures socket fit, and adjusts the socket to maintain a prescribed reference set point. Because the fit is automatically sustained, the prosthesis user is unaware of its operation."