Architecture of a Powered Prosthesis System: Actuators, Sensors, and Control

Abstract

A current strategy for providing a powered prosthesis capable of emulating the intricate features of the ankle-foot complex is through the application of the robotic architecture. The proposed robotic architecture consists of three levels: actuators, sensors, and control. An emphasis is placed upon the actuator level, for which the series elastic actuator is a subject of prosthetic research and development, and other types of actuators, such as the chemical-derived actuator and pneumatic actuator. Inclusive of the subject of actuators are advanced concepts that extend the technology of the series elastic actuator, such as the Robotic Tendon, with variable stiffness. A new perspective on muscle modeling that accommodates history dependence is featured, which is known as the Winding Filament Hypothesis. As a supplement, battery technology is discussed with a consideration of future capability. The sensor level addresses currently applied microelectronic devices, such as accelerometers, gyroscopes, angular encoders, linear encoders, and footswitches. The control level focuses on the application of the finite state machine, which derives the status of gait based on the acuity of sensor feedback.