Design of a knee and leg muscle exerciser for paraplegics using a shape memory alloy rotary joint actuator

Guoping Wang; Mohsen Shahinpoor

doi:10.1117/12.316862

20 July 1998 Design of a knee and leg muscle exerciser for paraplegics using a shape memory alloy rotary joint actuator

Guoping Wang, Mohsen Shahinpoor

Proceedings Volume 3324, Smart Structures and Materials 1998: Smart Materials Technologies; (1998) https://doi.org/10.1117/12.316862
Event: 5th Annual International Symposium on Smart Structures and Materials, 1998, San Diego, CA, United States

Abstract

This paper presents a design of an active knee and leg muscle exerciser using a shape memory alloy (SMA) rotary joint actuator. This active exerciser is designed for a paraplegic to exercise his or her knee and leg muscles. The exerciser is composed of a lower extremity orthosis or a knee brace, an SMA rotary joint actuator, and an electronic control unit. The lower extremity orthosis and knee brace are commercially available. The analysis model of the SMA rotary joint actuator is introduced and the design formulas are derived. A quasi-static analysis of the SMA rotary joint actuator is assumed in this design. The actuating component of the SMA rotary joint actuator is a bundle of lengthy SMA wires which are wrapped on several wrapping pulleys. A constant force spring is incorporated in this actuator to provide the SMA wires with a bias force to maintain a recoverable initial position of the actuator. A prototype of the active knee and leg muscle exerciser is designed, and an electronic control unit in the prototype provides users with a means of adjusting forward rotation speed and cycle time of the exerciser.

Citation Download Citation

Guoping Wang and Mohsen Shahinpoor "Design of a knee and leg muscle exerciser for paraplegics using a shape memory alloy rotary joint actuator", Proc. SPIE 3324, Smart Structures and Materials 1998: Smart Materials Technologies, (20 July 1998); https://doi.org/10.1117/12.316862

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