Control of electro-rheological fluid-based torque generation components for use in active rehabilitation devices

Jason Nikitczuk; Brian Weinberg; Constantinos Mavroidis

doi:10.1117/12.659576

11 April 2006 Control of electro-rheological fluid-based torque generation components for use in active rehabilitation devices

Jason Nikitczuk, Brian Weinberg, Constantinos Mavroidis

Author Affiliations +

Proceedings Volume 6174, Smart Structures and Materials 2006: Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems; 61742C (2006) https://doi.org/10.1117/12.659576
Event: SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, 2006, San Diego, California, United States

Abstract

In this paper we present the design and control algorithms for novel electro-rheological fluid based torque generation elements that will be used to drive the joint of a new type of portable and controllable Active Knee Rehabilitation Orthotic Device (AKROD) for gait retraining in stroke patients. The AKROD is composed of straps and rigid components for attachment to the leg, with a central hinge mechanism where a gear system is connected. The key features of AKROD include: a compact, lightweight design with highly tunable torque capabilities through a variable damper component, full portability with on board power, control circuitry, and sensors (encoder and torque), and real-time capabilities for closed loop computer control for optimizing gait retraining. The variable damper component is achieved through an electro-rheological fluid (ERF) element that connects to the output of the gear system. Using the electrically controlled rheological properties of ERFs, compact brakes capable of supplying high resistive and controllable torques, are developed. A preliminary prototype for AKROD v.2 has been developed and tested in our laboratory. AKROD's v.2 ERF resistive actuator was tested in laboratory experiments using our custom made ERF Testing Apparatus (ETA). ETA provides a computer controlled environment to test ERF brakes and actuators in various conditions and scenarios including emulating the interaction between human muscles involved with the knee and AKROD's ERF actuators / brakes. In our preliminary results, AKROD's ERF resistive actuator was tested in closed loop torque control experiments. A hybrid (non-linear, adaptive) Proportional-Integral (PI) torque controller was implemented to achieve this goal.

Citation Download Citation

Jason Nikitczuk, Brian Weinberg, and Constantinos Mavroidis "Control of electro-rheological fluid-based torque generation components for use in active rehabilitation devices", Proc. SPIE 6174, Smart Structures and Materials 2006: Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, 61742C (11 April 2006); https://doi.org/10.1117/12.659576

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