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FES of the lower limbs using feedback control


F. Jonasch

Master Thesis, HS 09

A number of rehabilitation technologies have been developed to improve walking function in gait impaired individuals, such as spinal cord injury and stroke patients. One is a robotic gait orthosis designed to provide automated treadmill training, such as the Lokomat. The device can provide body weight support and guide leg motions by means of electric drives based on force sensors. Another technology is functional electrical stimulation (FES), which has also been shown to improve function by coordinating artificial activation of otherwise paralyzed muscles. Although both technologies have shown to be effective, the two can be combined to overcome disadvantages of any single device. For example, the Lokomat on its own provides only passive movements of limbs. The use of FES during training would allow active muscle contractions that are important for the rehabilitation process. Furthermore, the Lokomat would allow FES training in a safely controlled environment that also reduces therapist effort. In this masters thesis, a closed-loop control of the ankle joint was implemented and extended by the necessary means in order to allow synchronous operation with the Lokomat system. Since gait training in a controlled environment such as the Lokomat is highly repetitive, the control scheme was based on an iterative learning approach. Despite the time-variant and nonlinear characteristics of muscles under FES, experiments with healthy subjects in the lab and on the Lokomat showed good and robust tracking of a reference signal while maintaining a high stimulation comfort.

Supersors: Prof. M. Morari, R. Nguyen, S. Micera


Type of Publication:

(12)Diploma/Master Thesis

M. Morari

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% Autogenerated BibTeX entry
@PhdThesis { Xxx:2010:IFA_3511
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