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FES Ankle Control for the Lokomat

Author(s):

S. Perala
Conference/Journal:

Semester/Bachelor Thesis, FS 09
Abstract:

A closed-loop control system has been developed to control the ankle angle during gait training using functional electrical stimulation (FES). The system is designed to be used during weight-supported, treadmill gait training on the Lokomat R . The controller uses amplitude modulated FES to stimulate the antagonistic muscle groups for dorsal and plantar flexion of the foot. Closed-loop feedback is achieved via a position sensor measuring the ankle angle. Feedforward control has been added to improve controller performance as well as phase correction feedback to allow real-time control at typical gait training velocities. The control system was evaluated on three healthy volunteers. The controller achieved a zero phase shift between the desired and measured ankle angle in as few as seven steps and an RMS error of 3.13 degrees with a gait period of 2 seconds. Although the phase was not affected by decreasing the gait period to 1.5 and 1 second, an increase of the RMS error was observed to 3.5 and 4.2 degrees, respectively. This study concluded that the developed system is capable to control the ankle with closed-loop FES during gait therapy. Future work includes patient trials as well as extension of the system to the knee and hip joints.

Year:

2009
Type of Publication:

(13)Semester/Bachelor Thesis
Supervisor:

S. Micera

No Files for download available.
% Autogenerated BibTeX entry
@PhdThesis { Xxx:2009:IFA_3419
}
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