Note: This content is accessible to all versions of every browser. However, this browser does not seem to support current Web standards, preventing the display of our site's design details.


FES Ankle Control for the Lokomat


S. Perala

Semester/Bachelor Thesis, FS 09

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.


Type of Publication:

(13)Semester/Bachelor Thesis

S. Micera

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