Path Control: A Method for Patient-Cooperative Robot-Aided Gait Rehabilitation

Abstract

Path control: a method for patient-cooperative robot-aided gait rehabilitation Abstract-Gait rehabilitation robots are of increasing importance in neurorehabilitation. Conventional devices are often criticized because they are limited to reproducing predefined movement patterns. Research on patient-cooperative control strategies aims at improving robotic behavior. Robots should support patients only as much as needed and stimulate them to produce maximal voluntary efforts. This paper presents a patient-cooperative strategy that allows patients to influence the timing of their leg movements along a physiologically meaningful path. In this "path control" strategy, compliant virtual walls keep the patient's legs within a "tunnel" around the desired spatial path. Additional supportive torques enable patients to move along the path with reduced effort. Graphical feedback provides visual training instructions. The path control strategy was evaluated with 10 healthy subjects and 15 subjects with incomplete spinal cord injury. The spatio-temporal characteristics of recorded kinematic data showed that subjects walked with larger temporal variability with the new strategy. Electromyographic data indicated that subjects were training more actively. A majority of iSCI subjects was able to actively control their gait timing. Thus, the strategy allows patients to train walking while being helped rather than controlled by the robot.

Retraining of interjoint arm coordination after stroke using robot-assisted time-independent functional training

“…The recently published article by Duschau-Wicke et al discusses a new modality for the Lokomat  (Hocoma AG, Volketswil, Switzerland) assistive robot for gait training [57]. This modality has some similarities to TIFT in that it uses joint space haptic walls to maintain the hip and knee within a desired joint space trajectory.…”

“…Similar to a recently reported training mode developed for gait training [57], we have developed a robotic intervention for arm rehabilitation that specifically targets impaired interjoint coordination by requiring active patient participation in coordinating multiple joints. We implemented this training mode in the ARMin III exoskeleton [50], which can apply torques directly to each of the six DOFs of the arm (three shoulder torques, elbow flexion/ extension, supination/pronation, wrist flexion/extension).…”

Adaptive Patientenunterstützung für Rehabilitationsroboter

“…Um das "Assist as needed"-Prinzip umzusetzen, arbeitet eine Reihe von Forschungsgruppen an sogenannten patientenkooperativen Robotern und Regelungsstrategien [5][6][7][8][9][10][11]. Basis vieler derartiger Strategien ist die Impedanzregelung, bei der die Nachgiebigkeit des Roboters durch ein simuliertes Feder-Dämpfer-Element zwischen Ist-Position und Soll-Position eingestellt wird [5; 12].…”

“…Weiterentwicklungen der Impedanzregelung erlauben Bewegungen mit freiem zeitlichem Ablauf entlang eines räumlichen Referenz-Pfades ("Pfadregelung", [8][9][10] …”

Voluntary gait speed adaptation for robot-assisted treadmill training

“…These control strategies recognize the movement intention of the patient and adapt the robotic assistance according to the patient's force contribution to the walking process [11]. Furthermore, virtual environments are used as they have proven to make repetitive rehabilitation exercises more motivating [12].…”