טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentShorr Yifat
SubjectRobotic and Hybrid Models (Using Functional Electrical
Stimulation)for the Rehabilitation of Human Gait
Cycle
DepartmentDepartment of Mechanical Engineering
Supervisor Professor Moshe Shoham
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

Over resent years efforts have been made to find a model that will help restore the gait cycle for paraplegic people. Research has been focused on:

  • Exoskeleton on the paraplegic legs, which enables the rehabilitation of the gait cycle, taking into consideration the gradual Wight load which is needed, strengthening the muscles and hybrid system which will work under automatic control
  • Functional electrical stimulation of the patient’s muscles, using implanted/external electrodes which bring to peripheral activation of the muscle. The activation leads to muscle contraction and helps to decrease spasm and atrophy that is caused due to lack of sufficient activation of the muscles.
  • Hybrid systems - Exoskeleton integrated with functional electrical stimulation and automatic control system

The work lists different models that are available today in order to rehabilitate gait cycle. The models focus on address difficulties which characterized paraplegic as fast fatigue, limited force available for production from the muscle, lack of anthropometric data, as follow:

  • Comparison between the muscles activated by treadmill walking to those who are activated by the robotic system called Lokomat. The system enables gradual rehabilitation without external professional help.
  • Robotic modeling - in order to overcome the lack of necessary anthropometric data, a robotic modeling system is being used (LaGrange and Denavit-Hartenberg).
  • Hybrid system - integrating robotic control systems and functional electrical stimulation. Overview of the control systems, sensors, human-computer interface, physiological and artificial interfaces, communication between the different interfaces
  • Macroscopic - Microscopic linkage: models that take into consideration the macroscopic and microscopic part of contractions as calcium changes in the contracting cell, fatigue effects, Actin- Myosin linkage using Hill’s model
  • Optimal stimulation pattern (maximum strength, Minimum Fatigue) comparison between different ways of stimulation as single, double and Variable frequency trains of stimulation
  • Epidural Implantable systems - epidural electrode that are implanted in the epidural space and help in the rehabilitation process.

One of the major problems that duplicate in all the simulation models is that in order to find a model, healthy people are being tested. However the physiology of paraplegia changes after injury, therefore it is hard to compare and build a model based on these findings.

 The second part is focused on simulation of mid-swing to terminal swing of the gait cycle. The stimulation includes the activation of the quadriceps (extension) in isometric stages. The results are compared to existing literature and present similarity.