Overview

My research is concerned with the problem of rehabilitation of lower limb motor functions. When controlling postural movements through prosthetic limbs or muscle Functional Electrical Stimulation (FES), an important issue is the interaction of the patient with the artificial system by means of his valid limb motions. We believe that the proper observation of some pertinent variables associated with valid limb motions would allow adapting the artificial control of deficient limbs, thus improving the global postural task enhancement.

A challenge is therefore to:

identify postural task transition as soon as possible after the patient made the decision, in order to allow for optimal posture preparation and execution,
during an ongoing task extract some of the movement parameters that can be used as state variables for a control system.

This novelty in control will improve the global functioning of the rehabilitation systems; yet, even more important enhance the therapeutic effects because the patient will have active role in controlling the posture and locomotion.

Overall schematics of our approach

Methods

To deal with the two adressed questions, I had to seek information, ideas, and methods from different fields of research.

First of all, I had to get familiar with the human sensori-motor system, its disabilities, and the different rehabilitation techniques. I'd like to thank D. Popovic for his hints, advices, and his book.

I have learned about abrupt changes detection, thanks to Michelle Basseville (see one of her books here.

I got used to the Central Pattern Generator (CPG) concept, sometimes used in robotics for online trajectory generation (an example).

To model a CPG, I also entered the fabulous world of non-linear oscillators and synchronization. I would recommend one book in particular: Synchronization: a universal concept in nonlinear sciences, by Pikowsky, Rosenblum, and Kurths.

The paper An Observer Looks at Synchronization by H. Nijmeijer (1997) helped me to make a the link between observation and synchronization.