Rehabilitation Robotics Newsletter

Project Showcase
Spring/Summer 1995

Machine Automation Helps--Rehabilitation Technologies at VTT

Virpi J. Santti
VTT Machine Automation

VTT is the Technical Research Centre of Finland. Research at VTT Machine Automation is targeted not only to applications in machine automation, e.g., heavy work machines in forestry, but also to mobile robotics. The approach is interdisciplinary, and multi-technical design services to industry are offered. This article describes two projects on rehabilitation.

In our project "Robotics helps disabled to work" (contact person Ari Virtanen), the pilot target was a 46 year old software developer with tetraplegia. He has some mobility left in his hands but when he works at home, he mainly uses a mouth stick for operating the computer. He works laying in a bed and hence the area he can reach is very limited; only a keyboard or a book in front of him can be reached at a time. Without the robot workstation, he requires a personal assistant to handle manuals and diskettes used in his work.

The installed robot workstation consists of a small industrial robot, Scorbot ER V with five degrees of freedom. Scorbot's working area was expanded with a linear axle. Some modifications were also needed in the gripper. This robot now takes care of handling diskettes and brings manuals on request.

One of the main design principles was safety. The robot was placed so that it could not come to close to the user and cause him any injuries. Special attention was also paid to maintaining the working place as a home, e.g., one had to see over the equipment (the maximum height of the equipment being 60 cm).

The system was installed in June, 1992 and the user is satisfied with its operation. It gives him more freedom and independence in his work. The reliability of the system has been quite good.

The other project is more general (contact person Olavi Karasti) since it is not built to serve one person only, but any wheelchair. The idea of the project is to develop a product module that helps in controlling the movement of a wheelchair. The implementation is based on a behavior-based concept and environment perception with ultrasonics.

Before anything is installed to a real wheelchair, the algorithm is tested on a JC-3 simulator. The simulator input is the environment (mostly walls), the user behaviouring algorithm and the wheelchair model. The wheelchair model also consists of ultrasonic sensors, which are simulated. During the simulation, the movement of the wheelchair is seen picture by picture.

For the real world test phase, we have a self-made mobile platform which has been used for other projects as well. This mobile robot has two driving wheels, one on each side, and two caster wheels (one in the front and one in the back). In addition to the fixed ultrasonic sensors which we use in this project, there are also other ultrasonic sensors which can be rotated with a stepper motor (scanning sensors) and US-sensors which can see a whole level on one measure (omnidirectional sensors). The behavior-based concept has successfully been tested with the vehicle.

In the final implementation, our module will be connected to M3S (a general-purpose Multiple Master Multiple Slave intelligent interface for the rehabilitation environment) in a way that it will capture the joystick signals and, depending on the selected driving mode, send the modified commands to the motors or guide the user with some interface media.

This project is a part of the project FOCUS (Focus On the Central position of Users in the integrated Systems), which in turn belongs to the TIDE program (Technology Initiative for Disabled and Elderly people) of the European Commission. FOCUS will be running until the end of 1995.
For further information, please contact:

Ari Virtanen / Olavi Karasti
VTT Automation
Machine Automation
P.O. Box 13021
FIN-33101 Tampere
Phone: +358 31 316 3609 / +358 31 316 3635
Fax: +358 31 316 3494
Email: /

The Project Showcase is a regular feature of the newsletter in which a selected project or program is spotlighted. If you are interested in having your project showcased, contact Tariq Rahman or Julia Mercier at ASEL.

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Last updated: October 24, 1996
Copyright © Applied Science and Engineering Laboratories, 1996.