An exoskeleton – how the Warsaw University of Technology scientists fight disabilities

From the left: mgr inż. Wojciech Credo, dr inż. Marcin Zaczyk, mgr inż. Błażej Kabziński, prof. nzw. dr hab. inż. Danuta Jasińska-Choromańska, mgr inż. Karol Bagiński, dr inż. Jakub Wierciak, phot. BPI

There is nothing more natural than walking if you are an able-bodied person. However, as a result of medical conditions, accidents or congenital defects some people cannot move about unassisted. Therefore, scientists from the Department of Design of Precision Devices operating within the Institute of Micromechanics and Photonics at the Faculty of Mechatronics have decided to deal with the problem.

In Poland, as many as 1.3m people are severely disabled and every fifteenth of them is unable to walk a distance of 500 metres or to use stairs without assistance. Prof. Danuta Jasińska-Choromańska is the supervisor of a project aimed at the development and construction of an exoskeleton, which will make such activities possible.

The implementation of the Verticalisation and Motion Aiding System resulted in some engineering and master’s theses and even doctoral ones. The exoskeleton was built as part of the “Ecomobility” project implemented under the Operational Programme Innovative Economy – Priority I. Prof.  Włodzimierz Choromański from the Faculty of Transport was the supervisor of the project. Among people involved in the construction of the exoskeleton were employees of the Faculty of Mechatronics of the Warsaw University of Technology, the University’s graduate, Dr. Mariusz Bojarski of New York University who was responsible for electronics, orthopaedists, physiotherapists, and people with disabilities, with whom the employees of the Faculty of Administration and Social Sciences operating at the Warsaw University of Technology conducted the tests.

Work on the exoskeleton started in October 2009. The scientists have built a prototype, which has not yet been tested on people, however, they wish to continue their work and make it possible for people with disabilities to use the device in the future.

When the impossible becomes possible

Exoskeletons have already been used by the army. They are meant to support soldiers who have to walk many kilometres carrying a significant load. However, in this case the apparatus receives signals from muscles – it helps walking, but it does not do the walking.

What the scientists from the Faculty of Mechatronics are building is actually an orthotic robot, which is a system aiding people with motor disabilities to move around. The disabled people’s muscles responsible for walking are inactive as they are not used. Orthotic robots are a chance of walking offered to people who up till now have been moving around in wheelchairs.

The system does not merely offer assistance with five basic activities such as getting up, sitting down, going upstairs or downstairs or walking, but above all gives disabled people a chance to function normally in society.

“Despite all that, disabled people will have to move using a walker or crutches, as they need three points of contact to keep balance”, says Prof. Danuta Jasińska-Chromańska of the Faculty of Mechatronics at the Warsaw University of Technology.

 

An intelligent system

Each function of the orthotic robot is programmed in a handheld control panel. To monitor the user’s movements, the system gathers information from all its sensors placed in the crutches, under the feet, at the tip of the “shoe” and on the heel. All data gathered in this way is converted to an electrical signal. “We get information from the sensors, for example how many points of contact the person has at the moment”, explains Prof. Danuta Jasińska-Chromańska. “When the person is going upstairs, the device has to be fed information where a step starts and where it finishes. The same refers to going downstairs.

This information is completed with data relating to angular displacements in the ankle, knee and hip joint. The control system converts these signals to information. Each of the five functions has specific algorithms reflected in individual modes of the control panel: walking, going upstairs and downstairs, sitting down in a chair and getting up. Energy needed to perform all those activities comes from a battery, which is currently hidden in a box carried on the person’s back.

Understanding how a disabled person functions

Doctors and physiotherapists have identified conditions, in which it will be possible to use the exoskeleton and in which it will not. The construction of that kind of a system was carried out in consultation with people who will be its prospective users. Sometimes the scientists from the Warsaw University of Technology found disabled persons’ problems and suggestions surprising.

“It turned out they did not want the system to be hidden under their clothes, they even prefer it to be put over them”, says Prof. Danuta Jasińska-Chromańska. “The only thing they do not want is a system that is shiny, clinking or deliberately attracting attention. Disabled people are wary of that kind of novelty as they have no sense of balance that those able bodied possess”.

People who have lost their physical ability as a result of an accident have a completely different approach to that kind of novelty. They remember themselves as able-bodied people and want to regain their physical ability as soon as possible, therefore, they are enthusiastic users of such facilities.

Closer and closer to the goal

The team wants to develop the project: they are working on more functions of the robot, for example on the mobility of the foot to facilitate making a turn. The scientists wish to apply for the Medical Ethics Committee’s consent to test the device on humans. It is only after such testing that the system will be allowed to be implemented.

The initial assumption was that the system should not cost more than PLN 35,000, which is an enormous amount for a disabled person anyway. “Now, we know that due to technical issues we will not be able to go below PLN 60,000”, says Prof. Danuta Jasińska-Chromańska.

It would be necessary to co-finance the system with the help of the Disabled Persons’ Fund, companies or perhaps foundations. Although the launch of an orthotic robot is a considerable investment, it is also a massive benefit to be derived not only by disabled people themselves but also by healthcare services. The disabled do not need the constant involvement of physiotherapists (they are only system operators), because when walking assisted by the device they undergo physiotherapy on their own. Moreover, remaining seated in wheelchairs all day long causes other conditions of the circulatory or digestive systems, which could be easily eliminated in this way.

The social and physical dimension of using the system is also important. Some of the disabled feel excluded from society because of their condition. They stay at home, which negatively influences their mental state. The exoskeleton would give them a chance to regain self-confidence and return to their normal life in society.

Monika Bukowska

Office for Promotion and Information