Brief description

This work considers the development of a wheelchair for people with special needs, which is capable of navigating semi-autonomously within its workspace. This system is expected to prove useful to people with impaired mobility and limited fine motor control of the upper extremities. Among the implemented behaviors of this robotic system are the avoidance of obstacles, the motion in the middle of the free space and the following of a moving target specified by the user (e.g., a person walking in front of the wheelchair). The wheelchair is equipped with sonars, which are used for distance measurement in pre-selected critical directions, and with a panoramic camera with a 360 degree field of view, which is used for following a moving target. After suitably processing the color sequence of the panoramic images using the color histogram of the desired target, the orientation of the target with respect to the wheelchair is determined, while its distance is determined by the sonars. The motion control laws developed for the system use the sensory data and take into account the non-holonomic kinematic constraints of the wheelchair, in order to guarantee certain desired features of the closed-loop system, such as stability. Moreover, they are as simplified as possible to minimize implementation requirements. An experimental prototype has been developed at ICS–FORTH, based on a commercially-available wheelchair. The sensors, the computing power and the electronics needed for the implementation of the navigation behaviors and of the user interfaces (touch screen, voice commands) were developed as add-on modules and integrated with the wheelchair.

Sample results

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Sample results on human tracking based on panoramic vision.

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Sample behaviour of the wheelchair in a dynamic environment

Contributors

Antonis Argyros, Pantelis Georgiadis, Dimitris Tsakiris, Panos Trahanias.

Relevant publications

  • A.A. Argyros, P. Georgiades, P. Trahanias, D. Tsakiris “Semi-autonomous Navigation of a Robotic Wheelchair”, Journal of Intelligent and Robotic Systems, Special Issue on Medical and Rehabilitation Robotics, Kluwer Academic Publishers, Vol. 34, pp. 315–329, July 2002.
  • A.A. Argyros, P. Georgiades, P. Trahanias, D. Tsakiris “Semi-Autonomous Navigation of a Robotic Wheelchair”, in proceedings of the KTISIVIOS Panhellenic Conference in Robotics and Automation, Santorini, Greece, July 28-29, 2001.

The electronic versions of the above publications can be downloaded from my publications page.