Virtual solution to wheelchair access?

Wheelchair users may soon be able to experience a ‘virtual tour’ of unconstructed buildings in order to highlight potential access problems.

Researchers at Strathclyde University hope the tour will help architects cater for the needs of disabled people who use wheelchairs.

The work is being carried out by Dr Bernie Conway of the University’s Bioengineering Unit and Professor Tom Maver of the School of Architecture and Built Environment in collaboration with Scottish disability groups.

The School of Architecture has a purpose built virtual reality laboratory in which three-dimensional, computer-generated images are projected onto a large, curved screen which fill the viewer’s field of vision. This is intended to create an ‘immersive effect’.

The system is designed to simulate mobility problems encountered by wheelchair users on a daily basis. The user sits in a wheelchair and propels the wheels as normal. When reaching a slope the wheels are meant to respond accordingly: increased resistance in the case of upward slopes and greater velocity when travelling down a slope.

The wheelchair has to remain in a fixed position and a special platform is being developed to accommodate this. The platform will consist of two rollers, one beneath each rear wheel of the chair, which will have an electric motor and a brake attached to it.

The rollers are connected to a PC which communicates with the graphics computer that is generating the scene.

The primary function of the rollers is to act as a ‘sophisticated’ computer mouse because when the rollers move the user is navigated through the virtual scene.

If the user ceased pushing the wheels when the chair was partially up a slope then this information would be conveyed to the control system and the electric motors would be activated to start the wheels rolling backwards. Similarly, if the chair ‘collided’ with an object the brakes would be applied immediately to cause a virtual bump.

Likewise, information about the surface of the floor is passed to the control computer so that changes in surface tension would result in a change in resistance for the chair.

A basic platform exists, as well as rollers and a clutch system for the brakes and motor.

The Strathclyde University team now face the challenge of working on the software to link up the graphics system with the control computer.