Robotic wheelchair docks like a spaceship

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A laser-guided robot wheelchair that automatically docks with the user's vehicle and loads itself into the back could give disabled drivers more freedom.

Using the new system, the user opens the door of their van and presses a button to lower the front seat so they can climb in. A remote control is then used to drive the chair round to the back of the van.

From here on, a computer inside the vehicle takes over. Using radio signals and laser guidance, it positions the chair onto the forks of a lift that hauls the wheelchair on board, and closes the door (see video, right).

The process is reversed once the driver reaches their destination.

Reliable docking
Researchers from Lehigh University in Bethlehem, Pennsylvania, US, working with a company called Freedom Sciences of Philadelphia, have demonstrated the system using a retrofitted, commercially available motorised wheelchair and a standard Chrysler minivan.

The researchers had originally planned to let users dock the empty wheelchair onto the forklift themselves, using the remote control and a camera mounted on the van. But it proved too difficult to position the chair accurately on the lift.

"The real challenge is to dock with 100% reliability. That is something you can't do with remote control," says John Spletzer, a roboticist at Lehigh who helped develop the system.

Instead they developed an on-board computer that uses a LIDAR (light detecting and ranging) system to position the chair. It bounces laser light off two reflectors on the armrests of the chair to track its position and align it with the forklift.

Space docking
Similar laser ranging was used by the uncrewed cargo spacecraft Jules Verne when it first docked with the International Space Station last month.

In tests, the system achieved a 97.5% success rate in docking the chair, even when facing complications such as rain, headlights, visible exhaust fumes, or loose gravel under the wheels.

If a docking attempt fails, the operator repositions the chair and tries again. If all else fails, they can take over, and keep trying until docking is successful.

Freedom Sciences expects to begin selling the system later this year in the US for around $30,000 each.

FDA approval
The price is comparable to having a vehicle modified so that a wheelchair can roll into the driver's area, and has the benefit that the equipment can be transferred when a new car is purchased, says Thomas Panzarella, Freedom Sciences' chief technology officer.

Because the product involves modifying a medical device – a wheelchair – approval is needed from the US Food and Drug Administration, but Panzarella expects this to take no more than a month or so.

The system tackles an interesting problem, says Joelle Pineau, a computer scientist at McGill University in Montreal. "It is well known that navigating in very constrained spaces and conditions is a major challenge for wheelchair users."

Journal reference: Journal of Field Robotics (DOI: 10.1002/rob.20236)