Performance testing of collision-avoidance system for power wheelchairs

The Drive-Safe System (DSS) is a collisionavoidancesystem for power wheelchairs designed to supportpeople with mobility impairments who also have visual, upperlimb,or cognitive impairments. The DSS uses a distributedapproach to provide an add-on, shared-control, navigationassistancesolution. In this project, the DSS was tested for engineeringgoals such as sensor coverage, maximum safe speed,maximum detection distance, and power consumption whilethe wheelchair was stationary or driven by an investigator.Results indicate that the DSS provided uniform, reliable sensorcoverage around the wheelchair; detected obstacles as small as3.2 mm at distances of at least 1.6 m; and attained a maximumsafe speed of 4.2 km/h. The DSS can drive reliably as close as15.2 cm from a wall, traverse doorways as narrow as 81.3 cmwithout interrupting forward movement, and reduce wheelchairbattery life by only 3%. These results have implicationsfor a practical system to support safe, independent mobility forveterans who acquire multiple disabilities during Active Dutyor later in life. These tests indicate that a system utilizing relativelylow cost ultrasound, infrared, and force sensors caneffectively detect obstacles in the vicinity of a wheelchair.