A few times now, we have covered various attempts to interface an electric wheelchair directly with thought control. The system we last looked at, and which is still being used, is to access the P-300 event related potential signal in brain waves. P-300 is a specialized type of brain wave, that operates out of the frontal lobe. Really two different waves, it is called P-300, because it is triggered about 300 milliseconds after the brain receives sensory stimulus that it deems relevant to the task it is currently focused on.

The video below, by the researchers working on this project, goes into considerable technical detail, whilst highlighting progress made since we last looked at the work in February 2009. Some of the definite improvements include the sophistication of the SLAM (Simultaneous Location And Mapping) navigation technology the wheelchair uses, enabling the operator to focus on general instructions, and have the machine navigate its own way there.

At 2:33 we see that the sensor system has advanced to the point where the wheelchair itself can react in real-time to a dynamic obstacle; that is to say, a human, or animal walking out in front of the chair. It adjusts its path to avoid a collision, seamlessly. Something the chair was incapable of, as little as two months ago.

Whilst it is navigating, the chair still responds to user input, meaning that if the user changes their mind about where to go, 300 milliseconds later, the chair will stop and recalculate a new path to the desired destination, dynamically factoring in its current position relative to the destination.

At 3:00 we see a difficult maneuver, where at a double door, the door on the right is open, the one on the left is closed. It is clear from the chair's behavior that this arrangement was reversed the last time it passed through. Yet, unbidden, the chair stops, analyzes the situation, and moves towards the open door, auto-correcting its own navigation system. The same procedure is used if furniture is moved around, or if in a completely new location.

References

Mind Controlled Wheelchair

Brain Machine Interface Enabled Wheelchair

A Wheelchair With Ears and Brain