Two heads better to control simulated spacecraft

Two heads with cogs between
A person with a joystick can do much better than one person with a BCI. However, a recent study on a much simpler task – and this was confirmed by our own study – showed that if you add enough brains there is a point where the person using a keyboard is outperformed both in terms of accuracy and, crucially, in terms of decision-making speed.
Professor Riccardo Poli
Researchers from the University of Essex have been working in concert with colleagues in the United States on brain-computer interface (BCI) technology which allows two people to steer a virtual spacecraft using only their brain power, via electroencephalography (EEG).

The BCI group at Essex was founded in 2004 and currently has one of the best equipped labs in the country. The group is collaborating with NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California on the Robotics, BCI and Secure Adaptive Systems (RoBoSAS) project, under the leadership of Professor Riccardo Poli from Essex's School of Computer Sciences and Electronic Engineering. ScienceOmega.com was able to ask Professor Poli some questions on the £500,000 project.

He explained that Adrian Stoica – the project's main collaborator at JPL – and his group members were already interested in electromyographic interfaces and EEG-based interfaces. He heads the Advanced Robotic Controls Group, looking at new and more powerful ways of interfacing with machines, and robots in particular.

"Our close collaboration has been made possible via a large grant from the Engineering and Physical Sciences Research Council (EPSRC) under their ‘global engagement’ scheme," said Professor Poli. "This was awarded in March last year to fund exchanges of and visits for personnel and students. Indeed, two of my PhD students are visiting JPL this month with sponsorship from the grant."

With the help of the project grant, the researchers have been developing a BCI mouse which allows two people to collaboratively steer a virtual spacecraft. Wearing caps to monitor their brain signals, the co-pilots must focus their attention on one of eight directional dots. Numerous benefits stem from merging the signals of two individuals. Controlling a simulated spacecraft by mind alone demands very intense effort. It requires a level of sustained concentration which is very difficult for one person to achieve over a period of time.

"With two or more people, however, if one has a lapse of concentration, nothing really bad happens provided the other or others do not have a concentration lapse at the same time," Professor Poli pointed out.

The brain signals picked up with EEG are very faint; they need to be amplified thousands of times and even then are embedded in a ‘bath’ of noise. Indeed, looking for patterns in EEG signals has been likened to listening to a concert from outside the concert hall. The noise in this case is caused by any muscular activity – swallowing, neck tension, eye blinks, respiration or heartbeat – which produces a much bigger voltage than the brain voltages, thereby completely masking them.

"By combining the signals from two people, the true signals from their brains are amplified because they are correlated, while the uncorrelated noise is reduced," remarked Professor Poli. "This provides much cleaner signals for the complex machinery that is required to turn brain waves into control commands for the simulator."

It is to be expected that two people will occasionally give slightly inconsistent commands. One may want to reach a location by going up first and then left, whereas the other might want to do it the other way round. I asked Professor Poli what happens if the two parties give conflicting ‘instructions’, and how this is dealt with.

"This is not a problem for our system," he replied. "The net effect is that the cursor controlling the steering of the spacecraft would move diagonally – which is actually the best strategy to achieve the original goal."

If one of the two pilots was a spy, Professor Poli hypothesised, who wanted to crash or misdirect the spacecraft, their commands would act against the commands of the other pilot and they would cancel each other out. No steering action would be produced, which would immediately trigger alarm bells in both the second pilot and ground control.

"A person with a joystick can do much better than one person with a BCI," admitted Professor Poli. "However, a recent study on a much simpler task – and this was confirmed by our own study – showed that if you add enough brains there is a point where the person using a keyboard is outperformed both in terms of accuracy and, crucially, in terms of decision-making speed."

By tapping directly into the brain’s electrical signals, the motor planning and execution processing required to complete any manual action are bypassed.

In future, it is possible that the applications of the BCI system could extend beyond helping people with disabilities to spell or control a wheelchair and move into actual spaceflight. For now, the collaboration is ongoing and the team are continuing to gather data with the current set-up.

"We are also looking at joint decision-making via BCI," Professor Poli shared. "I'll be visiting JPL myself again in two weeks' time and we still have several researchers there. Researchers from JPL have also visited us regularly over the past nine months or so."

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