Are neuristors the future of prosthesis and robotics?
If HP Labs and other research groups can get neuristor efficiency down to the level that neurons routinely operate, things may start to get a little more exciting. For one, when we get around to making devices safe enough to interface directly with the brain, neuristors already speak the local language, albeit one of rigid dialect. Smartphone sensors which represent data with spikes will be prosthesis-compatible out of the box, and sip juice from the battery at barely perceptible levels.
Robots perhaps stand to gain the most. The Disney robot which can play a fair game of catch with a human requires a good bit of processing power to perform. It must process encoder signals in its joints, likely at 10-bit or higher resolution, digitally solve an analog servo loop, and then generate an analog voltage or PWM (Pulse Width Modulation) control signal to drive its servomotors. If instead the entire job could be done with a handful of analog spiking neurons, much like a spinal loop of its human partner, there would be incredible gains in efficiency and speed.
If the network is rich enough, all the trainer might do is arrange things so that the total energy needed by the system is driven towards the minimal condition within the context of the desired goal, and the robot might eventually teach itself the task. For now, that is a whole lot easier said than done. One thing that neuristors on neuromorphic chips can’t do today is grow. They can change their strengths of interconnection, but they cannot actually seek out new connections according to any underlying principle. Growth on these chips might one day be approximated if sufficient latent connections can be integrated on the chip and activated when needed, but those capabilities are just beginning to be imagined.
Some readers may have been slightly irked that while the neuristor processes an analog input, its spike output sure looks like a digital event. That observation is certainly correct, but bear in mind that spikes are not bits. They are a different animal altogether, something in between, perhaps akin to an extreme analog signal, compressed at its critical points. If chips like those envisioned by HP Labs can be put into the hands of many experimenters, the larger community will become more familiar with these new ways to sense, compute, and control — inviting an era of analog computing to recommence.
Now read: How to create a mind, or die trying
Research paper: doi:10.1038/nmat3510 – “A scalable neuristor built with Mott memristors”
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