Not a question, just an observation.
My 85 year old mother-in-law has recently gone into a power wheel chair controlled via joystick. Her hands shake really badly, and before she went into the power chair, I was concerned as to whether she could at all steer it.
Over Thanksgiving I watched her negotiate a narrow ramp up into a doorway. It was an older home and definitely not wheelchair friendly. She went straight up and down the ramp and moved around with ease.
Now clearly the joystick output was filtered through an RC time constant to output the near "dc" control signal that my mother-in-law was sending, but upon which was superimposed a significant time-varying "noise" signal. My wife, who has been in a power wheelchair for years, told me ahead of time that they could adjust the joystick response to accommodate the needs of different users with hand tremors.
So the averaging time constant is adjusted based on the degree and timing of shake of different users, and conceptually that seems simple enough. But watching that hand shake and the chair move straight is an amazing sight, nonetheless.
But perhaps the more amazing feedback loop is the biological one. That old lady went right up and down that ramp, straight as an arrow, sending the right signal based on watching where the chair was going and ignoring the noise perturbations her hand was adding.
It must be something similar to walking while carrying a very full glass of water. We do better if we just walk and don't watch the glass. If we watch the glass, we try to compensate and our control system isn't fast or accurate enough and the stimulus and response get out of whack and it spills.
On several levels here, the human mind is seen once again to be an amazing machine.
Very cool control systems
Re: Very cool control systems
