Another linear actuator idea
- Remember playing with a loop of string threaded through a button or disk? You wind up the button a bit, then pull and release rhythmically until you've pumped so much energy into the system that the button buzzes as it spins.Now, with that image in mind, what if you reverse the idea: spin the tensioned loop of string with a pager motor until the button comes up to speed, and the loop length contracts as the string winds together until the button stops and reverses.If you pulse the motor at the right times -- the resonant frequency of the string/button system, you've got an actuator that periodically shortens and lengthens. You pick the period you want according to the natural periods involved in your walker's gait. No gears, no racks, no leadscrews.
- In my (robots42) folder Sting Actuators
I have just uploded scans of the Dexmart Twisted String Actuators hand