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 [DPRG] segway Message index sorted by: [ date ] [ thread ] [ subject ] [ author ] Previous message: [DPRG] segway Next message: [DPRG] segway Subject: [DPRG] segway From: Chuck McManis cmcmanis at mcmanis.com Date: Tue Dec 3 18:34:01 CST 2002 ```At 05:39 PM 12/3/02 -0600, cbrenizer wrote: > >I had wondered if a third wheel device costing 3 or 4 hundred dollars >would have happier customers than the multi-thousand dollar segway (I >know I'd be happier paying less and it probably wouldn't need much >electronics, since it wouldn't have to be self balancing) This is a common mis-perception. Two wheel, three wheel, or 18 wheel, you have to deal with torque of a vertical human body. The value proposition of the Segway is not about balance, its about inertial mass management. Consider a human standing on a "trolley" (you can imagine any number of wheels on it) moving forward at a velocity "V" When you decelerate your momentum (mV) is converted into a torque that is related to how far your center of mass is from the trolley. The harder you decelerate, the more torque you experience and the more likely you are to fly off the thing. The Segway, manages your momentum by changing the torque angle inversely proportional to your rate of deceleration (that is to say you "lean back") which causes your relative torque moment to be 0 (or put another way it keeps your angular momentum 0) so that you perceive the declaration as increased acceleration along your vertical axis. This translates in a shear force on the wheels and ground. Basically you don't fly over the handle bars because you are never being pushed toward them and conversely when it accelerates you don't fall off the back. Now you could put a tilting platform on your trolley and have it do this compensation (think of a coffee cup holder for your that uses gimbals to keep the cup level in the face of changing accelerations.) So to completely replace what the Segway does on a multiwheel vehicle is you would need to first have a platform that could roll over the kinds of terrain that a Segway does and can turn in place (this is essential for navigating human targeted environments), and then you need a hydraulic platform (or a fast electromechanical one) that could keep your inertial acceleration vector vertical in real time. The neat thing about the Segway is that it does both of these with exactly two motors. --Chuck ``` Previous message: [DPRG] segway Next message: [DPRG] segway Message index sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the DPRG mailing list