>Grin... are you calling me "levitatious" ?? Why Stephen... and I >hardly know you !! Hmmm. >As far as I can see Stephen, the only real problem here is to find >what Ik is, and to do that we need to first be sure of what you mean >it to be. Specifically your notation leads one to easily think of >either the keys inertia in general or the keys inertia at the center >of mass. Let's adopt the simpler [just as useful] approach you and Phil suggested. Point mass action acting at the capstan, plus distributed mass keystick. We need estimates for: (i) action mass at the capstan (weight will do), (ii) mass of the key *without* leads]. Perhaps you have such data from your key balancing work Richard? Also key geometry. >The center of mass rk having been now specified as a << distance >from the fulcrum quantity >> presumably is not exactly stable at one >point throughout the whole key stroke. >In either case I would guess that both the center of mass and the >keys inertia would change throughout a stable key stroke (stable >velocity) in a fashion somewhat more complicated then either a first >or second degree curve on a graph would represents. I'm just >guessing here of course. But maybe the shape of these two curves is >something that should concern us ?? None of this is important for simple illustration as we're doing, but it is all important for real action modelling - that's the reason for developing the more sophisticated dynamic model as I'm up to at the moment. Stephen -- Dr Stephen Birkett Associate Professor Department of Systems Design Engineering University of Waterloo Waterloo, Ontario Canada N2L 3G1 Davis Building Room 2617 tel: 519-888-4567 Ext. 3792 PianoTech Lab Ext. 7115 mailto: sbirkett[at]real.uwaterloo.ca http://real.uwaterloo.ca/~sbirkett
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