From: "Gerhard Fiedler"
>
> Look at the graph in this data sheet:
> http://www.casaferreira.com.br/pdf/CEP453042.pdf
>

Thanks for the link Gerhard, I'll digest them.

<snip>
> And don't forget that this is not a constant movement; you'll have an
> acceleration phase, you may or not have a phase with constant maximum
> speed, you'll have a deceleration phase and you'll have a "move in on the
> target" phase where your position controller is active and the torque goes
> up and down around 0.

I remember something about it from my robotics class, I think I still have 
my simulink programs (can I call them that?) that simulate a motor and a pid 
controller using triangular and trapezoidal profiles.

<snip>
> Re linear actuator: for these calculations, it doesn't matter much whether
> you use a gear motor that has a rotating output or a linear actuator that
> is a motor with a screw gear that then gets translated back into a 
> rotating
> movement. The torque, force, power calculations are pretty much the same;
> the only things that change are the friction losses and that the
> translation back into a rotating movement usually is not linear -- both
> often negligible effects.
>
> A linear actuator needs to do exactly the same a rotating actuator needs 
> to
> do: accelerate, move along, decelerate, move in on the target, and provide
> the same torque/rotational speed (at the steering column) in the various
> phases.
>

So if I'm reading right, no matter what the power required will always be 
the same (assuming all losses are equal), what should define the type of 
motor and gearing (linear or rotating) is the platform?

Padu 

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