A couple of tips, you generally find the stepper
or app will have a fairly definite top speed.
If you have a decent constant current driver
you can generally get the motor up to top speed
in about one revolution, maybe less.

Most traverses will consist of a very quick accel
ramp, long constant speed and quick decel.
As a general guide, max accel is about 1% per step,
so if you shorten the period of each step by 1%
you will get a very quick accel. If you have a
lower performance driver, like a unipolar constant
voltage driver etc, you may only get 0.2% per step.
Resonances will be your bigest prob on the accel
ramp, sometimes a stupidly quick accel will get
you through the resonance better than a more
relaxed accel. Start the motor about 1/3 of its
max start speed, then instantly accel from there.
Most motors will start fine at 1 or 2 revs/sec
as a ball park figure. :o)
-Roman


David P. Harris wrote:
>
> Hi Dwayne-
>
> I have done a rough cut, but that's all.  So I would be interested in your
> solution.  What I did is calculate the distance in steps from the starting, or
> stopping, point and use the distance to modify the rate.  So, for instance,
> RATE = (HERE-START)*2+1.  The nice thing about this is, it lets you calculate
> the deceleration so you stop in a certain place.  Ie: RATE = MIN( MAXRATE,
> (HERE-START)*2+1, (STOP-HERE)*2).   Note, the last expression will be zero when
> it reaches the destination, while the +1 in the first expression lets it start
> from the start position.
>
> (gee thanks Dwayne, I have now stated it clearly for myself :-)
>
> I am doing this for a turntable, so I have to worry about signs and stuff.
>
> David H
>
> Dwayne Reid wrote:
>
> > Good day to all.
> >
> > I am about to start a hobby project using a single standard stepper motor
> > that moves a specified number of steps each time it is triggered.  Easy, so
> > far.  But I'd like to add acceleration and deceleration ramps.  Not too
> > hard, really.  But before I get into it, I thought I'd check to see if
> > someone has seen something like this already done.

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