This is more of a theoretical question.
Let's say i have a stepper motor, the usual, like nema 17.
And i command it to move at a constant speed, not acceleration, very simple.
So, let assume i use a driver with 16 microsteps and some 16t gt2 pulley and i want to move at 40mm/sec.
SO, i calculate pulse rate for microsteps.
3200 usteps per rev, 32mm per rev, so, 100 usteps per 1 mm.
So i need to pulse 40100 / 1 second = 4000 pulses/second to get 40 mm/sec
And i just start banging 4000 p/s to the STEP pin of the driver.
Now the question: when the motor will actually acheive the speed of 40mm/sec
Let even assume there is no big load, just belt on a pulley.
The speed is set by the period between pulses (or pulse rate), so, if it start from 0 to 40mm/sec in just one step then the time is very short 0,00025 and the acceleration is unrealistic.
x= one ustep distance = 0.00001 m
a=(2x)/t^2=0.00002 m/ 0,0000000625 ss= 320m/s*s !!!
That's over 32g For a load of 100g it will result in a force of 32N
That additional 32N for the belt.
But i highly doubt that a stepper can really provide such acceleration.
So, how can i estimate on what ustep it will actually acheive the set speed of 40mm/sec?
I know that toque of usteps is less than full steps. I calculate incremental torque for 1 ustep and it is still enough to pull pretty big load. So it is not the limiting factor.
Maybe i should consider rotor inertia? Back EMF is still small at such speed, or maybe not if i make a first jerk, maybe it spikes. I am lost here.