ramp table of stepper motor

[nick703]

hello friends i want to know how to create ramp table for stepper motor rotation . just increase speed or decrease speed stepper motor rotate smoothly . so that time i want to create ramp table .

any link or any example may be helpful !!

 

[FvM]

I presume, the table will contain time intervalls between steps and be processed entry by entry when accelerating or decelerating the motor. The solution seems straightforward enough to code it from the scratch.

 

[nick703]

YES table contain time interval in step . i test lots of value of change in timer value but i didn't get accurate result at slow speed .

 

[FvM]

test lots of value of change in timer value but i didn't get accurate result at slow speed .

Don't understand what that means.

A stepper motor has a maximum start/stop frequency (which also depends on the externally connected load inertia). Below this frequency, it can be moved stepwise as you like and there's no purpose of a ramp table. If you want to rotate the motor at a speed above the start stop frequency, you'll execute the table up to the intended speed.

That's the problem viewn from the step motors perspective. Application-wise, you may want to move the motor along arbitrary step versus time profiles, but I won't understand this as a ramp table.

To make your problem understandable, you should precisely describe what you want to schieve and what you observe.

 

[betwixt]

I presume nick703 wants to dynamically change the speed so it goes faster when more steps are required. One option would be to forget the table and calculate it mathematically, more steps = shorter step delays. Obviously taking in to account the limitations of the motor and driver circuits.

Somethng like:

number of steps = abs(present position - desired position)
if(slowest step speed time - (number of steps * a constant) < fastest step time) step speed time = slowest step speed time - (number of steps * a constant)
else step speed time = fastest step time.

Please don't put that in a compiler and expect a result !

Brian.

 

[nick703]

yes betwixt i understand bro!!!.

and hi FVM

i want to achieve rotate stepper motor smooth no jerk or no vibration on motor when speed increase.