Stepper motor CW and CCW ?

[nick703]

OK now i have to know what is the best solution need to rotate bipolar stepper motor CW and CCW with maintain torque and smoothness .
my driver is standered Allegro 3977 and DPM stepper motor with 1.8 degree step angle 2.8 A .

once my stepper motor rotate command gives that time i send on command and lenth and speed also stepper motor jerk at low speed .

 

[barry]

Use microstepping.

 

[nick703]

ok first of all using micro stepping what detail should be required ? i know littel more about make a delay table and and accelerate to appropriate time period . and how we calculate perfect micro step ?

suppose initially my requirement is i want to rotate stepper motor maximum 3 round and minimum half round . when 3 round complete in forward direction that time immediate move reverse direction also 3 round and that process continues . and i configure when fast speed applied that time torque minimum that time my motor become unstable means if applied load that time the motor become stop ? so i believe is that problem in program technique right ? please suggest me best technique how to maintain torque at high speed . and when motor going to slow speed that time high torque so motor become jerk why and how-to resolve his?

 

[barry]

I'm not quite sure I understand. Are you saying the motor is losing steps ("motor becomes unstable") at high speed? If that's the case then you may either have a resonance problem, which can be solved with a damper, or you may have mismatched your motor/driver to your load.

The motor is "jerking" at low speed because, as I hope you understand, a step motor works by moving in discrete steps. That's why microstepping is used to smooth out the motion. I don't know how to answer your question "what detail should be required". I think YOU need to tell US what your details are. There is no "perfect micro step".

 

[nick703]

ok barry i give u my detail .

first of all i used MIMY motors stepper motor 57HS76H-2804B Model no . which has 1.8 degree step angle , 2.8A 1.13 ohm and 18.9kg.cm.

i have a driver Allegro 3977 . and micro is pic32mx575f256h c32 library right.

i have driven stepper motor cw and ccw with use of this items. but smoothness is the problem i have 400 pulse applied to rotate stepper motor one revolution in half step right. (200 in full step)

i read this thread also to accel and decel stepper motor
https://picprog.strongedge.net/step_prof/step-profile.html

 

[barry]

But you still are telling us nothing about your SYSTEM. What's your load? A fan? A conveyor belt? have you sized your driver/motor properly? And you haven't explained what you mean by "becomes unstable". A step motor has no 'stability' issues, but it might lose steps, as I explained.