Check out this thread http://www.cnczone.com/forums/showth...stepper+damper (My take on a stepper damper)
Hi guys, how's everyone doing? This is my first post here.
I'm having problem driving my motor at certain velocity under load. Below are my specs:
Stepper motor 1.8deg (i do not have the complete details, sorry)
Power settings 24V 1.5A
KT-5191 bipolar stepper motor chopper driver (using L297 & L298), running at half-step
Desired final velocity 16rps
I'm running at half-step, the final freq to generate my desired velocity is 6400Hz (16rps*360deg/0.9deg=6400). Since i can't have my motor start at 6400Hz i'm ramping my motor speed by incrementing my freq up to 6400Hz (under load). However, i have problems achieving this value without my motor stalling. I need to met certain accel specs thus i can't ramp too slowly.
Initially i tweaked with my ramping profile (through trial and error), thinking the motor may not have sufficient torque to overcome the load => unsuccessful
Recently i've discovered such a thing as the resonance issue with stepper motors. Based on what i have read i've concluded there are 2 ways around this:
1) Create a damping circuit between my stepper driver and my motor
2) Avoid the resonant bands altogether
2) Use micro-stepping driver
What are your comments on the 3 methods above?
With (1), i'm currently googling literature on this but no success yet. Can someone help me by pointing me to the right direction?
With (2), how do i first find this resonant band? I understand i can find the lower range by slowly ramping my freq up to a value until my motor stalls, but how do i find the upper range?
With (3), involves extra costs. No 100% sure it'll solve the problem, it's my Plan B if (1) and (2) fails.
Microstepping driver helps, but doesn't eliminate it. A driver with midband adjustment will help even further. Simplest solution is a stepper damper. The other issue is your desire for 16rps. Steppers naturally loose power as their rpms increase. Take a look at an example here: http://pminmo.com/PMinMOwiki/index.p...chanical_Power
It's based on a commercial Vexta motor and their own data.
Phil, Still too many interests, too many projects, and not enough time!!!!!!!!
Vist my websites - http://pminmo.com & http://millpcbs.com