BBB - Super-accurate small motor control with a BeagleBone Black

RE: BBB - Super-accurate small motor control with a BeagleBone Black

D_Hersey — Wed, 04 Feb 2015 15:55:38 GMT

A cool way to get some data on your nifty driver, Shabaz, would be to hook it up to a magnetorheological clutch optimised for linear operation. Then we could draw some curves!

RE: BBB - Super-accurate small motor control with a BeagleBone Black

D_Hersey — Wed, 04 Feb 2015 15:49:01 GMT

If you have a four-phase unipolar motor and it has more than 5 wires, it can be configured as a bipolar motor of twice the voltage, just mind the phasing dots. This has been a motion-control public-service announcement.

RE: BBB - Super-accurate small motor control with a BeagleBone Black

madiva — Tue, 03 Feb 2015 14:43:12 GMT

i will be using bipolar steppers, probably 12v 1A specifications. and i need to drive like six of them. The reason i asked whether u had worked with KL25Z with a stepper motor driver, is because shipping stuff to the country am in is a bit expensive, and i didnt want 2 ship smth then later it causes sm problems. So if can be assured or guaranteed of a working setup, then i can defntly ship them even if that will be expensive i will be assured of a working circuit setup. So thanks 4 the info, i will check them out, and if u get any info that is of help 2 me then i would gladly appreciate if u could inform me.

RE: BBB - Super-accurate small motor control with a BeagleBone Black

madiva — Sun, 01 Feb 2015 14:55:17 GMT

Hi, just a broad question here...... I was wondering if you could help me in suggesting a stepper motor driver for my freedom board. I have a FRDM-KL25Z which i have been trying to use with an allegro A4982 but the circuit doesnt seem 2 work. So by any chance might u have worked with this type of board (3 v logic pins) and driven sm stepper motors? and if so could u suggest which 1 i coulld use. Thanks in advance.

Regards

RE: BBB - Super-accurate small motor control with a BeagleBone Black

morgaine — Mon, 16 Sep 2013 18:13:10 GMT

Very interesting article indeed, shabaz.

I've never had much to do with motors, so inevitably this post made me think of one of the few instances where motors have put in a local appearance, namely my poor ol' Shapercube 3D printer which I've neglected totally after an initial period of excitement in kit construction. I really need to get back to it.

Like all traditional RepRap-generation printers, the Shapercube uses several stepper motors, NEMA 23 steppers for carriage movement and a smaller one for extrusion control. The NEMA 23 steppers are typical of the breed, in this case Nanotec ST5918M1008-A with a holding torque of 74 Ncm.

The reason I'm bringing this up is that I dislike open loop systems, and have long argued that the future of 3D printers lies in closed loop motor control for speed, accuracy, reliability, and the ability to compensate dynamically for the inevitable flexing of structural members. The use of steppers and open loop control may be tactical in these early days of home 3D printing, but not too far ahead we'll need more advanced movement control systems, I'm pretty certain.

So, do you have any feeling for how your closed loop tests with tiny brushed DC motors might scale to NEMA 23 sizes and this order of torque? Would we best stick with steppers even in closed loop operation just to obtain a holding torque for "free", or should we use electronic commutation with brushless DC motors to provide the desired holding torque when stationary? Can the ICs you used handle the latter?

RE: BBB - Super-accurate small motor control with a BeagleBone Black

fustini — Mon, 16 Sep 2013 16:21:15 GMT

Wow, another brilliant BeagleBone Black post!