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Author Topic: NeverStall Stepper Motor Controller  (Read 7162 times)

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NeverStall Stepper Motor Controller
« on: February 19, 2013, 09:38:49 AM »
I came across this video and was wondering if any of you had seen or had any experience with this product, because it sure looks good  ;D
http://www.youtube.com/watch?v=2SozZ7af3wg

Offline Hood

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Re: NeverStall Stepper Motor Controller
« Reply #1 on: February 19, 2013, 09:49:48 AM »
Unless you had feedback and a control that could slow all other axis as one slowed then its a waste of time in my opinion. One axis starts to slow because it gets overloaded but the rest continue as they are meant to and your part isnt going to look like its meant to ;)
Hood
Re: NeverStall Stepper Motor Controller
« Reply #2 on: February 19, 2013, 09:58:20 AM »
I thought the same thing and wondered if anyone had produced such a configuration, because that would be good, don't you think? It would have to work in a similar way to the wire EDM when it retracts for any reason.

Offline Hood

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Re: NeverStall Stepper Motor Controller
« Reply #3 on: February 19, 2013, 10:08:36 AM »
I dont really see any benefit, certainly not with regards to machine tools.
 For example even if you could slow all other axis in relation to the slowing axis,  what is it going to do to stainless if the feedrate slows down, it would work harden, cutter would snap and part is possibly wrecked.
 Similar in wood, you are happily machining,  one axis slows because its about to stall, all others slow to compensate and you burn your wood.
In some applications it may be fine but as far as I can see its a waste of time in the world of CNC machine tools, much better to just have motors that are capable of doing what you command.

Maybe I am just not seeing the benefits it could bring?
Hood
Re: NeverStall Stepper Motor Controller
« Reply #4 on: February 19, 2013, 10:10:25 AM »
Good point, thanks.

Offline Hood

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Re: NeverStall Stepper Motor Controller
« Reply #5 on: February 19, 2013, 10:48:31 AM »
I can remember years ago when Mariss (Gecko drives) announced he was working on the unstallable stepper. I thought this is going to be amazing but as I thought about it further I then realised there may not be many benefits, if any, at all. I still cant think of any with regards to machining but there may well be some.
Hood
« Last Edit: February 19, 2013, 10:54:27 AM by Hood »
Re: NeverStall Stepper Motor Controller
« Reply #6 on: February 19, 2013, 01:19:45 PM »
I have always struggled with the logic, and perceived benefit, of such systems.  The explicit base assumption of such systems is that the motor/controller simply cannot provide the torque required to do the job correctly, which means the system was poorly designed from the start.  "Closed loop steppers" seem a crazy expensive and complex solution to poor design.  For less money, you could design the system properly, and never have to worry about losing position.  For about the same money, you could build a servo system, and likely get better overall performance.

And, note that, even in the video, the motors do NOT maintain position.  When the guy grabs the wheels and turns, the motors move.  The only thing that's different is that AFTER he lets go, they return to where they should have been all along.  How is that "unstallable"??

Regards,
Ray L.
Regards,
Ray L.
Re: NeverStall Stepper Motor Controller
« Reply #7 on: February 20, 2013, 02:22:32 AM »
Perhaps these are the reasons why these systems are not common?

Offline mc

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Re: NeverStall Stepper Motor Controller
« Reply #8 on: February 20, 2013, 08:22:08 AM »
The main benefit of closed loop steppers is knowning when things have gone wrong. They give that piece of mind that should something go wrong, a correctly set-up machine will stop, whereas something with standard steppers will continue doing things it shouldn't.

They do work out cheaper than an equivalent servo, and if you don't need the speed of a servo (or don't want to add gearing), then a closed loop stepper does make sense. I've looked at the Leadshine closed loop system, and one benefit of the larger system is it tells you when it's on position, so they do give the possibility of increasing accuracy and letting you know if that accuracy is being held.

Offline RICH

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Re: NeverStall Stepper Motor Controller
« Reply #9 on: February 20, 2013, 05:01:52 PM »
Waste of money and effort as far as I am concerned and agree with Ray. Know and work within the capabilities of your stepper system and you won't have a problem.
RICH