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 Encoders. 
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Joined: Tue Apr 09, 2013 6:49 pm
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Post Encoders.
Hey people, here is a quick video showing the encoders I have setup to run with my rig through MANTIS.
http://youtu.be/7vNl4DHQk5A


Wed Jun 19, 2013 9:45 am
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Post Re: Encoders.
I like ! You made some changes to rig too . Wish i had some spare cash but blown pottering budget this year . Maybe next ,really do like the feedback you get with those encoders . Makes me envious :D


Wed Jun 19, 2013 11:16 am
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Post Re: Encoders.
That piece of kit has been evolving for some time, looking better after each phase of your upgrading.

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Thu Jun 20, 2013 5:11 am
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Post Re: Encoders.
Thanks guys. I made the decision to go back to my crane as opposed to a larger 3 axis head that would have accommodated cameras like an ALEXA or an EPIC. The reason is I am pretty much committed to stop motion right now and I don't have the funds to create both. A crane for stopmo is giving my animations a very cool look and the perspectives I can get on a small scale are going to I hope give my work more of a cinematic quality. So I will stick with this crane for now as it works really well for what I want.

As for the encoders, yeah they work really well. My next step is to make a jog box so I can be standing next to the rig while positioning each axis. So far all the features of my Mantis controller work with my little basement moco studio, intervalometer, SMS integration with Dragonframe and so on. I found some vintage youtube videos with John Dykstra explaining motion control systems at his company Apogee. Here is the link,
http://www.youtube.com/watch?v=bTOMP34q ... 25tXzXj5Bg

Sorry about the fact that it has a Japanese voice over.


Mon Jun 24, 2013 9:03 am
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Post Re: Encoders.
Hi Doug enjoyed the video not seen that before think will have a look at some of your others . You obviously done your researcher on vintage motion control.
Really like the old model stuff its got a rich quality CGI does just doesn't have . 2001 prob my favorite film closely followed by silent running . They still look great ! And we can do it in our sheds now :D Motion control and After Effects so much fun .


Mon Jun 24, 2013 11:39 am
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Post Re: Encoders.
Isn't it amazing what we can do now! I have scoured the net for videos on the early days of motion control but there does not seem to be much out there. I will keep looking, I will keep watching. How goes it with you Dman? I love that rig of yours. I wish I had the ability to CNC my stuff. Are you going into production to sell?


Mon Jun 24, 2013 5:35 pm
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Post Re: Encoders.
An interesting video, thanks for sharing, my rig has something in common with that set up........... at about 9:50 two G-clamps come into view ;)

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Tue Jun 25, 2013 11:14 am
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Post Re: Encoders.
Doug K wrote:
Isn't it amazing what we can do now! I have scoured the net for videos on the early days of motion control but there does not seem to be much out there. I will keep looking, I will keep watching. How goes it with you Dman? I love that rig of yours. I wish I had the ability to CNC my stuff. Are you going into production to sell?


Very small scale production just to animation company's its my background ( did you see my day job post viewtopic.php?f=10&t=9916) . Lots of company's already have very large rigs which are not really practical and to be honest look a bit daft with a dslar sat on top of them. Just a left over from 80s and 90s . My complete rig is smaller than the electronics that drive those old beasts so slowly converting people .
On the cnc front i didn't spend allot bought a Chinese sieg x2 mini mill and basically took the handles off and stuck some steppers on. The basic mill isn't the toughest thing in the world but that's the advantage of cnc you just do lots of gentle passes. So aluminum no prob at all and the tolerances are acceptable for what i do . If you consider going down that route PM me will try and help
Cheers Dman :)


Tue Jun 25, 2013 12:21 pm
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Post Re: Encoders.
Just went and had a look at your day job. I am impressed with the builds. What a day job to have. Most of my life has been spent either on a bike as a messenger or fixing bikes. Guess that is why I look so young for my 50 years. I remember the Wind in the Willows show. John Hurt was the lead voice on that wasn't he? I know I could look it up on google but me memory is still good for some things. Brian Blessed as well correct? Must have been fun to work on that in any department.


Tue Jun 25, 2013 1:05 pm
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Post Re: Encoders.
Hi,
Some model making / filming takes that may be of interest 8:00 onwards is where the motion kicks in.

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Sat Jul 13, 2013 10:24 am
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Post Re: Encoders.
Hey Mike,
Yeah I have watched that one countless times. Not sure why there are not more. Motion control is truly an esoteric arcane art! Did I put up the link to the one with Dykstra talking moco but with a Japanese VO? That is the best one I have ever seen. Lucky Japanese:)


Sat Jul 13, 2013 4:49 pm
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Post Re: Encoders.
Doug K wrote:
Hey Mike,
Yeah I have watched that one countless times. Not sure why there are not more. Motion control is truly an esoteric arcane art! Did I put up the link to the one with Dykstra talking moco but with a Japanese VO? That is the best one I have ever seen. Lucky Japanese:)


Hi Doug, 4th post down for the VO, that was interesting. There are 7 in the series for the one I posted, but I guess you will have seen those, showing different aspects of film production techniques posted by the same guy.
I expect a lot of good stuff has been lost due to storage constraints or is still waiting to be digitised?

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Sun Jul 14, 2013 1:23 am
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Post Re: Encoders.
Cheers for posts guys . This is all a really a dying art witch is a shame .Specially for me :( . Most company's wouldn't even consider model shots these days for either financial reasons or artistic. With CGI they have the ability to control every aspect . That tire always bounces into shot when a car explodes etc . Just all looks a bit to contrived to me . As the fella said in the clip happy accidents are sometimes best . Is this me going of topic again!


Sun Jul 14, 2013 1:54 am
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Post Re: Encoders.
DISPLACEMENT 1 wrote:
Is this me going of topic again!


When have you ever done that....... ;) ;)

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Sun Jul 14, 2013 5:07 am
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Post Re: Encoders.
MikeA wrote:
DISPLACEMENT 1 wrote:
Is this me going of topic again!


When have you ever done that....... ;) ;)


Well did say happy accidents always best and that's a bit like going of topic :D


Sun Jul 14, 2013 5:45 am
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Post Re: Encoders.
DMAN, perfectly acceptable to wander and meander anywhere you want:) I hope guys like Peter Jackson keep model building and the use of same alive and well! Fingers crossed:)


Sun Jul 14, 2013 6:13 pm
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Post Re: Encoders.
Doug K wrote:
DMAN, perfectly acceptable to wander and meander anywhere you want:) I hope guys like Peter Jackson keep model building and the use of same alive and well! Fingers crossed:)

Well seeing how its ok to go off topic here goes and lets face it its what i do best :D . Just to let you know rocks are still been made out of good old fashioned polystyrene here's last weeks job.
[flickr]Image
20130715_141154 by DISPLACEMENT101, on Flickr[/flickr]
[[flickr]url=http://www.flickr.com/photos/95526586@N02/9358470689/]Image[/url]
20130724_180818 by DISPLACEMENT101, on Flickr[/flickr]


Wed Jul 24, 2013 11:45 am
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Post Re: Encoders.
Hi Doug going back on topic hows it going with Mantis ? Was wondering if you have upgraded your drivers yet . I am still searching for some decent small ones was wondering if you had any luck or even better still you are finding the BEDs adequate for live moves. Hope all good and you busy .
Don't know if you so the post on Blender interface for MOCO looks interesting from a CGI composting point of view . viewtopic.php?f=31&t=10750.
Been playing with Blender last couple of days its free and open source :D The sculpting bit is quite intuitive did a head going to get it printed . They have 3D printer at one of the places i work so will see how it goes . Handy for puppet making the head should be really tough and light and no messy mold making and casting .
Cheers


Thu Aug 08, 2013 2:59 am
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Post Re: Encoders.
Hey DMAN,
yep still using the BEDs for real moves but I do on occasion run into a stalled motor problem. Not sure if that is a motor problem or the controller not being able to keep up. I am using roller blade bearings directly onto steel rails so I have cut down on friction/drag enormously. The skateboard wheels are fine for doing a realtime move but once you enter the realm of stopmotion where the rig can sit for hours you run into the problem of flat spots on the wheels which in turn generates a bumpy shot. So in my opinion, go with bearings right on steel rails, preferably very smooth polished rails. You can also use aluminum but there is the problem of nicks and the like. But you use alu without incident so maybe it is a case of use whats at hand.

Other than that still working on my animation and perfecting the rig day by day.


Fri Aug 09, 2013 9:34 am
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Post Re: Encoders.
Hi Doug yes i just use bearings directly onto a ladder . Must admit i was surprised how well it works. The ladders are manufactured to pretty good tolerance considering its supposed to be just a ladder. Do give the bearing surface a sand with fine wet and dry though . I to tried inline skate wheels but found them to be of center or out of whack somehow . But to keep it cheap and cheerful i do use standard skate board bearings when possible 22mm 8mmb bore . You can get them most sports suppliers at a really good price .
On the driver front will stick with the BEDs a bit longer . Just like the size of them i always mount the control box on the rig to keep down the amount of cables going to it . Now the cranes coming together this is even more important more axis more wires :( . The weight is building up to might have to do a bit of redesign on track carriage . Hey oh never ending this rig thing prob why i like it .
Hope film going well getting stuff together for my first proper animation to . Something to do over winter and its shed centric :D


Sat Aug 10, 2013 3:31 am
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Post Re: Encoders.
Hi guys,

It looks like I have sorted my crane vibration although I need to do more tests at different speeds, etc.

I used 150:1 reduction for the rotation and now I am going to try a different approach with 240:1 reduction. So far so good. I can't wait to finish it so I can post some pictures or video.

Anyway, cheers.


Edward


Sat Aug 10, 2013 12:57 pm
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Post Re: Encoders.
edward wrote:
Hi guys,

It looks like I have sorted my crane vibration although I need to do more tests at different speeds, etc.

I used 150:1 reduction for the rotation and now I am going to try a different approach with 240:1 reduction. So far so good. I can't wait to finish it so I can post some pictures or video.

Anyway, cheers.


Edward


Sounds good that's quite a reduction . Are you worried about loosing your top speed . But i suppose if you are mainly doing macro top speed isn't such a issue . Just out of curiosity what is the maximum pules per second output of Mantis. DF is only 20000 pulses per sec .
Still waiting for drive parts to turn up ballscrew etc so not managed to do any real testing yet of my crane .
Look forward to seeing your tests

Cheers


Sun Aug 11, 2013 4:38 am
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Post Re: Encoders.
Sorry, I don't know how many pulses/second, but whatever it is, it's fine.

Regarding the top speed, I have more than enough top speed on the crane rotation, and not just for macro, for anything, unless I was filming at very high frames per second, the crane rotates more than fast enough with 150:1

As you will find when you have completed your crane in metal, the crane arm has got a lot of inertia, due to its weight (camera, arm, weights) so you can only go so fast, as you need to be gentle with building up the speed, and then the motor has to stop all the built in inertia on decelerating. So unless you had one of these industrial factory type robots (Fanuk) that literally weigh a ton, I think with the typical crane like you are building or similar, the speed you can realistically achieve and work with is governed by factors other than just the motor speed.

If I wanted more speed (which I don't), I would use a higher feed voltage (maybe approx 40V) to the drives and I would decrease the micro stepping a little (which I may do anyway). But more voltage can result in slightly rougher running of the motor. At the moment I run the drives at 25V. And the micro stepping reduces the speed considerably if you go for silly numbers. In fact, I find the micro-stepping at anything beyond 800 steps per rev to be completely unnecessary in my case, because these minute steps have to go through the gear reduction, so the movement is continuous. Plus too much micro stepping reduces the torque considerably.

I am still using the Leadshine drives. Recently I got a Leadshine HBS57 Hybrid servo drive which runs a compatible motor with encoder. Although encoders are fun, I don't really need them, as I don't loose steps, and the encoder needs an extra cable, so for the moment I will stick to normal steppers which I find very accurate.

Edward


Sun Aug 11, 2013 10:15 am
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Post Re: Encoders.
Hey guys,
If I am not mistaken Mantis will go up to and I think beyond 200 kHz which is 200,000 steps per second I believe. Pretty much as fast as the DMC16 from DragonFrame.


Sun Aug 11, 2013 8:10 pm
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Post Re: Encoders.
According to the web site
Quote:
Mantis is based on the Dynomotion Kflop processor


Details here:
http://dynomotion.com/KFLOP.html

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Sun Aug 11, 2013 11:23 pm
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Post Re: Encoders.
MikeA wrote:
According to the web site
Quote:
Mantis is based on the Dynomotion Kflop processor


Details here:
http://dynomotion.com/KFLOP.html
Doug K wrote:
Hey guys,
If I am not mistaken Mantis will go up to and I think beyond 200 kHz which is 200,000 steps per second I believe. Pretty much as fast as the DMC16 from DragonFrame.


Cheers for that was aware it was a Kflop board just not sure how fast it could go .
Ball screw turned up from China not to bad about a week some UK companies take longer . Word of warning DONT TAKE THEM APART
. Just spent last three hours trying to get very small ball bearings back ware they belonged :(


Mon Aug 12, 2013 2:19 pm
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Post Re: Encoders.
hahaha! that happens when you are just too curious!

Glad you got it at last.


Mon Aug 12, 2013 3:25 pm
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Post Re: Encoders.
Actually maximum step rate of the Kflop is 1.6Mhz. In Mantis settings I allow for up to 500Khz since this seems enough in practice. But most cheaper drives won't work with this rate anyway - only more expensive industrial drives. With steppers 200Khz is more than enough since you just set the micro-step rate to suit the gearing and max speed required...

In reality these numbers are not what matters the most. Smooth running also depends on things like low jitter - ie. that the steps come at a regular rate. In this the Kflop is excellent.


Fri Jan 24, 2014 12:00 am
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