Timescapes - Digital Timelapse Discussion

Weird and Wonderful uses of Motion Control
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Author:  geraldft [ Thu Jun 09, 2016 8:11 pm ]
Post subject:  Weird and Wonderful uses of Motion Control


My friends at Kids of all Ages in Germany made this fun video using Mantis to control a variety of motion control apparatus...

Author:  sciencelookers [ Fri Jun 10, 2016 6:46 am ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

Far out! I hope I can make it do something that useful someday.

Author:  DISPLACEMENT 1 [ Fri Jun 10, 2016 10:54 am ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

Ah got the same problem my model mover has its to smooth ! I know they just messing about but it does highlight the problem that motion control can be to smooth . Think they need your Yost functionality to give the moves that realistic look. Been running my model mover and its getting to the point were it would be just as easy to animate it stop frame by the time i have entered enough key frame to make it look realistic . Ok that would only give ya one pass but a lot of animators i know would be happy with that . Soz i am talking animation again but it does apply to real time. .
In AE you can enter a wiggle amount to motion paths to introduce a slight randomness to the move . Wonder if you have thought of adding such a thing to Mantis i know it can look a bit contrived but its better than nothing.

Author:  geraldft [ Fri Jun 10, 2016 1:41 pm ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

Actually I think the robotic feel is part of the charm..? :) For sure there could be some fine tuning of relative speeds but that just takes a little more time programming. I'm not sure what part you would want to put random movement into?

If you did want to randomise it's pretty easy to add more keys here and there. Even with Yost I still do some manual adjustment to fine tune it.

I am also working on a math function that can add one axis to another. Then you could use a favorite wiggle track and superimpose it... But for many shots it's quicker to just program from scratch using trial and error method. Though it takes a bit of experience to do this efficiently.

Also interesting is that they assembled quite a range of off the shelf components and ran them from one control source.

Author:  Doug K [ Fri Jun 10, 2016 3:29 pm ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

Hey Gerald got a question for ya. If I were to add encoders to each axis of my rig, which is capable of being positioned by hand when the drives are disabled, could I keep the drives disabled, hit the record button and get any kind of data into Mantis as I move the rig? I'm thinking that would be a cool way to add in that human touch that would be repeatable. No what I mean? I think that is what you guys are talking about when you mean YOST thingy correct? Anyway just curious.

Author:  geraldft [ Fri Jun 10, 2016 5:40 pm ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

Ah yes. Of course you could record such manual input. It makes no difference to Mantis if the encoders are from a handwheel or attached to the rig.

This method can be called "learn mode" - ie. you guide the rig and record movement on the fly.

The main issue though, is that you are pushing against the motors so it's not going to be very easy unless you can de-clutch the motors or gears.

Also - if you did try it, you'll need to set the scaling of the encoders so they return values to match the axis units. ie. the scale value will depend on the PPR of the encoder compared to the motor microstep rate. For instance if an encoder is mounted on the motor shaft, and the resolution is 1,000 pulses per rev, but the motor is 3,200 ppr, then the scale factor will be a multiple of that ratio ie. 3.2:1.

If it's just for recording pan tilt data you might be better making a Waldo - ie. like a joystick with encoders instead of potentiometers. Similar to a pan bar which is normally a fluid head with encoders...

The Yost thing is just another way of doing much the same, but using a 3 degrees of freedom inertial sensor instead of encoders, which obviously can work for a handheld recording system. If I could to convert the sensor data to encoder signals, then it could also be recorded directly. But in the meantime the sensor has to be recorded by a separate application, then the file imported to Mantis.

Ultimately an encoder solution is more accurate than a sensor but requires mechanics to work... :(

Author:  Hamill [ Tue Aug 02, 2016 2:08 am ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

Weird? Mantis powered?
I have a few!


Definitely, vimeo embedded videos are not working or I donĀ“t know how to use it!

Author:  sciencelookers [ Wed Aug 03, 2016 7:13 am ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

The links to the vimeo videos are not working at present, but I copied the middle part and was able to view the videos. The orinthopter and boot are very cool. I think the boot could be produced and sold as a product if you can program it to make more of a kicking motion instead of the walking. College fraternities could use them for initiation ceremonies. With enough speed and power behind the boot, football teams might use them for practice. Kids would love it as a toy.

Gerald, I am intrigued by the teach mode. Of course, I love the idea of disabling the drivers and moving the rig by hand to program in more human-like movements when that is the goal. Thats a real good question Doug, thanks for bringing it up. I also have several robot arm frames left over from the mini rig conversion. They could easily be fitted with different end effectors like dremels or small router motors for carving foam or other soft stuff. Repetitive welding or other typical robot jobs might be pretty easy to program this way. It would sure beat jogging each motor manually from the computer. I wonder how many DPs would prefer to move the rig themselves by hand and then let it run the move over and over. Assuming the rig is well balanced, there isn't a lot of weight to shove around, just the resistance of the gearing to contend with. As you say, something designed with encoders on the rig joints instead of the motors would allow the drive to be un-clutched so the rig could be moved more freely. Even if the encoders needed their own gearing to achieve the required accuracy, these gearboxes could be small and comparatively easy to turn.

The realtime rig is still only a partial skeleton, so it would be possible to incorporate something like this with less effort than trying to add it onto a finished rig. Any thoughts or suggestions on how to go about making something to support this feature?

Author:  geraldft [ Thu Aug 04, 2016 5:48 pm ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

Nice kinetic sculptures Hamill...

SL - no easy way to do teach mode. Declutching mechanisms need to be backlash free. Then, unless encoders are high resolution they may need gearing up which creates resistance. So it's hard to get smooth recordings. Old fashioned programming is the best bet, or building moves in 3D if the rig has complex geometry.

Author:  geraldft [ Sun Aug 21, 2016 9:07 pm ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

Some new math functions showing the flexibility of Mantis. These can come in very useful and save a lot of programming time when creating repeated cycles of wave motion.. :)

Author:  geraldft [ Tue Aug 23, 2016 3:56 pm ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

Two clips from Klim in Kazakhstan showing his boom rig shooting a multipass TVC with Mantis.

And the result...

Author:  Doug K [ Tue Aug 23, 2016 5:27 pm ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

Cool rig. Is that boom section telescopic? Not like a techno crane but can be extended if needed? Kind of looks like it.

Author:  geraldft [ Tue Aug 23, 2016 5:51 pm ]
Post subject:  Re: Weird and Wonderful uses of Motion Control

The boom is fixed length - it's just he uses round tube rather than square. Looks very similar to the tube on a Jimmy Jib actually. On his earlier incarnation of the rig the arm is shorter - seems he has a couple of arms for different purposes, or this one has different length sections that can be substituted.

PS - the dolly drive belt is very chunky. Looks like T10 or AT10 about 25 - 30mm wide. The servo motor drives the big drive pulley via a planetary gear I think.

A another nice thing about the setup is the drives are on the rig, so only a light cable for step and direction is needed from the controller, plus a mains lead.

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