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 New Dmoco 6 Axis Rig Driven by DMC16 
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Joined: Wed Feb 15, 2012 3:36 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
That's a serious head you have there! And quite speedy too! Out of interest, what the weight of the head only?


BTW, yes, milling the eccentrics from the other side of the plate to separate them sounds like a better idea, and that way you can go and watch your plants grow for a little longer!

Edward


Fri May 20, 2016 10:40 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Edward its not light in fact a tried to weigh the head and boom end when i took the photograph . My scales complained and zeroed out :( which is annoying because in need to work out how much counter weight i need . Off to the weightlifting shop tom for you've guessed it weights !.
Got a feeling its prob about 6kg or over but will try and find some bigger scales tom . On the plus side i can increase the pocketing considerably now i know how rigid it is and believe me its rigid . Going to build myself one so will prob increase pocketing a bit more and take it from their .
D1


Fri May 20, 2016 11:24 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
For now, here's a link to the old video showing the first prototype of my vertical focus motor. The mold is made about halfway through the video in case you want to skip straight to it. I will try to make a better video next time I make a mold so it can include some narration and tips about making molds.



https://www.youtube.com/watch?v=fUZOBtp-PZw

I like using molded parts for prototyping. The original model doesn't need to be strong. I use a lot of glue and modeling clay. After making a mold and casting, the cast parts are monolithic and very strong. The focus motor being made in the video was run for some initial tests before being sent to an engineer who made CAD drawings so parts could be 3-D printed or machined on CNC mills and lathes in the big machine shop.

I got rid of the big printer and now use two home desktop printers. The Rostock Max Version2 has a large build volume and is really reliable about making a good print every time. It melts filament and squirts it through a nozzle to build parts. You can always see lines where the nozzle moved to build the part if you don't do some sort of finishing. My other machine is a B-9 Creator which hardens resin with light. They advertise 50 micron resolution. Actually, the surface finish of the parts is a lot better than you'd expect based on the resolution. This is because light does diffuse through the resin a tiny bit leading to a blurring of the scan lines and smoother finish on the parts. Jewelers love this machine for making models for lost wax casting. The parts have a very smooth finish right out of the printer. The resin burns out of ceramic molds almost as nicely as wax. I found it frustrating because it would make holes slightly undersize while making the outside of the part just a hair oversize. There is no scale setting that can fix both. They sell two different resins for the machine and I was finally able to make good gears by mixing 3 or 4 to 1 of Cherry to red. The B9 has a tiny build area about the size of a credit card if you want the highest resolution. It can print larger things up to about 4 by 5 inches if you zoom wide and refocus the projector, which is a real pain to do.

Finishing 3-D printed models involves files, finer and finer grit sandpapers finishing with very fine wet sanding, then an automotive paste wax with several layers of that. You can actually get a glossy finish if you do enough sanding first. Automotive sandable primer works great on cast parts going for another round of mold making. Put on a few coats of one color followed by several coats of another. When you start sanding into the first color, either stop there, or apply some more coats of the second color before sanding more. The first color warns you that you are getting close to the actual surface of the part. I have also heard people give ABS prints a glossy finish by exposing the part to acetone vapor. You don't wipe the part with liquid acetone, instead you put the part on a raised platform in a very shallow pool of acetone and enclose the whole thing in a box or bucket with a cover. I haven't tried it myself, but from what I've read it doesn't take long. Too long and your part can look sort of melted.


Fri May 20, 2016 11:33 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Mine of information, thank you! I'll take a look at that B-9 Creator printer.

And D1, my heavy duty head is about 5Kg, and that's without the rotary, just pan/tlt. It's the HD's that weigh a lot.

Edward


Fri May 20, 2016 1:11 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
edward wrote:
Mine of information, thank you! I'll take a look at that B-9 Creator printer.

And D1, my heavy duty head is about 5Kg, and that's without the rotary, just pan/tlt. It's the HD's that weigh a lot.

Edward


Yes i do wonder about the advantages HD sometimes. You already use a timing belt and pulley by adding one more of each you get can the same gear ratio without the cost and weight of a HD . I also find when using steppers the timing belts help isolate any resonance you may get from the motors. As for backlash i have my belts short and no slack . In the new head theirs no play or spongyness at all advantage of a much bigger belt profile i think. Of course this means bigger pulleys which can be hard to get but thats ware laser cutter helped a lot :D .
D1


Sat May 21, 2016 12:32 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
I don't think you can compare HD's with just using pulleys.

I have made 2-stage and even 3 stage belt gears and they work well, but they take up a lot of space and crucially for me, the belt stages don't hold the weight of even the smallest DSLR's because they are so effective. My HD's, being 50:1, hold the weight without rolling, plus they have a hollow shaft, plus the bearings are designed for heavy angular forcers.

However, against them, they are expensive and rather heavy. If you don't mind the camera rolling down, a 2 stage pulley system is fine, but quite bulky with large dia pulleys if you want to get to 50:1.

A worm gear system is something to consider too, cheap and light, but most probably no back driving is possible, which may not be of much importance anyway.. I have the higher tolerance OnDrive ones at around £200 each, and they guarantee practically no backlash. Unfortunately for me, I need a hollow shaft, which means building an extra stage, probably too much complication where a simple HD would solve the problem.

The 2 smaller HD's I have weigh 345 gms each including stepper motor. My aim is to produce a pan tilt with these HD's at a total of less than 1.5Kg, using a combination of metal for the "chassis" and 3D plastic for the covers, or maybe all plastic except for things like the hollow shaft and bearings and the tilt bracket which can be got off-the-peg cheaply anyway. For the printed plastic I use small M3 inserts for the screw threads, dirt cheap and they work so well.

I will use the SilentStepSticks, as I really like them, I even use them on my column arm and they are well…silent, and fast enough for me using Mantis, though not race horses at the mega silent, smooth micro step setting. I do recommend them, I had a few mysterious problems with them to start with, no doubt down to me doing something wrong, as I can't seem to fault them now. Only suitable for very small amp motors with gear reduction really, as otherwise the torque at these micro settings is quite small. The motors I use with them are rated at 1A or less.

Edward


Sat May 21, 2016 7:35 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Oh dear think we are going to have to agree to disagree on the pulleys thing . My new head will brake your fingers if one was to get in the way at a slow speed which concerns me slightly :( . Gearing is around the 50 to 1 and it dose not slump specially if the motor is plugged into the driver . The driver doesn't have to be powered up its just the electrical resistance . But each to his own. I do agree about the hollow shafts though i wouldn't build a head without them these days and its not that hard to do .
Managed to weigh the PT head 5.6Kg without camera or lens motor . I was always keen on building light stuff but people in studios just dont seem to like it ? So 5.6kg it is .
Gerald offered words of warning on vibration and wobble . Whats the general consensus More weight less vibration or more weight more vibration . My gut feeling is the more mass you have the less you are likely to suffer from wobble and vibration and perhaps this is why the camera boys like things heavy . Or maybe its just what they used to .
As for drivers and noise i quite like a bit of noise it lets people no to get out off the way :D and as long as the motors run well and dont get hot thats good enough for me
D1


Sat May 21, 2016 8:25 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
D1, I gotta say more weight and mass equals less vibration. If I stuck a GoPro on the end of my crane I could use way less counter weight which is kind of a contradiction but with less weight at those ends means the base becomes more stable. Unless I go big. I think if you just for fun took the weight of a Mitchell or whatever I see those big boys using on the Milo back in the day, the weight ratio/difference between the Milo and the camera must be massive. I think the rig you are making is going to be a sweet sweet beast. My two cents.


Sun May 22, 2016 5:51 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Doug hope all goes well . Think we are agreeing mass equals stability . I do think their are some down sides like momentum . Once you get all that mass moving it may be difficult to change direction in a hurry :( Bit like a huge ocean liner not the most agile thing .
Done my final measuring and testing and i have ended up with a boom of just under 3 meters . 1.75 meters of which is the length from the fulcrum. Giving me a up down travel of about 2.7meters
[flickr]ImageScreenshot (257) by D 1, on Flickr[/flickr]
15kg counter balance and about 8kg weight at head so its all mounting up . Never intended to build big heavy rigs but its a learning curve . Always planed to build lightweight things so this a bit of a wild card . Should be able to do some testing soon gonna have to move it out of the living room though ! Will let you know how it goes .
D1


Mon May 23, 2016 12:10 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Not sure why the concern about weight of HD's? The ones I use for small PT heads are 250gm each. So a two axis head comes in at 2kg with motors.

Otherwise re weight - well it depends on the distribution of that weight. In general the lower the overall center of gravity the better, but that should be fairly intuitive? Clearly more weight on the base can hep. Robot arms need to be dyna-bolted to the floor for best performance.

As D1 says - if you need to stop quickly then less weight on the end of the arm is better... Think of the camera like a pendulum - the heavier it is, the more it will tend to want to swing when it comes to a halt. Whether this translates to the camera depends on the direction of travel, plus the overall stiffness of the structure and the joints.

When tracking there can be other issues which are influenced by a combination of weight distribution and the natural harmonics of the arm. Any mechanical structure has a natural resonant frequency, and other forces can combine with and reinforce it. I find that horizontal movements give more problems than vertical moves. This is due to the effect of gravity which dampens vibrations... Even so, you can get low frequency wobbles when tracking longer distances - in that case more camera mass may help or simply removing a counterweight. Another factor is the width and length of the base relative to the height and reach - it's complex!

I have read that composite materials have better damping ability than solid metal, so maybe Carbon Fibre is a good idea - not simply for weight reduction.

At animation speeds most of the above is generally not a problem, especially since some settling time is always possible...


Mon May 23, 2016 12:43 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Been looking for big carbon fiber box the only person i know who as any is a lucky man called Mike . Think this is bespoke stuff so not like i can order any more . You may have more look in Aus do find the world of yacht building a good supplier of cutting edge composites .
So it will have to be ali for time been i am currently using a 3.6mm wall thickness i can get the same section in 5mm wall so that may be a upgrade . Hard to tell until i get the thing moving . Think the rack and pinion offers a bit of advantage when moving bigger masses round . Theirs a more positive drive if you know what i me when it stops it stops ! The revolve been rack pinon driven is def advantage. if i ever get my big CNC router/mill up and running think figured out a way to build nice big slew bearings with a gear ring :D
D1


Mon May 23, 2016 1:24 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
What is the good way to make big slew bearings and gear?


Mon May 23, 2016 4:02 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
DISPLACEMENT 1 wrote:
Been looking for big carbon fiber box the only person i know who as any is a lucky man called Mike . Think this is bespoke stuff so not like i can order any more . You may have more look in Aus do find the world of yacht building a good supplier of cutting edge composites .
So it will have to be ali for time been i am currently using a 3.6mm wall thickness i can get the same section in 5mm wall so that may be a upgrade . Hard to tell until i get the thing moving . Think the rack and pinion offers a bit of advantage when moving bigger masses round . Theirs a more positive drive if you know what i me when it stops it stops ! The revolve been rack pinon driven is def advantage. if i ever get my big CNC router/mill up and running think figured out a way to build nice big slew bearings with a gear ring :D
D1


2m x 100mm x 100mm and 2m x 180mm x 180mm ex Stortek system for picking and loading computer tapes, sadly last one now removed, 10 others went in the skip a year or two back :(

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Mon May 23, 2016 6:54 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi D1.

When you mention wall thickness and box sections are you referring to aluminium square tube for the arm? I think if you went for more than 3mm the arm will become quite heavy. If you use a 100mm square tube with 3mm thickness it will be plenty strong other than possibility of some twist. But that can be reduced by using internal ribs like inside boat hulls. They can be spaced to create a series of box structures which will not add so much weight.

Otherwise, with carbon fiber a round tube can work - given round is more readily available from said yachting supplies. A bit more work to make end fittings but do-able. Alternately look at the arm used on Sorenson Gazelle rigs. Much wider at the pivot and triangulated toward the end. From memory it uses carbon fiber sheet wrapped around a frame...


Mon May 23, 2016 8:08 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Gerald yep ali for boom arm and 3.6mm wall 100mm section it seems rigid enough . Got to cut a few holes in it but dont think it will weaken it any . Mikes a even luckier man he as 100mm tubes i wonder what the wall thickness they are . he may have said but i dont remember . Shame about the 10 that went to the dump i do remember him mentioning it last year .
Surprised nobody as built i crane using the same methods as a carbon fiber bike frame of formula one car chassis. Incredibly rigid and light not really worth the bother for a one off though .
I do use two tie bars though in the hope it offers more rigidity . It also takes out any play in the rod end bearings . It would be nice to angle the tie rods out from the boom end back to the fulcrum . Next job so will have a play .
D1
Ps had to type that twice forum went down i wonder if they are about to pull the plug on it . That would be the end of a lot of useful information :(


Tue May 24, 2016 12:37 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
DISPLACEMENT 1 wrote:
Hi Gerald yep ali for boom arm and 3.6mm wall 100mm section it seems rigid enough . Got to cut a few holes in it but dont think it will weaken it any . Mikes a even luckier man he as 100mm tubes i wonder what the wall thickness they are . he may have said but i dont remember . Shame about the 10 that went to the dump i do remember him mentioning it last year .
Surprised nobody as built i crane using the same methods as a carbon fiber bike frame of formula one car chassis. Incredibly rigid and light not really worth the bother for a one off though .
I do use two tie bars though in the hope it offers more rigidity . It also takes out any play in the rod end bearings . It would be nice to angle the tie rods out from the boom end back to the fulcrum . Next job so will have a play .
D1
Ps had to type that twice forum went down i wonder if they are about to pull the plug on it . That would be the end of a lot of useful information :(


Hi, just checked tube thickness, 2.8 - 3.1 mm. and weighing approximately (bathroom scales) 4-5Kg.
There is a label (Dec-1996) with some useful or not information:
Matl: Thiokol T300 -12K - 200NT / UF - 3327
Manuf: STK - Composites Technology.

Placed tube on an incline and a heavy 69Kg walked from one end to the other, not very scientific, but did not feel any give.

The mounting points have screw inserts placed in plates that are attached to the inside of the tube, glued I presume, to spread the load.

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Tue May 24, 2016 2:46 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Mike i thought you would be making the most of the nice weather today by taking your plants for a walk . I am still watching mine grow :D which they have been doing a lot of lately.
So both the ali tube http://www.aluminiumwarehouse.co.uk/Alu ... be_(6063T6)_4_in_x_4_in_x_10_swg/product_info.html and carbon fiber tube are similar spec . Thought the ali was 3.6 wall for some reason but its 3.2mm . Weight wise my scales cut out at 6kg but think its about 7kg for a 2.5 meter length . So not a huge amount in it which surprises me a little i thought the carbon fiber would be a lot lighter . Not going to risk walking on mine. Me a bit heavier and i do think it will deflect a bit..
Hope ya going to build something interesting with ya tubes .
D1
Ps checked the company couldn't find anything


Tue May 24, 2016 3:42 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Have to see this... from one of my Indian friends... Note the Mantis Controller on the ground...

Engineering is quite good and it looks very stable, if you can look past the incredible rolling shutter effect.

Perhaps the gear ratio (one stage of belt reduction) is a bit more suited for speed than finesse? I think he might have added planetary gears since...



If you continue at the U-tube site he's also made a solid looking model mover with 6 dof... powered by six 400 watt servo motors...


Tue May 24, 2016 5:34 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
The engineering is lovely! You can see why i want a bigger CNC Mill/Router most of that rigs i just 15mm plate . Not sure why people spend time and money with 3d
printers when for prob the same amount of money you can CNC stuff . 3d printing takes ages and not always successful to many variables. Not knocking 3D printers completely they good for organics but engineering wise got a long way to go . The stuff goes squidgy at ridiculously low temps :(
Model mover good to is it controlled by Mantis ? Not seen this guy before like is approach that head is certainly quick and he might have enough resolution if hes micro stepping enough . Mantis has a high enough pulse rate .
D1


Tue May 24, 2016 6:18 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
D1, a bit of planting earlier ;) If anything the tube weight is probably less than I posted, no suitable scales.

Gerald, is the head unit being driven from the "game" controller via Mantis? I guess that is what you might call a "wrap" part way through, good job the cable is quite long. Looked at the Hex, quite impressive, not sure why the safety cones - LOL

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Tue May 24, 2016 6:26 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hey Mike,
Yep, you can control a rig via any USB game controller. You plug it into your computers USB port. I am using an old controller I found in a pawn shop. All the buttons and joysticks can be programmed in Mantis. Not really good for realtime control, at least not that I have found, but if you have a DOP that wants to pick their start frame and end frame then you can just hand them the controller and tell them to go for it. I did that on a shoot last year. They loved it. Since they were from the gameboy era they took to the joystick gamepad really quickly. Oh, they can choose as many key frame points as Mantis allows, not just start and end.

Cheers.


Tue May 24, 2016 1:04 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Thanks Doug. I sometimes use a joystick to control the dolly - then it is appropriate - and if I give it to the grip to run - they are quite at home with the gamepad... :)

BTW - I trust he was using limits and planned on the cable length...

You can improve the experience by using an industrial quality stick in place of the gamepad, but ultimately it depends on what you are used to. Operators brought up on Jimmy jibs often don't like using wheels, even though they are more precise. A third alternative is to mount encoders on a fluid head, though that requires a little more engineering....


Tue May 24, 2016 3:21 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi, thanks for the info on the game pad, I have a serial controller + latest USB that came with MS elite Xbox, need to wrestle that one from my nephew :D . I have an encoder that I find very useful especially for focus control. Also have a 6050 MPU on order for a positioning project, may try taping that to the camera sometime, not sure if it will be accurate enough for creating data for Mantis.
MPU 6050: http://diyhacking.com/arduino-mpu-6050-imu-sensor-tutorial/

MPU 9250: http://www.lucidarme.me/?p=5057

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Tue May 24, 2016 10:40 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Mike... The IMU should give data that can be used to create a file which you can then import to Mantis. I use a Yost 3space which does all the processing for you, so the output is less prone to drift.

First though you'd need to know the data rate or have some way of constraining it, so it records data once per frame at 25hz or whatever your base is. If it is not constrained then your file will have too many data points, and you would need to reduce keys and then rescale time in Mantis. If the data is some exact multiple of the frame rate like 50hz or 100hz then it will be easier...

The main issues with IMU's are jitter and drift. If it is only using accelerometers then it will drift. Jitter you can reduce in Mantis by smoothing the data - either reduce the number of keys, or tweak the smoothing scale a little. Using it for direct control would be more difficult. Possibly you can emulate encoder signals with some clever coding...

But most IMU's will not create truly accurate data which matches the camera movement, but still useful for making moves quickly with a human feel...


Tue May 24, 2016 11:04 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
geraldft wrote:
Hi Mike... The IMU should give data that can be used to create a file which you can then import to Mantis. I use a Yost 3space which does all the processing for you, so the output is less prone to drift.

First though you'd need to know the data rate or have some way of constraining it, so it records data once per frame at 25hz or whatever your base is. If it is not constrained then your file will have too many data points, and you would need to reduce keys and then rescale time in Mantis. If the data is some exact multiple of the frame rate like 50hz or 100hz then it will be easier...

The main issues with IMU's are jitter and drift. If it is only using accelerometers then it will drift. Jitter you can reduce in Mantis by smoothing the data - either reduce the number of keys, or tweak the smoothing scale a little. Using it for direct control would be more difficult. Possibly you can emulate encoder signals with some clever coding...

But most IMU's will not create truly accurate data which matches the camera movement, but still useful for making moves quickly with a human feel...


Thanks Gerald, did not think it would be an easy project, 6050 has both accelerometer and Gyro sensors on chip.

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Tue May 24, 2016 11:21 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Mike.

The gyro accelerometer combo is good, but I think ideally it also needs a magnetic sensor to confirm compass bearing (yaw). Otherwise it will just give a relative bearing in that plane.

Still - looks like a fun project...


Wed May 25, 2016 12:51 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
geraldft wrote:
Hi Mike.

The gyro accelerometer combo is good, but I think ideally it also needs a magnetic sensor to confirm compass bearing (yaw). Otherwise it will just give a relative bearing in that plane.

Still - looks like a fun project...


Hi, 9250 has built in magnetometer but will stick with trying to make sense of data out from the 6050 first. Opps better let this thread get back on track ;)

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Wed May 25, 2016 4:09 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
MikeA wrote:
geraldft wrote:
Hi Mike.

The gyro accelerometer combo is good, but I think ideally it also needs a magnetic sensor to confirm compass bearing (yaw). Otherwise it will just give a relative bearing in that plane.

Still - looks like a fun project...


Hi, 9250 has built in magnetometer but will stick with trying to make sense of data out from the 6050 first. Opps better let this thread get back on track ;)



HI Mike dont worry i have never been afraid of a bit of off topic :D Its actually on topic for me anyways the model mover is 70% their so need a way of getting realistic motion into it . So for a can either motion capture or the yost thing . In fact my little brain doesn't see much difference between the Yost and the MPU 9250 other than a considerable amount of money .MPU 9250 = £5 plus arduino . Must admit its the dreaded code thing again that puts me off. Much better with big lumps of aluminium.
D1


Wed May 25, 2016 7:37 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Topic, just testing ;) Oracle and database design was my programming thing with some Visual basic, coding is not my strong point either these days. Might take a while but I try not to give up until I get some results.................. 6 months on..... ;)

First problem was sketch not loading to Ardunio - pre R3, connect an R3 and all ok so far, waiting for Winter and the rest of the components to arrive.

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Wed May 25, 2016 8:35 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Ah dont mention winter :( hopefully i got a lot of plant watching to do yet . I also have a frog i spend a lot of time talking to its a simple life :D
Hope you dont mind sharing any progress you make with the MPU 9250. You spurred me on with my model mover just assembling bits at this very mo . May even give it a test spin this evening think got the DMC for next month so best make the most of it .
D1


Wed May 25, 2016 9:37 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
DISPLACEMENT 1 wrote:
Ah dont mention winter :( hopefully i got a lot of plant watching to do yet . I also have a frog i spend a lot of time talking to its a simple life :D
Hope you dont mind sharing any progress you make with the MPU 9250. You spurred me on with my model mover just assembling bits at this very mo . May even give it a test spin this evening think got the DMC for next month so best make the most of it .
D1

Not so many frogs now, around end of Feb a few years ago there were literally hundreds coming into the garden and the ponds were full of spawn.
MPU update, got a Bosch DN0055 shield from Cool Components, 9 axis output (plugs directly to the Arduino uno. I have it streaming data using a supplied sketch and have captured it to a file using Real Terminal (free). Imported the file to a spreadsheet (Open Office) and separated out the data numbers from text in the file. A bit long winded and there should be other ways to do this via the Sketch but for now I just want to know if I can manipulate the file to replicate the MPU movement.
There is a 105 page manual with some useful (maybe) functions like only sending data when there is movement. Not sure how I will progress from here.

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Fri May 27, 2016 4:50 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Mike only got one frog been appearing last five years . Got quite attached to it apparently they can live up to 14 years they just hibernate during winter , Sensible creature !
Your MPU update sounds good its amazing what you can get in such a small package. NASA would have killed for such a thing in the sixties. Interesting you can extract the data and you can turn it into a spread sheet format . That means it would be able to tie into the Df and Blender stuff we did last year . If i can remember how i did it . Did you manage to get a sample rate that would match a frame rate eg 25 samples per sec or is it just a huge data burst ..
Back on rig front fulcrum machined out with a nice big 25mm shaft should cope with weights and loads involved :D
[flickr]Image2016-05-27 19.26.38 by D 1, on Flickr[/flickr]
D1


Fri May 27, 2016 11:55 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
I can talk to my television, not tried talking to frogs :D Hibernate in the mud at bottom of ponds I think.
Boom looking good, should be able to lift a bridge on that fulcrum ;) but better over than under engineer.

Data feed from Bosch BNO055, feed rate down to 1 line per second, data capture using Realterm can be controlled, continuous, timed or number of data characters received before file closes. It is a very powerful programme and can apparently feed out to file (done) or to say Excel directly if my quick glance at web site served me well.
Feed rate can probably go slower but not tried yet, it requires a single parameter change in the Arduino Sketch.

I have produced a "waving hand about" file and loaded to Mantis. I will at sometime run some rig moves and try to capture them to file, load to Mantis and see what happens.
Currently I have to take file make some manual changes before it is "usable" so it would probably be quicker to set up using Mantis ;)
If I get a suitable file I will send it to you and see what you can make of it in Blender but time for the garden now.

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Sat May 28, 2016 12:34 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Mike i wonder if one line a sec is enough ?
But main reason for posting is 8mm eccentrics . Theirs was a bit of a discussion about making them back in this thread. Easier still buy them :D Robocutters stocks them http://robocutters.co.uk/proddetail.asp ... ric_Spacer
D1


Wed Jun 01, 2016 10:55 am
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi, spacers look ok, especially at that price. What about Hex bar stock off set in a 4-jaw or 3-jaw and off set the tail-stock?

Running some MPU tests at 25Hz. I have produced a file (of numbers) via an Ardunio sketch with a Kuper format that can be captured in Realterm and the resulting file loaded directly to Mantis without additional formatting in Excel.
The load programme to Mantis then creates a keyframe from the file at 25 frame intervals as far as I can tell, can produce key frames every 1...... to xxx frames in load process to Mantis.

Big question that I have started on is:
1) can I create movements in Mantis,
2) run my rig with MPU attached,
3) create a file,
4) load the file to Mantis,
5) repeat the original moves in 1).

Got as far as 4) but need for food stopped play for today :D.
Also must continue reading manual to try an work out exactly what data I am capturing to ensure i am using it correctly.

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Wed Jun 01, 2016 12:15 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
MikeA wrote:
Hi, spacers look ok, especially at that price. What about Hex bar stock off set in a 4-jaw or 3-jaw and off set the tail-stock?


Yeah Edward mentioned that one i just dont like making lots of little things i do enough of that in my day job :(
As for MPU i take it you are hoping the data from the MPU will match the move original created in Mantis . It will be interesting to see how close it gets . Is it just pan and tilt at mo ?
Ps Me frog ugly fella but i quite like him . Prob my most off topic pic yet :D
[flickr]Image2016-05-30 14.39.46 by D 1, on Flickr[/flickr]
D1


Wed Jun 01, 2016 12:57 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
Hi Mike

Good to hear you got the Kuper format working. A suggestion to test how well the data matches the original - is to mount the sensor on a pan tilt head controlled by Mantis...

Make sure it is near as possible to nodal. Then run a programmed move and recording your IMU data. The resulting file can be imported back to Mantis, on spare channels, so you can compare visually with the original... it should be pretty apparent if you are close or not... You can also run both moves with a camera and check the alignment in Premiere.

My prediction is that matching will not be absolutely accurate, due to jitter and filtering in the IMU. It will also depend on how controlled the movements are. Quicker, more erratic moves would be expected not to match as well...

But as stated earlier - I think the most useful application for an IMU is to create moves with a human feel, especially when you don't want it to look like a moco move... I have developed a system where the director operates a camera rig with the YOST attached. He does several takes handheld, which I record. Then I transfer the preferred take to Mantis and play it back.

This process is the equivalent of shooting a move, then tracking it, then exporting tracking data to Mantis. But is all happens on the spot, so there is better interactivity...

In some cases I still prefer to simply program the move from scratch and create my own interpretation of a human foibles. And in some cases this can be quicker - if I get lucky - but equally can lead to endless fiddling with keyframes... so the IMU is a good way of hand-balling the responsibility to the director - no-one will complain to you if he is futzing around - whereas there will be anxiety from the AD if you spend a lot of time fiddling to get the curves just right.. :(


Wed Jun 01, 2016 4:53 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
DISPLACEMENT 1 wrote:

As for MPU i take it you are hoping the data from the MPU will match the move original created in Mantis . It will be interesting to see how close it gets . Is it just pan and tilt at mo ?
Ps Me frog ugly fella but i quite like him . Prob my most off topic pic yet :D
D1


Hi, D1, MPU - that's the idea with Mantis, Dolly, Pan, Tilt and Roll but one at a time for now. That frog could get quite fat, looks like plenty of insect like floating in the water. Mine like the moist conditions in a heather bed I have.

Hi,Gerald,
Quote:
Good to hear you got the Kuper format working. A suggestion to test how well the data matches the original - is to mount the sensor on a pan tilt head controlled by Mantis...

Doing that Gerald, but good idea using spare channels for comparison of data curves and setting on the nodal point. First attempt produced movement but probably 10% of the original distances. I have been reading the manual, mouth wash with soapy water ;) and I need to calibrate the MPU before use so will experiment some more over the coming weeks. No hurry at current rig has 600:1 ratio so not good for positioning manually ;)

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Fri Jun 03, 2016 2:15 am
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Location: Merritt Island, Florida, Estates Unitas
Post Re: New Dmoco 6 Axis Rig Driven by DMC16
D1, Thanks for the link to the larger eccentric spacers. I'll make a new trolley when they arrive. The cast plastic eccentrics were a compromise because I hadn't found any larger eccentrics. They are more expensive here. I ordered 16 of them and shipping to the colonies was 26 pounds, which is a lot here because dollars are only worth 2/3 of a pound.

The frog is cute too.


Sat Jun 04, 2016 2:03 pm
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Post Re: New Dmoco 6 Axis Rig Driven by DMC16
I should update my last post. They sent me a refund of 17.5 pounds because shipping to the US was less than anticipated. Very nice of them. This makes it a lot more affordable to buy stuff from them. Also very nice to have a source for larger eccentrics. They make it so much easier to throw together things like dollies, routers and basically anything that moves on small wheels.


Wed Jun 08, 2016 3:06 am
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