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Inmoov Robot Rotation Wrist

by hairygael, published

Inmoov Robot Rotation Wrist by hairygael Jun 17, 2012

Description

This part is a rotational wrist for the hand robot "InMoov",

For more parts and info, see thingiverse.com/thing:17773

Assembly instructions, see inmoov.blogspot.com

youtube.com/watch?v=BAs2F4sFVdA

youtube.com/watch?v=tXYF6yY1c9M

Video of rotation wrist: youtube.com/watch?v=lkmXFKQgZm8

Recent Comments

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Hope to see your plugins someday on MRL.
I have modified the parts.
I printed most of the parts at 0,5 thickness, 3 shells, 30% infill. Except the gears which need to be printed with best quality your machine can give you.

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Instructions

I should have made this part from the beginning, but at the time I never thought I would go that far with this project.
If you have already assembled the hand with it's rods, well first I have to say: Good job! But now let's take it a little apart again.
I have put many pictures of the assembly on my blog.
This thing can replace "robpart1" or "leftrobpart1" depending on which hand you did.
If you have or plan to make the left hand, print the parts that begin with "leftxxxx".
"cableholderwrist1", "rotawrist3" and "wristgears3" are for the right and left hand.
The gears inside are fine little things and require good tunning on your printer. I printed them at 0.4 thickness in ABS. They should be well finished other wise they won't fit or slip.

Update 24/06/12 modified "wristgears2" to "wristgears3", the others were losing steps after a while. The teeth were too fine for the torque.
Update 22/02/14 modified CableHolderWristV3 to V4. The V3 version was less easy to keep the cables in place during the closing assembly of the whole wrist.

What specs should the parts be printed at? I saw a good list on the hand parts that said 30% infill and supports/rafts, etc.
I printed most of the parts at 0,5 thickness, 3 shells, 30% infill. Except the gears which need to be printed with best quality your machine can give you.
Have you tried fitting bending sensors in the fingers? I started reading datasheets on a bunch of them but their reliability isn't up to what I would have expected and I fear that false readings from these sensors will throw off the robot, especially since I was planning on using a "machine learning" driven approach so that the robot learns to use its fingers instead of having to hardcode these instructions.

I'll probably develop custom plugins for MRL so I'll let you know how that goes.
Hope to see your plugins someday on MRL.
For those having problems fitting the servo inside the wrist because of the servo's cable, you have two options. Either try the remixed design ( thingiverse.com/thing:53739 ) or do like I did. Using a Dremel, I have made a new hole for the cables in the bottom plate of the servo. Now,the wires come out pointing downwards instead of sideways.
InMoov modified rotawrist
I have modified the parts.
After building the rotational wrist I suddenly noticed a very small discrepancy between the pictures for the assembly and the parts on here for printing...

All the photos show the 2 gears as herringbone gears, but the parts in the upload are normal gears. While this doesn't really cause any issues in my opinion on this particular application, I am curious why you chose to use herringbone gears on your design Gael?
The herringbone gears were my first iteration, I had used the Wade gears found on thingiverse which would only be created with herringbone shapes. The result was not okay because the teeth were too small, resulting in loosing steps. I, later, used an Openscad script to create the gears. But this is a long story which is detailed in my blog someplace.
I have a quick question. I am just starting to print out the parts to build the right hand, and saw this updated wrist before starting to print. To not needlessly print parts, I have been trying to figure out what parts are replaced by this, and I think I have it figured out... only thing I am left wondering about... Do I still need to print WristLargeV3 and WristSmallV3 from the right hand thingy? I assume they are still necessary but just want to make sure.
Hi, welcome to InMoov, hope you will post pictures.
Yes, WristLargeV3 and WristSmallV3 are necessary to create the palm of the hand.
This is incredible work. A friend of mine in Borneo and I have been working on an animatronic hand for several years with good progress. I printed your first attempt at a hand just after you posted it here, but you've gone far beyond what we've accomplished. Are you in Facebook?
Thanks for your comment, I hope the new versions are more adapted to your needs. My first attempt was a bit rough, I must say. Yes I'm on facebook, but I barely ever use it.
Hi ! I can't open the 3D files. please help
 Hi, what program are you using? These STL files, they can be opened with various programs. Blender, Netfabb, Kisslicer, and many others. I mention these because it's what I use.
Let me know.
I am sorry ! I dont recognize any of these programs. I downloaded blender but it didn"t work there was an error. which program do you recomend ?
 I will send you a private message it's better for to help you.
Thank you for doing this, thanks to you and so many others I'll be able to build a humanoid robot before this life ends, this truly means allot.
 You are welcome, hope to see your prints posted.
Regards
I was only going to print the Left and build a complete left hand with your new wrist but, it printed so well that I printed a right wrist to upgrade my InMoov version1/2. Soon I'll have two extra hands. It is really great to print an item - pull it off the platform and assemble. No trimming. 8-)
;)
Cool prints I always wonder how things will turn out on other printers, you should put it in "I made one" :)
cool, but what happends with cables when you rotate wrist? I mean, would they pull fingers becouse of hand movement?
Hi wulfnor, no it doesn't pull the fingers because the cables are centered in the wrist. But your servo shouldn't go more then 0 to 180
° though, otherwise of course it would start to twist the cables. I will soon upload a video. I didn't work on the animated eyes from your Blender file yet, because I'm running out of servos and time, but it's on my todo list. ;)
I dont have time too sadly :( So many projects so little time.

And about the eye, i used TowerPro SG-50 servos, but any 5g servo should fit.
As soon as I get back from work, I will work on that camera/eyes movments. Thanks for the file.
What do you use for the wires (rods)?
Hi, I use nylon fishing rods of 0.8 mm. See on thingiverse.com/thing:17773. Thanks for your interest
Hand robot InMoov
Maybe swap out some servos for small steppers and geared steppers? There are tiny ones available.
This is inspirational. You're nearly to the point where you can build a fuctional prostetic. An open source prostetic. Wow.
Thanks for your comment. I think for someone to use it as an every day prosthetic, there is some improvments to do (strength/precision). This is more to use as a start/study project, I think.
Then again, if they used it as an everyday prostetic and it breaks it'd be easy and cheap to fix/upgrade.
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