Inmoov bicep servo question

Question

Hello all! First of all I want to thank all of you for your support with inmoov/ezb. It has been very helpful to me to this point in my build. I was wondering if anyone has used the ez hdd servos in the bicep and if the pot hack is still necessary with this system? I'm having a hard time bringing myself to busting into brand new servos. Just curious if there are any other avenues i can explore. Thanks

cem · Answer

Kridge, I used the HDD servo for InMoov’s biceps. I didn’t remove the pot but modified the worm pinion to give it more range. I did a video of the bicep action on this forum a while ago, I’ll try to find it!

cem · Answer

Here’s the video. https://www.youtube.com/watch?v=bySzD2kxSSM

nallycat · Answer

@Kridge I built two inmoov robots and there are quite a few servo that need to be modified,  just take your time and be carefull, with Bruce-e my last inmoov robot I used aerius's design for a planitary gear elbow.  my advice is to print the gears with 100% infill and high detail use ABS or Nylon as the weight of the forarm puts a lot of stress on the planitary gear, this elbow uses an ez-robot hd regular size servo strong and less expensive but you still have to remove the pot and the pin on the main gear, easier to do with the EZ servo. Bruce-e can now touch his head with his hand.  If you want I made an inmoov hand that is easy to adjust.  I am thinking of making a video showing this. here is a picture of Bruce-e's elbow.  notice there is an iotiny in each forarm no long wires to the body.

3dGuy · Answer

@ Kridge , Opening up a servo and removing the pot is easy.  Take some pictures for reference after each step, like when you remove the base or when the gears are exposed.   If soldering isn't your thing then you can cut and splice the wires or better yet, get a good crimping tool and install a plug.   Crimper kit After you do one you'll get the hang of it.  Take an old one apart first  and you'll see how simple they are inside.  The Bicep servo has to rotate more than 180 degrees that is why the pot has to be removed.

Kridge · Answer

I am currently waiting on some more servos to arrive so I can continue my project. I guess I will bust into a couple when they arrive. @nallycat how is that planetary gear elbow working for you so far? I have been looking into it but from videos I've seen the movement seems very strenuous on the servos. I'm also interested in the hand model you mentioned, as well as any other derivatives that anyone can recommend. I've been doing industrial robotics for a few years now but this is my first solo project including smaller scale servos so I'm kind of learning as I go. I may go ahead and order the hs805bb's for the little extra torque but who knows. I appreciate all of you.

3dGuy · Answer

3dGuy · Answer

Here is a picture of my 2 thumbed hand.  Did you want the file?   I also have a forearm that  spring loads  each servo (fits EZ-Robot servos) so there is no slack in the cables/tendons.   They are self adjusting/tensioning.

3dGuy · Answer

Here is the Forearm

Kridge · Answer

Im definitely interested in the models to tinker with if you don't mind. I'm guessing with the servo bed the springs adjust the position of the servos themselves instead of tensioning the lines? Very cool design.

Edit: just read your comment above again and answered my own question lol

nallycat · Answer

The hand design I use does not require the tension on the lines at all, I will try to find time to take pictures or make a video.  the elbow works great, it is just more difficult to print, it must be exact.  the servo is strong enough  no problem so far.  Bob Houston made the planitary gear elbow, when aerius first introduced it, maybe Bob Houston could comment.

Kridge

Inmoov Bicep Servo Question

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