CHECK IT OUT: https://a360.co/2k58f1V
NOTE: If you download this, pay attention to the x12, etc posted at the end of the file name so that you can request/ print that many of each part.
I designed this robot ForeArm using fusion 360. I incorporated the universal joint thingy emulating two rolling spheres by notaii directly into the design. Please check out that project to understand how this wrist moves.
The end of the wrist is pulled with paracord. There are 12 strands of paracord. 8 strands are just to maintain tension all around. The other four are pulled by servos via worm gears which only allow the paracord to come in through a thin slot.
The difference in tension between the opposite paracord pieces determines the direction the joint leans and how much torque is applied.
There are 3 degrees of freedom in total: left - right, up - down, and rotational.
My other design attaches to it: 3 Finger Gripper, https://www.thingiverse.com/thing:3743865
All screws in the design are M3,
I'm currently working on a design for the lower arm base portion using the same pulley principle with thicker paracord and nema 17's. I'll post that later.
This forearm is in the process of being printed. I will update the project when that print finishes. I also plan to make a video introduction at that point.
Once I finish the different parts of the design, I will also release them as one larger robot arm. The goal of the arm is to be able to automate 3d printing with the formlabs form 3. There will be plenty of sensors in the final design, including pixy cams to autocalibrate and monitor the arm.