3 DOF Paracord Robotic ForeArm

thingiverse

CHECK IT OUT: https://a360.co/2k58f1V NOTE: When downloading this, pay close attention to the x12, etc posted at the end of the file name so you can request or print that many of each part. I designed this robot ForeArm using Fusion 360. I incorporated the universal joint mechanism emulating two rolling spheres by noting directly into the design. Please check out that project to understand how this wrist moves. The end of the wrist is pulled with paracord, featuring 12 strands. Eight strands maintain tension all around, while 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 opposite paracord pieces determines the direction the joint leans and how much torque is applied. There are three 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 being printed as we speak, and 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 release them as one larger robot arm. The goal of the arm is to automate 3D printing with the FormLabs Form 3. There will be plenty of sensors in the final design, including Pixy cams to auto-calibrate and monitor the arm.