Two DoF Arm with Custom Actuators
A 2 DoF arm with suction cups to attach to surfaces. The window 2-DoF arm makes it easy to leave large, easy-to-see, non-digital notes for yourself or others while away. I built it using OTS drone motors and motor control PCB, but designed my own gearbox and belt transmission that achieves a more compact design.
3D printed Gears
To get the right tolerance for the gearbox (sweeping backlash profile offset and root radius), I printed test pieces and also tried different gear designs. I settled for helical gears, as they have less backlash and are easy to assemble for planetary gearboxes, though are less efficient than spur gears.
Test Actuator
Testing a custom motor with a planetary gearbox, which has a gear reduction ratio of 8.909 to 1 (Sun=11, Ring=87, Planet=38) and a module of 0.75mm.
Belt Drive
To keep the design under the space constraint, the second DoF is indirectly driven via a belt drive. This allows the separation of the high speed motor and the planetary gearbox. The belt is tensioned by two slotted screw holes for adjusting the position of the motor and to perfectly tension the belt.
