Nathan Tsao
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3D-Printed Quasi-Direct-Drive Gearbox

2022•Robotics
RoboticsMechanical Design

Overview

Actuator section view I have developed a 3D-printed, planetary, quasi-direct-drive (4.5:1) actuator. The actuator is built on cheap BLDC drone motors and controlled using the B-G431B-ESC1 board with custom field-oriented-control (FOC) firmware GitHub.

The actuator weighs 500g with 75% PLA infill, and has dimensions 62.5mm (height) x 80mm (diameter). Each motor costs less than $150.

Section view of the actuator. The sun gear (18T) is screwed onto the motor, planet gears (24T) are aligned with dowel pins press-fit into the planetary carrier, and the planet carrier is supported on both sides by roller bearings. Actuator section view

Videos

Exploded view of the actuator:

Video of the actuator moving: