Actuator Atlas

How robot and industrial actuators actually work, in interactive 3D.

Live: https://zerotimedrift.github.io/actuator-atlas/

Ten mechanisms you can orbit, cut open, explode and drive. The gears mesh at their true ratios, and every number on the datasheet comes from a formula you can see.

Group	Mechanisms
Foundations	Spur gear pair · Brushless outrunner motor (live three-phase commutation)
Speed reducers	Planetary gearset (switch the fixed member) · Strain wave / harmonic drive · Cycloidal drive · Worm drive
Robot joint actuators	Quasi-direct drive (QDD) · Series elastic actuator (SEA)
Linear	Ball screw · Planetary roller screw · Lead screw
Fluid power	Hydraulic and pneumatic cylinders

What you can do

• Watch it move. Involute gear profiles, a cycloid disc that wobbles against its pins, and a flexspline that deforms in real time.
• Cut it open. Quarter-section cutaway with red section faces, an exploded view, and pitch circles with the line of action.
• See the roles. Parts are coloured by function: input, output, fixed, elastic, sensor. Hover any part to find out what it does.
• Run the numbers. Change tooth counts, the fixed member, lead, pressure or spring stiffness. Results show the formula with your values filled in.
• Compare. Why legged robots use 6–10:1: output torque, speed and reflected inertia (∝ i²) for one motor at any ratio, plus a side-by-side table and a picking guide.
• Learn the vocabulary. Backlash, backdrivability, reflected inertia, Kv/Kt, self-locking and more, each linked to a mechanism.

Run locally

It's a static site with no build step:

python3 -m http.server 8000

Then open http://localhost:8000.

Built with three.js r147. Specs are typical catalogue ranges for learning, not data for any specific product.