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.
