No carrier.
No bearings.
Full output support anyway.

ASDrive is a single-stage compound planetary drive for humanoid robot joints — designed to be smaller, lighter, and less costly than the planetary drives it replaces, and backdrivable for force-controlled robots.

A 3D-printed ASDrive Ø50 prototype held in one hand, ratio 27:1, with the working core masked. — First print of the Ø50, ratio 27:1 — and it already backdrives by hand. The interesting part is under the mark.

Parts list — deletions

Planet carrier

In a conventional planetary, the carrier and its pins set the size floor and a large share of the mass. ASDrive locates its planets without one.

Ball bearings

No planet bearings, no support bearings. Fewer precision parts to buy, press, preload, and eventually replace.

Cross-roller bearing

Usually the most expensive component in a robot-joint gearbox. The output is fully supported without it — and that is the part we protect.

Two classes carry the load-bearing joints of a working, full-size humanoid — fatigue-sized against a warehouse duty cycle carrying a 20 kg payload.

Class	Joints	Ratio	Rated	Overload
Ø50	elbow · shoulder	27:1	46 N·m	≥58 N·m
Ø70	knee · hip	34:1	120 N·m	≥200 N·m

ALL FIGURES ARE DESIGN TARGETS FROM ANALYSIS. MEASURED DATA SHIPS WHEN THE DYNO DOES.

Building in public

The prototype is being designed and built in the open — envelope CAD, analysis war stories, first parts, first spin, first measured numbers. The how stays under wraps until the patent allows; the journey doesn't.

Follow @ASDrive on X → hello [at] asdrive [dot] dev