ASDRIVE
Axially Symmetric Compound Planetary Drive

A new class of robot-joint gearbox

No carrier.
No bearings.
Full output support anyway.

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

PATENT PENDING PLANET CARRIER — DELETED BALL BEARINGS — DELETED CROSS-ROLLER BEARING — DELETED OUTPUT — FULLY SUPPORTED Ø82 Ø70-CLASS
FIG. 1 — SECTION A–A. INTERNAL ARRANGEMENT REDACTED PENDING PATENT.

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.

ClassJointsRatioRatedOverload
Ø50elbow · shoulder27:146 N·m≥58 N·m
Ø70knee · hip34:1120 N·m≥200 N·m

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

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 — that part is patent-pending.

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.