ASDrive

A new planetary gearbox: carrierless, bearingless, single-stage 25-40:1 class, designed for full size humanoid robot with 20kg payload. Building in public. 🌞

[ASDrive @asdrivedev]

No planet carrier. No ball bearings. No cross-roller bearings.

The output is fully supported anyway.

Single-stage 27:1 - and the raw 3D print already backdrives by hand.

Build it in public, for the load-bearing joints of full-size humanoids.

[ASDrive @asdrivedev]

Multi-stage planetary is today's default, and a reasonable one: cheap, tolerant, backdrivable at modest ratio.

The catch is ratio. One stage runs out near 8-10:1; the joint wants 25-40:1. Stacking a second doubles the parts and erodes the backdrivability.

[ASDrive @asdrivedev]

Harmonic, RV/cycloidal, and multi-stage planetary reducers dominate industrial robots.

Plot them against what a humanoid joint actually demands (green) and none of them covers it.

[ASDrive @asdrivedev]

@ErenChenAI exactly! the direction is now skewed towards entertainment, hopefully workhorses soon.

[ASDrive @asdrivedev]

Harmonic drives excel at precision and packaging: zero backlash, 50:1 and up in a thin, light unit.

But the gear train works by flexing a steel cup — and that costs both efficiency and durability.

[ASDrive @asdrivedev]

@TheFutureMemo now, carry out meaningful work

[ASDrive @asdrivedev]

The alternatives — harmonic, RV, and multi-stage planetary, and what each one is missing for a humanoid joint:

https://t.co/C5RUJMOiA0

[ASDrive @asdrivedev]

Harmonic. RV. Multi-stage planetary. The three gearboxes that run industrial robots.

Plot them against what a humanoid joint actually demands (green) and none of them covers it.

Five axes where the joint asks for everything. The incumbents reach full marks on one.

[ASDrive @asdrivedev]

@0xVisii0nary Run, Forrest! Run!

[ASDrive @asdrivedev]

@SciFry01 so close to cut the fingers

[ASDrive @asdrivedev]

@ai_robot_pulse knee joint failure 😞

[ASDrive @asdrivedev]

@realgalleryx Right framing. One addition: walking joints absorb energy every footfall — a reducer that can't pass force backward pays in heat and battery.

https://t.co/VTu1dvLrmh

[ASDrive @asdrivedev]

@intern 20 hours/day × 365 days/year × 7 years = 51,100 total hours! Very impressive!

[ASDrive @asdrivedev]

@UnitreeRobotics how long can it keep running at the top speed? < 1 min?

[ASDrive @asdrivedev]

@trippybrippy what are the root causes of joint failures?

[ASDrive @asdrivedev]

@elonmusk unimaginable 😇

[ASDrive @asdrivedev]

Why humanoid robots are gearbox-limited — the full note:

https://t.co/VTu1dvLrmh

#humanoid #robot

[ASDrive @asdrivedev]

A humanoid demo needs to survive three minutes on stage. A product needs to survive a shift.

It is usually called a motor problem. Mostly it isn't.

Battery. Heat. Payload. Durability. Safety. Cost. Trace each to its bottleneck — they all end at the same component: the gearbox.

[ASDrive @asdrivedev]

@spaceandtech_ those external cables can be easily trapped and damaged

[ASDrive @asdrivedev]

@DN_degen if this not AI generated, I'd love to have one.

[ASDrive @asdrivedev]

@yuji_fujima Figure 03 is more human like, even though about 3-year-old kid for now.