PRELIMINARY - LIGHTWEIGHT WHOLE-BODY HIP CANDIDATE ONLY - NOT APPROVED FOR PROCUREMENT, FABRICATION, ASSEMBLY, POWERED TESTING, MOTION, WALKING, OR ENERGIZATION

Four one-stage 4:1 hip drives replace the heavy compound layout.

Each hip uses one 15:60 EV5GT stage, a 340 mm belt, two thin two-boss carriers, a supported hollow output, an exact XH540 interface, and a vented removable guard.

Orbit the complete updated humanoid

whole-body STEP · hip-only STEP · URDF · MJCF.

4:1

One 15:60 stage instead of two 16:32 stages.

66.63 mm

solved nominal center distance for the catalog 340 mm belt.

1.447 kg

four complete candidate hip packages including actuators.

0.120 kg UNDER

the 10 kg tether-first maximum after full superseded-package replacement accounting.

Physical and mass boundary

The nominal four-package common-volume conflict count is 0. The output pulley is a deliberately lightweight hybrid: an exact 60-tooth count and pitch envelope, a webbed PA-CF body and a separate aluminum hub insert. Its final tooth toolpath, material system, insert joint and fatigue/capacity proof are unresolved; the CAD is not a fabrication release. The mass result uses every superseded hip actuator, belt, joint-hardware and joint-fastener line as a controlled replacement boundary.

What remains open

Belt capacity and tension, output-rim tooling, carrier/shaft/bearing/fastener strength, alignment, backlash, reflected inertia, efficiency, heat, cable/guard sweep, physical proof and qualified review remain mandatory. Passing mass and controller screens grants no work or walking authority.