A miniature bipedal duck in the spirit of Disney's BDX droid, about 42 cm tall with the legs extended. Each leg has hip yaw, hip roll, hip pitch, knee and ankle; the neck and head add pitch, yaw and roll, plus two antennas. All fourteen joints are Feetech STS3215 serial servos driven from a Raspberry Pi Zero 2 W, with an IMU, a 2S 18650 pack with BMS and a UBEC, and a camera, speaker and eye LEDs in the head. Walking comes from reinforcement-learning policies trained in MuJoCo and transferred to the robot.

Parts

The geometry is the author's Onshape document exported as one STEP and split into one component per URDF link: trunk, hip roll and roll-to-pitch brackets, two knee-and-ankle links per leg, feet, neck pitch, head pitch-to-yaw, neck yaw, head, antenna holders. Joint origins, axes, limits and link masses come from the repository URDF. The servos are part of the export.

Bill of materials

14 x Feetech STS3215 (7.4 V), Raspberry Pi Zero 2 W, serial bus servo driver board, IMU, 2 x 18650 with BMS and USB-C charger, UBEC, power switch, camera, speaker and microphone, eye LEDs, bearings, screws, PLA and TPU prints. Full list in the BOM spreadsheet.