BiDexHand V4

BiDexHand is a 16-DOF biomimetic dexterous robotic hand that mimics the kinematic structure of a human hand — complete with independent adduction/abduction for each finger and a 4-DOF opposable thumb.

The design uses a cable-and-pulley tendon system with 15 Feetech SCS0009 servos arranged in an N-configuration within the palm housing, plus a dedicated four-bar linkage for the DIP joint of each finger. The thumb has all four biomimetic degrees of freedom: CMC abduction/adduction, CMC flexion/extension, MCP abduction/adduction, and MCP flexion/extension.

Key specs:

• DOF: 16 total — 3 DOF per finger (MCP ab/ad, MCP flex/ext, PIP flex/ext + coupled DIP) × 4 fingers, plus 4-DOF thumb
• Actuation: Cable-and-pulley tendon system, 15× Feetech SCS0009 servos + servo2040 controller
• Grasps: Power grasp, pinch grasp, precision manipulation, VR teleoperation
• VR control: Meta Quest motion shadowing via WebXR (separate VR teleop repo)
• Franka integration: Full-arm VR teleoperation with BiDexHand as the end effector
• ROS 2: Full ROS 2 Jazzy packages included (motion shadowing, servo streaming, CLI)
• Design: Open CAD on OnShape, STEP + STL files in repository

V4 improvements over prior versions:

• Updated single-shear phalanx design (more durable under high-frequency grasping)
• Servo calibration modules for accurate joint position mapping
• Unified Feetech servo ecosystem throughout (SCS0009 everywhere)
• servo2040 PWM controller option alongside traditional SCS bus

MIT License. Original design by Zhengyang Kris Weng — https://github.com/wengmister/BiDexHand

Printing

The print set is the 26-part hand from the upstream BiDexHand cad_asset/_stl folder. BiDexHand has four identical fingers plus a distinct thumb, so several phalanx parts are printed in multiples — the static list shows each file once.

Finger phalanx parts — print x4 (one set per finger):

• plx--base, plx--proximal, plx--middle, plx--distal, plx--knuckle, plx--cover, plx--support

The four fingers (index, middle, ring, pinky) are mechanically identical, so each plx--* part is printed four times. Each finger is a 3-DOF unit (MCP ab/ad, MCP flex/ext, PIP flex/ext with a coupled four-bar DIP).

Thumb — print x1 each (4-DOF opposable thumb, unique parts):

• thumb--base, thumb--cmc, thumb--mcp, thumb--proximal, thumb--arm, thumb--bridge, thumb--cover

Palm / housing — print x1 each:

• palm--base, palm--coupler, palm--guard-2

Servo sleeve & carriage (palm servo housing) — print x1 each:

• sleeve--base, sleeve--servo-carriage, sleeve--servo-rack, sleeve--servo-rack-top, sleeve--servo-rack-back, sleeve--servo-single-rack, sleeve--servo-single-rack-top, sleeve--servo-single-rack-back

Tendon pulley — print x15 (one per servo):

• pulley--scs0009 — small SCS0009 cable pulley; the hand uses 15 Feetech servos, so print one pulley per servo.

Cleanup note: the imported list previously held 46 files — the 26 real parts plus 20 duplicates that were the same parts re-imported under a second name__part.STL (double-underscore) naming scheme alongside the primary name--part.STL set. The duplicates were verified by byte-size match and removed, leaving the clean, complete 26-part set. Servos (15x Feetech SCS0009), the servo2040/ESP32 controllers, cabling (DuraBraid line, PTFE tube), bearings, springs, and McMaster pivot hardware are sourced from the BOM, not printed.