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Mechanical Overview

Aero Hand Open – front view

Aero Hand Open is a compact, anthropomorphic five‑finger robotic hand designed to be easy to mount, wire, and control.

1. Form Factor & Appearance​

Overall size & weight​

  • Size (L × W × H): 198 mm × 95 mm × 53.5 mm
  • Mass: < 400 g (fully assembled)
  • Layout: 4 fingers + 1 thumb, human‑like proportions

The hand has a slim back‑of‑hand profile and a gently curved palm so it can work close to cameras, tools, and robot wrists without bulky back‑mounted motors.

Exterior materials​

  • Body & fingers: 3D‑printed PLA shell
  • Contact surfaces: optional silicone pads for the fingertips and palm to increase grip and impact protection

The external geometry is identical across kits; printing or color variations only affect appearance, not the interface.

Left / right variants​

Aero Hand Open is available as:

  • Right hand
  • Left hand (mirrored geometry)

Both versions share the same mechanical specs and control API.

Additional views​

Aero Hand – angled view Aero Hand – palm view Aero Hand – side view

2. Key Mechanical Specs​

ItemValue / Description
Size (L × W × H)198 × 95 × 53.5 mm
Mass< 400 g
StructureAnthropomorphic, 5‑finger hand
Joints16 joints total
Active DoF7 active DoF (3 thumb, 4 fingers)
Passive joints9 (underactuated finger/thumb mechanics)
Fingertip force≈ 12 N per fingertip
Open/close speed≈ 1.2 Hz full open + full close
Finger joint ROMUp to 90° flexion per finger
Thumb abduction ROM0°–100°
Thumb CMC flex ROM≈ 55°
Thumb proximal/distal≈ 90° combined flexion
Working voltage6 V DC (servo rail)
Max current8 A (entire hand)
CommunicationUSB 2.0 via on‑board ESP32‑S3

3. Degrees of Freedom​

DoF breakdown​

From the outside, the hand provides:

  • Thumb (3 DoF)

    • Abduction / adduction – thumb swings in and out of the palm
    • Base flexion – thumb moves across the palm
    • Thumb curl – tip of the thumb closes for grasping

  • Fingers (4 DoF)

    • Index finger flexion
    • Middle finger flexion
    • Ring finger flexion
    • Pinky finger flexion

Internally, these map to 16 joints (including passive joints) to produce human‑like curling and grasp shapes, but only 7 channels need to be commanded.

Typical motion ranges​

Approximate visible motion ranges:

  • Finger flexion (index / middle / ring / pinky): up to 90° (from straight to curled)
  • Thumb abduction: 0°–100° (from inline with the palm to fully spread)
  • Thumb CMC flexion: about 55° across the palm
  • Thumb curl (proximal + distal): about 90° toward the palm

These ranges allow the hand to perform pinch, tripod, cylindrical/power, and hook grasps.

4. Mounting Interface​

The wrist side of the palm provides a flat mounting surface with threaded inserts for attaching to robot wrists and adapters.

  • Mounting surface: flat circular/oval pad at the wrist
  • Fasteners: four M3 threaded inserts accessible from the outside
  • Usage: mount directly to your robot flange, or to an intermediate adapter plate

Exact hole spacing and coordinate frames are available in the open CAD:

Interactive CAD

5. Ports, Power & Electronics Access​

All electronics are inside the palm; externally, you only interact with a small set of ports.

Power​

  • Input voltage: 6 V DC
  • Max current: 8 A (for all 7 servos)
  • Typical supply: bench supply or robot power bus with appropriate 6 V regulation

The exact connector form factor may vary between board revisions (XT‑style or equivalent). See the PCB / electronics documentation for pinout and wiring examples.

Data / Communication​

  • On‑board MCU: ESP32‑S3

  • Interface: USB 2.0, single cable to your host

  • Usage:

    • Commanding actuator targets (positions/velocities)
    • Reading feedback (positions, currents, temperatures, status)
    • Firmware updates and configuration

USB appears as a standard serial device on the host; the GUI and SDK connect to this port directly.

6. Hand Features (At a Glance)​

  • Compact & lightweight

    • Sub‑400 g with a 198 mm length makes it suitable for desktop arms and mobile platforms.

  • Human‑like motion

    • 5 fingers, 16 joints, and 7 actuated DoF provide natural curling and thumb opposition.

  • Clean external interface

    • Flat wrist mounting pad with M3 inserts
    • Single USB data link + 6 V power rail

  • Consistent actuator API

    • Fixed 7‑channel layout for all units
    • Normalized [0.0, 1.0] command range for easy integration into controllers and RL policies.