SO-ARM100/101 Parallel Gripper

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✨ Key Features

Feature	Description
120N Gripping Force	Reliable parallel jaw mechanism
14 mm/s Speed	Gripper operation speed
84mm Full Stroke	Wide opening for various objects
0.5mm Repeatability	High precision positioning
Camera Compatible	Supports RealSense, Orbbec, USB cameras
3D Printable	All parts print on standard FDM printers
~$62 Total Cost	Affordable open-source solution
Easy Assembly	30-45 minutes with basic tools

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📸 Gallery

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📋 Specifications

Gripper Parameters

Parameter	Value
Maximum gripping force	120 N
Maximum gripping speed	14 mm/s
Full stroke	84 mm
Repeatability	0.5 mm
Assembly mass (PLA, 30% infill)	170 g
DOF	1

Dimensions

Dimension	Value
Width	128 mm
Depth	130.5 mm
Height	109 mm

Servo Parameters (Feetech STS3215)

Parameter	Value
Operating Voltage	12V
Stall torque	30 kg·cm
Speed (no load)	45 RPM
Encoder	Absolute magnetic 12-bit
Protocol	RS485/TTL up to 1 Mbps
Operating temperature	-20°C ~ 60°C

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📷 Camera Compatibility

The gripper supports multiple cameras via interchangeable camera holder:

Camera	Type	Use Case
IMX335 5MP USB	RGB	Basic vision tasks
GC2093 2MP USB	RGB	Budget option
Orbbec Gemini 2	RGB-D	3D perception
RealSense D405	RGB-D	Close-range depth
RealSense D435/D435i	RGB-D	General purpose
RealSense D455	RGB-D	Long-range depth

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💰 Bill of Materials

Total Cost: ~$62 (Full BOM with Amazon links)

Category	Components	Est. Cost
Electronics	Feetech STS3215 Servo + Servo Bus Adapter	~$40
Bearings	MF106ZZ (x2)	~$2
Aluminium/Carbon Tubes	D6x1×125mm (x2)	~$4
3D Printing	8 parts (~100-150g PLA)	~$12
Fasteners	M2/M4 screws, M2 nuts, M3 set screws	~$3

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🚀 Quick Start

1. Print the Parts (2-4 hours)

Download STL files from models/parts/. Compatible with popular printers like Bambu Lab A1 mini, Prusa MINI+, and any printer with ≥180×180mm bed.

Part	Qty	Settings
Main frame (RB9.01.062.010)	1	20% infill
Clamp (RB9.01.062.020)	2	20% infill
Gear rack (RB9.01.062.030)	2	30% infill
Gear (RB9.01.062.040)	1	30% infill
Camera holder (RB9.01.060.074)	1	20% infill
Holder (RB9.01.060.080)	1	20% infill
Camera Spacer (RB9.01.060.090)	1	20% infill

2. Order Components (1-2 days)

See Bill of Materials for direct Amazon links.

3. Assemble (30-45 minutes)

Follow the Assembly Guide with step-by-step images:

1. Mount gear on servo disc, install this assembly on servo
2. Insert servo cable
3. Using Feetech software move servo to its minimal position (move the slider in the software to the left)
4. Attach gear racks to clamps
5. Inserts the rods into both clamps
6. Install bearings on main frame and fix with srews
7. Snap the rods into the frame
8. Spread the clamps to the extreme positions on the left and right
9. Insert servo and fix it with screws
10. Attach Camera Spacer and UVC camera, fix with 4x screws and nuts M2 (optional)
11. Mount to robot arm (optional)

4. Software Setup

# Install STServo SDK
git clone https://github.com/FEETECH-RC/STServo_SDK_Python.git

# Install dependencies
pip install pyserial

# Run gripper control
python software/python/gripper_control.py

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📁 Repository Structure

├── assets/
│   └── images/
│       ├── assembly/          # Assembly step images
│       └── specification/     # Technical drawings
├── docs/
│   ├── assembly-guide.md                # Step-by-step assembly
│   ├── bom.md                           # Bill of materials with links
│   ├── Parallel gripper by Robo9.pdf    # Gripper product specification
│   ├── quick-start.md                   # Getting started guide
│   ├── SO-ARM101 by Robo9.pdf           # SO-ARM101 product specification
│   └── specifications.md               # Technical specifications
├── models/
│   ├── parts/                              # Individual STL files
│   └── Follower_Gripper_180x180_BedSize.STL  # Complete assembly (180×180mm bed)
├── simulation/
│   ├── README.md                  # Simulation overview
│   ├── gazebo/                    # Gazebo guide
│   ├── mujoco/                    # MuJoCo guide
│   ├── webots/                    # Webots guide
│   ├── coppeliasim/               # CoppeliaSim guide
│   ├── isaac_sim/                 # Isaac Sim guide
│   └── so_arm_101_description/    # ROS2 package (URDF, launch, Docker)
├── software/
│   └── python/                # Control software
└── examples/                  # Usage examples

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📖 Documentation

Document	Description
Quick Start Guide	Get running in 30 minutes
Assembly Guide	Step-by-step with images
Bill of Materials	Parts list with Amazon links
Specifications	Technical details
3D Models	Print settings and files
Parallel Gripper Product Spec (PDF)	Parallel gripper product specification by Robo9
SO-ARM101 Product Spec (PDF)	SO-ARM101 robot arm product specification by Robo9

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🔧 Hardware Requirements

Electronics

• 1× Feetech STS3215 Servo Motor
• 1× Bus Servo Adapter Board (Waveshare)

Mechanical

• 2× MF106ZZ Bearings (6×10×3 mm)
• 2× Aluminium/Carbon Tubes D6x1×125 mm

Fasteners

• 2× M4×8 DIN 7991 screws
• 4x M2x8 DIN 912 screws
• 4× M2 DIN 934 nuts
• 4× M3×4 DIN 913 set screws

Tools Required

• Phillips head screwdriver (PH1)
• Hex keys M2 (H1.5) and M4 (H2.5)

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🖥️ Simulation

The SO-ARM101 can be simulated in 5 physics engines using a ROS2 description package with a single parameterized URDF. No ROS2 installation required -- Docker handles everything.

Simulator	Status	Docker
Gazebo	Ready	docker compose run gazebo
MuJoCo	Ready	docker compose run mujoco
Webots	Unstable	docker compose run webots
CoppeliaSim	Not tested	External simulator
NVIDIA Isaac Sim	Not tested	External simulator

Quick start (Docker):

cd simulation/so_arm_101_description
docker compose run gazebo    # or mujoco, webots

See the Simulation Guide for full setup, architecture details, and robot commanding.

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🤝 Contributing

We welcome contributions! Please feel free to:

• 🐛 Report bugs and issues
• 💡 Suggest new features
• 🔧 Submit pull requests
• 📖 Improve documentation

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📄 License

This project is licensed under the GPL-3.0 License - see the LICENSE file for details.

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🔗 Links

• Feetech STS3215 Servo
• Waveshare Bus Servo Adapter
• STServo Python SDK

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👥 Engineering Team

Name	Role	Contact
Boris Kotov	Software Engineer	Telegram
Alan Subin	Design Engineer	LinkedIn

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