threefg15 0.1.0

Python driver and CLI for the OnRobot 3FG15 gripper via Modbus TCP/RTU

OnRobot 3FG15 Gripper Python Package

Overview

This package provides a Python driver and command-line interface (CLI) for controlling the OnRobot 3FG15 gripper. It supports communication over Modbus TCP and RTU protocols, enabling precise control over the gripper's 3-finger parallel mechanism, including external and internal gripping modes. The package also supports object detection features integrated into the gripper.

Package Features

• Python driver for OnRobot 3FG15 gripper
• Command-line interface (CLI) with subcommands for RTU and TCP communication to control all functions of the gripper
• Support for Modbus TCP and Modbus RTU protocols
• Object detection and grip force/diameter control

Communication Modes and Pin Connections

The gripper can be controlled via two Modbus communication modes:

• Modbus TCP: Connect via Ethernet using the Modbus TCP protocol.
• Modbus RTU: Connect via serial interface (RS-485) using Modbus RTU protocol.

Pin connections for the gripper electrical interface (female M8x8 connector):

• Pin 1: RS485+
• Pin 2: RS485-
• Pin 3: GND
• Pin 7: +24V

Requirements

Software

• Python 3.8 or higher
• pymodbus library for Modbus communication
• typer library for CLI interface

Hardware

• OnRobot 3FG15 Gripper
• Modbus interface (USB-RS-485 for RTU with a supported baudrate of 1 000 000, most Modbus TCP<->RTU interface wont work with such high baudrates!)

Installation

Install the package using pip:

pip install -e .

Usage

Importing the Driver

from threefg15.core import ThreeFG15

Example Python Code

For further examples and minimal demo code, refer to the src/examples folder.

from threefg15.core import ThreeFG15RTU, ThreeFG15TCP, GripType, ThreeFG15Status

# Initialize gripper with Modbus TCP or RTU connection
gripper = ThreeFG15TCP(ip_address="192.168.0.10", port=502)
gripper = ThreeFG15RTU(serial_port="/dev/tty.usbserial-A5052NB6")
# Open the gripper
gripper.open()
# Gripper opened to: 143.0 mm

# Close the gripper with specified force
gripper.close(force=50)
# Gripper closed to: 148.8 mm

# Check object detection status
detected = gripper.is_object_detected()
print(f"Object detected: {detected}")

print(f"Object detected: {gripper.get_status()}")
# Final status: ThreeFG15Status(busy=False, grip_detected=True, force_grip_detected=True calibration_ok=True)

Command Line Interface (CLI)

The CLI provides two subcommands for communication modes:

• rtu: Use Modbus RTU over serial
• tcp: Use Modbus TCP over Ethernet

RTU Usage Example

threefg15-cli rtu --serial-port /dev/ttyUSB0

TCP Usage Example

threefg15-cli tcp --ip 192.168.1.10 --port 502

Replace parameters such as IP address, port, serial port, and baud rate according to your setup.

The cli application offers the following commands:

• open [force], close [force], move <diam_mm> [force]
• griptype <external|internal>
• stop
• flex <diam_mm> [force] flexopen [force], flexclose [force]
• limits, force
• status, detect

---