dxl_py

Simple python wrapper over the Dynamixel API. Allows commanding and receiving positions for an arbitrary number of servos.

Use

Create a config dictionary with one entry per servo:

MY_SERVOS_CONFIG = {
    'test_servo': {
        'id': 1,  # Servo ID
        'model': 'mx',  # Servo model tag, one of 'MX' or 'PRO'
        'min': 0, # Minimum position (MX servos go from 0 to 4095)
        'max': 4095, # Maximum position
    },
    ...
}

Create the servo object using your config dictionary.

from dxl.servos import Servos
my_servos = Servos(config = MY_SERVOS_CONFIG, action_bounds = [-1.0, 1.0])

Set the servo position. The action_bounds kwarg determines how actions relate to positions. An action of 1.0 here sets the position of the servo to 4095.

my_servos.set({'test_servo' : 1.0, ...})

Get the servo position.

my_servos.get(['test_servo', ...])

Setup

Clone the DynamixelAPI repo into the desired directory. Install into your desired python environment (consider using Anaconda).

$ git clone https://github.com/ROBOTIS-GIT/DynamixelSDK.git .
$ cd DynamixelSDK/python/
$ pip install -e .

The wrapper can be installed as a pip package:

pip install dxl_py

This repo uses MX-28 model dynamixel servos connected via USB through a U2D2. After connecting the device, check it exists (the name might be different from the one below):

$ ls /dev/ttyUSB*
/dev/ttyUSB0

Now configure and add a custom udev rule using the fix_udev.sh script. You might need to reboot.

$ sudo ./fix_udev.sh

If we check the devices again we should now see the dynamixel device.

$ ls /dev/dynamixel
/dev/dynamixel

Connect a servo with id=1 and run the test with python -m unittest.