Overview

ROS 2 workspace for controlling AgileX Piper arms from ROS 2 or DLS controllers.

The repository is based on AgileX's new driver stack:

• pyAgxArm for the Python CAN driver
• agx_arm_ros for the official ROS 2 control, message, description, and MoveIt packages

The local ROS package named piper_sdk is kept as a thin wrapper around pyAgxArm, so the SDK is installed by colcon build without using pip install --break-system-packages.

Repository Contents

This workspace contains the following packages:

• piper_sdk: ROS 2 wrapper around the pyAgxArm git submodule, automatically installed by colcon build
• agx_arm_ros: Official AgileX ROS 2 packages for control, messages, description, and MoveIt
• agx_arm_pd_g_controller: A PD+G controller for the arm, based on the official AgileX ROS 2 HAL
• dls2_interface: Standard messages definition for DLS2
• dls2_piper_bridge: DLS2 hardware-abstraction-layer using the pyAgxArm API

Installation

You can follow a readme based on conda here or rosdep here

ROS2-DLS HAL (with custom messages)

To control the arm using ROS2 with custom messages from DLS, a single python script is provided to launch the HAL

python3 launch_piper_hal.py

These custom messages can be found here and are automatically compiled when launching the script above.

Important: We believe that some internal scaling are happening for Kp/Kd values for joints1-2-3. We identified these values, and we apply an inverse scaling in the hal (see the hal code). In this way, gains in simulation matches more closely the one on the real robot. Note that this scaling is not applied in the official ROS2 HAL, so it must be applied manually when using the official ROS2 HAL.

ROS2-Official HAL + MoveIt (with standard ros2 messages)

To control the arm using ROS2 with standard ros2 messages, the official ROS 2 HAL can be employed.

Before using the arm, CAN-bus communication must be manually enabled

bash ./src/agx_arm_ros/scripts/can_activate.sh

A convenient launch file is provided in agx_arm_ctrl to run the arm control node together with the MoveIt framework

ros2 launch agx_arm_ctrl start_single_agx_arm_moveit.launch.py arm_type:=piper_l effector_type:=agx_gripper follow:=true

Warning

Running this command will move the arm to the zero configuration. Ensure that there are no obstacles nearby and always start from a nearby configuration.

Maintainer

This repository is maintained by Giulio Turrisi and Antonio Langella.