rmf_fleet_adapter_python

Python bindings for the fleet adapters for rmf_core

Specifically:

• rmf_fleet_adapter

Pre-Requisites

• ROS2
• rmf_core must be in your workspace

Installation

• Place the pybind_ament and rmf_fleet_adapter_python packages in your ROS2 workspace, and run colcon build as per normal, remembering to source the workspace.
• The bindings will then be available as importable Python3 packages!

Do read the individual README.md files in each of the relevant packages for writeups on using the packages.

Description

Fleet adapters allow for interactions between rmf_core and robot fleets.

High level pathing or task assignments can be issued to robots from rmf_core, and a fleet adapter will take those assignments and handle it in an implementation specific manner to direct individual robots to execute certain actions while monitoring and updating rmf_core on their high-level states via rmf_core robot update handles.

For more information it is helpful to look at the docs for rmf_core

Usage

The individual README.md files in the relevant packages will go into more detail or talk about certain gotchas that should be kept in mind when using these bindings.

But barring that, you may also peruse the existing scripts in each package's scripts directory, or the unit tests in test.

The bound APIs are almost identical to the rmf_core ones as well, so if the written documentation for these packages, and the Python usage examples in the scripts or tests are insufficient, you can also look into the relevant C++ implementations as a last resort.

Alternatively, you may also explore any interfaces with:

# To list any available members or methods
dir(adpt.<WHATEVER_CLASS_YOU_WANT_TO_INSPECT>)

# To see function signatures
help(adpt.<WHATEVER_CLASS_YOU_WANT_TO_INSPECT>)

Binding Details

This package contains Python bindings to C++ code that is found in rmf_core and its associated packages. It was implemented using Pybind11.

Do note that as a result of that, if one needs to inspect the source, there are no Python implementations of any of the bound code, and it would be advisable to look directly into the appropriate rmf_fleet_adapter package, that contains the C++ code.. Additionally, C++ objects will get instantiated (generally) as references that can be used or called using the appropriate bound methods on the Python side.

Some of these bindings allow you to override virtual methods that would normally be called in the C++ side with Python code that you write in your Python scripts!

Features

There are enough functionalities bound to implement your own fleet adapters to communicate with the rest of the rmf_core systems in the ROS2 graph. Allowing you to:

• Adapter/MockAdapter: Communicate with rmf_core by adding fleets or requesting deliveries
• RobotCommandHandle: Specify custom robot command handles that can take commands from the rmf_core packages and implement or execute the following robot behaviors:
  • Docking
  • Path assignment
  • Starting
  • Stopping
  • RobotUpdateHandle: Update robot statuses
• Executor: Implement new event handlers for:
  • Docking
  • Door operation
  • Lift door operation
  • Lift moving
• Graph: Specify map geometries as they relate to waypoints and lanes
• VehicleTraits: Specify robot vehicle traits, including:
  • Footprint
  • Kinematic limits

Additionally, when you pair this with rclpy, you can interact with the other ROS2 message interfaces provided by rmf_core, and essentially write your own fleet adapter in Python!