CNS Flight Stack: ROS1 Watchdog

The ros_watchdog observers ROS1 topics and nodes, as well as system-defined drivers. Its settings are specified in INI- files, which can be specified as ROS1 parameters used during initalization.

Maintainer: Martin Scheiber

Credit

This code was written by the Control of Networked System (CNS), University of Klagenfurt, Klagenfurt, Austria.

License

This software is made available to the public to use (source-available), licensed under the terms of the BSD-2-Clause-License with no commercial use allowed, the full terms of which are made available in the LICENSE file. No license in patents is granted.

Usage for academic purposes

If you use this software in an academic research setting, please cite the corresponding paper and consult the LICENSE file for a detailed explanation.

@article{cns_flightstack22,
    title        = {CNS Flight Stack for Reproducible, Customizable, and Fully Autonomous Applications},
    author       = {Scheiber, Martin and Fornasier, Alessandro and Jung, Roland and Böhm, Christoph and Dhakate, Rohit and Stewart, Christian and Steinbrener, Jan and Weiss, Stephan and Brommer, Christian},
    journal      = {IEEE Robotics and Automation Letters},
    volume       = {7},
    number       = {4},
    year         = {2022},
    doi          = {10.1109/LRA.2022.3196117},
    url          = {https://ieeexplore.ieee.org/document/9849131},
    pages        = {11283--11290}
}

---

Getting Started

Prerequesites

This package is part of the CNS FlightStack and thus depends on the other packages of the flight stack:

• CNS FlightStack: Autonomy Engine

Further the following libraries are required

• Python3
• ROS noetic

Build

As this is a ROS package, please build it within the catkin environment with

catkin build watchdog_bringup # will automatically build ros_watchdog

Usage

The intended usage is together with the CNS FlightStack: Autonomy Engine, which will interact with the watchdog. Use the provided launchfile to start the watchdog

roslaunch watchdog_bringup watchdog.launch 

Default Launchfile Parameters

Launch parameter	description	default value
node_name	name of the node to be launched	watchdog
status_o	out topic where status is published	<node_name>/status
status_service_o	in service where status can be requested	<node_name>/status
start_service_o	in service where watchdog is activated	<node_name>/start
entity_check_rate	rate at which entities are checked (in Hz)	2.0
drivers_cfg_file	config file for drivers or other scripts	<watchdog_bringup>/config/drivers.ini
topics_cfg_file	config file for ROS1 topics	<watchdog_bringup>/config/topics.ini
nodes_cfg_file	config file for ROS1 nodes	<watchdog_bringup>/config/nodes.ini
do_verbose	enable verbose flag	false

Usage without Autonomy Engine

If required the watchdog can be used without the CNS FlightStack: Autonomy Engine. The easiest way to do this is to start the watchdog with the provided service:

rosservice call /watchdog/service/start "header:
  seq: 0
  stamp:
    secs: 0
    nsecs: 0
  frame_id: ''
startup_time: 10.0" # any time >(2/<rate>) should be provided here 

# feedback as Status.msg
header: 
  seq: 1
  stamp: 
    secs: <current_secs>
    nsecs: <current_nsecs>
  frame_id: "ros_watchdog"
successful: True|False
status: 
  entity: ''
  type: 0
  status: 0|1|2|4|8
  name: "/watchdog/global"
  info: "
    Status ObserverKeys.TOPIC: <no entries to watch>|0|1|2|4|8
    Status ObserverKeys.NODE: <no entries to watch>|0|1|2|4|8
    Status ObserverKeys.DRIVER: <no entries to watch>|0|1|2|4|8"
entity_ids: [...]

The status can be one of the following and is defined in the Status.msg

• 0: undefined condition
• 1: nominal condition
• 2: startup phase (while the service call is active only, i.e., the duration startup_time)
• 4: inconvenient failure (but topic/node/driver is still active)
• 8: severe failure (no communication of topic/node/driver)

Architecture

Please refer to the academic paper for further insights of the ros_watchdog

Known Issues

None at this point in time, please submit an issue request using the git interface if any issues arise.

Package Layout

/path/to/ros_watchdog$ tree -L 3 --noreport --charset unicode
.
|-- LICENSE
|-- README.md
|-- ros_watchdog
|   |-- CMakeLists.txt
|   |-- LICENCE
|   |-- nodes
|   |   `-- WatchdogNode.py
|   |-- package.xml
|   |-- README.md
|   |-- setup.py
|   `-- src
|       |-- observer
|       `-- watchdog
|-- watchdog_bringup
|   |-- CMakeLists.txt
|   |-- config
|   |   |-- drivers.ini
|   |   |-- nodes.ini
|   |   `-- topics.ini
|   |-- launch
|   |   `-- watchdog.launch
|   |-- package.xml
|   `-- scripts
|       `-- drivers
`-- watchdog_msgs
    |-- action
    |   `-- HandleError.action
    |-- CMakeLists.txt
    |-- LICENCE
    |-- msg
    |   |-- Action.msg
    |   |-- ActionStamped.msg
    |   |-- StatusChangesArray.msg
    |   |-- StatusChangesArrayStamped.msg
    |   |-- Status.msg
    |   `-- StatusStamped.msg
    |-- package.xml
    |-- README.md
    `-- srv
        |-- Reset.srv
        `-- Start.srv

---

Copyright (C) on changes 2021-2023 Roland Jung, Martin Scheiber, Alessandro Fornasier, and Christian Brommer, Control of Networked Systems, University of Klagenfurt, Austria. You can contact the authors at [email protected], [email protected], [email protected], [email protected].