This repository contains the software and electronic designs developed for the CLEAR (Control Logic for Easy Ackermann Robotization) project.
Related publications
del Pino, I., Munoz-Banon, M. A., Cova-Rocamora, S., Contreras, M. A., Candelas, F. A., & Torres, F. (2020). Deeper in BLUE. Journal of Intelligent & Robotic Systems, 98(1), 207-225.
Citation:
@article{del2020deeper,
title={Deeper in BLUE},
author={del Pino, Ivan and Munoz-Banon, Miguel A and Cova-Rocamora, Saul and Contreras, Miguel A and Candelas, Francisco A and Torres, Fernando},
journal={Journal of Intelligent \& Robotic Systems},
volume={98},
number={1},
pages={207--225},
year={2020},
publisher={Springer}
}
Cova Rocamora, S., Pino, I. D., Muñoz Bañon, M. A., Contreras, M. Á., Candelas, F. A., & Torres, F. (2018). CLEAR. Un módulo para la robotización de máquinas Ackermann. Actas de las XXXIX Jornadas de Automática, Badajoz, 5-7 de Septiembre de 2018.
Citation:
@inproceedings{cova2018clear,
title={CLEAR. Un m{\'o}dulo para la robotizaci{\'o}n de m{\'a}quinas Ackermann},
author={Cova-Rocamora, Sa{\'u}l and Pino, Iv{\'a}n del and Munoz-Banon, Miguel {\'A} and Contreras, Miguel {\'A} and Candelas, Francisco A and Torres, Fernando},
booktitle={XXXIX Jornadas de Autom{\'a}tica},
pages={372--378},
year={2018},
organization={{\'A}rea de Ingenier{\'\i}a de Sistemas y Autom{\'a}tica, Universidad de Extremadura}
}
The aim of this project is to gather in a single module all the common features needed to integrate an Ackermann (or car-like) robot in ROS. It contains a finite state machine that switches between different operational modes, namely, Remote Control Safe, Remote Control NOT safe, ROS control and Emergency Stop. Attending to the operational mode, the vehicle will accept commands from the active controller, either ROS or RC. Safety signals will override any command, limiting the vehicle speed or stoping it (reactive safety system not taken into account only in "Remote Control NOT safe" mode) or even putting the vehicle in Emergency mode if some critical signals are lost (ros communication, RC, etc). CLEAR module sees the hardware through objects of different classes that implement the hardware interface. With this approach we can change any hardware element easily, just changing the descriptor header file that contains the constant values that are hardware dependent, and readjusting the controller gains if needed. Finally the rest of the system, that is, the high level, is seen as a ROS interface, so for the micro-controller is indifferent if the commands are generated autonomously or by a human teleoperator.
The interface between the CLEAR module and the on-board computer is implemented through ROS topics using the rosserial command. These topics are described below:
desired_verbose_level
This topic sets the level of debugging information that is transmitted through the micro-controller serial port.
desired_ackermann_state
This topic sets the desired values for the low level controllers, using an Ackermann message. This message, as defined by the Ackermann Interest Group, consists of linear velocity, acceleration and jerk, and steering angle and rate. At the moment only the speed (linear velocity in meters per second) and the steering angle position (in degrees) are used to feed the controllers (i.e. you can not control the steering rate, but you can control the steering angle).
estimated_ackermann_state
This Ackermann message contains the Ackermann values discussed before (linear velocity, acceleration...) estimated using an EKF that relies in the control signals for the prediction and the available sensors (steering encoder, limit switches and a Hall effect sensor) to perform the correction stage. This information is sent to the high level system through the ROS interface.
desired_speed_gains
This topic enables the on-line adjustment of the low level speed controller.
desired_steering_gains
To dynamically adjust the low level steering controller.
speed_volts_and_steering_pwm
This topic shows the actual outputs that feed the actuators, so it gives the lower level information available to debug the low level controllers. (only published if verbose level = debug)
CLEAR_status
This topic is composed by five values: the operational mode (emergency, ROS control, remote control safe and remote control NOT safe), the error and two warning codes (interface warnings and robot warnings) and the verbose level selected.
In addition, every desired topic produces an echo topic to check communications. (only published if verbose level = debug)
Install Arduino software: "sudo apt-get install arduino"
Install Sloeber: launch Eclipse - click Help - click Eclipse Marketplace - search Sloeber - click Install
Copy this folder to PROJECT_LOC/arduinoPlugin/packages/arduino if you have not it: https://drive.google.com/file/d/1eAQtIZ6uP7VtDr6xbe-4p2OZSWTsh-2O/view
Download and install ackermann messages: https://github.com/ros-drivers/ackermann_msgs
Download and install rosserial: https://github.com/ros-drivers/rosserial or "sudo apt-get install ros-kinatic-rosserial-arduino"
Clone CLEAR repo in your catkin workspace:
In Eclipse:
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import Projects from Git - Existing local repository
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select CLEAR
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import existing Eclipse project
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click next
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click finish
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right click on the project from Project Explorer - click Properties - click Arduino (if it displays an error message keep trying until it enters the Arduino setup page)
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select platform folder
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select board "Arduino Genuino Mega or Mega 2560"
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keep "default" in upload protocol
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select processor Atmega2560
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apply and close
To check everything is fine just compile the project!
Ubuntu download: https://www.ubuntu.com/download/desktop
ROS download: http://wiki.ros.org/kinetic/Installation/Ubuntu
Coding style: http://wiki.ros.org/CppStyleGuide
Template* to autoformat with Eclipse: http://wiki.ros.org/IDEs#Auto_Formatting
*by the time I'm writting this, there is no kinetic version, but I've installed the Indigo version and works fine 😄
Eclipse Oxygen: http://www.eclipse.org/downloads/packages/eclipse-ide-cc-developers/oxygen1a
Install Sloeber: launch Eclipse - click Help - click Eclipse Marketplace - search Sloeber - click Install
Install Doxygen: type in the terminal sudo apt-get install doxygen
How to document the code for Doxygen: https://www.stack.nl/~dimitri/doxygen/manual/docblocks.html
Version Control with Git course: https://www.udacity.com/course/version-control-with-git--ud123
GitHub & Collaboration course: https://www.udacity.com/course/github-collaboration--ud456