UTD COMO package

The package is based on the barc package. The documentation for barc is in the next section. Our fork has changes made at the University of Texas at Dallas.

Cloning the repository

To clone our fork, open a new terminal, go to the directory where you want to clone the repository, and run the following: git clone --recurse-submodules https://github.com/TSummersLab/como.git We will use to refer to the directory where the repository is cloned; i.e. if you are in the repository and you type pwd in terminal, you would see <path>/como

Building the repository

• In a terminal window, navigate to the scripts folder in the repository: cd <path>/como/scripts
• Run the following commands in your terminal window:

./install_apps.sh
./install_ros_packs.sh
./gps_setup.sh

This will install the required applications and dependencies for the package. It will also add the required launch file to the gps package.

• Note: When gps_setup.sh is executed again, it overwrites the data in the old gps.launch file, if it already existed.
• To build the package run the following in your terminal window:

./rebuild_system.sh

If the Arduino nano was connected, rebuild_system.sh would also flash it.

• If the Arduino nano was not connected, or if you want to flash the nano without building the package, run the following in your terminal window:

./flash_nano.sh

Berkeley Autonomous Race Car (barc) Repo

The Berkeley Autonomous Race Car is a development platform for autonomous driving to achieve complex maneuvers such as drifting, lane changes, and obstacle avoidance. A 1/10 scale RC car and an embedded Linux computer make up the hardware platform of the project. This project aims to be fully open-source. The data collection process is cloud-based and brings new dimensions to the Vehicle Dynamics and Control Theory teaching and research world.

This site is home to the repository. The main site for the project is here. Although several directories contain their own README files, all of this information has been consolidated in the Github Wiki.

Organization

The primary folders in this repository include

• docs
  • Overview about the mechanical, electrical, and software deign of the vehicle. Descriptions of the vehicle models used for some control algorithms
• CAD
  • DWX files for fabricating the deck and side brackets for the chassis, and STL files for fabricating the sensor mounts (e.g. hall effect sensor, camera, ultrasound) and the cover for the odroid.
• Dator
  • Web server for cloud robotics. Provides a standard way to record data and events from one or more local computers for later analysis. Based on this repo from Bruce Wooton
• arduino
  • Files to program the arduino to (1) send commands to the electronic speed control (ESC) unit and the servo, and to (2) acquire measurements from the encoders and ultrasound sensors
• scripts
  • Bash programs that set up environment variables and launch the local server upon boot
• MATLAB
  • Useful MATLAB scripts for processing ROS bag file. The bag files store all the message data (time stamped sensor measurements, actuator commands, etc) during an experiment
• workspace
  • Robotic Operating System (ROS) workspace that contains the barc package. This package holds the source code to control the vehicle using the ROS framework

All software to control the vehicle resides in the Arduino and Workspace folders.

Getting started

1. Get the parts, list
2. Flash the odroid, instructions
3. Assemble the car, instructions
4. Charge the battery, instructions
5. Connect to the RC remotely, instructions

You can also scroll through the material under our docs section to find other useful information

Useful resources

Recommended reading and resources

• A Gentle Introduction to ROS, by Jason M. O'Kane, and this basic tutorial for writing ROS nodes in python
• Julia JuMP, Mathematical Programming using the Julia programming language
• Git - the simple guide, or for a more in-depth reading, consider this tutorial by Atlassian
• Electronic Speed Control (ESC) manual, which details how to calibrate and program the ESC
• Open source ESC, for building your own ESC
• Pulse Wide Modulation (PWM), notes from Michigan State ECE480 class, explaining the concept of PWM and its usage in an arduino.
• Arduino Servo Library, article by Make magazine, clarifying the usage of some functions within the library
• Mass moment of inertia calculation, a MATLAB newsletter explaining how to estimate the mass moment of inertia
• Computer Vision lecture series, from Professor Peter Corke aat Queensland University of Technology

Student projects

• Lane Keeping and Obstacle Avoidance, with demo, by Tony Abdo, Hohyun Song, Cheng Hao Yuan, UC Berkeley ME 131, Spring 2016

Potential issues

Bad IMU magnetometer readings

The magnetic field around car, perhaps from the motor or aluminum deck, may interfere with the magnetometer readings, meaning the roll, pitch, yaw measurements may be off

Wrong internal clock time / date

The time and date settings on the odroid may be incorrect. This may be because the Real Time Clock (RTC) battery is not connected or has a loose connection. To update the date / time settings, ensure the RTC battery is firmly connected, and ensure you are connected to the Internet via wifi or ethernet. Next, open a terminal and run the following network time protocol (ntp) commands

sudo service ntp stop
sudo ntpdate -s time.nist.gov
sudo service ntp start

If you have a "no server suitable for synchronization found", your hosting provider may be blocking ntp packets. Refer to this community question for more information