DonkeyCar for JetRacer ROS Tutorial I: Install Jetson Nano

Note: DonkeyCar is already installed by default using our configured image, no need to install it again, just skip this tutorial.

Step 1: Install Dependencies

By default, your jetson nano has the image installed and started. Open the control terminal and enter the following command to install the dependency library.

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install -y libhdf5-serial-dev hdf5-tools libhdf5-dev zlib1g-dev zip libjpeg8-dev liblapack-dev libblas-dev gfortran
sudo apt-get install -y python3-dev python3-pip
sudo apt-get install -y libxslt1-dev libxml2-dev libffi-dev libcurl4-openssl-dev libssl-dev libpng-dev libopenblas-dev
sudo apt-get install -y git nano
sudo apt-get install -y openmpi-doc openmpi-bin libopenmpi-dev libopenblas-dev

Step 2: Setup Virtual Environment

pip3 install virtualenv
python3 -m virtualenv -p python3 env --system-site-packages
source env/bin/activate  #enter the virtual environment

Note: After that, all operations of donkeycar need to be performed in this virtual environment. The newly opened terminal needs to run the source env/bin/activate command to enter this virtual environment.

Step 3: Install Python Dependencies

Install dependencies by pip.

pip3 install -U pip testresources setuptools
pip3 install -U futures==3.1.1 protobuf==3.12.2 pybind11==2.5.0
pip3 install -U cython==0.29.21 pyserial
pip3 install -U future==0.18.2 mock==4.0.2 h5py==2.10.0 keras_preprocessing==1.1.2 keras_applications==1.0.8 gast==0.3.3
pip3 install -U absl-py==0.9.0 py-cpuinfo==7.0.0 psutil==5.7.2 portpicker==1.3.1 six requests==2.24.0 astor==0.8.1 termcolor==1.1.0 wrapt==1.12.1 google-pasta==0.2.0
pip3 install -U gdown

# This will install tensorflow as a system package
pip3 install --pre --extra-index-url https://developer.download.nvidia.com/compute/redist/jp/v45 tensorflow==2.3.1

Install PyTorch

wget https://nvidia.box.com/shared/static/p57jwntv436lfrd78inwl7iml6p13fzh.whl
cp p57jwntv436lfrd78inwl7iml6p13fzh.whl torch-1.8.0-cp36-cp36m-linux_aarch64.whl
pip3 install torch-1.8.0-cp36-cp36m-linux_aarch64.whl
sudo apt-get install libjpeg-dev zlib1g-dev libpython3-dev libavcodec-dev libavformat-dev libswscale-dev
mkdir -p ~/projects; cd ~/projects
git clone -b v0.9.0 https://github.com/pytorch/vision torchvision
cd torchvision 
python setup.py install
cd ../

Step 4: Install Donkeycar

Get the latest stable version of donkeycar program from Github and install it.

git clone https://github.com/autorope/donkeycar
cd donkeycar
git fetch --all --tags
latestTag=$(git describe --tags `git rev-list --tags --max-count=1`)
git checkout $latestTag
pip install -e .[nano]

Step 5: Create Donkeycar Example

Create donkeycar example by the following commands.

donkey createcar --path ~/mycar

After running the program, get the latest stable version of donkeycar program from Github and install it.

Step 6: Modify the Config File

Open the following file, find the camera parameter setting section to modify the camera parameters:

nano ~/mycar/myconfig.py

Jetson Nano uses a camera based on Sony IMX219, the camera is changed to CSIC, and the resolution is set to 224*224. Find the camera settings section and uncomment it and modify it as follows.

#CAMERA
CAMERA_TYPE = "CSIC"   # (PICAM|WEBCAM|CVCAM|CSIC|V4L|MOCK)
IMAGE_W = 224
IMAGE_H = 224

Modify the steering throttle control settings, find the following statement and remove the comment, and modify it as follows.
Note: Steering is controlled by channel 0, and the throttle is controlled by channel 1. If the default setting is the opposite, it needs to be modified.

PWM_STEERING_THROTTLE = {
    "PWM_STEERING_PIN": "PCA9685.1:40.0",   # PWM output pin for steering servo
    "PWM_STEERING_SCALE": 1.0,              # used to compensate for PWM frequency differents from 60hz; NOT for adjusting steering range
    "PWM_STEERING_INVERTED": False,         # True if hardware requires an inverted PWM pulse
    "PWM_THROTTLE_PIN": "PCA9685.1:40.1",   # PWM output pin for ESC
    "PWM_THROTTLE_SCALE": 1.0,              # used to compensate for PWM frequence differences from 60hz; NOT for increasing/limiting speed
    "PWM_THROTTLE_INVERTED": False,         # True if hardware requires an inverted PWM pulse
    "STEERING_LEFT_PWM": 512,               #pwm value for full left steering
    "STEERING_RIGHT_PWM": 102,              #pwm value for full right steering
    "THROTTLE_FORWARD_PWM": 512,            #pwm value for max forward throttle
    "THROTTLE_STOPPED_PWM": 307,            #pwm value for no movement
    "THROTTLE_REVERSE_PWM": 102,            #pwm value for max reverse throttle
}

The car program realizes the analog PCA9685 chip logic through the RP2040 chip I2C slave control. The PWM range can be set as above, and the steering throttle does not need to be recalibrated.

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