19.1.2. Installing PX4

We try to stick to the original PX4 software as much as possible.

Feel free to modifiy your fork of the autopilot as much as you want, but if you add functionality, that should be shared with the rest of the world, create a pull request.

Note

The following instructions assume, you want to clone the PX4-Autopilot in your home directory. If you don’t, you have to modifiy the instructions accordingly.

Get The Code

git clone --branch v1.12.3 --recursive https://github.com/PX4/PX4-Autopilot.git

Export Environment Variables

PX4_DIR=$HOME/PX4-Autopilot

Choose the option depending on your shell:

zshbash

echo "source $PX4_DIR/Tools/setup_gazebo.bash $PX4_DIR $PX4_DIR/build/px4_sitl_default > /dev/null" >> ~/.zshrc
echo "export ROS_PACKAGE_PATH=\$ROS_PACKAGE_PATH:$PX4_DIR" >> ~/.zshrc
echo "export ROS_PACKAGE_PATH=\$ROS_PACKAGE_PATH:$PX4_DIR/Tools/sitl_gazebo" >> ~/.zshrc

Build The Code

Set up dependencies:

cd ~/PX4-Autopilot && bash ./Tools/setup/ubuntu.sh

Install xmlstarlet and python3-pip:

sudo apt install xmlstarlet python3-pip

Go to the firmware directory

cd ~/PX4-Autopilot

Build the firmware

Firmware for simulationFirmware for PixRacer

DONT_RUN=1 make px4_sitl gazebo_uuv_hippocampus

Sensible Modifications

Battery Invalid

If the battery parameters are set up correctly and your battery values are not shown in QGroundControl, this might be because the firmware detects the battery errenously as invalid. This happens for example on the BlueROV, where the FCU is powered via USB and the power sense module provides only the measurements but not the supply voltage.

In analog_battery.cpp:l:83 the following expression evaluates as false.

bool connected = voltage_v > BOARD_ADC_OPEN_CIRCUIT_V &&
                     (BOARD_ADC_OPEN_CIRCUIT_V <= BOARD_VALID_UV || is_valid());

As a quickfix, replace is_valid() with true.