##Hardware in the loop tool for PX4 Firmware

This is a tool for running hardware-in-the-loop (HIL) simulations for the px4 autopilot.

###HIL modes:

• State-level HIL: tests the control and guidance systems.
• Sensor-level HIL: tests the navigation system in addition to the control, and guidance systems. This requires a lot of data to be sent to the vehicle and a high baudrate.

Dependencies

PyMAVLink

Pymavlink is the python library required for running the runhil.py script, you can install it with easy install or pypi-install

If you are using a debian based system (e.g. Ubuntu), you can install using pypi-install so that it can be installed as debian package:

sudo apt-get install python-stdeb
pypi-install pymavlink

If you are using Mac OS / other unix systems:

sudo easy_install pymavlink

JSBSim

JSBSim is the C++ flight dynamics model. It can be built with cmake/ or autotools.

brew install autoconf automake

git clone https://github.com/PX4/jsbsim.git jsbsim
cd jsbsim
./autogen.sh
make

Usage

NSH Startup Script

You must use the startup script found in data/rc. The two main lines added to normal startup are:

kalman_demo start
control_demo start

Python Script

This python script runhil.py is used for conducting HIL. Both sensor-level and state-level HIL are supported. You can view the runhil.py usage with:

runhil.py -h

A call to runhil.py might look like this:

./runhil.py --waypoints data/sf_waypoints.txt --master /dev/ttyUSB1 --gcs localhost:14550 --mode sensor

Explanation:

• load the given waypoints in data/sf_waypoints.txt, NOTE: QGC waypoints are not compatible with pymavlink currently, you simply need to change the version number in the file to 110 if it is 120
• connect to the px4 autopilot on usb port 1
• setup external ground station communication of localhost:14550 udp.
• mode sensor says do sensor-level hardware-in-the-loop (HIL), this can be set to state as well

GroundControl Interface

Note that the script defaults to opening a mavlink slave port on udp:14550, this is the default udp port for QGroundControl. If you start QGC, it should start communicating with runhil.py automatically.

Notes

TODO:

• Magnetometer measurement model doesn't depend on lat/lot yet.
• Add noise.
• Initialization routines for EKF.

Source

This uses pymavlink and is based off of MAVProxy/ ardupilotemga SITL code.