usma_mavros

These instructions are for operating a small, multirotor UAS running a PX4 flight control unit or similar variant. They also include setup for a ROS interface using mavlink and mavros. The companion computer can be a number of embedded devices such as a NUC, Odroid, or RPi while using a ground station PC connected via WiFi and a telemetry radio.

Outdoor Operations

PX4 Instructions

1. We recommend first starting with a tethered configuration (power and communications). A Linux computer can connect to the PX4 using the USB port. Follow the PX4 development guide. See your instructor with questions.
2. Configure the PX4 using QGroundControl (download latest firmware, set up flight modes, etc).

• The SERIAL2_BAUD parameter is set to 921600. This paramater is the Telemetry 2 port on the PX4.

3. Once your PX4 is configured and calibrated, it can connect to a companion computer through an FTDI adapter to the Telemetry 2 port on the PX4 as described here.
4. These instructions assume the latest stable version of the firmware (v1.10.0 as of March 2020). Note: If the /tag/v*.. page does not have .px4 files, go to the next available stable release. For the Pixhawk v2.1 cube, you need fmu-v3, e.g. px4_fmu-v3_default.px4

Computer Instructions

1. Install the mavros package and dependencies (assuming the stable version of ROS is used).
2. Clone usma_mavros

• cd ~/catkin_ws/src
• git clone https://github.com/westpoint-robotics/usma_mavros

3. Build

• cd ~/catkin_ws/
• catkin_make -DMAVLINK_DIALECT=common

4. Configure mavros on computer:

• In px4.launch,
• The computer is connecting through ttyUSB0:921600 instead of ttyACM0:57600.
• Chage the gcs_url argument default to default="udp://:[email protected]:14550" to match the IP of the ground control station (which may be determined using ifconfig, or ip a).
• QGC can connect to the autopilot using the Default UDP link.

5. Execute mavros

• roslaunch usma_mavros px4.launch
• Check that there is a heartbeat with the PX4.
• [INFO] [1573276705.686808500]: CON: Got HEARTBEAT, connected. FCU: ArduPilot

----- Need to update indoor operations and below ------

Indoor Operations

1. We recommend first starting with a tethered configuration (power and communications). A Linux computer can connect to the PX4 using a USB extension and FTDI adapter to the Telemetry 2 port on the PX4 as described here. For initial testing and configuration, it is possible to connect to the PX4's micro USB port.

2. For general manual control, configure the PX4 using QGroundControl (download latest firmware, set up flight modes, etc).

3. If operating in mocap, follow the usma_optitrack instructions for set up motion capture.

   • Configure the PX4 to operate in mocap using external position estimation.

   • Instructions are included to build from source. The firmware can also be downloaded here.

   • Transmitter settings can be found here. At a minimum, the RC transmitter should have manual, position control, offboard control, and a kill switch.

   • First achieve position control of the vehicle using the transmitter.

   • Here is a summary of firmware parameters:

     -- The sys_companion field is set 921600. -- ATT_EXT_HDG_M parameter is set to 2.

Outdoor Operations

PX4 Instructions

1. We recommend first starting with a tethered configuration (power and communications). A Linux computer can connect to the PX4 using a USB extension and FTDI adapter to the Telemetry 2 port on the PX4 as described [here] (http://ardupilot.org/dev/docs/odroid-via-mavlink.html).
2. Configure PX4 using QGroundControl (download latest firmware, set up flight modes, etc).

• If operating in mocap, follow the usma_optitrack instructions for set up motion capture.
• Configure the PX4 to operate in mocap using [external position] (http://dev.px4.io/external-position.html).
• The sys_companion field is set 921600.
• ATT_EXT_HDG_M parameter is set to 1 (when using vision_pose topic).
• CBRK_NO_VISION parameter set to 0.
• Indoor navigation is only achieved by using the external headings from mocap.
• The offboard control documentation provides a good overview.

Computer Instructions

1. Install the mavros package and dependencies (assuming ROS Indigo used).

• sudo apt-get install ros-indigo-mavros ros-indigo-mavlink ros-indigo-diagnostic-updater ros-indigo-tf2-ros ros-indigo-angles ros-indigo-eigen-conversions ros-indigo-image-transport ros-indigo-cv-bridge ros-indigo-urdf ros-indigo-tf ros-indigo-control-toolbox

3. Clone usma_mavros

• cd ~/catkin_ws/src
• git clone https://github.com/westpoint-robotics/usma_mavros

4. Build

• cd ~/catkin_ws/
• catkin_make -DMAVLINK_DIALECT=common

5. Configure mavros on computer:

• Note some variations to the mavros configuration:
• Using QGC, the sys_companion field is set 921600 so that autopilot is enabled with a higher baud rate to communicate with the computer.
• In px4.launch,
• The computer is connecting through ttyUSB0:921600 instead of ttyACM0:57600.
• Chage the gcs_url argument default to default="udp://:[email protected]:14550" to match the IP of the ground control station (which may be determined using ifconfig, or ip a).
• QGC can connect to the autopilot using the Default UDP link.
• If using mocap, ensure that the vision_pose_estimate plugin is enabled and NOT blacklisted.

6. Execute mavros

• roslaunch usma_mavros px4.launch
• Check that there is a heartbeat with the PX4.
• Check the debug messages for a valid vision estimate: FCU: [inav] VISION estimate valid
• Echo the FCU local position to check for propoer coordinate frame conversions: rostopic echo /mavros/local_position/local

Instructions to set up a Raspberry Pi 2

1. [Install Ubuntu 14.04 LTS] (https://wiki.ubuntu.com/ARM/RaspberryPi)

• [These instructions are helpful as well] (https://www.raspberrypi.org/documentation/installation/installing-images/linux.md)

2. Connect your RPi2 using wired Ethernet.
3. Install linux-firmware drivers to enable wifi.

• sudo apt-get install linux-firmware
• sudo apt-get install wicd

4. [Setup WiFi on your device] (https://help.ubuntu.com/community/NetworkConfigurationCommandLine/Automatic)

• [Another reference] (https://learn.adafruit.com/adafruits-raspberry-pi-lesson-3-network-setup/setting-up-wifi-with-occidentalis)
• $ sudo nano /etc/network/interfaces

auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
  wpa-ssid "EECSDS3"
  wpa-psk "accessgranted"

5. [Install ROS] (http://wiki.ros.org/indigo/Installation/UbuntuARM) 6
6. Make these [hardware connections] (http://dev.ardupilot.com/wiki/raspberry-pi-via-mavlink/) between the RPi2 and PX4

• The software instructions in the above link are not followed.

2. Assume Ubuntu 14.04 and ROS Indigo installed and a catkin_ws created.
3. Setup serial port and baud rate on RPi2:

• Create a temp folder and clone this [package] (https://github.com/vooon/rarog.git)
• Follow the installation [instructions] (https://github.com/vooon/rarog/tree/master/rarog_configs/rpi2)
  • Ignore #4 and #5

4. Set up embedded computer to match MASTER_URI of base station

• cd ~
• vim .bashrc (or your preferred editor)
• Add this export to the end of your .bashrc file that matches the IP of your master machine (i.e. the basestation):
  • export ROS_MASTER_URI=http://192.169.200.50:11311
• Both the client and server should have this export in their .bashrc
• Edit your /etc/hosts to include the computer name and IP address for the other computer similar to these [instructions] (http://www.faqs.org/docs/securing/chap9sec95.html)
• Other references:
  • http://wiki.ros.org/ROS/Tutorials/MultipleMachines
  • http://wiki.ros.org/ROS/NetworkSetup

5. Run mavros on the embedded computer:

• roslaunch usma_mavros px4.launch
• Note some variations to the mavros configuration:
  • Using QGC, ensure the sys_companion field is set to 921600 so that autopilot is enabled with higher baud rate to communicate with onboard computer
  • In px4.launch, the RPi2 is connecting through ttyAMA0:921600 instead of ttyACM0:57600

Offboard Tracking

1. set up ROS_MASTER_URI and IP on all the terminals used in tracking
2. Run roslaunch mavros px4.launch on onboard computer
3. on remote host,set up ROS_MASTER_URI and IP and run roslaunch mocap_optitrack mocap.launch
4. on different terminal,set up ROS_MASTER_URI and IP and run roslaunch mavros_extras teleop_track.launch
5. Joystick button map is listed in f710_joy.yaml( for take-off ,land, track button reference)

New instructions

Quad rotor naming

All tail numbers must be unique

• Mocap rigid body naming - f450_<TAIL_NUM>
• Hostname - odroid-<TAIL_NUM>

PX4 setup

• Flash the firmware located in the config folder
• Load the params file in the config folder
• Calibrate all sensors

Odroid setup

During OS installation

• Hostname - odroid-<TAIL_NUM>

After OS install

echo "192.168.200.88 ros304" | sudo tee -a /etc/hosts

After ROS install

• clone and make mavros from source
• make sure to compile with one job otherwise it will most likely fail

cd ~/catkin_ws
catkin_make -j1

Generate and share SSH key (no password)

ssh-keygen
cat ~/.ssh/id_rsa.pub

Copy and paste this into the base station's authorized_keys file in a new line

Base station setup

Only once

echo  "export ROSLAUNCH_SSH_UNKNOWN=1" >> ~/.bashrc
echo  "export ROS_MASTER_URI=http://ros304:11311" >> ~/.bashrc

For each Odroid

echo "<IP_ADDRESS> odroid-<TAIL_NUM" | sudo tee -a /etc/hosts

An ssh key should already be setup. Share with the odroid

cat ~/.ssh/id_rsa.pub

Copy and paste this into the Odroid's authorized_keys file in a new line

How to run

Make sure a BATTERY is plugged in

Terminal A

roslaunch usma_mavros base_station.launch

Terminal B

roslaunch usma_mavros lpe_mavros_quad.launch TAIL_NUM:=131

Terminal C

rosrun usma_mavros test_flight __ns:=f450_131

Mavros Setup Insutruction - Fall 2021

Companion Computer OS Configuration

Configure ubuntu 20.04 appropraitely depending on your companion computer. It can be downloaded here

• Raspberry Pi 4 / Odroid: Download the armhf 32 bit version here onto an sd-card and configure it following the directions based on what OS your main laptop is running. Linux Windows (scroll to "On Windows" section).
• Up Core: Follow the instruction on this page.
• Intel NUC: NUC's from the RRC should already be running 18.04, this is okay.

Companion Computer ROS/Mavros Install

Now that an ubuntu operating system is downloaded we can install ROS and mavros.

• ROS Noetic: Follow the instructions at the page here
• Mavros: Once ROS Noetic is installed use the following command to install Mavros

  sudo apt-get install ros-kinetic-mavros ros-kinetic-mavros-extras
  

  You will also need GeographicLib which can be installed with these commands;

  wget https://raw.githubusercontent.com/mavlink/mavros/master/mavros/scripts/install_geographiclib_datasets.sh
  sudo bash ./install_geographiclib_datasets.sh
  

  You need to be in the same directory as install_geographiclib_datasets.sh to run the second command. You can ensure mavros is installed correctly in your system space with:

  roscd mavros
  

  You should be brought to

  /opt/ros/noetic/share/mavros
  

• IP Address Run:

  sudo apt-get install net tools
  

  Then use the command

  ifconfig
  

  and something similar to below should be retruned in the wlan0 section:

  wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
      inet 10.212.146.230  netmask 255.255.0.0  broadcast 10.212.255.255
      inet6 fe80::cb1f:1655:4a91:3e58  prefixlen 64  scopeid 0x20<link>
      ether dc:a6:32:a1:30:8a  txqueuelen 1000  (Ethernet)
      RX packets 1003  bytes 864468 (864.4 KB)
      RX errors 0  dropped 0  overruns 0  frame 0
      TX packets 692  bytes 299630 (299.6 KB)
      TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
  

  The ip address follows inet in this case it would be 10.212.146.230 It is helpful to note this for remoting into your companion computer.

Mavros Set-up

Now we need to configure mavros so you are ready to fly. First navigate to the launch files with

roscd mavros/launch

Use the following command to allow file editing:

chmod 777 px4.launch apm.launch

In your favorite text editor change line 5 to match the following:

<arg name="fcu_url" default="/dev/ttyUSB0:921600" />

Pixhawk Configuration

For this section you will need to download the following programs onto your laptop (not necessary for companion computer)

• QGroundControl
• MissionPlanner