RPi MAVROS Pixhawk connection

RPi 3+ Setup

Image

• Download preinstall ROS and OpenCV on Raspbian from ROSbots
• Install (Etcher)[https://etcher.io/] Flash OS images to SD cards & USB drives, safely and easily
• Flash the image

Enabled ssh

• In the boot partition
• Paste empty file named ssh

Enabled wireless

• In the rootfs partition goto /etc/wpa_supplicant

cd <rootfs>/etc/wpa_supplicant
sudo vim wpa_supplicant.conf

• Paste and edit at the end of the file

network={
    ssid="The_ESSID_from_earlier"
    psk="Your_wifi_password"
}

First boot

• Connect with ssh
  • user:pi password:rosbots!

Pi config

• change locals
• changed password
• changed rootfs partition size

sudo raspi-config

Resize swap file

sudo vim /etc/dphys-swapfile
# update
CONF_SWAPSIZE=1024
# save and exit
sudo /etc/init.d/dphys-swapfile stop
sudo /etc/init.d/dphys-swapfile start
#check
free -m

Install mavlink & mavros from source

Use wstool utility for retrieve source Use catkin tool for build

sudo apt-get install python-catkin-tools python-rosinstall-generator

sudo apt-get install libgeographic-dev
sudo apt-get install geographiclib-tools
sudo apt install python-future

• Create catkin workspace

mkdir - p ~/catkin_ws/src
cd catkin_ws
catkin init

• Crate MAVLink and MAVROS install instruction

# Mavlink
rosinstall_generator --rosdistro kinetic mavlink | tee /tmp/mavros.rosinstall
#MAVROS
rosinstall_generator --upstream 
mavros | tee -a /tmp/mavros.rosinstall

wstool merge -t src /tmp/mavros.rosinstall
wstool update -t src -j4
rosdep install --from-paths src --ignore-src -y

• Got Error

ERROR: the following packages/stacks could not have their rosdep keys resolved
to system dependencies:
mavros: No definition of [geographic_msgs] for OS [debian]
mavros_extras: No definition of [tf] for OS [debian]
test_mavros: No definition of [control_toolbox] for OS [debian]
mavros_msgs: No definition of [geographic_msgs] for OS [debian]

• Install dependencies (run rosinstall_generator for each of the packages)
• Todo: dependency resolve ?

rosinstall_generator --rosdistro kinetic $XXX | tee -a /tmp/mavros.rosinstall

geographic_msgs
uuid_msgs
nav_msgs
tf
control_toolbox

actionlib_msgs
realtime_tools
diagnostic_msgs
urdf
eigen_conversions
tf2_ros

dynamic_reconfigure
tf2_eigen
rosconsole_bridge
orocos_kdl
visualization_msgs
angles
tf2_py

tf2
tf2_msgs
urdf_parser_plugin
diagnostic_updater
control_msgs

trajectory_msgs
actionlib

rosbag_migration_rule

• Run again

wstool merge -t src /tmp/mavros.rosinstall
wstool update -t src -j4
rosdep install --from-paths src --ignore-src -y

• Build

catkin  build

• todo: Installer script

files=()
for file_name in files
do
rosinstall_generator --rosdistro kinetic $file_name | tee -a /tmp/mavros.rosinstall
done

Mavros_extra compile error

tf2_eigen/tf2_eigen.h: No such file or directory
 #include <tf2_eigen/tf2_eigen.h>

• check if tf2_eigen compile

Starting  >>> tf2_eigen               Starting  >>> tf2_py                  Finished  <<< mavros_msgs                          [ 11.3 seconds ]         
Finished  <<< tf2_eigen                            [ 0.9 seconds ] 

• Add tf2_eigen to find_package (CMakeLists.txt)

find_package(catkin REQUIRED COMPONENTS
  mavros
  roscpp
  mavros_msgs
  sensor_msgs
  geometry_msgs
  std_msgs
  visualization_msgs
  urdf
  tf
  tf2_eigen
)

install GeographicLib

- Download from git `install_geographiclib_dataset.sh`
- Run it

Connect with USB

• Connect pixhawk usb to RPI usb
• Use default fcu_url "/dev/ttyACM0:57600"
• Note Don't forget to source (add to .bashrc)
• From RPi run roslaunch mavros apm.launch
• Run diagnostic

rostopic echo -n1 /diagnostics

level: 0
    name: "mavros: Heartbeat"
    message: "Normal"
    hardware_id: "/dev/ttyACM0:57600"
    values: 
      - 
        key: "Heartbeats since startup"
        value: "10"
      - 
        key: "Frequency (Hz)"
        value: "0.948061"
      - 
        key: "Vehicle type"
        value: "Quadrotor"
      - 
        key: "Autopilot type"
        value: "ArduPilotMega / ArduCopter"
      - 
        key: "Mode"
        value: "GUIDED"
      - 
        key: "System status"
        value: "Standby"

• Note: if No GPS data

 name: "mavros: GPS"
    message: "3D fix"
    hardware_id: "/dev/ttyACM0:57600"
    values: 
      - 
        key: "Satellites visible"
        value: "0"

• Run rosrun mavros mavsys rate --all 10 (need configure stream rate parameters.)

Todo: connect Serial