ROS2 on i.MX8 M Mini NavQ for Mobile Robotics (*DRAFT)

iaingalloway — Thu, 01 Oct 2020 20:30:10 GMT

NavQ is described on Gitbook - https://nxp.gitbook.io/8mmnavq/

***DRAFT*** This is a work in progress and may have errors.

This page holds suggestions for general settings of navq.
**** NOTE your hardware configuration may differ from the instructions here. Please post a reply where you find issues and we'll update.
**** These instructions are for a setup that includes MAVLINK over an Ethernet Connection between the NavQ and the RDDRONEFMUK66. Unfortunately you will not have the RJ45 to 2-wire ethernet adapter that is needed. Modifications will be needed to make this work with UART based communications

[Credits - Gerald Peklar, Peter Van Der Perk]

Documentation below assumes internet access of navq via wifi. Guide on how to enable wifi is available on navq gitbook - https://nxp.gitbook.io/8mmnavq/getting-started/quickstart#connecting-to-wifi

The editor nano is helpful. Install nano with (internet access required).

~$ sudo apt install nano

Since several NavQs might be present in a Wifi Network it's desired to set an unique hostname to determine the "right" navq to connect to.

Modify /etc/hostname with a unique host name. Proposal is to use

navq-[Vehicle Mavlink SysID]

e.g. if Mavlink SysID is 10 the navq should be named navq-10

~$ sudo nano /etc/hostname

navq-10

Setting a fixed IP to use eth for FMU communication

Since there is no DHCP on a drone and FMUK66 has a fixed IP of 10.0.0.2 we need to set a fixed IP for eth0 to be able to communicate via ethernet to FMUK66.

Suggestion is to use 10.0.0.3 for navq. 10.0.0.1 is reserved for the D2X gen1 board acting as a network switch.

connman is used for setting the network . To force connman to use a fixed IP in case of no DHCP is available the following file needs to be created.

~$ sudo nano /var/lib/connman/ethernet.config

[global]
Name = Ethernet_config
Description = Ethernet fixed IP setting

[service_onboard_ethernet]
Type = ethernet
IPv4 = 10.0.0.3/255.255.255.0/10.0.0.1

The IP4 settings are ownIP/netmask/router. 10.0.0.1 is set assuming a D2X board is in place.

Connecting navq to FMUK66 requires a T1 media converter - https://nxp.gitbook.io/8mmnavq/navq-add-on-modules/100baset1-2-wire-automotive-ethernet-media-converter

Setting up FMUK66 for mavlink over T1 ethernet

T1 ethernet is supported by PX4 on FMUK66 with latest master.

To enable FMUK66 sending mavlink telemetry via UDP to a specific IP is done by setting up the following file on the FMUK66 SDcard.

/etc/extras.txt

mavlink start -x -u 14551 -o 14551 -r 200000 -t 10.0.0.3 -m onboard

10.0.0.3 is the IP address of navq on the vehicle.

Description of the mavlink start parameters on https://dev.px4.io/v1.9.0/en/middleware/modules_communication.html

Additionally the MAV_BROADCAST parameter on the FMU needs to be set to 2 - only multicast.

Setting up mavlink_router

(The first section is general setup/configuration)

(The second section is about installing ROS2 on the NavQ itself)

To be able to have several end nodes communicating via mavlink we need to set up mavlink-router on the navq.

End nodes can be

a process for onboard control running on navq.
a QGC computer the navq connects to via wifi.
other mavlink enabled peripherals on the vehicle.

Compile and installation of mavlink router is done with the following steps on the navq (internet access required):

~$ mkdir src
~$ cd src
~/src$ git clone https://github.com/intel/mavlink-router.git
~/src$ cd mavlink-router 
~/src/mavlink-router$ git submodule update --init --recursive
~/src/mavlink-router$ ./autogen.sh && ./configure CFLAGS='-g -O2' --sysconfdir=/etc --localstatedir=/var --libdir=/usr/lib --prefix=/usr
~/src/mavlink-router$ make
~/src/mavlink-router$ sudo make install

Configuration of mavlink router is done via a single configuration file expected as /etc/mavlink-router/main.conf

This file needs to be created from scratch. Example configuration file - https://github.com/intel/mavlink-router/blob/master/examples/config.sample

Setup the config file with minimal configuration

~$ sudo nano /etc/mavlink-router/main.conf

#Mavlink router configuration navq
#
[General]
TcpServerPort=5790
ReportStats=false
MavlinkDialect=auto

[UartEndpoint FMUuart]
Device=/dev/ttymxc2
Baud=155200

[UdpEndpoint FMUeth]
Mode = Eavesdropping
Address = 0.0.0.0
Port = 14551

[UdpEndpoint QGConMobile]
Mode = Normal
Address = 192.168.43.1
Port = 14550

The configuration above assumes that the navq gets mavlink data from FMU either via UART3 (/dev/ttymxc2) or UDP.

You can leave out the unused connection.

Via the UdpEndpoint QGConMobile section the mavlink stream is forwarded to a QGC computer/mobile device assuming it has 192.168.43.1 and navq is connected to this network via e.g. wifi.

Enable the autostart of mavlink-router via systemd and start it

~$ sudo systemctl enable mavlink-router
~$ sudo systemctl start mavlink-router

Finally you can check the status of mavlink router via

~$ sudo systemctl status mavlink-router

Locale environment settings

Good source for how-to do locale setting is https://help.ubuntu.com/community/Locale#List_current_settings

Example settings for Germany

First generate the German locales

sudo locale-gen de_DE.UTF-8

Set the German locales but have messages in english still. This is defined by LC_MESSAGES setting.

sudo update-locale LANG=de_DE.UTF-8
sudo update-locale LC_MESSAGES=POSIX

Setting up FMUK66 for fastRTPS

Update PX4 build environment to latest status and build the code with
make nxp_fmuk66-v3_rtps
upload the generated nxp_fmuk66-v3_rtps FW into FMUK66.
Prepare the FMU's SD card by adjusting /etc/extras.txt file.
This will autostart the fastRTPS communication at boot time.
Add the following line in to /etc/extras.txt

micrortps_client start -t UDP -i 10.0.0.3

Assuming that NavQ is running with IP 10.0.0.3

Setting up ROS2 on NavQ

All commands to be executed on NavQ

Install ROS2 foxy using

Follow the guide on https://index.ros.org/doc/ros2/Installation/Foxy/Linux-Install-Debians/#setup-sources

Note (1): at Setup Sources step you might get an error message by curl

To avoid this do upfront

sudo rm -rf /usr/lib/libcurl*
sudo apt install curl

Note (2): at Install ROS2 package step use

sudo apt install ros-foxy-ros-base

Desktop is not needed on a headless system!

System requirements

~$ sudo apt update
~$ sudo apt install cmake python3-pip gradle python3-colcon-common-extensions gradle
~$ pip3 install --user pyros-genmsg

Setting up PX4 Ros com for ROS2 Foxy

If you have no src directory yet on NavQ's home directory just create it

~$ mkdir src

~$ cd src 
~/src$ git clone --recursive https://github.com/eProsima/Fast-RTPS.git -b 1.8.x FastRTPS-1.8.2
~/src$ cd FastRTPS-1.8.2
~/src/FastRTPS-1.8.2$ mkdir build
~/src/FastRTPS-1.8.2$ cd build 
~/src/FastRTPS-1.8.2/build$ cmake -DTHIRDPARTY=ON -DSECURITY=ON .. 
~/src/FastRTPS-1.8.2/build$ make 
~/src/FastRTPS-1.8.2/build$ sudo make install

cd ~/src
~/src$ git clone --recursive https://github.com/eProsima/Fast-RTPS-Gen.git -b v1.0.4 Fast-RTPS-Gen
~/src$ cd Fast-RTPS-Gen
~/src/Fast-RTPS-Gen$ unset TERM
~/src/Fast-RTPS-Gen$ ./gradlew assemble
~/src/Fast-RTPS-Gen$ sudo su
~/src/Fast-RTPS-Gen# unset TERM
~/src/Fast-RTPS-Gen# ./gradlew install
~/src/Fast-RTPS-Gen# exit
~/src/Fast-RTPS-Gen$

cd ~/
mkdir -p ~/px4_ros_com_ros2/src
git clone https://github.com/PX4/px4_ros_com.git ~/px4_ros_com_ros2/src/px4_ros_com
git clone https://github.com/PX4/px4_msgs.git ~/px4_ros_com_ros2/src/px4_msgs

# Note building px4_ros_com requires a lot of ram, enable a swap disk is recommended

# see https://linuxize.com/post/create-a-linux-swap-file/

Execute building PX4 ROS2

~$ ./px4_ros_com_ros2/src/px4_ros_com/scripts/build_ros2_workspace.bash

Starting MicroRTPS bridge Prerequisit - Ethernet configuration

-NavQ 10.0.0.3/24

-K66 10.0.0.2/24

NavQ

~$ source /opt/ros/foxy/setup.bash
~$ source ~/px4_ros_com_ros2/install/setup.bash

~$ micrortps_agent -t UDP -i 10.0.0.2

K66

see Setting up FMUK66 for fastRTPS in Wiki

Optional debugging

source /opt/ros/foxy/setup.bash
source ~/px4_ros_com_ros2/install/setup.bash

sudo apt install ros-foxy-rqt-topic

rqt_topic --force-discover

Autostart micrortps client via systemd on NavQ

The instruction below assumes that you have successfully executed Setting up ROS2 on NavQ in Wiki

Generate a start up script for the micrortps client under /usr/local/bin

sudo nano /usr/local/bin/start_micrortps_agent.sh

with content

#!/bin/bash
## startup script for micro_rtps_agent
## agent will communicate to FMUK66 via UDP
## FMUK66 IPv4 addr = 10.0.0.2 
##
## Author: Gerald Peklar <gerald.peklar@nxp.com>

source /opt/ros/foxy/setup.bash
source ~/px4_ros_com_ros2/install/setup.bash

micrortps_agent -t UDP -i 10.0.0.2

Save the file and exit nano.

Make the file executable

sudo chmod +x /usr/local/bin/start_micrortps_agent.sh

Generate a systemd service file to start the startup script at boot

sudo nano /etc/systemd/system/micrortps_agent.service

with content

[Unit]
Description=PX4 micrortps service
After=network.target

[Service]
Restart=always
TimeoutStartSec=10
User=navq
Group=navq
WorkingDirectory=~
ExecStart=/usr/local/bin/start_micrortps_agent.sh

[Install]
WantedBy=multi-user.target

Save the file and exit nano.

Check if the process starts

sudo systemctl start micrortps_agent.service
sudo systemctl status micrortps_agent.service

You should see an state active (running)

quit with <q>

Enable the systemd service file finally to be active at boot

sudo systemctl enable micrortps_agent.service

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ROS2 on i.MX8 M Mini NavQ for Mobile Robotics (*DRAFT)