5g_drone_ROS2/README.md

# 5G RCID
## 5G Remote Controlled Inspection Drone
By Sem van der Hoeven

## Table of contents
- [Introduction](#introduction)
- [Installation on new flight computer](#installation-on-new-flight-computer)
- [Connecting to API](#connecting-to-api)
- [Building PX4 firmware](#building-px4-firmware)
- [ROS2 nodes overview](#ros2-nodes-overview)

## Introduction
This is the code for the 5G RCID of the 5G Hub. All ROS2 nodes and the API code can be found here. The flight computer currently already contains the latest version of the software. 
- The code for the ROS2 nodes can be found in the [src folder (src/)](/src/)
- The code for the API can be found in the [api folder (api/)](/api/)
- Further information about how the drone is built and how it works can be found in my report in the [docs folder (doc/)](/doc/)

To add new ROS2 functionality, you can edit the code, push to the repository, pull on the flight computer (ubuntu@10.100.0.40, password is `raspberrypi`) and build the ROS2 workspace again. An example of how to do this is shown below:
```bash
# (On your computer) commit changes
git commit -a -m "Added new functionality"
git push
# (On the flight computer) pull changes
cd /home/ubuntu/ros2_ws
git fetch
git pull
# (On the flight computer) build workspace
colcon build --allow-overriding drone_services
# (On the flight computer) source workspace
source install/setup.bash
# (On the flight computer) restart ROS2 nodes
drone_scripts/restart_services.sh
```
To add new API functionality, you can do the same, but for the code in the api folder. Then, log in on the edge computer and pull the changes. The API is automatically restarted when the code is changed. If you want to manually restart the API, you can do so using the following command:
```bash
# (On the edge computer) restart API
sudo systemctl restart webserver
```
## Pin layout
A pinout of the raspberry pi can be found [here](https://www.raspberrypi.com/documentation/computers/raspberry-pi.html). The connections are visible in the table below:
|Raspberry Pi pin|Function|Connected to|
|---|---|---|
|2|5V|Power input from PDB|
|4|5V|Power to relais|
|6|GND|Ground from PDB|
|8|UART TX|To RX of Pixhawk TELEM 1|
|9|GND|Ground to relais|
|10|UART RX|To TX of Pixhawk TELEM 1|
|11|GPIO 17|Relais|
|13|GPIO 27|Relais|

## Connecting to API
To connect to the API, make sure you are connected to the 5G Hub network. Then, the API is located at http://10.1.1.41:8080/. When the drone is finished booting (the relais is switched on), you can connect to the drone using the `Connect` button.

## Installing API
To be able to run the API, npm and nodejs must be installed:
```bash
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.3/install.sh | bash
nvm install node
# to be able to run npm and nodejs as sudo, run the following commands:
n=$(which node)
n=${n%/bin/node}
chmod -R 755 $n/bin/* 
sudo cp -r $n/{bin,lib,share} /usr/local 
```
To install the API on a new edge computer, you must first clone this repository. Then you can run the NodeJS webserver using npm. You can do that using the following commands:
```bash
git clone https://github.com/etmeddi/5g_drone_ROS2.git
cd 5g_drone_ROS2/api
npm start
```
## Installation on new flight computer
The drone currently has a Raspberry Pi that contains a ROS2 installation. The Raspberry Pi runs Ubuntu 20.04 and ROS 2 Foxy. If you want to install this on a new Pi, you should [get Ubuntu Server 20.04](https://ubuntu.com/download/server#downloads), and [install ROS2 Foxy](https://docs.ros.org/en/foxy/Installation/Ubuntu-Install-Debians.html) on it. Then, you should clone this repository into a `ros2_ws` folder. You can do that using the following commands:
```bash
git clone git@github.com:etmeddi/5g_drone_ROS2.git
mv 5g_drone_ROS2 ros2_ws
```

After that, to make sure the connection to PX4 works, you should follow the [PX4 ROS2 User Guide](https://docs.px4.io/main/en/ros/ros2_comm.html#installation-setup) provided by PX4.

## Building PX4 firmware
The RCID uses a custom version of the PX4 firmware to include the battery percentage and CPU load of the flight controller. Before building the firmware, make sure the [developer toolchain](https://docs.px4.io/main/en/dev_setup/dev_env.html) is set up correctly. To build the firmware, first clone the repository (from [the PX4 docs](https://docs.px4.io/main/en/dev_setup/building_px4.html)):
```bash
# enter home directory
cd
# clone git repository
git clone https://github.com/PX4/PX4-Autopilot.git --recursive
```
In the PX4 directory, edit the file `src/modules/uxrce_dds_client/dds_topics.yaml`. Above the line that says `subscriptions:`, add the following:
```yaml
  - topic: /fmu/out/battery_status
    type: px4_msgs::msg::BatteryStatus
  - topic: /fmu/out/cpuload
    type: px4_msgs::msg::Cpuload
```
The file can also be found in this repository at [dds_topics.yaml](dds_topics.yaml). After changing the file, you can build the firmware using the following command:
```bash
# navigate to root of PX4 directory
cd ~/PX4-Autopilot
# build firmware
make px4_fmu-v5_default
```
The built firmware file will be located at `PX4-Autopilot/build/px4_fmu-v4_default/px4_fmu-v4_default.px4`. You can then flash this to the flight controller using [QGroundControl](http://qgroundcontrol.com/). Make sure to select the [custom firmware](https://docs.px4.io/main/en/config/firmware.html#installing-px4-master-beta-or-custom-firmware) option when flashing, and select the built firmware file.
## ROS2 nodes overview
An overview of all the ROS2 nodes, services and topics can be found below (also visible in my report)

![ROS2 nodes overview](/doc/ROSNodes.jpg)

## PX4 parameters
To enable communication with the flight computer, the following parameters should be set in QGroundControl:
|Parameter|Value|Function|
|---|---|---|
|UXRCE_DDS_CFG|101|run microxrce-dds on TELEM 1|
|MAV_0_CONFIG|TELEM 4|run mavlink on TELEM 4 because XRCE-DDS runs on TELEM 1|
|SER_TEL1_BAUD|921600|high baud rate because serial|
|COM_RC_IN_MODE|4|allow arming without GPS|
|COM_RCL_EXCEPT|5|don't check for GPS|