Here, the DDS tutorial you want | first experience of fastdds - source code compilation & Installation & Testing

Hello everyone , I'm little fish , I was urged by my friends in the group yesterday DDS In related articles , Say a good source code and experience DDS Here it is , Little fish can't coo anymore , So let's share today ,FastDDS Installation and experience .

1. On FastDDS Three ways to open

FastDDS And the general ROS The bag is the same , There are binary installations 、 Source code compilation 、Docker Three installation methods .

Because the official binary and Docker Put it on the official website .. And you have to fill in your personal information to download .. And the download speed is super slow .. And it's inconvenient to observe the source code .. So Xiaoyu takes you to install from the source code .

Originally wanted to make a one click installation , Everyone in the province typed the script ！！

Love a person must not be used to him , So is fish meal , In order to make everyone think more when copying and pasting （ In fact, it's to count the words of the article ）, Xiaoyu will take you step by step to install and compile the source code

However, the source code installation is also very simple , Don't be afraid ..

because DDS and ROS2 relevant , We can also use colcon To compile the , You don't have to cmake 了 ( Yes cmake Go to the official website by yourself )

2. Source code compilation and installation FastDDS

Download and compile DDS There are three steps , Step 1 if you have installed ROS2 You can skip ..

1. Installation tools

sudo apt install python3-colcon-common-extensions python3-vcstool zip openjdk-8-jdk  -y

2. Create directory , Download warehouse

mkdir -p fastdds_ws/src 
cd fastdds_ws && wget https://downloads.gradle-dn.com/distributions/gradle-6.4-bin.zip && unzip gradle-6.4-bin.zip 
wget http://fishros.com/tools/files/fastrtps.repos && vcs import src < fastrtps.repos

3. compile

colcon buildcd src/fastddsgen/ &&  gradle assemble

The last step : Configure environment variables

xxx Is your directory prefix

echo 'source xxx/fastdds_ws/install/setup.bash' >> ~/.bashrcecho 'export PATH=$PATH:xxx/fastdds_ws/gradle-6.4/bin/' >> ~/.bashrcecho 'export DDSGEN=xxx/fastdds_ws/src/fastddsgen/scripts' >> ~/.bashrc

3.HelloFish routine

DDS The use of RTPS, Namely Real-Time Publish Subscribe agreement , Actually sum ROS And ROS2 The feeling of publishing and subscribing in is the same , So we run a routine to send and receive messages , The message content is called HelloFish

The program written by Xiaoyu is ready , Put it in github On , You can download it directly and compile the test ~

Download code

git clone https://github.com/fishros/dds_tutorial.git

Compile routine ​​​​​​​

cd dds_tutorial/examples/01-hellofishrosmkdir build && cd buildcmake .. make

Execute routine

Open a terminal

./DDSHelloFishRosPublisher

Open another terminal

./DDSHelloFishRosSubscribe

View results

The correct result looks like this , Has proved everything OK 了 ~

DDS Publish and subscribe test

4. summary

Isn't it amazing to see familiar publish and subscribe ,FASTDDS The bottom layer uses a variety of protocols for data transmission , Including unreliable but really fast UDP, Reliable but not very fast TCP, There is also a memory exchange that does not feel transferred （SHM).

In order to show you what is called low yield （ lazy ）, Xiaoyu decided to explain the code to you tomorrow ~

The above content is written by Xiao Yu who stayed up late and stepped on the pit , If you look carefully, it's equivalent to staying up late for free ~