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ROS–Unity Integration: Publisher

Create a simple Unity scene which publishes a GameObject's position and rotation to a ROS topic.

These instructions cover the setup for both ROS1 and ROS2. If you're using ROS2, start with the Setting Up ROS2 section. Instructions for ROS2 users are marked with this icon: .

Setting Up ROS

Follow the ROS–Unity Initial Setup guide.

Setting Up Unity Scene

In the Project tab, create a new C# script and name it RosPublisherExample. Paste the following code into the new script file.
- (Alternatively, you can drag the script file into Unity from tutorials/ros_unity_integration/unity_scripts/RosPublisherExample.cs in this repo.)

using UnityEngine;
using Unity.Robotics.ROSTCPConnector;
using RosMessageTypes.UnityRoboticsDemo;

/// <summary>
/// 
/// </summary>
public class RosPublisherExample : MonoBehaviour
{
    ROSConnection ros;
    public string topicName = "pos_rot";

    // The game object 
    public GameObject cube;
    // Publish the cube's position and rotation every N seconds
    public float publishMessageFrequency = 0.5f;

    // Used to determine how much time has elapsed since the last message was published
    private float timeElapsed;

    void Start()
    {
        // start the ROS connection
        ros = ROSConnection.instance;
        ros.RegisterPublisher<PosRotMsg>(topicName);
    }

    private void Update()
    {
        timeElapsed += Time.deltaTime;

        if (timeElapsed > publishMessageFrequency)
        {
            cube.transform.rotation = Random.rotation;
            
            PosRotMsg cubePos = new PosRotMsg(
                cube.transform.position.x,
                cube.transform.position.y,
                cube.transform.position.z,
                cube.transform.rotation.x,
                cube.transform.rotation.y,
                cube.transform.rotation.z,
                cube.transform.rotation.w
            );

            // Finally send the message to server_endpoint.py running in ROS
            ros.Send(topicName, cubePos);

            timeElapsed = 0;
        }
    }
}

Add a plane and a cube to the empty Unity scene
Move the cube a little ways up so it is hovering above the plane
Create another empty GameObject, name it RosPublisher and attach the RosPublisherExample script.
- Drag the cube GameObject onto the Cube parameter.
Press play in the Editor. You should see the connection lights at the top left corner of the Game window turn blue, and something like [INFO] [1622242057.562860400] [TCPServer]: Connection from 172.17.0.1 appear in the terminal running your server_endpoint.

Start the Echo monitor

To prove that messages are actually being received by ROS, let's run the rostopic echo command.
Open a new terminal window, navigate to your ROS workspace, and run the following commands:
```
source devel/setup.bash
rostopic echo pos_rot
```

In ROS2, the commands to run are

source install/setup.bash
ros2 topic echo pos_rot

If it's working correctly, you should see the contents of the message Unity is sending appearing every 0.5 seconds.

Please reference networking troubleshooting doc if any errors are thrown.

Continue to the ROS Subscriber tutorial.

3.5 KiB 原始文件 文件历史

ROS–Unity Integration: Publisher

Setting Up ROS

Setting Up Unity Scene

Start the Echo monitor

3.5 KiB

原始文件文件历史