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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.

Setting Up ROS

Copy the tutorials/ros_packages/robotics_demo folder of this repo into the src folder in your Catkin workspace.
Follow the ROS–Unity Initial Setup guide.

Open a new terminal window and run the following commands:

 source devel/setup.bash
 rosrun robotics_demo server_endpoint.py

Once the server_endpoint has started, it will print something similar to [INFO] [1603488341.950794]: Starting server on 192.168.50.149:10000.

Open another new terminal window, navigate to your ROS workspace, and run the following commands:
```
 source devel/setup.bash
 rostopic echo pos_rot
```

Setting Up Unity Scene

In the menu bar, find and select Robotics -> Generate ROS Messages...
Set the ROS message path to PATH/TO/Unity-Robotics-Hub/tutorials/ros_packages/robotics_demo.
- Expand the robotics_demo subfolder and click "Build 2 msgs" to generate new C# scripts from the ROS .msg files.

The generated files will be saved in the default directory Assets/RosMessages/RoboticsDemo/msg.
Create a new directory in Assets and name it Scripts
Create a new script in the Scripts directory and name it RosPublisherExample.cs
Open RosPublisherExample.cs and paste the following code:
- Note Script can be found at tutorials/ros_unity_integration/unity_scripts

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

/// <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;
    }

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

        if (timeElapsed > publishMessageFrequency)
        {
            cube.transform.rotation = Random.rotation;

            PosRot cubePos = new PosRot(
                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
In the main menu bar, open Robotics/ROS Settings.
- Set the ROS IP address and port to match the ROS IP and port variables defined when you set up ROS.
Create another empty GameObject, name it RosPublisher and attach the RosPublisherExample script.
- Drag the cube GameObject onto the Cube parameter.
Pressing play in the Editor should publish a message to the terminal running the rostopic echo pos_rot command every 0.5 seconds

Continue to the ROS Subscriber tutorial.

3.6 KiB 原始文件 文件历史

ROS–Unity Integration: Publisher

Setting Up ROS

Setting Up Unity Scene

3.6 KiB

原始文件文件历史