/unity_car_2_wheels

Primary LanguageC#

Unity Car 2 Wheels

This project uses Unity version 2022.3.15f1.

The Scripts/ directory in Assets/ is a submodule whose source is from alianlbj23.

Debug Environment

  • .NET SDK 8.0

Restore Scene

  • After cloning the repository, navigate to Assets/Scenes/ in Unity and double-click the scene file. e.g. SampleScene

Steps

URDF Importer

Reference: https://github.com/Unity-Technologies/URDF-Importer

  1. Open the Package Manager from the Unity Menu. Click Window -> Package Manager. A new package manager window will appear.

  2. Click on the + sign on the top left corner of the package manager window and click on Add Package from Git URL.

  3. Enter the git URL for the URDF Importer with the latest version tag (currently v0.5.2) https://github.com/Unity-Technologies/URDF-Importer.git?path=/com.unity.robotics.urdf-importer#v0.5.2 in the text box and press Enter.

  4. Click Import URDF.

ROS TCP Connector

Reference: https://github.com/Unity-Technologies/ROS-TCP-Connector

  1. Open the Package Manager from the Unity Menu. Click Window -> Package Manager. A new package manager window will appear.
  2. Click on the + sign on the top left corner of the package manager window and click on Add Package from Git URL.
  3. Enter the git URL for the URDF Importer with the latest version tag (currently v0.5.2) https://github.com/Unity-Technologies/ROS-TCP-Connector.git?path=/com.unity.robotics.ros-tcp-connector in the text box and press Enter.

NuGet for Unity

Reference: https://github.com/GlitchEnzo/NuGetForUnity

  1. Open Package Manager window (Window | Package Manager)
  2. Click the + button on the upper-left of a window, and select "Add package from git URL..."
  3. Enter the following URL and click the Add button
https://github.com/GlitchEnzo/NuGetForUnity.git?path=/src/NuGetForUnity
  1. At this point, you'll see NuGet in the Unity Menu. If doesn't, restart the Unity.

*NOTE:* To install a concrete version, specify the version by prepending #v{version} e.g. #v2.0.0. For more see Unity UPM Documentation.

WebSocket Sharp - Net Standard

  1. Open the NuGet from the Unity Menu. Click Nuget -> Manage NuGet Packages. A new NuGet for Unity window will appear.
  2. Search the package websocketsharp-netstanderd and then install it.

Newtonsoft.json

Reference: https://www.nuget.org/packages/Newtonsoft.Json/

  1. Open the NuGet from the Unity Menu. Click Nuget -> Manage NuGet Packages. A new NuGet for Unity window will appear.
  2. Search the package Newtonsoft.json and then install it.

Slam

You have to modify the URDF file to add the base_footprint link at the appropriate part.

	...
</gazebo>

<link name="base_footprint" />
<joint name="base_joint" type="fixed">
    <parent link="base_footprint" />
    <child link="base_link" />
    <origin rpy="0 0 0" xyz="0 0 0.010" />
</joint>

<link name="base_link">
    ...

Import Your Car Model from URDF

Structure of the URDF

.
├── car_v2_copy1019_description
│   ├── meshes
│   │   ├── base_link.prefab
│   │   ├── base_link.stl
│   │   ├── base_link_0.asset
│   │   ├── base_link_1.asset
│   │   ├── ...
│   │   ├── base_link_23.asset
│   │   ├── c2_v1_1.prefab
│   │   ├── c2_v1_1.stl
│   │   ├── c2_v1_1_0.asset
│   │   ├── c2_v1_1_1.asset
│   │   ├── c2_v1__1__1.prefab
│   │   ├── c2_v1__1__1.stl
│   │   ├── c2_v1__1__1_0.asset
│   │   ├── c2_v1__1__1_1.asset
│   │   ├── lidar_v1_1.prefab
│   │   ├── lidar_v1_1.stl
│   │   ├── lidar_v1_1_0.asset
│   │   ├── lidar_v1_1_1.asset
│   └── meshes.meta
├── test_abb_4600.urdf

We show the part of the URDF file test_abb_4600.urdf.

...
<link name="base_link">
    <inertial>
      <origin xyz="-0.033614332957262155 -0.004539784516663659 0.05035636914443814" rpy="0 0 0"/>
      <mass value="10.997959919526476"/>
      <inertia ixx="0.068393" iyy="0.12963" izz="0.139744" ixy="1.4e-05" iyz="-4e-06" ixz="-0.00959"/>
    </inertial>
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <mesh filename="package://car_v2_copy1019_description/meshes/base_link.stl" scale="0.001 0.001 0.001"/>
      </geometry>
      <material name="silver"/>
    </visual>
    ...
</link>
...

Pay some attention to the mesh tag. It specifies the locations of the packages. Hence, you must put the corresponding mesh .stl files like the above structure.

Rename the wheels and lidar in Unity

rename_wheels

base_scan

right_back_forward_wheel

left_back_forward_wheel

(2 Wheels Car Model Only) Create a Sphere in the Front of the Car

Create a sphere at the location of the structure shown above.

Add Articulation Body in base_footprint

  1. Click on the base_footprint component.
  2. Click the Add Component in the Inspector, search for the Articulation Body and add it.

Lidar Script

  1. Click on the base_scan component.
  2. Add the LidarSensor.cs component to the base_scan.

Robot Script

  1. Click on your car model name. In the case shown above, click car_v2_copy1019.
  2. Toggle (Uncheck) the Controller Script shown in the Inspector in Unity.
  3. Add the Robot.cs component to this car model object.

Setup Lidar

  1. Click on your car model name. In the case shown above, click car_v2_copy1019.
  2. Add base_scan component into Lidar field in Robot.cs script in the Inspector in Unity.

Motor Move Forward (Maybe doesn't need?)

  1. Click on your wheels.
  2. Add MotorMoveForward.cs into your wheel components.

Create Target

  1. Create a 3D object and rename it to Target
  2. In the inspector field, scale the object size to 0.1.
  3. Move the target to the appropriate location by moving the axes.

Create Wall, Floor, and Move to Proper Location

Just create the 3D objects.

頑張って

Create Anchors

  1. Create the empty objects
  2. Put them into the corners of the wall and assign them to either clockwise or counterclockwise order.
  3. Put them into the TrainingManager.cs script in the TrainingManager Unity object.

Training Manager

  1. Create a new empty Unity object and rename it to TrainingManager
  2. Add the TrainingManager.cs component to this object.
  3. Add the Target into the Target field in TrainingManager.cs script in the Inspector in Unity.

Note

  • The submodule is set to the main branch because the codes in the develop branch have bugs.
  • Modify the MotionSensor class in MotionSensor.cs
public class MotionSensor : MonoBehaviour
{
    ...
}
  • Since we've added a base_footprint in our URDF car model, the TrainManager.cs have to match this structure.
void Start()
{
    base_footprint = robot.transform.Find("base_footprint");
    baselink = base_footprint.transform.Find("base_link");
    if (baselink == null)
    {
        Debug.Log("Testing");
    }
...
}
  • There are still many scripts in TrainingManager.cs like Target, Obstacle 1, ..., etc. You have to create empty objects and put them into these scripts. We've created and put them into the Unneed object.