Main Content

Tune PID Controller Parameters Using Android Application for LEGO EV3 Object Tracking System

This example shows how to create an Android™ application to tune the PID controller parameters of an object tracking system using an Android device. This object tracking system has been built using the LEGO® MINDSTORMS® EV3™ hardware and the Pixy2 vision sensor.

Introduction

Android devices, such as phones and tablets, are used extensively in robotic applications for controlling and provisioning parameters of robotic devices.

Follow the workflow laid down in this example after completing tasks 1 to 4 in the LEGO EV3 Object Tracking System Using Pixy2 Vision Sensor and PID Controller (Simulink Support Package for LEGO MINDSTORMS EV3 Hardware) example.

In this example, you deploy an application on the Android device with a graphical user interface (GUI) to fine-tune the PID controller parameters used for object tracking. The GUI dashboard has interactive knobs and sliders that you can use to fine tune these parameters. Use the network connection set up between the Android device and the EV3 robot to channel this change in the parameters. You can change the position of the knobs and sliders to smoothly track the trained object.

In this example, you will perform the following tasks:

  • Set up a network connection between the Android device and the EV3 robot.

  • Configure and run the Simulink model for the Android device to send and receive the TCP/IP packets from the EV3 robot to tune the PID controller parameters.

Dependency

Implementing the LEGO EV3 object tracking system using the PID controller requires successful deployment of these Simulink models on their respective hardware.

        Simulink Model Name                |    Deployed Hardware    |                           Purpose
----------------------------------------------------------------------------------------------------------------------------------------------------
1. ev3_android_pixy2_tracking_pidcontrol   |   LEGO MINDSTORMS EV3   |   Implement and deploy the object tracking system on EV3 robot
2. androidEv3PIDTuner                      |        Android          |   Tune PID controller parameters through the Android application dashboard

Prerequisites

Required Hardware

  • Android device such as phone or tablet

  • Micro USB cable

Task 1: Set up EV3 Robot

Task 2: Configure Model and Calibrate Parameters

This support package provides a preconfigured model that you can use to tune the PID controller parameters for the object tracking robot.

1. To open the model, run this command at the MATLAB® Command prompt:

open_system('androidEv3PIDTuner')

2. Connect the Android device to the host computer using the micro USB cable.

3. On the Modeling tab of the toolstrip, select Model Settings.

4. In the Configuration Parameters dialog box, select Hardware Implementation. Verify that the Hardware board parameter is set to Android device.

5. From the Groups list under Target hardware resources, select Device options.

6. From the Device list, select your Android device. If your device is not listed, click Refresh.

Note: If your device is not listed even after clicking Refresh, ensure that you have enabled the USB debugging option on your device. To enable USB debugging, enter androidhwsetup in the MATLAB Command prompt and follow instructions on the screen.

The Android device and the EV3 robot communicate with each other over the TCP/IP network, where the Android device acts as a client (the one that sends data) and the EV3 robot acts as a server (the one that receives data). Any changes you make in the PID controller parameters through the knobs and sliders in the application dashboard are reflected as a subsequent change in the motor power of the EV3 robot.

7. Configure all the TCP/IP Send blocks consistently for the PID controller parameters.

  • Set the Connection mode parameter is set to its default value Client.

  • Set the Remote IP address to match the IP address configured in the LEGO EV3 robot.

  • Set the Remote IP port to match the port value of the LEGO EV3 robot. The default starting port number is 25000.

Task 3: Run Model on Android Device

1. On the Hardware tab of your Simulink model, click Build, Deploy & Start to build and deploy the model on the Android device. The androidEv3PIDTuner application launches automatically.

This interface uses knobs and sliders to fine-tune the PID controller parameters.

For more information on the PID controller parameters, see Task 3 of the LEGO EV3 Object Tracking System Using Pixy2 Vision Sensor and PID Controller (Simulink Support Package for LEGO MINDSTORMS EV3 Hardware).

2. Change the position of the knobs and sliders and observe the corresponding changes in the EV3 motor to improve the efficiency of the object tracking system.

androidEv3PIDTuner Application

The androidEv3PIDTuner application has these three sections.

  • Dashboard: The position of the knobs and sliders corresponding to the various PID controller parameters are preconfigured to a default value.

  • Info: This section provides details such as IP address of the connected LEGO EV3 robot, the device serial number, and the name of the model deployed on the Android device.

  • Log: This section provides the detailed TCP log description of the application.

Related Links

LEGO EV3 Object Tracking System Using Pixy2 Vision Sensor and PID Controller (Simulink Support Package for LEGO MINDSTORMS EV3 Hardware)