# TortoiseBot Mini

1. Installation:

1.1 Download Arduino IDE:

Download the latest version Arduino IDE from https://www.arduino.cc/en/software

1.2 Setup ESP board in Arduino IDE:

Follow the following tutorial to add ESP board in your Arduino IDE - https://randomnerdtutorials.com/how-to-install-esp8266-board-arduino-ide/

Simply go to Files > Preferences and add the following line in the Additional Board Managers URLs:

https://dl.espressif.com/dl/package_esp32_index.json, http://arduino.esp8266.com/stable/package_esp8266com_index.json

After that go into Tools > Board > Boards Manager and search for "esp32" and install the ESP32 board. That's it!

1.3 Install ROS Serial Library for Arduino on Ubuntu:

sudo apt-get install ros-noetic-rosserial-arduino
sudo apt-get install ros-noetic-rosserial

2. Setup:

2.0 Creating a ROS workspace and cloning the repository

Create a ROS workspace, let's call our workspace tb_ws

mkdir -p ~/tb_ws/src

Change directory to tb_ws/src folder

cd tb_ws/src

Clone the TortoiseBot Mini repo into your src folder of your ROS workspace

git clone https://github.com/FocasLab/tortoisebot

Change directory to tb_ws

cd ..

Build or make your workspace

catkin_make

or

catkin build

2.1 Build the Arduino serial library and msgs

Navigate to Arduino > libraries Open a terminal in the current directory

rosrun rosserial_arduino make_libraries.py .

This should build the required msgs

In your linux system in home,in Arduino folder-->Library the ros_lib folder will be present after building using the above command Inside this ros_lib folder create a new folder tortoisebot_mini and paste the diff.h file inside

CONNECTIONS- There are 6 connecting wire from motor- Blue - Motor negative pole Green - Motor positive pole Yellow - Hall Power positive - connect to 5V pin(18,19 and 16,17) Orange - Hall H2 output signal - connect to gpio pin Red - Hall H1 output signal - connect to gpio pin Brown - Hall power negative - connect to ground pin

// Motor 1 pins and encoder variables const int encoderPinA1 = 18; const int encoderPinB1 = 19; const int motorPWMPin1 = 32; const int motorDirPin1_1 = 25; const int motorDirPin1_2 = 26;

// Motor 2 pins and encoder variables const int encoderPinA2 = 16;

const int encoderPinB2 = 17; const int motorPWMPin2 = 33; const int motorDirPin2_1 = 13; const int motorDirPin2_2 = 27;

2.2 Change Wi-Fi's SSID and Password:

Open the tortoisebot_mini_ros code in Arduino IDE and change the SSID and Password of the Wi-Fi Connection.

const char* ssid = "";
const char* password = "";

2.3 Change the ROS Master IP Address:

Run the following command on the machine which will act as ROS Master PC (in our case the lab computer) after connecting to the lab's wifi.

hostname -I

Use the this IP address the .ino file.

IPAddress server(192,168,x,x);

Check the IP Address of your ROS Master PC using ifconfig command and put that in line number 13 of tortoisebot_mini_ros code with commas(,) instead of dot(.)

2.4 Check Board and Port:

Make sure the switch on motor driver board is turned off and battery is not connected and then connect your ESP32 board to your computer using USB type B cable. Make sure the board is selected to "ESP32 Dev Module" in Arduino IDE and select the appropriate Port as well.

2.5 Upload the Code:

Upload the tortoisebot_mini_ros code on your ESP32 board.

2.6 Connection:

Once code is Successfully uploaded, disconnect the USB Cable and connect the DC Jack of Battery to the Board .
DO NOT TURN ON THE ROBOT YET!

2.7 Connecting your laptop to ROS Master:

After Setting up the robot and uploading the code we will now setup the ROS on Multiple Machines. Add this lines to end of you .bashrc file.

export ROS_IP=<IP of your machine>
export ROS_MASTER_URI=http://<IP of Master Machine>:11311

Example:-

export ROS_IP=192.168.0.203
export ROS_MASTER_URI=http://192.168.0.127:11311

3. Demo:

3.1 Running ROS Master:

Launch the tortoisebot_mini.launch file on your Master PC to start ROS Master along with ROS Serial Node.

roslaunch tortoisebot_mini tortoisebot_mini.launch

It will prompt a INFO message saying "Waiting for socket connections on port 11411 waiting for socket connection"

3.2 Turning on Robot:

Once the above INFO message is popped up, then you can turn on your Robot upon which you will see that different ROS topics start automatically.

3.3 Testing out Teleop:

Keep the previous terminal running add on a new terminal type the following command to start the teleoperation node.

rosrun teleop_twist_keyboard teleop_twist_keyboard.py

Note that the minimum operational speed for the robot is :

• Linear Velocity : 0.131 m/s
• Angular Velocity : 2.175 r/s

Now you can control the robot using teleoperation commands.

If the Twist keyboard does not work try directly publishing the velocity commands

rostopic pub /cmd_vel geometry_msgs/Twist '{linear: {x: 0.3, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.2}}'

References:

• http://wiki.ros.org/rosserial_arduino/Tutorials/Arduino%20IDE%20Setup
• https://github.com/agnunez/espros
• https://github.com/RoboTakao/NX15A