README

andino_firmware

Firmware code to be run in the arduino microcontroller for proper control of the motors of the robot.

Connection

Check encoder_driver.h and motor_driver.h files to check the expected pins for the connection.

Installation

Arduino

In Arduino IDE, go to tools->Manage Libraries ... and install:

  • “Adafruit BNO055”

Verify and Upload andino_firmware.ino to your arduino board.

PlatformIO

  1. Install dependencies sudo apt-get install python3.10-venv

  2. Install platformio

curl -fsSL -o /tmp/get-platformio.py https://raw.githubusercontent.com/platformio/platformio-core-installer/master/get-platformio.py
python3 /tmp/get-platformio.py

  1. Add platformio to your $PATH:

echo "PATH=\"\$PATH:\$HOME/.platformio/penv/bin\"" >> $HOME/.bashrc
source $HOME/.bashrc

  1. Build and upload the firmware

    • If you’re using an arduino uno pio run --target upload -e uno

    • If you’re using an arduino nano pio run --target upload -e nanoatmega328

Description

Via serial connection (57600 baud) it is possible to interact with the microcontroller. The interface is described in the commands.h file. Here are the most used commands:

  • Get encoder values: 'e'

  • Set open-loop speed for the motors[pwm] 'o <left> <right>'

    • Example to move forward full speed: 'o 255 255'

    • Range [-255 -> 255]

  • Set closed-loop speed for the motors[ticks/sec] 'm <left> <right>'

    • Important!: See the Test it! section.

  • Set PID values: 'u <kp> <kd> <ki> <offset>'

Note: Remember the carriage return character at the end of the message.

Test it!

A serial port connection must be created at 57600 bauds. You can use the serial monitor from Arduino IDE for example.

  • Open loop verification:

    • Send o 255 255 to go full speed

    • Send o 0 0 to stop it.

  • Read the encoders

    • Send e to get the encoders values.

  • Get the ticks per revolution of your motor.

    • First set the encoders to zero, (reeboting with r).

    • Then rotate your motors as many revs you want,(say 10 for example) and then divide the encoder ticks per the number of revs. -> Then you get the ticks per revolution. Save this value, it is calibration for the control loop.

  • Closed loop verification

    • Send m <tps> <tps> where tps stands for ticks per second. For example if your motor-encoder system gets 700 ticks per revolution then sending m 700 700 will rotate both motors at 1 rev per sec. (~3.14rad/sec)