LINE FOLLOWER ROBOT

This repository contents the software elements to control a differential movie Robot with a Turbine Engine based on a ir-sensor array to follow a black line on a white surface.

The overall electronics setup except for the power, which was provided by a constant voltage battery Li-Po of 2 cells with a boost converter tunned at 12 VDC. We selected the an ATMEGA328P-AU clocked at 20 MHz from ATMEL as the slave controller given its small size, rapid prototyping and readily available community support. On the other hand a mbed LPC1768 microcontroller performs the master controller tasks such as: communications data recording and control algorithm. In these applications, the used micro motors, speed control unit and sensors are generally from Pololu company. The motors 10:1 Micro Metal Gearmotor HPCB 12V are brushed DC motor with a metal gearbox, 3000 RPM and 100 mA with no load, 4 oz-in (0.3 kg-cm) and 0.8 A at stall. The encoders use a magnetic disc and hall effect sensors to provide 12 counts per revolution of the motor shaft. The Dual Motor Driver Carrier DRV8833, can deliver 1.2 A per channel continuously (2 A peak) to a pair of DC motors. With an operating voltage range from 2.7 V to 10.8 V and built-in protection against reverse-voltage, under-voltage, over-current, and over-temperature, this driver is a great solution for powering small, low-voltage motors. The line sensor used was the QTR-8A Reflectance Sensor Array from Pololu, which has 8 IR LED/phototransistor pairs mounted. Finally in order to decrease the slip effects generated by at high speeds, agressive curves and friction reduction by dust, a suction EDF27 turbine was implemented on the robot. Although this turbine can reach 0.7 N of pushing force to improve the performance in curves, also the current consumption has a big increase reaching the 5.2 amperes, which has big negative impact on battery and the LFR autonomy. In this sense, a power activation equation in function of the LFR speed was tuned from experimental data.

• Read the related publication here.

• Watch YouTube video 1 here.

• Watch YouTube video 2 here.

This repository contents:

• Circuit Design (schematic diagram and PCB)
• Source codes (Master and Slave devices)

/your_root        - path
|--data                 /Folder where you can find the project data
  |--PCB             	/Electronic design 
|--src                  /Folder with source codes
  |--master             /Mbed codes C++
  |--slave             	/Arduino code 
|--Readme   / Instructions to use the repository

Hardware Requirements:

• Mbed LPC178
• Atmega328p SMD
• Pololu DVR8833
• Pololu Motors 10:1
• BLE Sparkfun
• Sensors QTR8-A
• Encoder Pololu
• LiPo battery 2S
• Turbine
• MotherBoard, see /yourPath/data/PCB/

Software Requirements:

• Mbed compiler
• Arduino IDE 1.6.1

How to Install:

• Load the file /yourPath/src/slave/slave.ino on the Arduino device
• According to your interest load the .cpp file on your Mbed device:
  • Load the file /yourPath/src/master/Q_Learning for Q-Learning control
  • Load the file /yourPath/src/master/pd_simple.cpp for simple PD controller
  • Load the file /yourPath/src/master/guarantyControl.cpp for PD controller with guaranty control algorithm
  • Load the file /yourPath/src/master/cascade for cascade controller

Notes:

• Remember you need to create an account on Mbed online site to program de Microcontroller.
• In case you need, change the controller constants Kp,Ki,Kd to tune the controllers.

How to Run:

• Connect the battery
• Load the desired controller on the Mbed device
• Press botton 2 and calibrate (move the sensors array from one side to other). When the leds ubicated under motors turn off, the turbine going to turn on
• Press botton 1 and wait during 3 seconds to start the robot, also you can start the robot from an IR remote control

Authors:

Universidad de Ibagué - Ingeniería Electrónica Proyecto de Grado 2019/A

• Harold F. Murcia
• Yeison Daniel Tapiero

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