Automated Mobile Robot with RFID Scanner and Self Obstacle ... · sensor modules and pre -loaded intelligence. The RFID scanner is used for identification and verification of destination

Automated Mobile Robot with RFID Scanner and Self Obstacle

Avoiding System 1Asif Ahmed Neloy,

2Aziz Arman,

3Mohammad Samiul Islam,

*4Tamanna Motahar

1234Department of Electrical and Computer Engineering,North South University

Dhaka, Bangladesh

Email: {asif.neloy, aziz.arman, samiul.mohammad,* tamanna.motahar}@northsouth.edu

Abstract

An Automated Mobile Robot can navigate on a floor freely by avoiding obstacles and

walking on the shortest path between two points. It uses a vector map of the floor and Dijkstra's

shortest path algorithm for calculating shortest path. For obstacle avoidance, it uses ultrasonic

sensor modules and pre-loaded intelligence. The RFID scanner is used for identification and

verification of destination and re-calibrating position of the robot on a path by detecting other

locations on the path. This system requires 195 RPM and 1.75 seconds duration for the robot to

successfully read the RFID tag.

Keywords:Mobile Robot; Obstacle Avoiding System; RFID; Delivery Robot; Dijkstra’s

Algorithm;

1. Introduction

1.1Background

Robotics is a growing field around the world, including Bangladesh. Over the past few

years, there has been a significant increase in the number of Robotics competition among

universities. [1] Most of these competitions are about constructing “Line Following Robots”.

Recently, a restaurant has opened where food is served by a “Line Following Robot” [2]. It is rare

to see robots in Bangladesh that are autonomous and capable of making complex decisions. An

autonomous intelligent robot that can go from one place to another within a building while

avoiding the obstacle is quite formidable to build. It comes with many challenges solving which

will take the robotics sector of Bangladesh another step forward [3].

1.2 Problem Formulation

Automating delivery of items between rooms using an “Automated Mobile Robot” that

can find its path from one point to another while avoiding obstacles, without any lines to follow.

Also, it can identify the source and destination by RFID scanning. After delivering the items, the

robot will backtrack its path to return to its source.

1.3Overviewof Automated Delivery Robot

The robot is called “Automated” because it is able to run without manual control of a

user. The user simply needs to input which rooms the delivery needs to go and the robot will

carry the item there.

The ADR uses the shortest path between source and destination. It calculates this path using

Dijkstra’s Shortest Path Algorithm [4].

International Journal of Pure and Applied MathematicsVolume 118 No. 18 2018, 3139-3150ISSN: 1311-8080 (printed version); ISSN: 1314-3395 (on-line version)url: http://www.ijpam.euSpecial Issue ijpam.eu

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While traveling between source and destination, the robot can avoid obstacles. Once it reaches

the destination, it verifies the destination by scanning an RFID tag with the unique code on the

door. Once it is verified, it will wait there for a fixed amount of time (so that someone can pick

the item from the robot) and then backtrack to a source. If the verification is failed, it will still

return to the source.

2. Related Works

Robotics is a growing field and there are plenty of works which are related to ours.

Below are some of the works which relate to ours. This robot uses “Obstacle Avoidance”

techniques to reach a destination from the source. Obstacle Avoider Robot using ultrasonic sensor

HC-SR04 can sense the obstacle in its path and by identifying the object, it avoids the path [5] In

Bangladesh, popular trends in robotics have been regarding line follower robots and recently

restaurants using line follower robots for delivery. Yet there a scarcity of obstacle avoiding robot

systems likes ours and we can say that ours is the first of its kind in Bangladesh. Also from

Worcestershire Polytechnic Institute have developed an obstacle avoiding robotic system [6] but

it lacks the idea of delivering goods from one room to another that can help disabled people and

also small and big business ventures.

3. Proposed work

3.1 Basic Design of Robot

In our proposed design, the robot has 30 cm length, 20 cm width, and 15cm height. The

body is built of PVC cardboard. The whole system is controlled by Arduino Mega 2560 R3 which

has 16 MHz oscillators and ICSP header. It has 4 DC motors (12 volts, 400 RPM). These motors

are controlled by two L298N Dual Motor Driver for PWM control. The motors use positive polar

to indicate forward move and negative polar to move on backward direction. Sensors and

modules are also corporate with the circuits to control the system. Ultrasonic Sensor HC-SR04

for observing obstacles, RFID RC522 for RFID Reader and Scanner, Buzzer to emulate sound.

Figure 1: Automated Mobile Robot with RFID Scanner and Self Obstacle Avoiding

3.2 Algorithm

International Journal of Pure and Applied Mathematics Special Issue

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The floor on which the robot will work on is first modeled into a graph. Each room is a

node. In order to travel from one node to another, the floor is further divided into a mesh of nodes

[13]. There are edges between a pair of nodes whose weights are the distance between that pair of

nodes. These all nodes are considered as row and column of a 2-D matrix.

We have modified the Dijkstra’s shortest path algorithm to find the shortest distance between two

nodes [12]. First, the robots need the distance between source and destination. Suppose the

Source is U and the destination is V. The robot will calculate the shortest distance by Vector

Mapping (VecSLAM) [7] using the following algorithm.

{

measure_source();

measure_destnation();

motor_reading ();

shortest_path();

if (sonar_reading() == true) {

avoid_obstacle();

}else {

motor_reading();

}

}

Shortest Path Calculation:

For each node distance, n, in the graph:

n.destination_distance = Infinity (Keypad Reading)

Create an possible path list

start.source_distance = 0, (motor off)

While path list not empty:

current_source = node in the list with the smallest distance from destination, remove current from

list

For each node from source, n that is adjacent to current distance:

if source.distance>current.distance + length of edge from n to current destination

destination.distance = current.distance + length of edge from n to current source (distance

measuring for RPM of robot, motor starts)

Mainly, the robot calculates the vector mapping source and destination distance from the

user input[8]. If the node distance is 10 cm, each node from the source will be calculated with

pre-loaded vector mapping. 2-D grip will define the row and column between source and

distance. The robot will calculate row to row and column to column distance to measure actual

path.


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Figure 2: Row-Column divination for path measurement

3.3 System Design

3.3.1 Equipment list:

One of the main specialties of this robot is, it is cost and power efficient. Very few

Drivers and Sensors have been used and all of them are operable in a very low Power supply. All

the equipment’s are listed with power capacity.

Arduino Mega 2560 R3: Arduino mega 2560 has integrated as the main development board in

this robot where Input Voltage (limits) : 6-20V and Operating Voltage : 5V[9].

Motor Driver: L298N motor driver has been used to control the PWM of the Robot where

Operating Voltage: up to 46V and Total DC Current: up to 4A [9]

Motor: 4 DC Motors with 400 RPM controls the movement and speed whereVoltage: 12V and

Voltage Range: 6-12V[9]

Wheels:42x19mm pololu is associated with the DC Motors whereDiameter: 1.65 inches (42

mm) and Width of tire: 0.75 inch (19mm) [9]

Sensors:Ultrasonic Sensor HC-SR04 is used to sense the obstacle for the robot. 4 of them has

been used in Front, Rear, Left and Right where Voltage: DC5V and Current: less 2mA[9]

RFID Reader: Mifare RC522 Module RFID Reader Scans the RFID tags and

recirculates the result to the robot where Frequency: 13.56MHz [9]

Keypad: Flexible 4*4 Matrix Keypad has been used to take the input of Room Number from the

User. Buzzer: 5V Continuous Tone Beeper Creates the sound when the robot successfully scans

the RFID tag while Roaming where Voltage Range: 2 ~ 5VDC and Sound Pressure Level: 82 dB

[9]

Mini Breadboard:Mini breadboard of 170 Points have been used to regulate the whole circuit.


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Power Source:LIPO 2200mAh 11.1V battery is the power source for the whole robot and

circuits.

3.4 Assemble and System Principle:

DC Motor Connection with Motor Drivers-DC motors are connected to the L298N

dual motor. 2 L298N motor controls 4 motors. Positive polar of the DC motor will work as the

Forward movement and Negative polar will be the Backward Movement.

Ultrasonic Sensor connection: Trig and Echo Pin of Ultrasonic Sensor are connected to

Arduino Mega (Digital Pin 33-41) and VCC GND shorted in Breadboard.

RFID RC522 connection: RC522 is placed on Right Side of the Robot and GND VCC is shorted

in Breadboard. RST/Reset - D5, SPI SS - D53, SPI MOSI - D51, SPI MISO - D50, SPI SCK-

D52

Keypad: 4*4 Matrix Keypad is the input source to define source and destination for the Robot.

All the input Pins are connected on Digital Pin of Mega. Here, Row Pins = {23, 25, 27, 29} and

Col Pins= {28, 26, 24, 22}

LIPO:Lipo is the power source for both Bread Board and Arduino Mega. So the positive

terminal is connected to the VCC and 9V terminal is connected in the GND phase.

3.5 Implementations:

After the assembly we have to test or implement the system. For testing following steps

are followed- 1. We have tested the polarity of the motors if they are rotating in the same

direction also their rotation speed. 2. Ultrasonic Sensor reading will provide the actual distance

between objects, which has illustrated in figure 3(a). 3. Test the RFID Tag serial number if they

are being able to read correctly, this test confirms the range and tag id of RFID. Figure 3(b)

shows the result of this test.


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Figure 3: (a) Ultrasonic Sensor reading from Arduino Serial Monitor, (b) RFID Scanner Result

from Arduino Serial Monitor

3.6 System Principle: RFID and Ultrasonic Sensors are quite complex to handle on a Robotics

System. To handle both sensors and modules, the construction of the robot is shown in Figure 4.

3.7 Circuit: Sample Circuit has been generated by Fritzing [10]. Infigure-4 illustrates the whole

circuit that are implemented in the Robot (digital pin numbers of Arduino mega are changed in

the figure).


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Figure 4: (a) Circuit Diagram, (b) Work Process

3.7 Result and Discussion:


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This intelligent robot is capable of moving from one node to another, but only when

certain conditions are met. The robot is able to neutralize some of the errors by regularly scanning

rooms across its pathway using RFID.

The sonar module used for detecting obstacles is pretty accurate, but they still have their

limitations. Experiments have been run to determine the distance of obstacle that sonar modules

can accurately read. An object is placed at a distance of D from the sensor and reading are taken

for a cross check. The distance D is then gradually decreased until 0 while readings are

continuously monitored. A chart (Figure-6) has been generated from the experiment readings

using an online tool Meta-Chart [11]. Black Straight lines of Figure 5 are the error that observed

during taking sensor values of HC-SR04. These values obtained from 20 experiments.

Figure 5: Error range of Ultrasonic Sensor


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Table 1: RFID Tag Reading time comparing to Speed

Generated by Meta-Chart

Another experiment has been run on reading capabilities of RFID scanner under motion, using

Arduino Serial Monitor. The experiment has been run to determine the optimal speed of the robot

such that it does not skip over the target.

Here, RPM refers to “Revolutions per Minute” of the wheel (speed of the robot) “Time Duration”

refers the amount of time RFID scanner takes two processes reading. As the speed of robot

increases, the RFID scanner finds it difficult to make a proper reading. From this trial and error

experiment (Arduino Serial Monitor), it has been decided to use 195 RPM and 1.75 seconds

duration for the robot to successfully read the RFID tag.

4. Conclusion

The robot can navigate on the floor as long as the detailed map is provided to it

beforehand. A smart robot that can navigate without any line to follow can open doors to further

innovation of the robot industry in Bangladesh. The robot has to room further improvements such

as using indoor positioning system to accurately track position on the floor, voice control for ease

of use and more structural supports to avoid a wider range of obstacles.

References:


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Website:

[1]Chowdhury,A.M. (26 May, 2017).Prospects Of Robotics In Bangladesh. Daily Sun, Retrieved

from http://www.daily-sun.com

[2] Senior Correspondent (2017-11-15).First-ever 'Robot Restaurant' launched in

Bangladesh.Bdnews24,

Retrieved from https://bdnews24.com

[3]Farhin,N. (September 27, 2017).Bangladesh looks to take robotics education to the next level.

DhakaTribune, Retrieved from http://www.dhakatribune.com

[4]Abiy,T et. al. Dijkstra's Shortest Path Algorithm. Retrieved from

https://brilliant.org/wiki/dijkstras-short-path-finder/

[5]Kinshy, P et. al. and Yang, Z et. al. Obstacle Avoidance Robot. Retrieved from

https://pdfs.semanticscholar.org/fa08/e2f266c1eba32340519003a62b53adc47bd7.pdf

[9] Retrieved from https://www.robotshop.com/

[10] Retrieved from http://fritzing.org/home/

[11]Retrieved from https://www.meta-chart.com/

Journal:

[6]Hanumante,V et. al., 2013. Low Cost Obstacle Avoidance Robot. International Journal of Soft

Computing and Engineering (IJSCE), 3(4), pp.52-55.

[7]Sohn, H et. al., 2009. VecSLAM: An Efficient Vector-Based SLAM Algorithm for Indoor

Environments.Journal of Intelligent & Robotic Systems, 56(3), pp.302-318

[8]Se, S et. al., 2002. Mobile Robot Localization and Mapping with Uncertainty using Scale-

Invariant Visual Landmarks, 21(8), pp.735-758

Conferences

[12] Brendan, H., Gordon, J., 2005. Generalizing Dijkstra's Algorithm and Gaussian Elimination

for Solving MDPs. In International Conference on Automated Planning and Scheduling/Artificial

Intelligence Planning Systems - ICAPS (AIPS), 2005 (pp. 151-160).

[13]Sudhakar, T.D.,Vadivoo, N.S., Slochanal, S.M.R., Ravichandran, S., November,2004. Supply

restoration in distribution networks using Dijkstra's algorithm. In International Conference on

Power System Technology, Singapore. 2004(PowerCon 2004)

Authors Biography


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Asif Ahmed Neloy was born in Mymensingh, Bangladesh, in 1997. He is now doing his

undergraduate in Computer Science and Engineering at North South University. His research interests are

Robotics, Artificial Intelligence, Machine Learning, and Data Science. He was the 1st Runner up of IEEE

Day Hackathon 2017, BUET Hackathon, IUT Hackathon, MIST Robot fight contest. He is the author of a

fundamental basic robotics book called “Esho Robot Banai” which means “Let’s learn Robotics”.

Aziz Arman was born in Noakhali, Bangladesh, in 1997. He is an undergraduate student of

Computer Science and Engineering at North South University. His research interests are Augmented

Reality, Machine Learning, Artificial Intelligence and Robotics, Mobile Applications. He was the

Champion of IEEE Day Hackathon 2017. He was the finalist of Tech for Peace Hackathon.

Mohammad Samiul Islam was born in 1993. He is an undergraduate student of Computer

Science and Engineering at North South University, Dhaka, Bangladesh. His research interests are Web-

based application and Mobile Applications.

TamannaMotahar is a lecturer in Electrical and Computer Engineering department at North

South University, Dhaka, Bangladesh. She earned her M.Eng. Degree at University of Alberta, USA. She

specializes in computational electromagnetics, Human-Computer Interaction, and computer simulation.


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Automated Mobile Robot with RFID Scanner and Self Obstacle ... · sensor modules and pre -loaded intelligence. The RFID scanner is used for identification and verification of destination