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Design and Development of Control Algorithm of a Prototype Fire-Fighting Robot to

Extinguish a Candle Flame

Final Year Project Progress ReportTeoh Chieh Loon (081061128)

Mechatronic Programme

School of Mechatronic Engineering Universiti Malaysia Perlis,

E-mail: [email protected]

Abstract

Fire can be useful in human daily life but it can cause

disaster when it became big fire. Fire fighter has beendangerous job as them have to put risk of their life to save

other. So this come the role of the fire fighting robot to put

out fire and reduce the risk of any human life lost including

fire fighter. A candle used to replace the role of fire. When fire fighting robot detects the flame of candle in a mock

house, it can navigate through a mock house and avoid anyobstacle before it reach near the fire. By using the

ultrasonic, sharp analogue distance and flame sensor whichinterface with a suitable control algorithm, it will use the

programmed locomotion to navigate the obstacle and wall. Program code to control the fire fighting robot is written in

PIC18F4580 C language. When the flame of candleappeared in the sensing range of the fire fighting robot, then

it will put out the flame of candle as it supposed to do. Based on the experiment conducted, the autonomous navigation

showed satisfactory result. The developed firefighting robot

will provide a test bed for advanced path planning and navigation projects in the future.

Keywords Locomotion, control algorithm, fire fighting robot, obstacle,

1. Introduction

1.1. Background of Research

Fire is an unwanted element which often causes loss of

properties or life. Fire fighting is a dangerous core even for

the experienced fire fighters. Therefore, a fire fighting robotwill serve as a substitution to help extinguishing big fireswhich are dangerous to human beings. Instead of taking the

great leap to develop a real fire fighting robot, the proper step is to gather more knowledge and experiences from

designing a smaller scale fire fighting robot.

1.2. Motivation of Research

Robots assisting fire-fighters are not an often seen sight.However, there are robotic devices that can already be used

for such purposes. These include bots that can be throwninto the fire site to inspect the situation, as well as large

remote controlled fire extinguishers such as Anna Konnda,Hoya Firefighters' Assistance Robot, DRB Fatec ArchiBots,IZ HOLDING Firo-Series firefighting robots, Ryland

research limited Firemote, DOK-ING JELKA firefightingrobots.

1.3. Research Objectives

The objective of this project is to design a fire fighting

robot to extinguish a candle flame which is a located in a

mock house

1.4. Scope of Research

1. An efficient method to ensure robot to approach and

extinguish the candle flame.2. A well-developed algorithm for the robot navigation,

distance control and flame blow off control.3. A robot which can navigate around the field of operation

(mock house).

2. Literature review

2.1 Control Algorithm for Robot PathAlgorithm is playing an important role in determine bestway to make the fire fighting robot to be more efficient to

navigate through the mock house. Then, it searches for thefire source. If it detect fire source from candle, it will use

suited algorithm to find the candle position and move untilright in front of the candle.

2.1.1 Obstacle-Avoidance Behaviour Algorithm

The first implementation of the obstacle-avoidance

behaviour was long and complex and consisted of both proportional and integral control. Each time the behaviour

is called, it checks the front hemisphere of sonar sensors(labelled 0-8 in figure 2.1) to see if any of their ranges are

less than the minimum tolerated sonar distance. If none of these ranges are less than the minimum, the behaviour

returns the commands “full speed ahead” so the robot willcontinue to move. Otherwise, it checks to see which of the

sum of left-front ranges (sensors 0-3) or right-front ranges(sensors 5-8) is smaller, and sends commands to turn the

robot in the opposite direction.

This is illustrated in Figure 2.1. Currently, the obstacle-avoidance behaviour is keeping the robot traveling from

right to left in the centre of the hallway or at least on asinusoidal path down the centre of the hallway if it is wide.

As the robot approaches the corner, the sonar ranges will



grow smaller on the robot’s left-front side (sensors 0-3).

Some of the sonar ranges on the right-front side of robot

(sensors 5-8) will grow smaller as well, but the codecompares the sums of these two sets of sensors. When any

sonar range is less than the minimum tolerated sonar distance, the robot will turn right and proceed through the

doorway. If there was no doorway, and the sum of the leftsonar ranges matched the sum of the right sonar ranges, the

robot would turn left by default. So, this will create a dead-lock situation in which the robot gets stuck in a corner

turning back and forth. [2]

Figure 2.1 show how the sonar sensor direction and how thebehaviour will works.

2.1.3 Wall Following Algorithm

Wall following can be accomplish by using four method

which have be contact method, noncontact with active

sensor method, noncontact with passive sensor method, softcontact method. Contact method is where the robot uses a

mechanical switch, or a stiff wire connected to a switch, to

sense contact with the wall. This is the simplest method, but

the switch prone to mechanical damage over time.

Noncontact, active sensor method is the robot uses active

proximity sensors, such as infrared or ultrasonic, todetermine its distance from the wall. No physical contact

with the wall is needed for the uses of this method. In atypical noncontact system, two sensors are used to judge

when the robot is parallel to the wall. (See figure 2.2 robotB)

Noncontact, passive sensor method is the robot uses passive

sensors, such as linear Hall Effect switches, to judgedistance from a specially prepared wall by referring to

figure 2.2 robot C. In the case of Hall Effect switches, the baseboard or wall can be outfitted with an electrical wire

through which a low-voltage3 alternating current is fed.When the robot is in the proximity of the switched the

sensors will pick up the induced magnetic field provided by

the alternating current.

For soft contact method, the robot uses the mechanical

means to detect with the wall, but the contact is softened byusing pliable material. For example, the lightweight foam

wheel is used as wall roller as shown in figure 2.2 robot D.the benefit of soft contact is replace the failure of the

mechanical which may be reduced or eliminated becausethe contact with the wall is made through an elastic or

pliable medium. [3]

Figure 2.2 show four method of wall following algorithm: a,Contact switch; b, noncontact active sensor (such as

infrared); c, noncontact sensor (e.g., Hall Effect sensor and

magnetic, electromagnetic, or ferrous metal wall/baseboard); and d, “soft contact” using pliablematerial such as foam rollers.

For the uses of fire fighting robot which faces the maze of

the mock house, so the suitable method is the noncontact,active sensor method. This because the simple ultrasonic

wall follower can use single headed transmitter and receiver or two ultrasonic transmitter, receiver pair. Open doorways

that lead into other rooms or space can be sensed using alonger-range ultrasonic transducer.

2.1.3 Convergence behaviours path

In the path planning algorithm, there are two immutable

laws that must accept:a) A robot is never exactly where its position estimate says

it is. b) A robot`s position estimate is never exactly where it

wants to be.

In a straight path to a destination, the ends of path segmentsas nodes. In figure 2.2.4.1, the robot supposed to be at Node

A, and was to travel to Node B. When robot move, itrealized that its position was actually some distance from

where it should have been at Node A. The first possible

strategy is to ignore the path and move straight for thedestination Node B. the obvious problem with the strategy,is that the robot will run into an obstacle that maybe stop it

from moving to the Node A.

The second strategy is to play it safe and first move straight

to the correct starting position (node A) before heading for Node B. This strategy may be safer, but still it cause time

consuming for taking this strategy. There a problem occurs

when the robot reach Node A, it had to execute the 90-degree turn to the turn which facing Node B.

The third strategy is called by “wagon tongue” method, as it

works like a child pulling a wagon by its tongue. If thechild stays on the path, the wagon will smoothly converge



onto the path as well. In software, the robot is given a rabbit

to chase that is on the path, the lead distance closer to the

goal than the robot. As robot chases the rabbit, the rabbitcontinues to stay the same distance ahead.

Figure 2.3 show three strategies for getting to destination

2.1.4 Closing behaviours path

There are two methods of deciding how much further todrive. The first method is to continually recalculate thedistance as the robot drive. The problem with this comes

with the fact that as robot approaches the end, and the

destination is to the side or rear, the vector distance is still positive.

The second method involves calculating the distance at beginning of the run, and simply counting down the

distance remaining as a parallel process in the odometry.The problem with this approach is that we may end up

weaving about for any number of reasons, requiring a longdrive distance than calculated. But the figure 2.4 show that

an extreme case of the second law which robot do not get tothe stop at desired point because it maybe had some bad

navigation data and forced to circumnavigate an obstacle before reaching Node B. One answer is to use the parallel

distance to the node to plan the stop, not the vector distance.

As the robot approaches the end of the path, it must switch

out of the wagon tongue behaviour and attempt to close onthe end point.so it is more important that the robot end the

path at the correct heading than at the perfectly correct place. One solution is to limit the angle between the robot

and the path ever more tightly as it approaches the end.Thus, at the end of the path the robot will be consistentlyoriented parallel to the path.

Figure 2.4 shows calculating the distance remaining

2.1.5 Running on path

If the robot expected to run on from one node to the next

node without stopping, as showed figure 2.5, it will be more

complex. In this case, the robots should know ahead of timethat it is not actually running to the node B but is actually

arcing past Node B to get to Node C. The robot should plans to radius the turn and this is the distance away from

node B that it must begin to turn in this case. Once into theturn, it steers at a constant rate until the heading is that of

the B-C, similar to the wagon tongue method. When theheading matches, it can revert to convergence behaviours

and the speed in the turn must be slower as the radius ismade smaller. [4]

Figure 2.5 shows running on past a node.

3. Methodology

3.1 Basic Principle for Control System

This chapter explain the control algorithm that applied inthe fire fighting robot design and navigation process. The

subtopics for this chapter include control algorithm of sensors, servo motor and conclusions. Finally, the output

from the three types of sensors are analysed and defined for

the development of the programming codes so that therobot can make decisions based on the output from sensor.

Control systems are an integral part of modern society. Numerous applications are all around us: the rocket fire,

and the space shuttle lifts off to earth orbit; a self-guidedvehicle delivering material to workstation in an aerospace

assembly plant glided along he floor seeking its destination.These are just a few examples of the automatically

controlled systems that we can create.

A control system consists of subsystem and process (or

plants) assembled for the purpose of controlling the output

of the processes. For example, a fire fighting robot produces wind to blow off candle as a result of appearance

of the flame at the candle. In this process, subsystems,called the flame sensor detect the appearance of the flame

at the candle.

Robot designed by control system principles cancompensate for human disabilities. Control systems are

useful in remote or dangerous location. For example, amicrocontroller-controlled fire fighting robot can be useful

to blow off fire which in dangerous and hot condition.[5]

Explanation of the how does the control system works can be more understand through the figure 3.1 below, it show

the input or stimulus which is desired response will control



by control system and give the output response which is

actual response.

Figure 3.1 of sample control system block diagram

There are two type of control system which are open loop

system and closed loop system. The open loop system hasonly input, input transducer, controller, disturbance 1, plant

disturbance 2 and output. But the closed loop system havethe input, input transducer, controller, disturbance 1, plant,

disturbance 2 and output transducer which give feedback tothe system, plant and output.

Figure 3.2 show a) open loop system, b) closed loop system[5]

3.2 Control Algorithm

The main control for this fire fighting robot is to

control its navigating system and fire detection. The certainsteps that the program must take before it can complete it's

task which is to put out a candle flame can understand byseeing flow chart below. By using sensors use by the robot,

the task can be completed. The fire fighting robot have togoing the map which will represent the mock house

according to figure 3.3

Figure 3.3 A map of the fire fighting robot routes

3.3 Process Flow Chart

3.3.1 Process flow chart how the fire fighting robot works

1. At first, robot will be place at the starting point, itwill monitoring and stay at initial position. If there

is no flame signal, it will continue monitor for anyflame signal

2. If flame detected, the robot will move andapproaching the direction of the candle.

3. If the flame is not near and no obstacles detected,it will continue repeat the step 2 and move to the

candle direction.4. If the flame not near but the robot detects obstacles

at front, left or right side, robot will turn to avoidthe obstacles and repeat back to step 2.

5. If the flame is near but there is not candle in frontof the robot, it will decide to adjust the direction

and repeat step 2 to approach until in front of thecandle.

6. But when it detect the flame is near and the candle

in front of the robot, the fire fighting robot willtrigger on the fan to blow off the flame.

7. If the flame not blown off, the robot will continue

blow off the candle.

Figure 3.4 show how the flow charts of fire fighting robot

work toward its objective.

3.3 Control System with Servo motor



This robot is programmed for known environment that is

not expected to change. So this helps us to give a

programming technique to navigate the robot to its possibledestinations for searching for the objective of blow off the

candle. The basic of the control system with servo motor can be tabulated from the figure 3.4.

Figure 3.5 show the feedback from ultrasonic, analogue

distance sensor and flame sensor to servo motor control system.

4. Project Progress

Based on the Gantt Chart proposed, the project are wellmanage to carry out all the progress within the desired date

and time. As for now, progression is assembly andfabrication of fire fighting robot stage. But starting with the

project proposal preparation and submission, basic idea wasgenerated on how the project will be done. The literature

review based on the related field was studied and study of fire fighting robot also carried out including journal

presentation with the supervisor. Testing and analysis of thefire fighting now commencing as robot are been tested for

programming and control algorithm for how does it chooseits locomotion to find the flame of the candle and

extinguish it by blowing the fan toward the flame of thecandle.

Figure 4.1 Grant Chart

4.1 Result and Discussion

From the assembly and fabrication of the fire fightingrobot, the result of design of the fire fighting robot can be

seen in the picture below:

Figure 4.2 Front view of the fire fighting robot

Figure 4.3 Side view of fire fighting robot



Figure 4.4 Top view of fire fighting robot

Figure 4.5 Bottom view of fire fighting robot

As for voltage regulator circuit for the fire fighting robot,

the list of component in the circuit component consists:1 unit voltage regulator LM7805,

1 unit voltage regulator LM7806,

2 unit of capacitor 0.33 µF,2 unit of capacitor 0.1 µF,1 unit diode 1N4001,

1 unit LED ,1 unit transistor 2N2222A,

2 unit of resistor 1kΩ1 unit relay

Figure 4.6 Donut board mounted with Circuit of fire fighting robot

5. ConclusionBy reading and review the journal, innovative ideas andtheories about the application of fire fighting robot, the

method of previous and past project of the fire fighting

robot have inspired and implemented to this project. Thus,

this robot going to better in term of its function and

application compared with others.

In the nut shell, this project has meet up to its progressaccording planned in the Grant Chart which proposed in

previous report.

For future work, this project planned to accomplish

objective and scope of the fire fighting robot according to

the Grant Chart. More effort on analysis will given

in order to ease troubleshooting of the

locomotion of the fire fighting robot.

ReferencesBibliography[1]Tom Duckett and Ulrich Nehmzowb.(2001) Mobile

robot self-localisation using occupancy histograms anda mixture of Gaussian location hypotheses

a)Centre for Applied Autonomous Sensor Systems,Department of Technology, University of Orebo, S-

70182 Orebo, Sweden b) Department of Computer Science, University of

Manchester, Manchester M13 9PL, UK

Data retrieved December 4 2011 fromhttp://citeseerx.ist.psu.edu/viewdoc/summary?

doi=10.1.1.26.9985

[2]Adam A. Ray “Cooperative Robotics UsingWireless Communication” A Thesis Submitted to the

Graduate Faculty of Auburn University in Partial

Fulfilment of the Requirements for the Degree of Master of Science Data retrieved December 4 2011from http://citeseerx.ist.psu.edu/viewdoc/summary?

doi=10.1.1.26.9985[3]Gordon McComb, Myke Predko “Robot Builder`s

Bonanza” McGraw-Hill, Third Edition 2006.References obtained from Chapter 33 page 599.

[4] John M. Holland “Designing Autonomous MobileRobots”Newnes 2004 Reference from chapter 9 page

127.[5]Norman S.Nise “Control System Engineering”

Fourth Edition, Wiley Publication

Evaluated by:

_________________________________ Supervisor Name: Dr. IR. Marwan Affandi

Date: 13 January 2012Official stamp:





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