microsoft word - users manual

8/7/2019 Microsoft Word - Users Manual

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.jpg of AFFR

Autonomous Fire Fighting RobotUsers Manual

Isaac N. Dupre

Chad W. Ives

Table of Contents:

Section I

Background 3

Introduction 3


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Features 3

Specifications 4

Mechanical 4

Electrical 4

Software 5

Section II

Installation 6

Operation 7

Section III

Theory of Operation ........... 9

Navigation

System 9

Detection/Suppression

System 10

Section I

Background

The Autonomous Fire Fighting Robot (AFFR) project was originally designed forthe 13th annual Trinity College Fire Fighting Competition held in April. There werenumerous specifications and rules that governed the size, mobility and software/hardwarecharacteristics that are implemented on the vehicle (see Specifications and Rules section


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for a complete listing). In a nut shell the objective of this contest is to build anautonomous computer-controlled robot that could: Navigate through an arena thatrepresents a model house (see arena in Specifications section) and ultimately Find a litcandle that represents a fire in the house and extinguish it with a suppressant.

Introduction

Fire kills more Americans than all other natural disasters combined. Every yearmore than 5,000 people die in fires, over 25,000 are injured, and direct property loss isestimated at over $9 billion. Fortunately, most fire losses can be prevented througheffective public education, awareness initiatives and fire suppression systems likeAFFFR. Many Americans believe "fires can only happen to other people not to me andnot in my home." Yet, over 80 percent of fire deaths occur in the home, most oftenclaiming the lives of the young, the elderly and the disadvantaged.The decision you havemade in purchasing the AFFR will give you peace of mind while you sleep and theprotection that you and your loved ones deserve. Again we applaud you for taking theinitiative in protecting your family and project that the AFFR will surpass everyexpectation or pre-conceived notion that you may have regarding Autonomous FireFighting and suppression systems.

Features

A 12inch diameter vehicle housing to prevent getting stuck in cornersCompletely Autonomous- Turns on when fire detector alarm sounds (3-5 kHz)and uses a number of different sensors to navigate and detect the fire.Fire suppression is accomplished via water and features a clear reservoir forrecognition of water level.Returns to home position when fire is suppressedIs un-tethered (no power or PC cords attached to vehicle)Uses 12V dry cell batteryIncludes standard battery chargerInterchangeable standard part sizes

Specifications

Mechanical

Tracked vehicle which uses skid steer for navigation


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Dual motorsDual motor gearbox

12 diameter vehicle housingRotational Sweeping targeting system with 12V stepped down to 3.5V Cam motor

and linkage

12Vpump with

Advantages to Tracks:

Allows for tight turning radius

Allows for mobility over stairs and various forms of clutter

Vehicle does not get belly-hung readily

Advantage to circular design:

Vehicle will not get stuck on foreign objects or corners of room

Advantage to Rotational targeting system:

Suppression system will be targeted with UVtron sensor

position. Water is a real world solution that does not rely on

air to blow the flame out and aids a bonus of 5% in time trialcompetition.

Electrical

Standard 12V (DC) Dry Cell Battery- AutomotiveDual motor controller board that interfaces to PWM output from internal CPUSingle motor controller board that interfaces to internal CPUAuto start circuitry (fire alarm detection)

Fire detection and spectral analyzer of flame boardSignal processing and manipulation boardIR Scanner circuitry

Advantage to 12V (DC) battery packs:

Standard, reliable/proven to work and easily rechargeable

Advantage to Dual motor controller with PWM:

Can control both navigational motors with same board and

have variable speed controls using PWM

Advantage Auto start:

Does not need human aid to start Uses standard frequency of

fire detector alarm (4-5 kHz)Advantage to UVtron Fire Detection Kit:

Proven to work- takes spectral analysis input and outputs a 0-

5V digital signal

Software


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Navigation:Mobility (right turn, left turn, stop, forward, reverse)

Ramp speed PWMWall Follow

Enter Room:Line detection

Enter Hallway:Increment counter if count=0 in hallway

Fire Detection:Sweep for flame detection

UVtron Fire Detection Sensor inputLock on target

Suppression system engagedReturn Home

Stay in Hallway till home circle is found

Advantage to Navigation:

Does not rely on single system for guidance. It utilizes multiple

IR scanner sensors that are calibrated in regards to position

and placement on vehicle

Advantage to Enter Room:

Line detection will allow for flame detection system to start-

not continuously sweeping for flame-Power saving

Advantage to fire detection/suppression sweep X-axis:

Only need to find the flame in single axis

When flame is detected by UVtron sensor the system willrelease the suppressant and sweep via Cam and linkage in the

Y-axis.

Advantage to Return Home:

Does not need Human interaction to return to start position

Bonus of 15% in time trial competition.

Section II

Installation


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Charge battery packs by:

A). Plugging the charger into a standard 120V 60Hz wall outlet (see

figure 1a)

Figure 1a

B). Inserting the battery packs into the charger (see Figure 1b)

Figure 1b

When the first battery pack is charged replace with the second.

Once both battery packs are charged:

1). Insert Battery pack A into the undercarriage of vehicle platform

(see Figure 2a)

Figure 2a

2).Insert Battery pack C into driver circuit access panel (see Figure

2b)


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Figure 2b

3).Make sure to have a charged battery pack on standby a standby

pack is included.

CHANGE OUT BOTH BATTERY PACKS EVERY 6 MONTHS AS YOU DO

WITH SMOKE DETECTOR ALARM BATTERY

Once these simple tasks are preformed there is nothing else that needs to be

done for installation and set up.

Operation

Select TEST under mode of operation indicated by the green circle -located on the

undercarriage of vehicle platform (see Figure 3a)

Figure 3a

Set the vehicle on the floor and make sure that it starts the flame detection andnavigation process by

A). the vehicle should start moving and following the walls

B). When it enters a room the fire detection UVtron sensor will be activated

(see figure 3b)


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Figure 3b

C). should there be a flame detected the system will suppress the flame

engaging the pump and water reservoir. The small slit cut in the Sensors

housing is to limit the area that the sensor can view.

Note: This is only a test of the operation of the system no flame should be

detected and consequently no suppressant emitted.

D). If everything went as directed switch mode to STANDBY indicated by

the purple circle (see Figure 3c) and leave in desired home position. This

should be a place out of the way where the AFFR system will stay alert

awaiting for the smoke detector to sound- activating the system.

Enjoy the security and peace of mind knowing that your house is protected against

fire by the AFFR system.

Section III

Theory of Operation


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Navigation

Navigation is accomplished via IR sensors that are originally analog that are

averaged and converted to digital for the HC12 to operate. The system is activated by thesound of a smoke detector 3-5 kHz signal. A microphone and frequency analyzeraccomplishes this task (see AFFR project binder for details). The Programming is asimple state machine with multiple scenarios. The first is wall following: by calibratingeach of the IR sensors based on their physical placement on the vehicle the inputs are fedinto the HC12. Going straight involves both side mounted IR sensors to have the samevalue. IR sensors output a voltage based on the distance from the wall. If both areoutputting an equal voltage they are the same distance from the wall. If they havedifferent voltage outputs than the system compensates by increasing the PWM to thecorrect track. The mobility is a tracked vehicle with independent gear trains and motors,allowing for this type of action.

The next task of the navigation program is to turn. A left turn is accomplished bythe input from the front IR sensor. Once the threshold voltage from the front mounted IRsensor is breached, indicating a wall in front the vehicle turns left. Feedback from thetwo side mounted IR sensors indicate when the vehicle is parallel with the wall again andforward movement can begin. A right turn is accomplished when the front IR sensor seesnothing and first side mounted IR sensor sees nothing while the back side mounted IRstill sees the wall. The vehicle then starts the turn right routine until it is again parallelwith the wall. The fire detection program is not called until the vehicle enters a room.Recognition of room entering is accomplished by floor mounted Fairchild IR sensorscalibrated to pick up the White marking before a room (see manufacturer Specification inAFFR Project Binder). This activates the Suppression/Detection system. Depending on

the message sent from the Suppression/Detection System the system will either continuesearching for a flame or find the home circle. Searching for the flame is accomplished inthe same manner as indicated above until a FireFound signal is sent from the HC08(Suppression/Detection MCU) to the HC12 (Navigation MCU).

Return Trip or find home is accomplished by not sweeping for the flame when aroom is entered rather looking for the home circle. Three Fairchild IR sensors aremounted on the bottom of the vehicle facing the floor. They are calibrated to go high onwhite surfaces. Once all three sensors, arranged in a lateral triangle pattern are high thevehicle is in the home circle- this indicates the end of the competition.

Suppression/Detection System

After receiving a start signal for the HC12 (navigation system) the suppressionalgorithm is implemented. The system uses a 12V unipolar 1.8 degree step stepper motor(see manufacture specification sheet in AFFR Project Binder) to sweep for the flame.Input from the UvTron flame detection sensor is feed into the IRQ interrupt of the


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systems state machine. If the spectral response of a flame is detected the system goesinto flame saturation mode (see source code in AFFR Project Binder). However one keyelement to the system is the time needed for spectral response. The internal signalprocessing of the sensor and driver board output random capture times. The five volthigh pulse that indicates a flame is present ranges from 40mS (best case) to 160mS

(worst case). It was necessary to design for the worst case so the stepper motor takes onestep every 170mS to allow enough capture time for worst case scenarios.The IRQ interrupt located on the HC08 at pin 4 is set up to stop the scanning

cycle on the falling edge of the pulse output of the UvTron kit. The system triggers onthe falling edge and needs three consecutive falling edges to move into a halt/suppressionstate. The stepper motor is controlled by the HC08 in conjunction with a unipolar stepperdriver board. A UN508B allegro driver chip was implemented to accomplish this task.Pulsing a square wave signal equivalent to 6Hz (one pulse every 170mS) allowed for thedwell at each step needed for flame detection. This was designated as the output of pin15 on the HC08. The direction was controlled via a logic high or low (0-5v) pin 14. Tochange directions two limit switches were impregnated on the sweep mechanism. There

are three direction states: Clockwise, Counter Clockwise and Halt. Each state is writtenin C with switch case statements (see source code). If either limit switch was it morethan once the system defaults to stop and send a message to the navigation controller withone of two messages. The two possible scenarios are fire detected and suppressed or nofire. A variable in C was designated to go high if the fire state was reached. After thesystem goes through the suppression it again sweeps for the flame to make sure that it isout (accomplished via limit switch greater than one). Had it entered the fire state and thelimit switch counter variable greater than one the system would send a Yes2Fire had thesystem simply reached LimitCounter>1 and Yes2Fire was still zero it would send aNoFire to the HC12. Ports PTA1 and PTA2 pins 2 and 13 respectively. PTA1 representsthe FireFound and PTA2 is the NoFire.

The HC12 based on the output of the HC08 will either continue searching for theflame or find the home circle. Consequently the search for flame is a result of being sentNoFire from pin 13 and find home circle from pin 2.

The suppression (Fire) state, as indicated earlier, is a result from three consecutivefalling edges on the IRQ interrupt (pin 4 HC08). This state sets the Yes2Fire variable toone and activates the pump and cam motor. Using standard MosFets (see manufacturerSpecifications in AFFR Project Binder) the PWM output of the HC08 activates them.With a 12V supply the pump is turned on and a simple voltage divider to step the 12Vdown to 3.5V the cam motor is activated. Since the state machine is called every 170mSand a 2second delay is required for the cam motor to sweep the vertical area three times(sufficient water saturation to extinguish the flame) a variable called FireCount is used tocreate a two second delay.

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