Ultrasonic Tracking SystemUltrasonic Tracking System

Group # 4Group # 44/22/03 4/22/03

Bill HarrisBill Harris

Sabie PettengillSabie Pettengill

Enrico TelemaqueEnrico Telemaque

Eric ZweighaftEric Zweighaft

OverviewOverview

►ObjectiveObjective►MotivationMotivation►SpecificationsSpecifications►Design ApproachDesign Approach►ResultsResults►Design EvaluationDesign Evaluation►ConclusionConclusion

ObjectiveObjective

►Design a pan/tilt system which acts as Design a pan/tilt system which acts as a tracking device using ultrasonic a tracking device using ultrasonic transmitters and receivers transmitters and receivers

MotivationMotivation

►Applications of tracking are basic tasks Applications of tracking are basic tasks worked on by engineers in various fieldsworked on by engineers in various fields Aerospace- Flight control radarAerospace- Flight control radar Defense- Smart targeting smart weaponsDefense- Smart targeting smart weapons Sensors- Smart collision sensors on carsSensors- Smart collision sensors on cars

► Incorporation of tracking in model Incorporation of tracking in model teaches fundamentals of sensor teaches fundamentals of sensor technology in conjunction with control technology in conjunction with control technology technology

SpecificationsSpecifications

► The system will track objects between 2 and The system will track objects between 2 and 10 meters from the array10 meters from the array

► The system will track objects between 0 and The system will track objects between 0 and 2 meters off the ground2 meters off the ground

► The system will track items within .5 degree The system will track items within .5 degree of accuracy (within 10 cms of the object with of accuracy (within 10 cms of the object with beacon)beacon)

► The system must be able to track the The system must be able to track the beacon at the speed of a human walking beacon at the speed of a human walking (.64 rad/sec)(.64 rad/sec)

Design ApproachDesign Approach

►CAD and Matlab used to model core CAD and Matlab used to model core pan/tilt system with addition ofpan/tilt system with addition of Motors, belts, gears, pulleysMotors, belts, gears, pulleys L shaped sensor structureL shaped sensor structure Laser pointerLaser pointer

►Linear simulation of system withLinear simulation of system with MatlabMatlab Simulink diagramsSimulink diagrams

Cad drawing of systemCad drawing of system

► Key IssuesKey Issues L Shape sensor L Shape sensor

mountmount Mounting sensors on Mounting sensors on

to the beamsto the beams

t

Motor SpecificationsMotor Specifications

►Pittman GM8724S017Pittman GM8724S017 19.5:1 internal gearing ratio19.5:1 internal gearing ratio Encoder mounted directly to rotor Encoder mounted directly to rotor

increases accuracy of encoder (encoder is increases accuracy of encoder (encoder is not geared down)not geared down)

External transmission gives additional External transmission gives additional reduction ratio of 3:1reduction ratio of 3:1

Larger motor size needed to meet system Larger motor size needed to meet system specificationsspecifications

Linear ApproachLinear Approach

► Linear design of Linear design of controllercontroller PD controller PD controller

designeddesigned► SISO design tool used SISO design tool used

for testingfor testing

Step Response

Time (sec)

Am

plit

ud

e

0 0.05 0.1 0.15 0.2 0.25 0.3 0.350

0.2

0.4

0.6

0.8

1

1.2

1.4

Nonlinear ApproachNonlinear Approach

►Nonlinear design of controllerNonlinear design of controller Input of transfer functions from linear Input of transfer functions from linear

designdesign Motor feasibility, torque requirements, Motor feasibility, torque requirements,

and tracking ability observedand tracking ability observed

Circuit ApproachCircuit Approach

►Circuit design for sensorsCircuit design for sensors Input- Logic gates obtain time difference Input- Logic gates obtain time difference

between signals received by sensorsbetween signals received by sensors Output – 12-bit accuracy in pitch and yaw Output – 12-bit accuracy in pitch and yaw

directiondirection 3 additional digital I/O for circuit/controller 3 additional digital I/O for circuit/controller

communicationcommunication

Circuit Diagram Circuit Diagram

► Key IssuesKey Issues► DC OpAmpsDC OpAmps► Flip FlopsFlip Flops

Circuit Diagram Circuit Diagram

R12RESISTOR

R7RESISTOR

R12RESISTOR

Q32N2222

R3RESISTOR

R1RESISTOR

+5V+5V

Q32N2222

R12RESISTOR

+5V

R12RESISTOR

R12

RESISTOR

R12RESISTOR

R12

RESISTOR

R5RESISTOR

R6RESISTOR

R12

RESISTOR

-

+

U1A

LM358

3

21

84

+5V

-

+

U1A

LM358

3

21

84

R12RESISTOR

R2RESISTOR

R12RESISTOR

-

+

U1A

LM358

3

21

84

+5V

R12RESISTOR

+5V

R12RESISTOR

Q32N2222

R12RESISTOR

R4RESISTOR

R10RESISTOR

R12RESISTOR

R9RESISTOR

R8RESISTOR

R12RESISTOR

R11RESISTOR

+5V

R12RESISTOR

R7RESISTOR

R12RESISTOR

Q32N2222

R3RESISTOR

R1RESISTOR

+5V+5V

Q32N2222

R12RESISTOR

+5V

R12RESISTOR

R12

RESISTOR

R12RESISTOR

R12

RESISTOR

R5RESISTOR

R6RESISTOR

R12

RESISTOR

-

+

U1A

LM358

3

21

84

+5V

-

+

U1A

LM358

3

21

84

R12RESISTOR

R2RESISTOR

R12RESISTOR

-

+

U1A

LM358

3

21

84

+5V

R12RESISTOR

+5V

R12RESISTOR

Q32N2222

R12RESISTOR

R4RESISTOR

R10RESISTOR

R12RESISTOR

R9RESISTOR

R8RESISTOR

R12RESISTOR

R11RESISTOR

+5V

Software DevelopmentSoftware Development

►Software Algorithms have several Software Algorithms have several levelslevels Binary to Decimal ConversionBinary to Decimal Conversion

►Gives us magnitude of time difference, and Gives us magnitude of time difference, and sign of differencesign of difference

Angle Calculation AlgorithmAngle Calculation Algorithm►Takes these 2 inputs, along with estimated Takes these 2 inputs, along with estimated

distance, and returns the desired change in distance, and returns the desired change in angle to the controllerangle to the controller

ControllerController

Software DevelopmentSoftware Development

►Binary ConversionBinary Conversion Takes in 12 Digital Takes in 12 Digital

I/O inputs and I/O inputs and treats them as a treats them as a binary number, binary number, then converts this then converts this number to an number to an integerinteger

Software DevelopmentSoftware Development

► Current Angle Current Angle Calculation AlgorithmCalculation Algorithm

► d2 = sqrt(Xd2 = sqrt(X22 + Y + Y22))► d1 = sqrt((X – c)d1 = sqrt((X – c)22 + Y + Y22))

► dm = sqrt((X – c)dm = sqrt((X – c)22 + Y + Y22) - sqrt(X) - sqrt(X22 + Y + Y22))

► 4 Lookup Tables were generated 4 Lookup Tables were generated using a range of Y’s, and a range of using a range of Y’s, and a range of dm’sdm’s One each for positive pan, negative One each for positive pan, negative

pan, positive tilt, and negative tiltpan, positive tilt, and negative tilt

Sensor 1 Sensor 2

Transmitter (point X,Y)

θ

d1d2

ce

dm = d1 – d2

x

y

Software DevelopmentSoftware Development

► This only calculates the This only calculates the angle we are currently atangle we are currently at

► We also need to calculate We also need to calculate the angle we want to be at, the angle we want to be at, given the Range estimate Ygiven the Range estimate Y

► θ = atan2(Y , e + 0.5 * c)θ Sensor 1 Sensor 2

ce

(X,Y)

Software DevelopmentSoftware Development

►Now that we know our current angle, Now that we know our current angle, and desired angle, we subtract the and desired angle, we subtract the two, and send this value to the two, and send this value to the controller.controller.

Linear ResultsLinear Results

► Simulation resultsSimulation results Step response of Step response of

controllercontroller Within 1% steady Within 1% steady

state errorstate error

Nonlinear ResultsNonlinear Results

► Simulation resultsSimulation results Motor torqueMotor torque

Motor trackingMotor tracking

Nonlinear ResultsNonlinear Results

► Simulation resultsSimulation results Motor feasibilityMotor feasibility

0 0.05 0.1 0.15 0.20

200

400

600

800

1000

1200

motor 1 torque (Nm)

mot

or 1

vel

ocity

(ra

d/s)

feasible

not feasible

Pittman GM8724S010

0 0.05 0.1 0.15 0.20

200

400

600

800

1000

1200

motor 2 torque (Nm)

mot

or 2

vel

ocity

(ra

d/s)

feasible

not feasible

Pittman GM8724S010

0 0.05 0.1 0.15 0.20

200

400

600

800

1000

1200

motor 1 torque (Nm)

mot

or 1

vel

ocity

(ra

d/s)

feasible

not feasible

Pittman GM8724S010

0 0.05 0.1 0.15 0.20

200

400

600

800

1000

1200

motor 2 torque (Nm)

mot

or 2

vel

ocity

(ra

d/s)

feasible

not feasible

Pittman GM8724S010

Friction ID ResultsFriction ID Results

► PanPan CoulombCoulomb

► Pos: 0.13Pos: 0.13► Neg: -0.13Neg: -0.13

ViscousViscous► Pos: .01Pos: .01► Neg: -.0089Neg: -.0089

Final ResultsFinal Results

►Original specifications vs Final Original specifications vs Final specificationsspecifications Tracking accuracyTracking accuracy Tracking accuracy with motionTracking accuracy with motion Affect of friction compensationAffect of friction compensation

Results DemoResults Demo

►System demo videoSystem demo video DemoDemo

Design EvaluationDesign Evaluation

►Problems encounteredProblems encountered Sensor functionalitySensor functionality

►Future ImprovementsFuture Improvements Improved integration of sensor and Improved integration of sensor and

control systemcontrol system Faster sensor algorithmsFaster sensor algorithms Addition of filters to improve motion of Addition of filters to improve motion of

systemsystem

ConclusionConclusion

►PD controller usedPD controller used►Accurate linear vs nonlinear results Accurate linear vs nonlinear results

obtainedobtained►System is expandable for future System is expandable for future

improvementsimprovements

►Questions?Questions?