Ultrasonic Tracking System
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Transcript of Ultrasonic Tracking System
Ultrasonic Tracking SystemUltrasonic Tracking SystemGroup # 4Group # 4
4/22/03 4/22/03
Bill HarrisBill HarrisSabie PettengillSabie Pettengill
Enrico TelemaqueEnrico TelemaqueEric 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 2 The system will track objects between 0 and 2
meters off the groundmeters 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 beacon The system must be able to track the beacon at the speed of a human walking (.64 rad/sec)at the speed of a human walking (.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 testingStep Response
Time (sec)
Am
plitu
de
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
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 levelsSoftware Algorithms have several levels
Binary to Decimal ConversionBinary to Decimal Conversion►Gives us magnitude of time difference, and sign Gives us magnitude of time difference, and sign
of differenceof 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
(rad
/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