Ultrasonic Tracking Ultrasonic Tracking SystemSystem

Group # 4Group # 4

Bill HarrisBill Harris

Sabie PettengillSabie Pettengill

Enrico TelemaqueEnrico Telemaque

Eric ZweighaftEric Zweighaft

IntroductionIntroduction What is our project?What is our project?

Pan and tilt implemented system tracking an ultrasonic Pan and tilt implemented system tracking an ultrasonic beacon which sends a signal to 3 ultrasonic receivers, is beacon which sends a signal to 3 ultrasonic receivers, is carried around the room by a team membercarried around the room by a team member

How does it work?How does it work? The signal coming from an ultrasonic transmitters is The signal coming from an ultrasonic transmitters is

measured at three different locationsmeasured at three different locations The difference in the time the signal is received at each The difference in the time the signal is received at each

sensor is used to calculate a distance relationship sensor is used to calculate a distance relationship Why is this project practical?Why is this project practical?

Mitsubishi Motor company uses a similar design in their Mitsubishi Motor company uses a similar design in their automobiles for a collision avoidence systemautomobiles for a collision avoidence system

Various pest and animal repellent systems use Various pest and animal repellent systems use ultrasonic waves for tracking and repelling.ultrasonic waves for tracking and repelling.

ObjectiveObjective Simulation of pan & tilt system used as a cost Simulation of pan & tilt system used as a cost

efficient method to determine:efficient method to determine: Motor required to drive systemMotor required to drive system Gear, belt and pulley combination neededGear, belt and pulley combination needed Response of system to motor, gear, belt and Response of system to motor, gear, belt and

pulleypulley Maximum performance variables for system Maximum performance variables for system Rough estimate of system response to Rough estimate of system response to

sample payloadsample payload Chance to show that we were paying Chance to show that we were paying

attention in all those math classesattention in all those math classes

SpecificationsSpecifications The system will track objects between 2 and 10 The system will track objects between 2 and 10

meters from the arraymeters 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 of The system will track items within .5 degree of

accuracy (within 10 cms of the object with accuracy (within 10 cms of the object with beacon)beacon)

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

Major Change in DesignMajor Change in Design

With our previous sensor structure, With our previous sensor structure, there was not a large enough motor that there was not a large enough motor that could handle the torquecould handle the torque

We decided make a more compact We decided make a more compact sensor structure which allowed us to go sensor structure which allowed us to go with a much smaller motor in the with a much smaller motor in the Pittman 8000 series. Pittman 8000 series.

The sensor structure was made L shaped The sensor structure was made L shaped instead of T shaped to allow for a instead of T shaped to allow for a simpler timer circuitsimpler timer circuit

MotorMotor

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

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

MotorMotor

Pittman GM8724S017Pittman GM8724S017 Larger gearing ratio does not allow us Larger gearing ratio does not allow us

to meet our speed requirementsto meet our speed requirements Smaller gearing ratio does not allow us Smaller gearing ratio does not allow us

to meet our torque requirementsto meet our torque requirements Gains must be chosen carefully to Gains must be chosen carefully to

remain inside the feasible range for remain inside the feasible range for both speed and torqueboth speed and torque

MotorMotor

0 2 4 6 8 10 12 14 16 18 20-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1Desired Input and Actual Output for Theta1

time

radia

ns

inputtheta1

0 2 4 6 8 10 12 14 16 18 20-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1Desired Input and Actual Output for Theta1

time

radia

ns

inputtheta1

•SimulationSimulation•Sinusoidal Sinusoidal inputinput•Frequency of Frequency of 0.63 rad/s0.63 rad/s

MotorMotor

•Speed vs. Torque Speed vs. Torque plotplot

•Shows that Shows that motor is well motor is well within limits, as within limits, as long as gains long as gains are kept at are kept at reasonable reasonable levelslevels

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

ControllerController

By intuitive By intuitive adjustment of adjustment of gains, a reasonable gains, a reasonable response was response was obtainedobtained But “guessing” is But “guessing” is

not a valid design not a valid design approachapproach

0 0.5 1 1.5 2 2.5 30

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1Theta1 from 1 radian to zero

Time (in Sec)

Rad

ians

0 0.5 1 1.5 2 2.5 30

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1Theta1 from 1 radian to zero

Time (in Sec)

Rad

ians

0 2 4 6 8 10 12 14 16 18 20-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1Desired Input and Actual Output for Theta1

time

radi

ans

inputtheta1

0 2 4 6 8 10 12 14 16 18 20-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1Desired Input and Actual Output for Theta1

time

radi

ans

inputtheta1

ControllerController

SISO Design tool was usedSISO Design tool was used Linearized model was obtained using the Linearized model was obtained using the

linearlization routines providedlinearlization routines provided Alternatively, the “linmod” command could be Alternatively, the “linmod” command could be

called to create a linear State Space model from called to create a linear State Space model from the Simulink Diagramthe Simulink Diagram

This allows the designer to view pole/zero This allows the designer to view pole/zero locations, bode plots, AND response plots all locations, bode plots, AND response plots all at the same time, and adjust poles, zeros, and at the same time, and adjust poles, zeros, and gains in any of these formatsgains in any of these formats

ControllerController

SISO WindowSISO Window Step ResponseStep Response

Overshoot is very undesirableOvershoot is very undesirable

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

ControllerController

SISO WindowSISO Window Step ResponseStep Response

PM = 98.2° GM = Inf. Zero overshoot, PM = 98.2° GM = Inf. Zero overshoot, 1% e1% essss

Step Response

Time (sec)

Am

plit

ud

e0 0.05 0.1 0.15

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Notes on ControllerNotes on Controller

Because of assumptions made in order Because of assumptions made in order to linearize the system, this controller to linearize the system, this controller does not perform perfectly on the non-does not perform perfectly on the non-linearized model, so some adjustments linearized model, so some adjustments will have to be made during assembly will have to be made during assembly and testingand testing

We may wish to add an Integral term We may wish to add an Integral term later to cancel the 1% overshootlater to cancel the 1% overshoot Does not seem necessary now- it would only Does not seem necessary now- it would only

hurt our transient response, and require hurt our transient response, and require more torque and speed from the motormore torque and speed from the motor

Justification for Sensor Justification for Sensor PartsParts

Given the cost of larger motors, needed Given the cost of larger motors, needed to have a design with a small moment of to have a design with a small moment of inertiainertia

The higher the clock frequency of timer The higher the clock frequency of timer circuit, the smaller our sensor structure circuit, the smaller our sensor structure has to behas to be

The cheapest TTL components had a The cheapest TTL components had a maximum functional frequency of 5 MHzmaximum functional frequency of 5 MHz

Chose an oscillator accordinglyChose an oscillator accordingly

CostCost

Pan and Tilt PartsPan and Tilt Parts

Total $478.64Total $478.64

PartPart Part #Part # QuanityQuanity Price Price Total $Total $$$

MotorMotor GM8724S0GM8724S017 17 22 192.86192.86 385.72385.72

Gear Gear (large)(large)

A 6A 6-A 6A 6-75NF01812 75NF01812 22 15.1515.15 30.3030.30

Gear Gear (small)(small)

A 6A 6-A 6A 6-25DF01806 25DF01806 22 7.767.76 15.5215.52

Carbon Carbon FiberFiber

T155-5T155-5 11 43.4043.40 43.4043.40

Timing BeltTiming Belt A6Z16-A6Z16-C018 C018 22 1.861.86 3.703.70

Additional CostsAdditional Costs

Total Amount for Timing Circuit and Total Amount for Timing Circuit and Sensors: $46.52Sensors: $46.52

Total Cost for project: $533.84Total Cost for project: $533.84

February

Week 2 Week 3 Week 4

Hardware

Placing parts and payload on CAD

drawings to calculate P,I,M

values for Matlab simulation (Bill,

Sabie)

Hardware - CAD designed payload

added to Ben’s CAD drawings system and edited P,I,M values

are calculated(Eric, Sabie)

Final design specifications are

met(All members)

Parts are ordered(Eric, Sabie)

Software

Simulation of pan and tilt system to

obtain feasibility and performance of test

motor with a test payload

(Bill)

Final Motor feasibility simulation with payload on pan

and tilt system(Bill, Enrico)

Testing of control system’s ability to

track a signal using amplitude, or

distance and time measurements(All members)

Reports Presentation writeup (Enrico Eric)

Proposal writeup (Sabie, Enrico)

TBD

March

Weeks 1-2 Week 3 Week 4

Hardware

Sensor development with focus on time\

distance relationship(Eric, Sabie)

Encoder and amplifier properties

researched(Bill, Enrico)

Design model assembled

(Enrico, Sabie)

Sensor assembly(Bill, Eric)

Further tolerance testing of physical

equipment

Software

Current Feedback control analyzing and testing to find proper gains for

accurate tracking(Bill, Enrico)

Encoder and amplifier properties

simulated(Eric, Sabie)

Testing and fine tuning of control feedback system

(Bill, Sabie)

Sensor testing with system

(Enrico, Eric)

Test mechanics of system in terms of

motion(Bill, Enrico)

Test mechanics of system in terms of

tracking(Eric, Sabie)

Reports Progress Report(All members)

TBD TBD