This is really stupid
Control System TerminologyControl System Terminology
Input - Excitation applied to a control system from an external source .(REFERENCE)
Output - The response obtained from a system Feedback - The output of a system that is returned
to modify the input. Error - The difference between the input and the
output.
Thermostat
Temp Wanted
Air Temp
Heater Control
Types of Control SystemsTypes of Control Systems
Open-Loop– Simple control system which performs its
function without concerns for initial conditions or external inputs.
– Must be closely monitored.Closed-Loop (feedback)
– Uses the output of the process to modify the process to produce the desired result.
– Continually adjusts the process.
Advantages of a Closed-Loop Advantages of a Closed-Loop Feedback System Feedback System
Increased Accuracy– Increased ability to reproduce output with varied
input. Reduced Sensitivity to Disturbance
– Self-correcting minimizes effects of system changes.
Smoothing and Filtering– System induced noise and distortion are reduced.
Increased Bandwidth– Produces sat. response to increased range of input
changes.
Major Types of Feedback Major Types of Feedback UsedUsed
Position Feedback– Used when the output is a linear distance or
angular measurement.Rate & Acceleration Feedback
– Feeds back rate of motion or rate of change of motion (acceleration)
– Motion smoothing– Uses a electrical/mechanical device called an
accelerometer
Building a Gun Fire Control System
Job Description: Train the gun turret to the proper firing position by moving a joy stick left or right depending on the direction needed. This must be performed as fast as possible.
Safety Consideration:For your protection,you will be located insidea windowless protectiveenclosure inside the gunturret.
MIDN Pineda
Time
Old Position
NewPosition
Turret Position with Feedback
DampingDamping
Old Position
New Position
Underdamped
OverDamped
Critically Damped
Realistically Damped
Tracking Systems??Tracking Systems??
Determines location or direction of a target on a near-continuous basis.
Ideal system would maintain contact and constantly update the target’s bearing (azimuth), range and elevation.
WHAT IS A TARGET?…
This is not a TargetThis is not a Target
Automatic Tracking Systems Automatic Tracking Systems (Related to Feedback)(Related to Feedback)
Target Tracking Parameters Line-of-Sight(LOS) Tracking Line
Target Tracking ParametersTarget Tracking Parameters
AzimuthElevationRangeRelative Target Velocity
– Target’s motion with respect to the platform’s motion
Tracking TermsTracking Terms
TrackingElement
Line-of-Sight
Tracking Line
Error
Angle-Tracking Servo Angle-Tracking Servo SystemsSystems
Five Basic FunctionsSense position error magnitude and
directionProvide position feedbackProvide data smoothing / stabilizationProvide velocity feedbackProvide a power-driving device
RELATE TO FEEDBACK CONTROL SYSTEMS
Uses of Angle-Tracking Servo Uses of Angle-Tracking Servo SystemsSystems
Monotrack fire control radarsHoming missilesAcoustic homing torpedoesAviation fire control tracking systems
Methods of trackingMethods of tracking
Sequential Lobing Conical scanConical scan on receive only (COSRO)Monopulse
Basic Principle: Target energy return is strongest on the axis of the beam, diminishes further from the axis.
axis
Methods of Tracking: * Sequential Lobing * Conical Scan * COSRO * Monopulse
Position Error Magnitude & Position Error Magnitude & DirectionDirection
Sequential LobingSequential LobingL L LR R R
Antenna looking left of target
Antenna Pointing directly at target
Antenna looking right of target
Return Signals form Two Beams
* Simplest Method
* Multiple Beams * Compare Returns
* Relatively Slow
* Still used by some countries
Conical ScanningConical Scanning
* Rotates a beam in a circle producing a cone of energy.
*Rotate the feed horn in a small circle around the axis of the fixed parabolic antenna.Antenna
Lobe Of Energy
Pattern of scanning
Determining Tracking Error Determining Tracking Error Using Conical ScanUsing Conical Scan
Locus of Beam Centers
Beam
Time
PulseReturnAmplitude
Equal AmplitudeSensor Return Signal
Antenna Axis
Target Position is in the Center of the Conical Scan (On Antenna Axis)
Determining Tracking Error Determining Tracking Error Using Conical ScanUsing Conical Scan
Locus of Beam Centers
Beam
Time
PulseReturnAmplitude
Varying AmplitudeSensor Return Signal
Antenna Axis
Target Position Off the Center of the Antenna Axis
Example: AN/SPG-53AExample: AN/SPG-53A
COSROCOSROConical Scan on Receive OnlyConical Scan on Receive Only
* Transmits pulses on axis of the antenna.* Measured strength of return around the axis of the antenna.* Positions the antenna based on the return. DECEPTIVE: Looks like non-Scanning pulse radar Antenna
MonopulseMonopulse
Developed to overcome tracking errors involved with conical scanning and sequential lobing.
Two or more beams are transmitted simultaneously and an amplitude comparison is mode between the returns. – One reflector but uses two or more feed horns.– Each simultaneous beam can be identified by tagging it with
some type of information such as slight polarization.– Usually 4 beams: 2 for elevation and 2 for azimuth
Very complex and expensive.
Providing a Stable Tracking Providing a Stable Tracking SystemSystem
All tracking systems require some stabilization. Three classes of stabilization for Tracking
Systems– Unstabilized - Not stabilized in any axis
– Partially Stabilized - Subsystem is stabilized on one axis.
– Fully Stabilized - Completely free of any rotational disturbances.
Gyroscopes provide the stable reference.
Basic Gyroscope PrinciplesBasic Gyroscope Principles
The gyro spins at a very high velocity, and its spin axis remains aligned with terrestrial meridians.
Inertia– Rigidity (A gyro will remain at a fixed
orientation in space if no force is applied to it)– A gimbaled gyro makes a good reference to
cancel out platform role, pitch and yaw. (On a ship!)
Basic Gyroscope PrinciplesBasic Gyroscope Principles
Precession– A gyro’s spin axis has a tendency to turn at right angles
to the direction of the force applied to it.
– Used to convert torque required to move the gyro is converted into a means of controlling system gain.
The gyro has three axes:– spin axis
– torque axis
– precession axis
Gyroscope TheoryGyroscope Theory
Accelerometers!!!
Now, put ‘em together!!!!Now, put ‘em together!!!!
Range Tracking Angle Tracking
One dead duck…………………..One dead duck…………………..
Questions?Questions?
QuizQuiz
Question 1Question 1
What does COSRO stand for?
Question 2Question 2
Damping is:A. A type of horizontal polarization.
B. The process by which your weapon system/tracking system turns to a new contact without overshooting the target.
C. Transmission from a Phased Array Radar.
D. Getting really wet.
Question 3Question 3
Give an example of an Open Loop Control System.
Not a stovetop burner
Question 4Question 4
Give an example of an Closed Loop Control System.
Question 5Question 5
In order to stabilize your weapons launcher or tracking system, the system must be able to receive input from what piece of equipment?
A. BSY-1
B. The Captain
C. The Gyroscope
D. The SPY-1D
Extra CreditExtra Credit
How many Nuclear Powered ships does the Navy currently own and operate?