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Control Systems Engineering Introduction IESL-Part III 2013. What is a Control System? Why need Control? What is the subject about?. History of Control Engineering . * Greece (BC) – Float regulator mechanism * Holland (16 th Century)– Temperature regulator. - PowerPoint PPT Presentation
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Control Systems Engineering
Introduction
IESL-Part III
2013
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What is a Control System?Why need Control?
What is the subject about?
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History of Control Engineering * Greece (BC) – Float regulator mechanism* Holland (16th Century)– Temperature regulator
* Watt’s Flyball Governor (18th century)
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Water-level float regulator
History of Control Engineering
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Applications of Control
System Engineering
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Example of Control Systems
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Control System Concepts• A system is a collection of components which
are co-ordinated together to perform a function.
• Systems interact with their environment across a separating boundary.
• The interaction is defined in terms of variables.– system inputs– system outputs– environmental disturbances
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System
Disturbance InputsSystem Outputs
Subsystem
Environment
Control Inputs
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System Variables• The system’s boundary depends upon the
defined objective function of the system.• The system’s function is expressed in terms of
measured output variables.• The system’s operation is manipulated
through the control input variables.• The system’s operation is also affected in an
uncontrolled manner through the disturbance input variables.
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Car and Driver Example• Objective function: to control the direction
and speed of the car.• Outputs: actual direction and speed of the car• Control inputs: road markings and speed signs• Disturbances: road surface and grade, wind,
obstacles.• Possible subsystems: the car alone, power
steering system, braking system, . . .
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Antenna Positioning Control System
• Original system: the antenna withelectric motor drive systems.
• Control objective: to point theantenna in a desired reference direction.
• Control inputs: drive motor voltages.• Outputs: the elevation and azimuth of the
antenna.• Disturbances: wind, rain, snow.
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Studying Part III Control Engineering • Objective function:
• Outputs:
• Control inputs:
• Disturbances:
• Subsystems:
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• Objective function:
• Outputs:
• Control inputs:
• Disturbances:
• Subsystems:
Traffic Control Lights
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Control System Design Objectives
• Primary Objectives:1. Dynamic stability2. Accuracy3. Speed of response
• Addition Considerations:4. Robustness (insensitivity to parameter variation)5. Cost of control6. System reliability
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Response of a position control system showing effect of high and low controller gain on the output response
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Response of a position control system
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Video Segments
Master-Slave of Humanoid Robot
Laser cutting robot
Brain control hand Inverted Pendulum
Balancing Robot
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Types of Control system Configurations
Multivariable Control System
Open-Loop Control Systems utilize a controller or control actuator to obtain the desired response.
Closed-Loop Control Systems utilizes feedback to compare the actual output to the desired output response.
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Open loop Control
Close loop control
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Close loop control system
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Control System Components• System or process (to be controlled)• Actuators (converts the control signal to a power
signal)• Sensors (provides measurement of the system
output)• Reference input (represents the desired output)• Error detection (forms the control error)• Controller (operates on the control error to form
the control signal, sometimes called compensators)
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Feedback
• Feedback is a key tool that can be used to modify the behavior of a system.
• This behavior altering effect of feedback is a key mechanism that control engineers exploit deliberately to achieve the objective of acting on a system to ensure that the desired performance specifications are achieved.
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Examples of Control SystemsShip Autopilot Control System
• Actual heading is measured by a gyro-compass (or magnetic compass), compared with desired value. Error are send to autopilot (Course-keeping system)
• Actual rudder angle is sensed, and autopilot controls the ship course by steering-gear.
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Examples of Control SystemsRoom Temperature Control System
• Proportional mode: Better accuracy, complex
• On/Off control mode: Thermostatic control, simple, low accuracy
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Examples of Control SystemsAircraft Elevator Control System
• Hydraulic servomechanisms have a good power/weight ratio, and are ideal for applications that require large forces to be produced by small and light devices.
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Summary
We have introduced:• Why do we need Control?• What is a Control System?• What are the main performance we care
for a control system?• Feedback is very important.
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Summary The central problem in control is
to find a technically feasible way to act on a given process so that the process behaves, as closely as possible, to some desired behavior. Furthermore, this approximate behavior should be achieved in the face of uncertainty of the process and in the presence of uncontrollable external disturbances acting on the process.
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What is a Control System?Why need Control?
What is the subject about?
Did you get answers to following?......
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