1. Control Systems Engineering
Introduction
IESL-Part III
2013

2. What is a Control System? What is the subject about?
Why need Control?
What is the subject about?

3. History of Control Engineering
* Greece (BC) – Float regulator mechanism
* Holland (16th Century)– Temperature regulator
* Watt’s Flyball Governor (18th century)

4. History of Control Engineering
Water-level float regulator

5. Applications of Control System Engineering

6. Example of Control Systems

7. 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

8. Environment System Disturbance Inputs System Outputs Control Inputs
Subsystem
Environment
Control Inputs

9. 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.

10. 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, . . .

11. Antenna Positioning Control System
Original system: the antenna with electric motor drive systems.
Control objective: to point the antenna in a desired reference direction.
Control inputs: drive motor voltages.
Outputs: the elevation and azimuth of the antenna.
Disturbances: wind, rain, snow.

12. Studying Part III Control Engineering
Objective function:
Outputs:
Control inputs:
Disturbances:
Subsystems:

13. Traffic Control Lights
Objective function:
Outputs:
Control inputs:
Disturbances:
Subsystems:

14. Control System Design Objectives
Primary Objectives:
1. Dynamic stability
2. Accuracy
3. Speed of response
Addition Considerations:
4. Robustness (insensitivity to parameter variation)
5. Cost of control
6. System reliability

15. Response of a position control system showing effect of high and low controller gain on the output response

16. Response of a position control system

17. Master-Slave of Humanoid Robot
Laser cutting robot
Brain control hand
Video Segments
Inverted Pendulum
Balancing Robot

18. Types of Control system Configurations
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.
Multivariable Control System

19. Open loop Control
Close loop control

20. Close loop control system

21. 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)

22. 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.

23. Examples of Control Systems Ship 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.

24. Examples of Control Systems Room Temperature Control System
Proportional mode: Better accuracy, complex
On/Off control mode: Thermostatic control, simple, low accuracy

25. Examples of Control Systems Aircraft 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.

26. 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.

27. 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.

28. What is a Control System? What is the subject about?
Did you get answers to following?......
What is a Control System?
Why need Control?
What is the subject about?