Control System-I(EIC-501)

Mr. Rudra Kumar Mishra

EN Department

What is a Control System?

• A Control System is interconnection of components for forming a system configuration that will provide a desired response.

Control System another view

• A Control System is an arrangement of physical components connected/related in such a manner as to command, direct or regulate itself or another system.

Examples

• Central Temperature Control

• Fluid Level maintenance systems

• Battery Voltage Control

• Human has numerous control systems built in

Industry

………Everywhere

Advantages of Control system• Power amplification (gain)

ex: Positioning a large radar antenna by low pow rotation of a knob.

ex: Opening and closing valves

• Remote control

ex: Robot arm used to pick up radioactive material.

ex: Unmanned Aerial Vehicles.

ex: Remote Terminal Unit in oil production

• Convenience of input form

ex: Changing room temperature by thermostat position.

ex: Quality Control using limit switch

• Compensation for disturbances

ex: Controlling antenna position in the presence of

large wind disturbance torque.

ex: Control Inventory under variable demand

Syllabus• UNIT-1

Basic Components of a control system….

• UNIT-2

State-Variable Analysis

• UNIT-3

Time domain Analysis of Control Systems

• UNIT-4

Stability of Linear Control Systems

• UNIT-5

• Frequency Domain Analysis:

Unit-1• Basic Components of a control system

• Feedback and its effect

• Types of feedback control systems.

• Block diagrams and signal flow graphs

• Modeling of Physical systems: Electrical networks Mechanical systems elements

• Equations of mechanical systems,

• Sensors and encoders in control systems

• DC motors in control systems

Basic Components of a control system

The basic ingredients of a control system can be described as:

1.Objective of control

2.Control –system component

3.Result or output

Relation among these shown in fig.1.1.

Classification of control system The control system can be classified as:(1). Open loop system(2). Close loop system

Feedback and its effect

Feedback• The feedback is used to reduce error between the

reference input and output of the system.

• The Feedback output may be in phase or out-of –phase with respect to input.

When the feedback output is in phase with the input it is termed positive.

When the feedback output is out-of-phase with the input it is termed negative.

• All control system are usually negative feedback system as shown in following figure 2.

Fig.2 Feedback system

Effect of feedback

The effect of feedback are as followings:

1.Effect of feedback on over all gain

2.Effect of feedback on stability

3.Effect of feedback on sensitivity

4.Effect off feedback on external Disturbance or noise

5.Effect of feedback on Bandwidth, Impedance, Transient Response and Frequency Response

Types of feedback control systems• The feedback control is operation in which the

output is sampled and a proportional signal is feedback to the input.

• Feedback control system may be classified in a number of ways, depending upon the purpose of classification. For instant according to the method of analysis, control system are classified as:

1. Linear and Nonlinear Control System

2. Time varying and time invariant

3. Continuous Data control system

4. Discrete-Data control system.

Block diagrams and signal flow graphs

Modeling of Physical systems

Equations of mechanical systems

Sensors and encoders in control systems

DC motors in control systems