Introduction to control engineering.pptx

Control Engineering

1. Prof. Sankalp Bhatia Assistant Professor Mechanical Engineering Department A. D. PATEL INSTITUTE OF TECHNOLOGY New Vallabh Vidyanagar INTRODUCTION TO CONTROL ENGINEERING

2. What is Input? The stimulus or excitation applied to a control system from an external source in order to produce the output is called input. I np u t

3. What is Output? Output I np u t Th e a c tual r e s p o ns e o b t a i ne d f r o m a s y s t em is called output.

4. What is System? SYSTEM I np u t Ou t put A system is an arrangement of or a combination of different physical components connected or related in such a manner so as to form an entire unit to attain a certain objective.

5. To regulate, direct or command a system so that the desired objective is attained. What is Control? System + Control = Control System

6. Control System C ONT R OL SYSTEM Inp u t Output It is an arrangement of different physical elements connected in such a manner so as to regulate, direct or command itself to achieve a certain objective.

7. Difference between System & Control System System Inp u t Co n t r ol System Inp u t D e si r ed Output Proper Output (May or may not be desired)

8. Difference between System & Control System Fan ( S y s t em) 23 V / 50Hz AC Supply Air Flow Input Outp u t

9. A Fan: Can’t say a System Output Input A Fan without blades cannot be a “SYSTEM” Because it cannot provide a desired / proper output. i.e. airflow

10. A Fan with blades but without regulator can be a “SYSTEM” Because it can provide a proper output. i.e. Airflow B ut it ca n not b e a “Cont r ol S ystem ” B ecaus e it c annot provide desired output i.e. Controlled Airflow A Fan: Can be a System Input Output

11. A Fan with blades and with regulator can be a “CONTROL SYSTEM” Because it can provide a Desired Output. i.e. Controlled Airflow A Fan: Can be a Control System

12. Classification of Control System (Depending on control action)

13. “A system in which the control action is totally independent of the output of the system is called as open loop system ” Definition: Open Loop System Block Diagram of Open loop Control System

14. Electric hand drier – Hot air (output) comes out as long as you keep your hand under the machine, irrespective of how much your hand is dried. Example of Open L oop System

15. Automatic washing machine : This machine runs according to the pre-set time irrespective of washing is completed or not. Example of Open L oop System

16. Bread Toaster : This machine runs as per adjusted time irrespective of toasting is complete or not. Example of Open L oop System

17. Automatic tea/coffee Vending Machine : These machines also function for pre adjusted time only. Example of Open L oop System

18. Light Switch : L amps glow whenever light switch is on irrespective of light is required or not. Volume on Stereo System : Volume is adjusted manually irrespective of output volume level. Example of Open L oop System

19. Simple in construction and design Economical Easy to maintain Generally stable Convenient to use as output is difficult to measure Advantages of Open Loop System

20. Inaccurate Unreliable Any change in output can’t be corrected automatically Disadvantages of Open Loop System

21. “ A s y s t em i n w h i c h t h e c o n t r o l a c tion i s s o meh o w dependent on the output is called as closed loop system ” . Definition of Close Loop System

22. Block Diagram of Close Loop System

23. Au t om a tic Elect r ic I r o n : He a ti n g ele m e n ts a r e controlled by output temperature of the iron. Example of Close Loop System

24. Servo Voltage Stabilizer: Voltage controller operates depending upon output voltage of the system. Example of Close Loop System

25. Perspiration Example of Close Loop System

26. Closed loop control systems are more accurate even in the presence of non-linearity Highl y accu r a t e as a n y e r r o r a r is i n g i s c or r ec t ed d u e to presence of feedback signal Bandwidth range is large Facilitates automation The sensitivity of system may be made small to make system more stable This system is less affected by noise Advantages of Close Loop System

27. They are costlier They are complicated to design Required more maintenance Feedback leads to oscillatory response Overall gain is reduced due to presence of feedback Stability is the major problem and more care is needed to design a stable closed loop system Disadvantages of Close Loop System

28. Difference between Open Loop & Close Loop System

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