Open Loop & Closed Loop System.pptx

Open loop and close loop

1. O p en Lo o p & Closed Lo o p S y s t em ▶ N A M E - N I T Y A N A ND A G H O S H ▶ D E P A R T M E N T - A P P L I E D E L E C T R O N I C S & I N S T R U M E N T A T I O N E N G I N EER I N G ▶ U N I V ER S I T Y R OL L N O - 10505522026 ▶ S E M E S T E R - 5 TH ▶ C L A S S R OL L N O - 17

2. Con t r o l S y s t ems An integral part of any industrial society Ma n y a pp li c a t i o n s i n c l u d i n g t r a n spor t a t i o n , a u t o m a t i o n , m a n u fa c t u r i n g, h o me a pp li a n c es , … H e l p ed e x p l o r a t i o n o f t h e o c e a n s a n d sp a c e E x a mp l es : – ▶ T e m p er a t u re c o n t rol ▶ F l i g h t c o n t rol ▶ Pr o c ess c o n t rol

3. T y p e s o f C o n t r o l S y s t e m s P l an t r S e n s o rs control input u C on t r o l l er Act ua t o rs d i s t ur b a n c e d command ou t put y Open loop system P l an t S e n s o rs e rror e control input u C o n t r o l l e r A ct ua t o rs d i s t ur b a n c e d c o mm a nd + r _ ou t put y Closed loop system

4. C o n t r o l S y s t e m C o m p a r i s o n Openloop: 🠞 The output variables do not affectthe inputvariables 🠞 T h e s y s t e m w il l f o l o w t h e de s ire d re f eren c e c o mm and s i f n o unpredi c t abl e e f f e c t s occur 🠞 It can compensatefor disturbancesthat are takeninto account 🠞 It does not change the system stability Closedloop: 🠞 The output variables do affectthe input variables in order to maintain a desired system behavior 🠞 Requiresmeasurement(contro l ed variables or other variables) 🠞 Requirescontrol errorscomputedas the di f erence between the contro l ed variable an d t h e re f eren c e c o mm an d 🠞 Computescontrolinputs based on the control errorssuch that the controlerror is minimized 🠞 Ab l e t o re j e c t t h e e f f e c t o f di s t urban c e s 🠞 Can make the system unstable, where the contro l edvariables grow without bound

5. Overview of Closed Loop Control Systems D i st u r ban ces Computer / Microcontroller Plant Inputs O utput s Sensors A ct u at o r s ADC D A C C o nt ro l A l gor ithm S c o p e Model P o w e r A mp Function Generator Ref e r e n ce I nput s (Setpoints)

6. Ex a mpl e - O p en Lo o p System ▶ The clothes dryer is one of the examples of the open-loop control system. In this, the control action can be done physically through the operator. Based on the clothing’s wetness, the operator will fix the timer to 30 minutes. So after that, the timer will discontinue even after the machine clothes are wet. The dryer in the machine will stop functioning even if the preferred output is not attained. This displays that the control system doesn’t feedback. In this system, the controller of the system is the timer.

7. Ex a mpl e - O p en Lo o p System ▶ The best example of the closed-loop control system is AC or air conditioner. The AC controls the temperature by evaluating it with the nearby temperature. The evaluation of temperature can be done through the thermostat. Once the air conditioner gives the error signal is the main difference between the room and the surrounding temperature. So the thermostat will control the compressor. These systems are accurate, expensive, reliable, and requires high maintenance.