The document describes a fuzzy logic modification of a PID controller for DC motor speed control. It was implemented using a microcontroller. The fuzzy logic controller was designed to improve on PID controllers and reduce the effects of nonlinearity in DC motors. The design process included defining linguistic variables and membership functions for the inputs and outputs, then adjusting the functions and rules to improve performance. The hardware implementation used a microcontroller with analog and digital input/output ports to receive sensor feedback and control the motor. The fuzzy logic controller was able to achieve better speed control of the DC motor compared to a traditional PID controller.

1. FUZZY LOGIC MODIFICATION OF PID
CONTROLLER & IMPLEMENTATION
FOR DC MOTOR SPEED CONTROL
Presented by:
TRIDIB BOSE(13101102042)
ARPITA KUNDU(13101102057)
SUSANTA PAL(141012089)
4th Year, EE,
JALPAIGURI GOVERNMENT ENGINEERING COLLEGE
UNDER THE GUIDANCE OF:-
GAUTAM KUMAR PANDA
HEAD OF THE DEPARTMENT,
ELECTRICAL ENGINEERING,
JALPAIGURI GOVERNMENT ENGINEERING COLLEGE

2. ABSTRACT
THIS DESCRIBES AN ALTERNATIVE METHOD TO IMPLEMENT A FUZZY LOGIC
SPEED CONTROL FOR DC MOTOR
THE CONTROLLER CAN BE IMPLEMENTED BY USING ONLY A SMALL AMOUNT
OF COMPONENTS AND EASILY IMPROVED TO BE AN ADAPTIVE FUZZY
CONTROLLER

3. INTRODUCTION
(PROBLEM STATEMENT)
THE MAJOR PROBLEM IN APPLYING A CONVENTIONAL
ALGORITHM IN A SPEED CONTROLLERS ARE THE EFFECT OF NON LINEARITY IN
A DC MOTOR
MANY ADVANCED MODEL-BASED CONTROL METHODS SUCH AS VARIABLE-
STRUCTURE CONTROL AND MODEL REFERENCE CONTROL METHODS ARE BEEN
DEVELOPED TO REDUCE THESE EFFECT

4. INTELLIGENT TECHNIQUE HAS BEEN USED TO IMPROVE OR TO
CONTROL THIS NON LINEARITY IN DC MOTOR
A FUZZY LOGIC CONTROLLER TECHNIQUE IS USED
IT WAS USED BECAUSE IT IS PROVED ANALYTICALLY TO BE
EQUIVALENT NON LINEAR PI CONTROLLER
BY USING FUZZY LOGIC WE CAN REDUCE THE EFFECT OF NON
LINEARITY IN A DC MOTOR AND IMPROVE THE PERFORMANCE OF
CONTROLLER

5. INTRODUCTION
(FUZZY MODIFICATION OF PID)
PID CONTROLLERS CONSTITUTE AN IMPORTANT PART AT INDUSTRIAL CONTROL SYSTEMS SO
ANY IMPROVEMENT IN PID DESIGN AND IMPLEMENTATION METHODOLOGY HAS A SERIOUS
POTENTIAL TO BE USED AT INDUSTRIAL ENGINEERING APPLICATIONS.
THE PID CONTROLLERS WHICH WERE INVENTED IN THE 1900S ARE STILL USED IN MORE THAN
95% OF INDUSTRIAL CONTROL LOOPS .
THEY HAVE SURVIVED MANY CHANGES IN TECHNOLOGY FROM MECHANICS AND PNEUMATICS TO
MICROPROCESSORS VIA ELECTRONIC TUBES , TRANSISTORS AND INTEGRATED CIRCUITS.
PRESENT DAY PID CONTROLLERS ARE MADE BY USING
MICROPROCESSORS/MICROCONTROLLERS AND USING PROGRAMMABLE LOGIC CONTROL
TECHNOLOGY.
3

6. CHRONICLE:
Lotfi A. Zadeh, a professor of UC Berkeley in California, soon to be known as
the founder of fuzzy logic observed that conventional computer logic was
incapable of manipulating data representing subjective or vague human
ideas such as "an atractive person" .
Fuzzy logic, hence was designed to allow computers to determine the
distinctions among data with shades of gray, similar to the process of
human reasoning.
This theory proposed making the membership function (or the values
False and True) operate over the range of real numbers [0.0, 1.0]. Fuzzy
logic was now introduced to the world.

7. FUZZY LOGIC
FUZZY LOGIC IS AN APPROACH TO COMPUTING BASED ON ‘DEGREES OF TRUTH’ RATHER THAN THE USUAL ‘TRUE OR
FALSE’(1 OR 0) BOOLEAN LOGIC ON WHICH THE MODERN COMPUTER IS BASED.
BOOLEAN LOGIC IS A SUBSET OF FUZZY LOGIC.
THE FL IS BASED ON THE IMPLEMENTATION OF HUMAN UNDERSTANDING AND HUMAN THINKING IN
CONTROL ALGORITHMS.
FUZZY LOGIC HAS BEEN APPLIED TO MANY FIELDS, FROM CONTROL THEORY TO ARTIFICIAL INTELLIGENCE.
AS THE COMPLEXITY OF A SYSTEM INCREASES, IT BECOMES MORE DIFFICULT AND EVENTUALLY IMPOSSIBLE TO
MAKE A PRECISE STATEMENT ABOUT ITS BEHAVIOUR, EVENTUALLY ARRIVING AT A POINT OF COMPLEXITY WHERE
THE FUZZY LOGIC METHOD IS THE ONLY WAY TO GET AT THE PROBLEM.

8. THE NON-FUZZY APPROACH
SUPPOSE THAT THE TIP ALWAYS EQUALS 15% OF
THE TOTAL BILL.
TIP=0.15
THE FUZZY APPROACH
THIS TAKES INTO ACCOUNT THE QUALITY OF THE SERVICE.
BECAUSE SERVICE IS RATED ON A SCALE OF 0 TO 10, LET THE
TIP GO LINEARLY FROM 5% IF THE SERVICE IS BAD TO 25% IF
THE SERVICE IS EXCELLENT.
TIP=0.20/10*SERVICE+0.05
EXAMPLE
Given a number between 0 and 10 that represents the quality of service at a restaurant
(where 10 is excellent), what should the tip be?

9. PID CONTROLLER
 A PROPORTIONAL-INTEGRATING-DERIVATIVE CONTROLLER IS A GENERIC CONTROL LOOP FEEDBACK
MECHANISM WIDELY USED IN INDUSTRIAL CONTROL SYSTEMS.
 A PID CONTROLLER CALCULATES AN "ERROR" VALUE AS THE DIFFERENCE BETWEEN A MEASURED PROCESS
VARIABLE AND A DESIRED SET- POINT.
 THE CONTROLLER ATTEMPTS TO MINIMIZE THE ERROR BY ADJUSTING THE PROCESS CONTROL INPUTS.
 ALGORITHM
P- Depends on present error
I - Depends on accumulation of past errors
D - Is a prediction of future errors

10. DESIGNING OF PID CONTROLLER
AN OPEN-LOOP RESPONSE IS TAKEN AND THE PARAMETERS TO BE IMPROVED ARE LISTED .
VALUES OF KP, KI, AND KD ARE ADJUSTED UNTIL WE OBTAIN THE OPTIMUM RESPONSE .
Constants Rise time Overshoot Settling Time ess
Kp ↑ Decrease Increase Small change Decrease
Ki ↑ Decrease Increase Increase Eliminate
Kd ↑ Small Change Decrease Decrease Small Change

11. NECESSITY OF TUNING
TUNING IS THE PROCESS OF FINDING APPROPRIATE PARAMETERS FOR THE PID CONTROLLER .
TUNING DETERMINES THE OVERALL PERFORMANCE OF CONTROL LOOP WHICH AFFECTS QUALITY
OF PRODUCT , COST ETC .
A PID CONTROL SYSTEM NEEDS TUNING IF –
A) CAREFUL CONSIDERATION WAS NOT GIVEN TO THE UNITS OF GAINS AND OTHER PARAMETERS.
B) THE PROCESS DYNAMICS WERE NOT WELL-UNDERSTOOD WHEN THE GAINS WERE FIRST SET, OR
THE DYNAMICS HAVE (FOR ANY REASON) CHANGED.
C) SOME CHARACTERISTICS OF THE CONTROL SYSTEM ARE DIRECTION-DEPENDENT (E.G.
ACTUATOR PISTON AREA, HEAT-UP/COOL-DOWN OF POWERFUL HEATERS).

12. Block diagram for PID Tuning

13. SYSTEM DESCRIPTION
Here a simple DC motor is used for motor control design as shown in equation

14. DC MOTOR PARAMETERS

15. CONTROLLER DESIGN
The performance of the FLC is then improved by adjusting the rules and
membership function. The design procedures are described as follows
Procedure 1: Defining inputs , outputs ,and universe of discourse

16. Procedure 2: defining fuzzy membership function and rules
To perform fuzzy computation the input and output s must be converted from
crisp value to linguistic forms
IN THIS PAPER THE LINGUISTIC TERMS THAT USED TO REPRESENT THE INPUT AND
OUTPUT VALUES ARE DEFINEDN BY SEVEN FUZZY VARIABLES AS SHOWN IN THE TABLE
BELOW

17. INITIAL MEMBERSHIP FUNCTION

19. Procedure 3:Adjusting fuzzy membership functions and rules
In order to improve the performance of the FLC, the rules and membership
functions are adjusted
The membership functions are adjusted by making the area of membership
function near ZE region narrower to produce final control resolution
On the other hand making the area far from the ZE region gives the faster
response

20. CONTROLLER IMPLEMENTATION
HERE THE FUZZY MICROCONTROLLER MOTOROLA 68hc812A 4 used for the
implementation it used 16-bit microcontroller with full 16 bit data (A/D),4K EEPROM
,1K RAM , and multiple input/output ports

21. HARDWARE BLOCKDIAGRAM

22. Input condition circuit

24. Conclusion
This paper has demonstrated the implementation of a FLC
for a velocity control of DC motor by using a fuzzy logic
microcontroller .The FLC is easy to implement and requires a
small amount of inexpensive components in the compact size