automatic control systemsprofsite.um.ac.ir/~karimpor/autocontrol/lec6_aut_con.pdfautomatic control...

AUTOMATIC CONTROLAUTOMATIC CONTROLSYSTEMSSYSTEMS

Ali KarimpourAssociate Professor

Ferdowsi University of Mashhad

Reference: Microcontroller Based Applied Digital ControlDogan Ibrahim, John Wiley & Sons Ltd, 2006

Lecture 6

Ali Karimpour Apr 2013

2

Lecture 6

Topics to be covered include:

Design of a sample controller in time domain.

Liquid Level Digital Control System:A Case Study

Lecture 6


A typical liquid level control system

3

Lecture 6


A typical liquid level control system (Schematic of the system)

4

Lecture 6


System Model

5

Lecture 6


66

Series Compensation Structureجبران سازي سري

Ziegler-Nichols Design for PID Controller

This procedure is only valid for open loop stable plants. Open-Loop Tuning

Closed-Loop Tuning

According to Ziegler and Nichols, the open-loop transfer function of a system can be approximated with time delay and single-order system, i.e.

Lecture 6


7

Ziegler-Nichols Open-Loop Case

For open-loop tuning, we first find the plant parameters by applying a step input to the open-loop system.

The plant parameters K, TD and T1 are then found from the result of the step test as shown in Figure.

طراحی زیگلر نیکولز حالت حلقه باز

Lecture 6


Identification of System Model

8

200

5*200/256=3.906 v

2.5*3.906=9.76 v

Lecture 6


Microcontroller program to send a step to D/A

9

For program the Microcontroller we just need to:

1- Define PORTB as 200.

2- Enable DAC

3- Disable DAC

That’s all

Lecture 6


Identification of System Model

10G(s) is transfer function of tank+amplifier

Lecture 6


Controller Design and Implementation

11

Controller Implementation

sKK

sesusD ip )()()( )()()( seKsseKssu ip )(

)()( teKdttdeK

dttdu

ip

)()()()()( teKT

TteteKT

Ttutuip

)()()()()( TteKteTKKTtutu pip

)()()()()( 11 tezKteTKKtuztu pip 11)(

)()(

zTKK

zezuzD ip

Lecture 6


1212

Series Compensation Structureجبران سازي سري

Continues block diagram

Digital block diagram +z.o.h.

Lecture 6


Sampling period

13

First of all we need sampling period

Digital block diagram +z.o.h.

Time constant is 31 so we must consider T

Lecture 6


System

14

Lecture 6


15

Complete system

Lecture 6


16

Lecture 6


Microcontroller program to implement the controller

17

Chip selection Code WizardAVRProject information Code WizardAVRPort configuration Code WizardAVRExternal interrupts Code WizardAVRLCD configuration Code WizardAVRADC configuration Code WizardAVRTimers configuration Code WizardAVRMain program By yourselfController output calculation By yourself

Lecture 6


Chip selection

18

Chip selection Code WizardAVR Tools Code WizardAVR

Lecture 6


Project information

19

/*****************************************************This program was produced by theCodeWizardAVR V2.05.0 EvaluationAutomatic Program Generator© Copyright 1998-2010 Pavel Haiduc, HP InfoTech s.r.l.http://www.hpinfotech.com

Project : Level ControlVersion : 1Date : 2012/12/27Author : KarimpourCompany : Ferdowsi University of MashhadComments: This is a simple example for class.

Chip type : ATmega16Program type : ApplicationAVR Core Clock frequency: 4.000000 MHzMemory model : SmallExternal RAM size : 0Data Stack size : 256*****************************************************/#include

Lecture 6


Port configuration

20

Lecture 6


21

void main(void)}// Input/Output Ports initialization// Port A initialization// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T PORTA=0x00;DDRA=0x00;

// Port B initialization// Func7=Out Func6=Out Func5=Out Func4=Out Func3=Out Func2=Out Func1=Out Func0=Out // State7=0 State6=0 State5=0 State4=0 State3=0 State2=0 State1=0 State0=0 PORTB=0x00;DDRB=0xFF;

// Port C initialization// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=Out // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=0 PORTC=0x00;DDRC=0x01;

// Port D initialization// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T PORTD=0x00;DDRD=0x00;}

Port configuration

Lecture 6


External interrupt configuration

22

// External Interrupt 0 service routineinterrupt [EXT_INT0] void ext_int0_isr(void){// Place your code here}

// External Interrupt 1 service routineinterrupt [EXT_INT1] void ext_int1_isr(void){// Place your code here}

void main(void){……..// External Interrupt(s) initialization// INT0: On// INT0 Mode: Low level// INT1: On// INT1 Mode: Low level// INT2: OffGICR|=0xC0;MCUCR=0x00;MCUCSR=0x00;GIFR=0xC0;

// Global enable interrupts#asm("sei“)}

Lecture 6


LCD configuration

23

// Alphanumeric LCD Module functions#include

void main(void){……..// Alphanumeric LCD initialization// Connections specified in the// Project|Configure|C Compiler|Libraries|Alphanumeric LCD menu:// RS - PORTC Bit 1// RD - PORTC Bit 2// EN - PORTC Bit 3// D4 - PORTC Bit 4// D5 - PORTC Bit 5// D6 - PORTC Bit 6// D7 - PORTC Bit 7// Characters/line: 16lcd_init(16);

while (1){// Place your code here}

}

Lecture 6


ADC configuration

24

#include

#define ADC_VREF_TYPE 0x40

// Read the AD conversion resultunsigned char read_adc(unsigned char adc_input){ADMUX=adc_input | (ADC_VREF_TYPE & 0xff);// Delay needed for the stabilization of the ADC input voltagedelay_us(10);// Start the AD conversionADCSRA|=0x40;// Wait for the AD conversion to completewhile ((ADCSRA & 0x10)==0);ADCSRA|=0x10;return ADCH;}

void main(void){........// ADC initialization// ADC Clock frequency: 125.000 kHz// ADC Voltage Reference: AVCC pin// ADC Auto Trigger Source: Free RunningADMUX=ADC_VREF_TYPE & 0xff;ADCSRA=0xA5;SFIOR&=0x1F;while (1)

{// Place your code here}

}

Lecture 6


Timers configuration

25

// Timer 0 overflow interrupt service routineinterrupt [TIM0_OVF] void timer0_ovf_isr(void){// Place your code here}

void main(void){// Timer/Counter 0 initialization// Clock source: System Clock// Clock value: 15.625 kHz// Mode: Normal top=0xFF// OC0 output: DisconnectedTCCR0=0x04;TCNT0=0x00;OCR0=0x00;

// Timer(s)/Counter(s) Interrupt(s) initializationTIMSK=0x01;

// Global enable interrupts#asm("sei")}

Lecture 6


Total Program from CodeWizardAVR

26

#include

#include

#include

interrupt [EXT_INT0] void ext_int0_isr(void){// Place your code here}

interrupt [EXT_INT1] void ext_int1_isr(void){// Place your code here}


#define ADC_VREF_TYPE 0x40

unsigned int read_adc(unsigned char adc_input){ADMUX=adc_input | (ADC_VREF_TYPE & 0xff);delay_us(10);ADCSRA|=0x40;while ((ADCSRA & 0x10)==0);ADCSRA|=0x10;return ADCW;}

Lecture 6


Total Program from CodeWizardAVR

27

void main(void){// Declare your local variables herePORTA=0x00;DDRA=0x00;

PORTB=0x00;DDRB=0xFF;

PORTC=0x00;DDRC=0x01;

PORTD=0x00;DDRD=0x00;

TCCR0=0x04;TCNT0=0x00;OCR0=0x00;

TCCR1A=0x00;TCCR1B=0x00;TCNT1H=0x00;TCNT1L=0x00;ICR1H=0x00;ICR1L=0x00;OCR1AH=0x00;OCR1AL=0x00;OCR1BH=0x00;OCR1BL=0x00;

ASSR=0x00;TCCR2=0x00;

TCNT2=0x00;OCR2=0x00;

GICR|=0xC0;MCUCR=0x00;MCUCSR=0x00;GIFR=0xC0;

TIMSK=0x01;

UCSRB=0x00;

ACSR=0x80;SFIOR=0x00;

ADMUX=ADC_VREF_TYPE & 0xff;ADCSRA=0xA5;SFIOR&=0x1F;

SPCR=0x00;

TWCR=0x00;

lcd_init(16);

// Global enable interrupts#asm("sei")

while (1){// Place your code here}}

Lecture 6


Setting Timer

28

Ts=0.1

Timer counts 256 cycle.

Clock of timer is 15625 Hz.

Every 156 counts = 0.01 Sec.

So 10 times of counter = 0.1 Sec.

So 256-100=156.

Start of timer is 100 or 0x64 (in hex)


void main(void){// Timer/Counter 0 initialization// Clock source: System Clock// Clock value: 15.625 kHz// Mode: Normal top=0xFF// OC0 output: DisconnectedTCCR0=0x04;

TCNT0=0x00;

OCR0=0x00;


// Global enable interrupts#asm("sei")}

TCNT0=0x64;

// Reinitialize Timer 0 valueTCNT0=0x64;time_set++;if (time_set ==10){time_set = 0;// Controller update must be here}

// Reinitialize Timer 0 valueTCNT0=0x64;time_set++;if (time_set ==10){time_set = 0;yk = read_adc(0);yk = yk *5000 / 1024; // convert ADC

ek=(ref-yk);uk = pk_1+(kp+ki*ti)* ek;uk = uk * 256/5000 ;

if (uk >255)uk_im = 255;else uk_im = (unsigned char )uk ;

PORTB = uk_im ;PORTC.0 = 1 ; // write to D/A converterPORTC.0 = 0 ;pk_1 = uk-kp*ek ;}

)()()()()( teTKKTteKTtutu ipp

Lecture 6


External interrupt program

29

// External Interrupt 0 service routineinterrupt [EXT_INT0] void ext_int0_isr(void){// Place your code here

}

// External Interrupt 1 service routineinterrupt [EXT_INT1] void ext_int1_isr(void){// Place your code here

}

ref++;itoa(ref,ch);lcd_clear();lcd_puts(ch);}

ref--;itoa(ref,ch);lcd_clear();lcd_puts(ch);}

Lecture 6


Parameter Definition and Initial Values

30

#include unsigned int time_set = 0;int ref= 2280;float kp , ki , pk_1 ,ek ,yk , uk, T;unsigned char uk_im ; char ch[20];

….kp =279.0;T= 0.1 ;ki=42.3;pk_1 = 0;PORTC.0 = 0 ; // disable write D/Aitoa(ref,ch);lcd_puts(ch);while (1)

{// Place your code here}

Lecture 6


Total Program of System

31

/*****************************************************This program was produced by theCodeWizardAVR V2.05.0 EvaluationAutomatic Program Generator© Copyright 1998-2010 Pavel Haiduc, HP InfoTech s.r.l.http://www.hpinfotech.com

Project : Level ControlVersion : 1Date : 2012/12/30Author : Freeware, for evaluation and non-commercial use onlyCompany : Ferdowsi University of MashhadComments: This is a simple example for lecture#16.

Chip type : ATmega16Program type : ApplicationAVR Core Clock frequency: 4.000000 MHzMemory model : SmallExternal RAM size : 0Data Stack size : 256*****************************************************/

Lecture 6



32

#include #include #include #include

unsigned int time_set = 0;int ref= 2280;float kp , ki , pk_1 ,ek ,yk , uk, T;unsigned char uk_im ; char ch[20];// Alphanumeric LCD Module functions

#define ADC_VREF_TYPE 0x40// Read the AD conversion resultunsigned int read_adc(unsigned char adc_input){ADMUX=adc_input | (ADC_VREF_TYPE & 0xff);// Delay needed for the stabilization of the ADC input voltagedelay_us(10);// Start the AD conversionADCSRA|=0x40;// Wait for the AD conversion to completewhile ((ADCSRA & 0x10)==0);ADCSRA|=0x10;return ADCW;}

Lecture 6



33

// External Interrupt 0 service routineinterrupt [EXT_INT0] void ext_int0_isr(void){// Place your code hereref--;itoa(ref,ch);lcd_clear();lcd_puts(ch);}

// External Interrupt 1 service routineinterrupt [EXT_INT1] void ext_int1_isr(void){// Place your code hereref++;itoa(ref,ch);lcd_clear();lcd_puts(ch);}

// Timer 0 overflow interrupt service routineinterrupt [TIM0_OVF] void timer0_ovf_isr(void){// Reinitialize Timer 0 valueTCNT0=0x64;time_set++;if (time_set ==10){time_set = 0;yk = read_adc(0);yk = yk *5000 / 1024; // convert ADC

ek=(ref-yk);uk = pk_1+(kp+ki*T)* ek;uk = uk * 256/5000 ;

if (uk >255)uk_im = 255;else uk_im = (unsigned char )uk ;

PORTB = uk_im ;PORTC.0 = 1 ; // write to D/A converterPORTC.0 = 0 ;pk_1 = uk-kp*ek ;}}

Lecture 6


34

void main(void){// Input/Output Ports initialization// Port A initialization// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T PORTA=0x00;DDRA=0x00;

// Port B initialization// Func7=Out Func6=Out Func5=Out Func4=Out Func3=Out Func2=Out Func1=Out Func0=Out // State7=0 State6=0 State5=0 State4=0 State3=0 State2=0 State1=0 State0=0 PORTB=0x00;DDRB=0xFF;

// Port C initialization// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=Out // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=0 PORTC=0x00;DDRC=0x01;

// Port D initialization// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T PORTD=0x00;DDRD=0x00;


Lecture 6



35

// Timer/Counter 0 initialization// Clock source: System Clock// Clock value: 15.625 kHz// Mode: Normal top=0xFF// OC0 output: DisconnectedTCCR0=0x04;TCNT0=0x00;OCR0=0x00;

// External Interrupt(s) initialization// INT0: On// INT0 Mode: Low level// INT1: On// INT1 Mode: Low level// INT2: OffGICR|=0xC0;MCUCR=0x00;MCUCSR=0x00;GIFR=0xC0;


// ADC initialization// ADC Clock frequency: 125.000 kHz// ADC Voltage Reference: AVCC pin// ADC Auto Trigger Source: Free RunningADMUX=ADC_VREF_TYPE & 0xff;ADCSRA=0xA5;SFIOR&=0x1F;

// Alphanumeric LCD initialization// Connections specified in the// Project|Configure|C Compiler|Libraries|Alphanumeric LCD menu:// RS - PORTC Bit 1// RD - PORTC Bit 2// EN - PORTC Bit 3// D4 - PORTC Bit 4// D5 - PORTC Bit 5// D6 - PORTC Bit 6// D7 - PORTC Bit 7// Characters/line: 16lcd_init(16);

Lecture 6



36

// Global enable interrupts#asm("sei")kp =279.0;T= 0.1 ;ki=42.3;pk_1 = 0;PORTC.0 = 0 ; // disable write D/Aitoa(ref,ch);lcd_puts(ch);while (1)

{// Place your code here

}}

automatic control systemsprofsite.um.ac.ir/~karimpor/autocontrol/lec6_aut_con.pdfautomatic control...

Documents