current_control.c 6.71 KB
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/*********************************************

 Current regulation - Aleks Ponjavic 18/09/07
           for LTH - reglerteknik

   Note that the voltage is actually a duty
   cycle for the PWM. The PWM is running at
  12V with a duty cycle set by a 10bit value

*********************************************/

//#include <math.h>		//Only include if sin will be used, takes up memory!
#include <avr/io.h>
#include <avr/signal.h>
#include <avr/interrupt.h>
#include <inttypes.h>

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// reference generation variables
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volatile int16_t ref = 100;
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volatile int16_t refCount = 0;
volatile int8_t refFlag = 0;
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// control variables
volatile unsigned char lbyte,hbyte;  
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volatile int16_t y;
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volatile uint8_t alt = 1;
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volatile uint8_t low, high;

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//test variables
volatile int16_t e = 0;
volatile int16_t v = 0;
volatile int32_t I = 0;
volatile int16_t u = 0;
volatile int16_t K = 20;//5;//375; // 7 frac bits
volatile int16_t Ke = 8;//2;//6; //7 frac bits, K*h/Ti
volatile int16_t Ksat = 51;//1; // 7 frac bits, h/Tr


// logging variables
#define log_len 100
volatile int16_t ctrl_log[log_len];
volatile int16_t error_log[log_len];
volatile int32_t I_log[log_len];
volatile int16_t skipSamples = 200;
volatile int16_t countSamples = 0;
volatile int16_t jj=0;
volatile int8_t stop = 0;
volatile int16_t temp;
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/* Routine used to set the red LED */
void setLED(uint8_t on)
{
  if (on) PORTB &= 0x7f;	//Turn on
  else PORTB |= 0x80;	//Turn off
}

/* Routine used to set pin PD7 */
void setPA4(uint8_t on)
{
  if (on == 0) PORTA &= 0xef;	//Turn off
  else PORTA |= 0x10;	//Turn on
}

/* Routine used to transmit bytes on the serial port */
static void putchar(unsigned char ch)
{
	while ((inp(UCSRA) & 0x20) == 0) {};
	outp(ch, UDR);
	while ((inp(UCSRA) & 0x20) == 0) {};
}

/* Interrupt service routine for handling incoming bytes on the serial port 
 might be needed to catch incoming bytes */
SIGNAL(SIG_UART_RECV){}
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static inline int16_t readInput() {
  uint8_t low, high;
  ADCSRA |= 0x40;
  while (ADCSRA & 0x40);
  low = ADCL;
  high = ADCH;
  return ((high<<8) | low) - 512;
}
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/* Write 8-bit output using the PWM-generator */
static inline void writeOutput(int16_t val) {
  if (val < 0) {
    PORTC = 0x80+(PORTC & 0x7F);
    OCR1BH = 0;    //(unsigned char) (-val)&0xff00;
    OCR1BL = (unsigned char) (-val)&0x00ff;
  } else {
    PORTC = (PORTC & 0x7F);
    OCR1BH = 0;    //(unsigned char) (val&0xff00);
    OCR1BL = (unsigned char) (val&0x00ff);
  }
}


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/* Send logged data over Serial connection */
static inline void sendData() {
  int16_t ii = 0;
  while (ii < log_len) {

    putchar((unsigned char) ((ctrl_log[ii]&0xff00)>>8));
    putchar((unsigned char) (ctrl_log[ii]&0x00ff));

    putchar((unsigned char) ((error_log[ii]&0xff00)>>8));
    putchar((unsigned char) (error_log[ii]&0x00ff));

    putchar((unsigned char) ((I_log[ii]&0xff000000)>>24));
    putchar((unsigned char) ((I_log[ii]&0x00ff0000)>>16));

    putchar((unsigned char) ((I_log[ii]&0x0000ff00)>>8));
    putchar((unsigned char) (I_log[ii]&0x000000ff));


    ii++;
  }
}

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/* Interrupt when AD-conversion completes */
SIGNAL(SIG_ADC)
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{
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  setPA4(1);
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  // Read input
  low = inp(ADCL);
  high = inp(ADCH);
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  y =  ((high<<8) | low) - 512; //y 9 frac bits

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  // Scale incoming current measurement
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  //y = y*3; //!!!!!!!!!!!!!!!!!!!!!!!
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  // Scale incoming current measurement
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  y += 70;
 
  //control, since negative measurements
  e = ref+y; //e 9 frac bits

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  v = (int16_t)(((K*e+(1<<6)) >> 7)+(int16_t)((I+(1<<6))>>7));

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  //saturation/rounding to 8 bit
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  if (v > 511)
     u = 511;
  else if (v < -512)
    u = -512;
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  else
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    u = v;
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  I = I +((int32_t)Ke)*((int32_t)e) + ((int32_t)Ksat)*((int32_t)(u-v)); //16 frac bits 

  // write output, inverting mode means set pwm to 127-ctrl_out
  
  u = (u)>>2; //7 frac bits to pwm 
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  if (u < 0) {
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    PORTC = 0x80+(PORTC & 0x7F);
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    OCR1BL = (unsigned char) (128-(-u));
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  } else {
    PORTC = (PORTC & 0x7F);
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    OCR1BL = (unsigned char) (127-u);
  }

  // For logging
  countSamples++;
  if (countSamples == skipSamples) {
    ctrl_log[jj] = y;
    I_log[jj] = I;
    error_log[jj] = e;
    jj++;
    countSamples = 0;
  }
  
  if ((jj == (log_len-1)) & !stop) {
    outp(0x7f,OCR1BL);
    stop = 1;
    sendData();
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  }
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  setPA4(0);
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}


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/* reference square- or triangle wave generator with timer 0 */
SIGNAL(SIG_OVERFLOW0) {
  int8_t rectangle = 1;
  refCount++;
  if (rectangle == 1) {
    if (refFlag == 0) {
      if (refCount == 10) {
	refFlag = 1;
	ref = -ref;
	refCount = 0;
      }
    } else {
      if (refCount == 20) {
	ref = -ref;
	refCount = 0;
      }
    }
  } else {
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    if (refCount <= 20) {  // ref*2
      ref -= 2;
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    } else {
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      ref += 2;
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    }
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    if (refCount == 40) { // ref*4
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      refCount = 0;
    }
  }
}


int main()
{
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  cli();
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  int i,j;
  
  //Port directions
  outp(0x80,PORTB); // LED off
  outp(0x80,DDRB);  // output on LED
  outp(0x08,PORTC); // pull up on overtemp signals
  outp(0xa0,DDRC);  // output on dir and brake
  outp(0x80,PORTD); // pull up on reset switch
  outp(0x10,DDRD);  // output on pwm for motor 1
  
  outp(0x10,DDRA);  // test pin output

  /* Timer section */
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  // Enable timer0 overflow interrupts
  outp(BV(TOIE0),TIMSK);
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  // Timer 1, fast PWM no prescaling (inverting mode (start low, switch to high))
  outp(BV(COM1A1)|BV(COM1B1)|BV(COM1A0)|BV(COM1B0)|BV(WGM11)|BV(WGM10),TCCR1A);
  outp(BV(CS10)|BV(WGM13)|BV(WGM12),TCCR1B);
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  // Reset Timer1 and set TOP-value to 128 (means 7-bit pwm-signal-> h_pwm=8.61 micros)
  outp(0x00,OCR1AH);
  outp(0x7f,OCR1AL);
  outp(0x00,TCNT1H);
  outp(0x00,TCNT1L);
  outp(0x00,OCR1BH);
  outp(0x7f,OCR1BL); // to not start motor-rotation before control
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  /* Timer 2 (control loop), prescaler 256, clear on compare match (28), -> h = 0.5 ms */
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  //  outp(BV(WGM21)|BV(CS22)|BV(CS21),TCCR2);
  //outp(28,OCR2);
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  /* Reset timer 2 */
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  //outp(0,TCNT2);
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  /* Timer 0 for reference generation, prescaler = 1024 periodic h = ? */
  outp(BV(CS02)|BV(CS00),TCCR0);
  
  //Serial communication
  outp(0x00, UCSRA);	// USART:
  outp(0x98, UCSRB);	// USART: RxIntEnable|RxEnable|TxEnable
  outp(0x86, UCSRC);	// USART: 8bit, no parity
  outp(0x00, UBRRH);	// USART: 115200 @ 14.7456MHz
  outp(7,UBRRL);	// USART: 115200 @ 14.7456MHz
  

  /* AREF (AREF is 5V) pin external capacitor, MUX0 for current, MUX3?? for pendulum angle */
  outp(BV(REFS0)|BV(MUX0),ADMUX); 	
  
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  // Enable ADC interrupts, start first conversion (what do adps0-2 do), prescaler 32
  outp(BV(ADEN)|BV(ADATE)|BV(ADSC)|BV(ADIE)|BV(ADPS2)|BV(ADPS0),ADCSRA);
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  // outp(BV(ADEN)|BV(ADSC),ADCSRA);
  
  /* Wait a little bit, probably not needed...*/
  int tmp;
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  //  for(i=0;i<2000;i++) 
  //   for(j=0;j<400;j++)
  //   tmp = j*j*j;
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  //Enable interrupts
  sei();

  // loop
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  while (1) {
    if (stop) {
      cli();
      OCR1BL = 0x7f;
    }
  }
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}