xctd692
10 years ago
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5e7c66f454
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#include <digitalWriteFast.h>
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//this is to use DWF library, it will increase the speed of digitalRead/Write command
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//used in the interrupt function doEncoderMotor0, but may be used everywhere.
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/*
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https://github.com/danithebest91/ServoStrap
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i have made this code for the LMD18245 motor controller,
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i have merged the pid code of Josh Kopel
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whith the code of makerbot servo-controller board,
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you can use this code on the some board changing some values.
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Daniele Poddighe
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external ardware require a quadrature encoder, timing slit strip and a dc motor,
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all you can find inside an old printer, i have took it from canon and hp printers(psc1510)
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for motor controll you can choose different type of H-bridge, i have used LMD18245,
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you can order 3 of it on ti.com sample request, the hardware needed is explained on the datasheet but i'm drowing
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the schematic and PCB layout on eagle.
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read a rotary encoder with interrupts
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Encoder hooked up with common to GROUND,
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encoder0PinA to pin 2, encoder0PinB to pin 4 (or pin 3 see below)
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it doesn't matter which encoder pin you use for A or B
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is possible to change PID costants by sending on serial interfaces the values separated by ',' in this order: KP,KD,KI
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example: 5.2,3.1,0 so we have KP=5.2 KD=3.1 KI=0 is only for testing purposes, but i will leave this function with eeprom storage
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This code use Port manipulation :
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Port registers allow for lower-level and faster manipulation of the i/o pins of the microcontroller on an Arduino board. The chips used on the Arduino board
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(the ATmega8 and ATmega168) have three ports:
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B (digital pin 8 to 13)
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C (analog input pins)
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D (digital pins 0 to 7)
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https://www.arduino.cc/en/Reference/PortManipulation
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https://www.arduino.cc/en/Hacking/PinMapping
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https://www.arduino.cc/en/Hacking/PinMapping168
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*/
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#define encoder0PinA 2 // PD2 (INT0) You can't modify port mapping here because this code use Port manipulation (I2)
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#define encoder0PinB 8 // PB0; (I8)
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#define MotorIN1 5 //(I5) IN1
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#define MotorIN2 6 //(I6) IN2
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//from ramps 1.4 stepper driver
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#define STEP_PIN 3 //PD3 (INT1) (I3)
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#define DIR_PIN 14 //PC0; (A0)
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//#define ENABLE_PIN 13 //PB5; for now is USELESS (I13)
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//to use current motor as speed control, the LMD18245 has 4 bit cuttent output
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//#define M0 9 //assign 4 bit from PORTB register to current control -> Bxx0000x (x mean any)
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//#define M1 10 // PB1; PB2; PB3; PB4
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//#define M2 11
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//#define M3 12
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volatile long encoder0Pos = 0;
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long target = 0;
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long target1 = 0;
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int amp=212;
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//correction = Kp * error + Kd * (error - prevError) + kI * (sum of errors)
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//PID controller constants
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float KP = 6.0 ; //position multiplier (gain) 2.25
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float KI = 0.1; // Intergral multiplier (gain) .25
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float KD = 1.3; // derivative multiplier (gain) 1.0
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int lastError = 0;
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int sumError = 0;
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//Integral term min/max (random value and not yet tested/verified)
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int iMax = 100;
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int iMin = 0;
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long previousTarget = 0;
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long previousMillis = 0; // will store last time LED was updated
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long interval = 5; // interval at which to blink (milliseconds)
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//for motor control ramps 1.4
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bool newStep = false;
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bool oldStep = false;
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bool dir = false;
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void setup() {
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pinModeFast(2, INPUT);
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pinModeFast(encoder0PinA, INPUT);
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pinModeFast(encoder0PinB, INPUT);
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pinModeFast(DirectionPin, OUTPUT);
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//pinMode(SpeedPin, OUTPUT);
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//ramps 1.4 motor control
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pinModeFast(STEP_PIN, INPUT);
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pinModeFast(DIR_PIN, INPUT);
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//pinModeFast(M0,OUTPUT);
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//pinModeFast(M1,OUTPUT);
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//pinModeFast(M2,OUTPUT);
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//pinModeFast(M3,OUTPUT);
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attachInterrupt(0, doEncoderMotor0, CHANGE); // encoder pin on interrupt 0 - pin 2
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attachInterrupt(1, countStep, RISING); //on pin 3
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Serial.begin (115200);
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Serial.println("start"); // a personal quirk
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}
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void loop(){
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while (Serial.available() > 0) {
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KP = Serial.parseFloat();
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KD = Serial.parseFloat();
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KI = Serial.parseFloat();
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Serial.println(KP);
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Serial.println(KD);
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Serial.println(KI);
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}
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if(millis() - previousTarget > 1000){ //enable this code only for test purposes because it loss a lot of time
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Serial.print(encoder0Pos);
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Serial.print(',');
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Serial.println(target1);
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previousTarget=millis();
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}
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target = target1;
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docalc();
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}
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void docalc() {
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if (millis() - previousMillis > interval)
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{
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previousMillis = millis(); // remember the last time we blinked the LED
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long error = encoder0Pos - target ; // find the error term of current position - target
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//generalized PID formula
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//correction = Kp * error + Kd * (error - prevError) + kI * (sum of errors)
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long ms = KP * error + KD * (error - lastError) +KI * (sumError);
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lastError = error;
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sumError += error;
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//scale the sum for the integral term
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if(sumError > iMax) {
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sumError = iMax;
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} else if(sumError < iMin){
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sumError = iMin;
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}
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int motorspeed = map(ms,0,amp,0,255);
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if( motorspeed >= 255) motorspeed=255;
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if(ms > 0){
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digitalWriteFast ( MotorIN1 ,LOW );
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analogWrite ( MotorIN2, motorspeed );
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}
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if(ms < 0){
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digitalWriteFast ( MotorIN1 ,HIGH );
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analogWrite ( MotorIN2, 255-motorspeed );
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ms = -1 * ms;
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}
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}
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}
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void doEncoderMotor0(){
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if (((PIND&B0000100)>>2) == HIGH) { // found a low-to-high on channel A; if(digitalRead(encoderPinA)==HIGH){.... read PD2 (I2)
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if ((PINB&B0000001) == LOW) { // check channel B to see which way; if(digitalRead(encoderPinB)==LOW){.... read PB0 (I8)
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// encoder is turning
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encoder0Pos-- ; // CCW
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}
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else {
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encoder0Pos++ ; // CW
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}
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}
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else // found a high-to-low on channel A
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{
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if ((PINB&B0000001) == LOW) { // check channel B to see which way; if(digitalRead(encoderPinB)==LOW){.... read PB0 (I8)
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// encoder is turning
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encoder0Pos++ ; // CW
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}
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else {
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encoder0Pos-- ; // CCW
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}
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}
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}
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void countStep(){
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dir = (PINC&B0000001); // dir=digitalRead(dir_pin) read PC0, 14 digital;
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//here will be (PINB&B0000001) to not use shift in the stable version
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if (dir) target1++;
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else target1--;
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}
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