-ยังคงคิดปัยหากับการที่เราจะนำสัญญาณมาควบคุมPWM และในตอนแรก เขียน PWM โดยไม่ใช้ poten ไม่ได้แต่ทำได้โดยใช้ map และไม่ใช้
โค้ดตัวอย่าง
int val ;
void setup() {
Serial.begin(9600);
}
void loop()
{
val = map(210, 0, 1023, 0, 500);
analogWrite(9, val);
Serial.println(val);
}
แหล่งที่มา http://www.arduino.cc/en/Reference/Map
-วิธีการควบคุม DC motor speed control using PID controler
แหล่งที่มา https://www.youtube.com/watch?v=pdYqjlY9jdA
ตัวอย่างโค้ดที่นำมาในการศึกษา
const int analogInPin = A0; // Analog input pin that the potentiometer is attached to
int sensorValue = 0; // value read from the pot
float v=0.0;
float vf=0.0;
float u=0.0;
float ui=0.0;
float e1=0.0;
float e1_dotf=0.0;
float e1_old=0.0;
float kp=0.105;//0.101-0.515
float ki=0.152;//0.102-0.852
float kd=0.021;//0.011-0.081
// reading a PWM signal using interrupts
int pin1 = 2; // arduino pin number numbers 0 (on digital pin 2)
int intrnum1 = 0; // interrupt number 0-1 for others//and 1 (on digital pin 3)
volatile unsigned long width1 = 4294967295; // width of most recent signal
volatile unsigned long start1 = 0; // start time of rising signal
//Used for timing
int i = 0;
unsigned long timer=0;
unsigned long dtime=1;
// myisr -- interrupt handler
void myisr1()
{
unsigned long now1 = micros();
width1= now1 - start1;
start1 = now1;
}
void setup(){
Serial.begin(9600);
pinMode(pin1,INPUT);
pinMode(9, OUTPUT);
attachInterrupt(intrnum1, myisr1, RISING);
//LOW to trigger the interrupt whenever the pin is low,
//CHANGE to trigger the interrupt whenever the pin changes value
//RISING to trigger when the pin goes from low to high,
//FALLING for when the pin goes from high to low.
timer = millis();//start timing
}
void loop(){
dtime = millis()-timer;
if(dtime >= 20)
{
timer = millis();//start timing
sensorValue = analogRead(analogInPin);
sensorValue = map(sensorValue, 0, 1023, 0, 290); //0-290 rpm
v = 60000000.0/(width1*2.0); //rpm
vf = vf + ((v-vf)*0.251);//filter
//PID control
e1 = sensorValue - vf;
float e1_dot = (e1 - e1_old)/0.02;
e1_old = e1;
e1_dotf = e1_dotf + ((e1_dot - e1_dotf)*0.251);//filter
ui = ui + (e1*ki*0.02);
ui = constrain(ui, -60, 60);
u = (kp*e1) + ui + (e1_dotf*kd);
if(sensorValue == 0)
{
width1 = 4294967295;
u = 0;
}
u = constrain(u, 0, 255);
analogWrite(9, u);
i++;
if(i > 10)
{
i=0;
Serial.print(e1); Serial.print("\t");
//Serial.print(v);Serial.print("\t");
Serial.print(vf);Serial.print("\t");
Serial.print(ui);Serial.print("\t");
Serial.println(dtime);
}
}
}
โค้ดที่เขียนและยังไม่สมบูรณ์
int sensorValue = 0; // value read from the pot
float v=0.0;
float vf=0.0;
float u=0.0;
float ui=0.0;
float e1=0.0;
float e1_dotf=0.0;
float e1_old=0.0;
float kp=0.105;//0.101-0.515
float ki=0.152;//0.102-0.852
float kd=0.021;//0.011-0.081
// reading a PWM signal using interrupts
int motor = 9;
volatile unsigned long width1 = 4294967295; // width of most recent signal
volatile unsigned long start1 = 0; // start time of rising signal
int i = 0;
unsigned long timer=0;
unsigned long dtime=1;
// myisr -- interrupt handler
void myisr1()
{
unsigned long now1 = micros();
width1= now1 - start1;
start1 = now1;
}
void setup(){
Serial.begin(9600);
pinMode(motor, OUTPUT);
attachInterrupt(0, myisr1, RISING);
timer = millis();//start timing
}
void loop(){
dtime = millis()-timer;
if(dtime >= 20)
{
timer = millis();//start timing
sensorValue = map(1023, 0, 1023, 0, 500); //0-500 rpm
v = 60000000.0/(width1*2.0); //rpm
vf = vf + ((v-vf)*0.251);//filter
//PID control
e1 = sensorValue - vf;
float e1_dot = (e1 - e1_old)/0.02;
e1_old = e1;
e1_dotf = e1_dotf + ((e1_dot - e1_dotf)*0.251);//filter
ui = ui + (e1*ki*0.02);
ui = constrain(ui, -60, 60);
u = (kp*e1) + ui + (e1_dotf*kd);
if(sensorValue == 0)
{
width1 = 4294967295;
u = 0;
}
u = constrain(u, 0, 255);
analogWrite(motor, u);
i++;
if(i > 10)
{
i=0;
Serial.print(e1); Serial.print("\t");
//Serial.print(v);Serial.print("\t");
Serial.print(vf);Serial.print("\t");
Serial.print(ui);Serial.print("\t");
Serial.println(dtime);
}
}
}
-การใช้งาน Module L298N
ชุดขับมอเตอร์อเนกประสงค์ด้วย IC เบอร์ L298 / L298N ซึ่งเป็น IC ขับมอเตอร์แบบ H-Bridge - สามารถใช้ขับมอเตอร์ DC ได้พร้อมกันจำนวน 2 ตัว
การต่อวงจร
ENA >> PWM 9 ของ arduino
IN1 >> PIN7
IN2 >>PIN8
ENAB>> PWM 9 ของ arduino
IN1 >> PIN7
IN2 >>PIN8
การทดลองใช้งาน
const int analogOutPin = 9; // Analog output pin that the LED is attached to
void setup() {
// initialize serial communications at 9600 bps:
Serial.begin(9600);
pinMode(7,OUTPUT);
pinMode(8,OUTPUT);
}
void loop() {
analogWrite(analogOutPin, 255);
digitalWrite(7,HIGH);
digitalWrite(8,LOW);
delay(5000);
analogWrite(analogOutPin, 127);
digitalWrite(7,HIGH);
digitalWrite(8,LOW);
delay(5000);
analogWrite(analogOutPin, 0);
digitalWrite(7,HIGH);
digitalWrite(8,LOW);
delay(5000);
analogWrite(analogOutPin, 255);
digitalWrite(7,LOW);
digitalWrite(8,HIGH);
delay(5000);
analogWrite(analogOutPin, 127);
digitalWrite(7,LOW);
digitalWrite(8,HIGH);
delay(5000);
analogWrite(analogOutPin, 0);
digitalWrite(7,LOW);
digitalWrite(8,HIGH);
delay(5000);
analogWrite(analogOutPin, 0);
digitalWrite(7,HIGH);
digitalWrite(8,HIGH);
delay(5000);
}
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