corso 2018 L5

by / giovedì, 07 Dicembre 2017 / Published in Archivio Robotica

 

LEZIONE n° 5 – MOTORI

 

 

La lezione è sui motori e sulla loro gestione. Si useranno i motori, ma vedremo che abbiamo bisogno di una schield di controllo degli stessi (in pratica stiamo usando l’equivalente di un “ponte H”, il vecchio integrato 298). Per far funzionare i motori sarà necessaria una potenza superiore a quella che possiamo prelevare dalla porta USB del PC. Dovremo necessariamente utilizzare un generatore esterno.

Per provare a fare le modifiche proposte copiare il listato (colorato in rosso) ed incollarlo in un editor di solo testo [Notepad ad esempio]

listato programma esempio numero 8:

/*

contollo motori

*/

//const int ledPin = 13; // the number of the LED pin

int pwm_a = 3; //PWM control for motor outputs 1 and 2 is on digital pin 10

int pwm_b = 11; //PWM control for motor outputs 3 and 4 is on digital pin 11

int dir_b = 13; //direction control for motor outputs 3 and 4 is on digital pin 13

// TAVOLA UNO

int dir_a = 12; //direction control for motor outputs 1 and 2 is on digital pin 12

int speed_outA = 100; //speed

int speed_outB = 100; //speed

int speedL = 50; //speed sotto i 40 non riescono a girare

int speedH = 100; //speed

void setup()

{

Serial.begin(9600);

pinMode(pwm_a, OUTPUT); //Set control pins to be outputs

pinMode(pwm_b, OUTPUT);

pinMode(dir_a, OUTPUT);

pinMode(dir_b, OUTPUT);

analogWrite(pwm_a, speedL); //set both motors to run at (100/255 = 39)% duty cycle (slow)

analogWrite(pwm_b, speedL);

}

void loop()

{

int tempo = 3000;

Serial.print(” AVANTI \n ” );

delay(10);

digitalWrite(dir_a, HIGH); //Set motor direction, 1 low, 2 high

digitalWrite(dir_b, LOW); //Set motor direction, 3 high, 4 low

speed_outA = speedL;

speed_outB = speedL;

analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)

analogWrite(pwm_b, speed_outB);

Serial.print(“velocita motore A = ” );

Serial.print(speed_outA);

delay(10);

Serial.print(” velocita motore B = ” );

Serial.print(speed_outB);

Serial.print(“\n “);

delay(10);

// digitalWrite(ledPin, HIGH);

delay(tempo);

speed_outA = speedH;

speed_outB = speedH;

analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)

analogWrite(pwm_b, speed_outB);

Serial.print(“velocita motore A = ” );

Serial.print(speed_outA);

delay(10);

Serial.print(” velocita motore B = ” );

Serial.print(speed_outB);

Serial.print(“\n “);

delay(10);

// digitalWrite(ledPin, LOW);

delay(tempo);

Serial.print(” INDIETRO \n ” );

delay(10);

digitalWrite(dir_a, LOW); //Set motor direction, 1 low, 2 high

digitalWrite(dir_b, HIGH); //Set motor direction, 3 high, 4 low

speed_outA = speedL;

speed_outB = speedL;

analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)

analogWrite(pwm_b, speed_outB);

Serial.print(“velocita motore A = ” );

Serial.print(speed_outA);

delay(10);

Serial.print(” velocita motore B = ” );

Serial.print(speed_outB);

Serial.print(“\n “);

delay(10);

// digitalWrite(ledPin, HIGH);

delay(tempo);

speed_outA = speedH;

speed_outB = speedH;

analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)

analogWrite(pwm_b, speed_outB);

Serial.print(“velocita motore A = ” );

Serial.print(speed_outA);

delay(10);

Serial.print(” velocita motore B = ” );

Serial.print(speed_outB);

Serial.print(“\n “);

delay(10);

// digitalWrite(ledPin, LOW);

delay(tempo);

}

 

 

listato programma esempio numero 9:

/*

controllo di una coppia di motori secondo il valore letto da due potenziometri

*/

int sensorPin = A0;

int sensorValue = 0; // variable to store the value coming from the sensor

int pwm_a = 3; //PWM control for motor outputs 1 and 2 is on digital pin 10

int pwm_b = 11; //PWM control for motor outputs 3 and 4 is on digital pin 11

int dir_a = 12; //direction control for motor outputs 1 and 2 is on digital pin 12

int dir_b = 13; //direction control for motor outputs 3 and 4 is on digital pin 13

int speed_outA = 100; //speed

int speed_outB = 100; //speed

int speedL = 50; //speed sotto i 40 non riescono a girare

int speedH = 100; //speed

int versusH = HIGH; //speed

int versusL = LOW; //speed

int versusA = 0; //speed

int versusB = 0; //speed

int soglia = 500; //soglia

int TEMPO = 2000; //soglia

void setup()

{

Serial.begin(9600);

pinMode(pwm_a, OUTPUT); //Set control pins to be outputs

pinMode(pwm_b, OUTPUT);

pinMode(dir_a, OUTPUT);

pinMode(dir_b, OUTPUT);

analogWrite(pwm_a, speedL); //set both motors to run at (100/255 = 39)% duty cycle (slow)

analogWrite(pwm_b, speedL);

}

void loop()

{

// read the state of the pushbutton value:

sensorValue = analogRead(sensorPin);

// print the results to the serial monitor:

Serial.print(“\n “);

Serial.print(“sensor = ” );

Serial.print(sensorValue);

Serial.print(“\n\n “);

delay(10);

if (sensorValue <= soglia){

versusA = versusH;

versusB = versusL;

Serial.print(” AVANTI \n ” );

delay(10);

}

else {

versusA = versusL;

versusB = versusH;

Serial.print(” INDIETRO \n ” );

delay(10);

}

digitalWrite(dir_a, versusA); //Set motor direction, 1 low, 2 high

digitalWrite(dir_b, versusB); //Set motor direction, 3 high, 4 low

speed_outA = speedL;

speed_outB = speedL;

analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)

analogWrite(pwm_b, speed_outB);

Serial.print(“velocita motore A = ” );

Serial.print(speed_outA);

delay(10);

Serial.print(” velocita motore B = ” );

Serial.print(speed_outB);

Serial.print(“\n “);

delay(10);

// digitalWrite(ledPin, HIGH);

delay(TEMPO);

speed_outA = speedH;

speed_outB = speedH;

analogWrite(pwm_a, speed_outA); //set both motors to run at 100% duty cycle (fast)

analogWrite(pwm_b, speed_outB);

Serial.print(“velocita motore A = ” );

Serial.print(speed_outA);

delay(10);

Serial.print(” velocita motore B = ” );

Serial.print(speed_outB);

Serial.print(“\n “);

delay(10);

// digitalWrite(ledPin, LOW);

delay(TEMPO);

}

Modifiche proposte:

 

  • Cambiare i tempi
  • Cambiare il potenziometro
  • Accendere un led (di colore diverso) secondo il verso

 

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