dcControl.py

import RPi.GPIO as GPIO
import time
  
GPIO.setmode(GPIO.BCM)
  
GPIO_DIR1 = 23
GPIO_PWM1 = 24
GPIO_DIR2 = 27
GPIO_PWM2 = 22
  
GPIO.setup(GPIO_DIR1, GPIO.OUT) 
GPIO.setup(GPIO_PWM1, GPIO.OUT)
GPIO.setup(GPIO_DIR2, GPIO.OUT) 
GPIO.setup(GPIO_PWM2, GPIO.OUT)
  
def setSpeed(speed1, speed2):
    p1.ChangeDutyCycle(speed1)
    p2.ChangeDutyCycle(speed2)
      
try:
    p1 = GPIO.PWM(GPIO_PWM1, 100) # 100hz
    p1.start(0) # start the PWM on 0% duty cycle
    p2 = GPIO.PWM(GPIO_PWM2, 100) # 100hz
    p2.start(0) # start the PWM on 0% duty cycle

    while True:
        GPIO.output(GPIO_DIR1, GPIO.HIGH)
        GPIO.output(GPIO_DIR2, GPIO.HIGH)
        setSpeed(13, 13)
        print("front")
        time.sleep(5)
        
        setSpeed(0, 0)
        print("stop")
        time.sleep(5)
        
        GPIO.output(GPIO_DIR1, GPIO.LOW)
        GPIO.output(GPIO_DIR2, GPIO.LOW)
        setSpeed(13, 13)
        print("back")
        time.sleep(5)
        
        setSpeed(0, 0)
        print("stop")
        time.sleep(5)
        
        GPIO.output(GPIO_DIR1, GPIO.HIGH)
        GPIO.output(GPIO_DIR2, GPIO.LOW)
        setSpeed(7, 7)
        print("right")
        time.sleep(5)
        
        setSpeed(0, 0)
        print("stop")
        time.sleep(5)

        GPIO.output(GPIO_DIR1, GPIO.LOW)
        GPIO.output(GPIO_DIR2, GPIO.HIGH)
        setSpeed(7, 7)
        print("left")
        time.sleep(5)
        
        setSpeed(0, 0)
        print("stop")
        time.sleep(5)

finally:    
    GPIO.cleanup()