如何使用编码器测量直流电机来控制Python的机器人运动？

Question

I have a robot car with 2 dc motor a dc encoder that connect to RPi 3 b and dc motor I want to make a robot move according to number of rotation that measure by encoder . so that robot move and encoder start to measure when it reach 5 rotation, robot will stop, Now my problem is I can't turn right or left, how to do that I used python and RPi

import RPi.GPIO as GPIO

import time

GPIO.setmode(GPIO.BOARD)

GPIO.setwarnings(False)

GPIO.setup(31,GPIO.IN)


GPIO.setup(29,GPIO.IN)

GPIO.setup(12,GPIO.OUT)

GPIO.setup(16,GPIO.OUT)

GPIO.setup(35,GPIO.OUT)

GPIO.setup(33,GPIO.OUT)


pwm=20

frequency=70000

right=GPIO.PWM(12,frequency)

left=GPIO.PWM(33,frequency)

left.start(0)

right.start(0)

def on():

    right.ChangeDutyCycle(pwm)

    left.ChangeDutyCycle(pwm)

def off():

    right.ChangeDutyCycle(0)

    left.ChangeDutyCycle(0)

prv=0

i=0

while True:

          on()  

          if(GPIO.input(31)==(1) and GPIO.input(29)==(1)):

             print"something"

             if prv==0:

                  prv=1

                  i=i+1

                  print"hole"+ str(i)+"times"

                  if i==50

                     off()

                     break     


          else:

                   print"button not pushed"

                   prv=0

Answer 1

Turning left or right is a matter of turning one of the motors on instead of both (or running one side faster than the other). You could try writing the functions turnleft() and turnright() and running them in the loop (hook them to a button or something).

The function for turning left would look something like this:

def turnleft():
    right.ChangeDutyCycle(pwm)
    left.ChangeDutyCycle(0)