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Robot simple sur MK esp8266 avec micropython

Bonjour, Habr!

Cet article décrit le processus de mise à niveau d'une plate-forme automotrice basée sur l'esp8266 MK avec micropython , vers un robot simple équipé d'un capteur d'obstacles à ultrasons à balayage, d'une LED clignotante, d'un bouton marche / arrêt, ainsi que d'un serveur Web intégré, dans le cadre d'un projet de formation.

KDPV:



Ainsi, les deux premières parties décrivent la fabrication d'une plateforme automotrice contrôlée via une interface web wifi.

La tâche de l'étape actuelle est d'équiper cette plate-forme à ultrasons du capteur HC-SR04 et d'ajouter la possibilité de travailler hors ligne.

Pour commencer - la partie mécanique:
il faut fixer le capteur et le servo dans le boîtier, concevoir (j'ai utilisé FreeCAD pour cela ) et fabriquer les pièces manquantes:





Ensuite - la partie électrique:
dessiner le circuit (par exemple, à Fritzing ) et effectuer la commutation conformément à cela:



Après cela, essayez de tout faire voler ...

Comme je voulais que certaines fonctions du programme robot soient exécutées en parallèle (par exemple, le processus de balayage de la distance aux obstacles et la fonction de mouvement), j'ai dû plonger dans les capacités du module asyncio . Un travail plus détaillé avec asyncio est décrit dans cet article et dans ces articles.

Par exemple, pour faire clignoter une LED, vous pouvez appliquer une telle coroutine, qui n'est pratiquement pas différente de synchrone:

import uasyncio as asyncio
from machine import Pin

# onboard LED is connected to D0(GPIO16)
syst_led =  Pin(16, Pin.OUT)

async def blink_led(led, interval_ms):
    led_val = True
    while True:
        led_val = not(led_val)
        led_state = led.value(int(led_val))
        await asyncio.sleep_ms(interval_ms)

# define loop
loop = asyncio.get_event_loop()

#create looped tasks
loop.create_task(blink_led(syst_led, interval_ms=250))

# loop run forever
loop.run_forever()

La différence est que de telles coroutines qui effectuent différentes tâches peuvent être lancées plusieurs en même temps (les ressources seront allouées par le planificateur).

Ainsi, nous écrirons des coroutines pour mesurer la distance et balayer le secteur, ainsi qu'un rappel pour une interruption matérielle (bouton) qui démarre ou arrête le balayage. Le transfert d'état entre coroutines dans le cas le plus simple peut se faire via des variables globales:

Rappel du bouton:

from machine import Pin

run_flag = False

# on/off button
button =  Pin(15, Pin.IN, Pin.PULL_UP) # connected to D8 (GPIO15)

# callback function for start/stop button
def callback(p):
    global run_flag
    run_flag = not(run_flag)
    print('set run_flag', run_flag, p)

# create callback for button:
button.irq(trigger=Pin.IRQ_FALLING, handler=callback)

Mesure de distance:

import uasyncio as asyncio
from utime import sleep, sleep_us
from machine import Pin, time_pulse_us

# HC-SR04 ultrasonic sensor connected to GPIO12(D6)-trigger and GPIO13(D7)-echo
trig=Pin(12, Pin.OUT)
echo=Pin(13, Pin.IN)

async def async_measure_range():
    echo_timeout_us=500*2*30 # Timeout in microseconds to listen to echo pin.
    trig.off() # Stabilize the sensor
    sleep_us(5)
    trig.on()
    sleep_us(10) # Send a 10us pulse.
    trig.off()
    try:
        pulse_time = time_pulse_us(echo, 1, echo_timeout_us)
    except:
        pass
    dist = (pulse_time / 2) / 29.1
    return dist

Balayage de secteur (avec appel de la coroutine de mesure de distance):

import uasyncio as asyncio
from machine import Pin, PWM

pos_actual = 75
dist_cm = 50

# servo SG90 connected to GPIO14(D5)
p14 =  Pin(14, Pin.OUT)
servo = PWM(p14, freq=50)

async def radar_scan(interval_ms):
    pos_list = [45,75,105,75]
    global pos_actual
    global dist_cm
    while True:
        if run_flag:
            for pos in pos_list:
                servo.duty(pos)
                await asyncio.sleep_ms(interval_ms)
                dist_cm = await async_measure_range()
                pos_actual = pos
                print('pos_actual = %s, dist_cm = %s' % (pos_actual, dist_cm)
        elif not run_flag:
            await asyncio.sleep(0) # do nothing

# define loop
loop = asyncio.get_event_loop(

#create looped tasks
loop.create_task(radar_scan(interval_ms=250))

# loop run forever
loop.run_forever()

Dans le processus de débogage, le capteur, de temps en temps, a donné une valeur de distance négative. Il s'est avéré - «L'électronique est la science des mauvais contacts» , lorsque le capteur a été tourné, le câble a été tiré et le contact a été perdu.

Reste à fixer la logique du choix de l'action en fonction des résultats de l'analyse:

avoid_left = False
avoid_right = False
avoid_backward = False

async def make_decision(interval_ms, avoid_limit_cm):
    global avoid_left
    global avoid_right
    global avoid_backward
    while True:
        if run_flag:
            # make decision what to do
            if pos_actual == 45 and dist_cm < avoid_limit_cm :
                avoid_left = True
                if debug : print('avoid_left = %s' % avoid_left)
            elif pos_actual == 45 and dist_cm >= avoid_limit_cm :
                avoid_left = False
                if debug : print('avoid_left = %s' % avoid_left)
            elif pos_actual == 75 and dist_cm < avoid_limit_cm*1.25 :
                avoid_backward = True
                if debug : print('avoid_backward = %s' % avoid_backward)
            elif pos_actual == 75 and dist_cm >= avoid_limit_cm*1.25 :
                avoid_backward = False
                if debug : print('avoid_backward = %s' % avoid_backward)
            elif pos_actual == 105 and dist_cm < avoid_limit_cm :
                avoid_right = True
                if debug : print('avoid_right = %s' % avoid_right)
            elif pos_actual == 105 and dist_cm >= avoid_limit_cm :
                avoid_right = False
                if debug : print('avoid_right = %s' % avoid_right)
            # for debuging
            if debug : print('pos = %s, dist_cm = %s' % (pos_actual,dist_cm))  
            await asyncio.sleep_ms(interval_ms)
        elif not run_flag:
            await asyncio.sleep(0) # do nothing

#create looped tasks
loop.create_task(make_decision(interval_ms=250, avoid_limit_cm=15))

Fonctions motrices:

from random import getrandbits

async def moving(interval_ms):
    while True:
        if run_flag:
            # moving functions
            if avoid_backward :
                print('avoid_backward = %s' % avoid_backward)
                await backward(interval_ms*2)
                if bool(getrandbits(1)) :
                    await right_rotate(interval_ms+getrandbits(3)*100)
                    await stop_all()
                else:
                    await left_rotate(interval_ms+getrandbits(3)*100)
                    await stop_all()
            elif avoid_left :
                print('avoid_left = %s' % avoid_left)
                await left_turn(interval_ms)
            elif avoid_right :
                print('avoid_right = %s' % avoid_right)
                await right_turn(interval_ms)
            else:
                print('move_forward')
                await forward(interval_ms)
                
            await asyncio.sleep_ms(interval_ms)
        elif not run_flag:
            #stop all motors first
            await stop_all()
            await asyncio.sleep(0) # do nothing

#create looped tasks
loop.create_task(moving(interval_ms=1000))

Et contrôle moteur
# nodemcu pins from the motor shield
p5 = Pin(5, Pin.OUT)  # connected to GPIO4(D1)
p4 = Pin(4, Pin.OUT)  # connected to GPIO4(D2)
revrs_L = Pin(0, Pin.OUT, value=0)  # connected to GPIO0(D3)
revrs_R = Pin(2, Pin.OUT, value=0)  # connected to GPIO2(D4) , also connected to onboard wifi LED
motor_L = PWM(p5, freq=1000, duty=0)
motor_R = PWM(p4, freq=1000, duty=0)
speed = 1023  #TODO: variable speed

async def stop_all():
    revrs_L.value(0)
    motor_L.duty(0)
    revrs_R.value(0)
    motor_R.duty(0)

async def forward(interval_ms):
    revrs_L.value(0)
    motor_L.duty(speed)
    revrs_R.value(0)
    motor_R.duty(speed)
    await asyncio.sleep_ms(interval_ms)

async def backward(interval_ms):
    revrs_L.value(1)
    motor_L.duty(speed)
    revrs_R.value(1)
    motor_R.duty(speed)
    await asyncio.sleep_ms(interval_ms)

async def right_rotate(interval_ms):
    revrs_L.value(0)
    motor_L.duty(speed)
    revrs_R.value(1)
    motor_R.duty(speed)
    await asyncio.sleep_ms(interval_ms)

async def left_rotate(interval_ms):
    revrs_L.value(1)
    motor_L.duty(speed)
    revrs_R.value(0)
    motor_R.duty(speed)
    await asyncio.sleep_ms(interval_ms)

async def right_turn(interval_ms):
    revrs_L.value(0)
    motor_L.duty(speed)
    revrs_R.value(0)
    motor_R.duty(0)
    await asyncio.sleep_ms(interval_ms)

async def left_turn(interval_ms):
    revrs_L.value(0)
    motor_L.duty(0)
    revrs_R.value(0)
    motor_R.duty(speed)
    await asyncio.sleep_ms(interval_ms)


Ainsi qu'une LED clignotante pour contrôler le fonctionnement du programme:

async def blink_led(led, interval_ms):
    led_val = True
    while True:
        if run_flag:
            led_val = not(led_val)
            led_state = led.value(int(led_val))
            await asyncio.sleep_ms(interval_ms)
        elif not run_flag:
            await asyncio.sleep(0) # do nothing

#create looped tasks
loop.create_task(blink_led(syst_led, interval_ms=250))

Après quoi, il ne reste plus qu'à collecter tout cela

en un seul morceau
import gc
import uasyncio as asyncio
from utime import sleep, sleep_us
from machine import Pin, PWM, time_pulse_us
from random import getrandbits

# nodemcu pins from the motor shield
p5 = Pin(5, Pin.OUT)  # connected to GPIO4(D1)
p4 = Pin(4, Pin.OUT)  # connected to GPIO4(D2)
revrs_L = Pin(0, Pin.OUT, value=0)  # connected to GPIO0(D3)
revrs_R = Pin(2, Pin.OUT, value=0)  # connected to GPIO2(D4) , also connected to onboard wifi LED
motor_L = PWM(p5, freq=1000, duty=0)
motor_R = PWM(p4, freq=1000, duty=0)
speed = 1023  #TODO: variable speed

# servo SG90 connected to GPIO14(D5)
p14 =  Pin(14, Pin.OUT)
servo = PWM(p14, freq=50)
# on/off button
button =  Pin(15, Pin.IN, Pin.PULL_UP) # connected to D8 (GPIO15)
# onboard LED is connected to D0(GPIO16)
syst_led =  Pin(16, Pin.OUT)
# HC-SR04 ultrasonic sensor connected to GPIO12(D6)-trigger and GPIO13(D7)-echo
trig=Pin(12, Pin.OUT)
echo=Pin(13, Pin.IN)

#global flags and variables
run_flag = False
avoid_left = False
avoid_right = False
avoid_backward = False
pos_actual = 75
dist_cm = 50
debug = False


# callback function for start/stop button
def callback(p):
    global run_flag
    run_flag = not(run_flag)
    print('set run_flag', run_flag, p)

# sync fuctions
def stop_all_sync():
    revrs_L.value(0)
    motor_L.duty(0)
    revrs_R.value(0)
    motor_R.duty(0)
    
# async fuctions
async def stop_all():
    revrs_L.value(0)
    motor_L.duty(0)
    revrs_R.value(0)
    motor_R.duty(0)

async def forward(interval_ms):
    revrs_L.value(0)
    motor_L.duty(speed)
    revrs_R.value(0)
    motor_R.duty(speed)
    await asyncio.sleep_ms(interval_ms)

async def backward(interval_ms):
    revrs_L.value(1)
    motor_L.duty(speed)
    revrs_R.value(1)
    motor_R.duty(speed)
    await asyncio.sleep_ms(interval_ms)

async def right_rotate(interval_ms):
    revrs_L.value(0)
    motor_L.duty(speed)
    revrs_R.value(1)
    motor_R.duty(speed)
    await asyncio.sleep_ms(interval_ms)

async def left_rotate(interval_ms):
    revrs_L.value(1)
    motor_L.duty(speed)
    revrs_R.value(0)
    motor_R.duty(speed)
    await asyncio.sleep_ms(interval_ms)

async def right_turn(interval_ms):
    revrs_L.value(0)
    motor_L.duty(speed)
    revrs_R.value(0)
    motor_R.duty(0)
    await asyncio.sleep_ms(interval_ms)

async def left_turn(interval_ms):
    revrs_L.value(0)
    motor_L.duty(0)
    revrs_R.value(0)
    motor_R.duty(speed)
    await asyncio.sleep_ms(interval_ms)

async def moving(interval_ms):
    while True:
        if run_flag:
            # moving functions
            if avoid_backward :
                print('avoid_backward = %s' % avoid_backward)
                await backward(interval_ms*2)
                if bool(getrandbits(1)) :
                    await right_rotate(interval_ms+getrandbits(3)*100)
                    await stop_all()
                else:
                    await left_rotate(interval_ms+getrandbits(3)*100)
                    await stop_all()
            elif avoid_left :
                print('avoid_left = %s' % avoid_left)
                await left_turn(interval_ms)
            elif avoid_right :
                print('avoid_right = %s' % avoid_right)
                await right_turn(interval_ms)
            else:
                print('move_forward')
                await forward(interval_ms)
                
            await asyncio.sleep_ms(interval_ms)
        elif not run_flag:
            #stop all motors first
            await stop_all()
            await asyncio.sleep(0) # do nothing


async def blink_led(led, interval_ms):
    led_val = True
    while True:
        if run_flag:
            led_val = not(led_val)
            led_state = led.value(int(led_val))
            await asyncio.sleep_ms(interval_ms)
        elif not run_flag:
            await asyncio.sleep(0) # do nothing
            
async def async_measure_range():
    echo_timeout_us=500*2*30 # Timeout in microseconds to listen to echo pin.
    trig.off() # Stabilize the sensor
    sleep_us(5)
    trig.on()
    sleep_us(10) # Send a 10us pulse.
    trig.off()
    try:
        pulse_time = time_pulse_us(echo, 1, echo_timeout_us)
    except:
        pass
    dist = (pulse_time / 2) / 29.1
    return dist

async def make_decision(interval_ms, avoid_limit_cm):
    global avoid_left
    global avoid_right
    global avoid_backward
    while True:
        if run_flag:
            # make decision what to do
            if pos_actual == 45 and dist_cm < avoid_limit_cm :
                avoid_left = True
                if debug : print('avoid_left = %s' % avoid_left)
            elif pos_actual == 45 and dist_cm >= avoid_limit_cm :
                avoid_left = False
                if debug : print('avoid_left = %s' % avoid_left)
            elif pos_actual == 75 and dist_cm < avoid_limit_cm*1.25 :
                avoid_backward = True
                if debug : print('avoid_backward = %s' % avoid_backward)
            elif pos_actual == 75 and dist_cm >= avoid_limit_cm*1.25 :
                avoid_backward = False
                if debug : print('avoid_backward = %s' % avoid_backward)
            elif pos_actual == 105 and dist_cm < avoid_limit_cm :
                avoid_right = True
                if debug : print('avoid_right = %s' % avoid_right)
            elif pos_actual == 105 and dist_cm >= avoid_limit_cm :
                avoid_right = False
                if debug : print('avoid_right = %s' % avoid_right)
            # for debuging
            if debug : print('pos = %s, dist_cm = %s' % (pos_actual,dist_cm))  
            await asyncio.sleep_ms(interval_ms)
        elif not run_flag:
            await asyncio.sleep(0) # do nothing

async def radar_scan(interval_ms):
    pos_list = [45,75,105,75]
    global pos_actual
    global dist_cm
    while True:
        if run_flag:
            for pos in pos_list:
                servo.duty(pos)
                await asyncio.sleep_ms(interval_ms)
                dist_cm = await async_measure_range()
                pos_actual = pos
        elif not run_flag:
            await asyncio.sleep(0) # do nothing
    
#stop all motors first
stop_all_sync()

# move servo to initial position
print('Move sensor to initial position...')
servo.duty(75)
sleep(1) #wait 1s for servo reaching initial position
print('Waiting for start button...')

#enable gc
gc.enable()

# create callback fo button:
button.irq(trigger=Pin.IRQ_FALLING, handler=callback)

# define loop
loop = asyncio.get_event_loop()

#create looped tasks
loop.create_task(blink_led(syst_led, interval_ms=250))
loop.create_task(radar_scan(interval_ms=250))
loop.create_task(make_decision(interval_ms=250, avoid_limit_cm=15))
loop.create_task(moving(interval_ms=1000))

# loop run forever
loop.run_forever()

et vérifier le travail:

Cependant, je voudrais garder la possibilité d'un contrôle manuel via la page web ...

Pour cela, dans une coroutine séparée, ajoutez un simple serveur web:

async def web_page(request):
    global auto_run_flag
    motor_state="Stopped"
    if request.find('GET /?forward') > 0:
        motor_state="Going Forward"
        auto_run_flag = False
        forward_sync()
    elif request.find('GET /?left_rotate') > 0:
        motor_state="Rotate Left"
        auto_run_flag = False
        left_rotate_sync()
    elif request.find('GET /?right_rotate') > 0:
        motor_state="Rotate Right"
        auto_run_flag = False
        right_rotate_sync()
    elif request.find('GET /?left_turn') > 0:
        motor_state="Turn Left"
        auto_run_flag = False
        left_turn_sync()
    elif request.find('GET /?right_turn') > 0:
        motor_state="Turn Right"
        auto_run_flag = False
        right_turn_sync()
    elif request.find('GET /?backward') > 0:
        motor_state="Going Backward"
        auto_run_flag = False
        backward_sync()
    elif request.find('GET /?stop') > 0:
        motor_state="Stopped"
        auto_run_flag = False
        stop_all_sync()
    elif request.find('GET /?auto') > 0:
        auto_run_flag = not auto_run_flag
        if  auto_run_flag :
            motor_state="Autopilot"
        elif not auto_run_flag :
             motor_state="Stopped"
             stop_all_sync()

    html = """<html><head><title>RoboTank WEB</title> 
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="icon" href="data:,"> <style>
    html{font-family: Helvetica; display:inline-block; margin: 0px auto; text-align: center;}
    h1{color: #0F3376; padding: 2vh;}p{font-size: 1.5rem;}
    .button{display: inline-block; background-color: #33c080; border: none; 
    border-radius: 4px; color: white; text-decoration: none; font-size: 30px; width:100%}
    .button2{background-color: #4286f4; width:30%}
    .button3{background-color: #eb2b10; width:35%}
    .button4{background-color: #8386f4; width:44%}
    </style></head>
    <body> <h1>RoboTank WEB</h1> 
    <p>Status : <strong>""" + motor_state + """</strong></p>
    <p><a href='/?forward'><button class="button">Forward</button></a></p>
    <p><a href='/?left_turn'><button class="button button2">LEFT</button></a>
    <a href='/?stop'><button class="button button3">STOP</button></a>
    <a href='/?right_turn'><button class="button button2">RIGHT</button></a>
    <p><a href='/?backward'><button class="button">Backward</button></a></p>
    <p><a href='/?left_rotate'><button class="button button4">L-rotate</button></a>
    <a href='/?right_rotate'><button class="button button4">R-rotate</button></a></p>
    <p><a href='/?auto'><button class="button button3">AUTO</button></a></p>
    </body></html>"""
    return html

async def web_handler(reader, writer):
    try:
        request = str(await reader.read(1024))
        #print('request = %s' % request)
        header = """HTTP/1.1 200 OK\nContent-Type: text/html\nConnection: close\n\n"""
        response = await web_page(request)
        await writer.awrite(header)
        await writer.awrite(response)
        await writer.aclose()
        print("Finished processing request")
    except Exception as e:
        print(e)
    
async def tcp_server(host, port):
    server = await asyncio.start_server(web_handler, host, port)

#create looped tasks
loop.create_task(tcp_server('0.0.0.0', 80))

Et des fonctions de mouvement synchrones pour un contrôle manuel.
def stop_all_sync():
    revrs_L.value(0)
    motor_L.duty(0)
    revrs_R.value(0)
    motor_R.duty(0)

def backward_sync():
    revrs_L.value(1)
    motor_L.duty(speed)
    revrs_R.value(1)
    motor_R.duty(speed)

def forward_sync():
    revrs_L.value(0)
    motor_L.duty(speed)
    revrs_R.value(0)
    motor_R.duty(speed)

def right_rotate_sync():
    revrs_L.value(0)
    motor_L.duty(speed)
    revrs_R.value(1)
    motor_R.duty(speed)

def left_rotate_sync():
    revrs_L.value(1)
    motor_L.duty(speed)
    revrs_R.value(0)
    motor_R.duty(speed)
    
def right_turn_sync():
    revrs_L.value(0)
    motor_L.duty(speed)
    revrs_R.value(0)
    motor_R.duty(0)

def left_turn_sync():
    revrs_L.value(0)
    motor_L.duty(0)
    revrs_R.value(0)
    motor_R.duty(speed)


Apparence de l'interface:



Tests de la version finale:


Les sources sont disponibles ici.

Sources d'inspiration:

docs.micropython.org/en/latest/library/uasyncio.html
habr.com/en/post/484446
habr.com/en/post/337420
habr.com/en/post/484472
github.com/peterhinch /micropython-async/blob/master/TUTORIAL.md
github.com/rsc1975/micropython-hcsr04
medium.com/@pgjones/an-asyncio-socket-tutorial-5e6f3308b8b0

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