クラウドの力でロボットを遠隔から操作してみよう！

export TURTLEBOT3_MODEL=waffle_pi
roslaunch turtlebot3_gazebo turtlebot3_house.launch

cd ~/environment && mkdir certs

python3 -m pip install awsiotsdk
cd ~/environment/ && touch main.py

import rospy
from rospy.exceptions import ROSInterruptException
from geometry_msgs.msg import Twist
from awsiot import mqtt_connection_builder
from awscrt import mqtt, http
import json
from math import pi

host = '<ホスト>'
thingsName = 'turtlebot3-sim'
topic = thingsName + '/control'

certsPath = './certs/'
rootCAPath = certsPath + '<Amazon Root CA1>'
certificatePath = certsPath + '<デバイス証明書>'
privateKeyPath = certsPath + '<プライベートキーファイル>'
port = 8883
    
def shutdown_turtlebot():
    disconnect_future = mqtt_connection.disconnect()
    disconnect_future.result()
    print("Disconnected from AWS IoT!")
    rospy.loginfo('Stop Turtlebot')
    cmd_vel_pub.publish(Twist())
    rospy.sleep(1)
    
cmd_vel_pub = rospy.Publisher('cmd_vel', Twist, queue_size=1)
rospy.init_node('turtlebot3_sim_control_node')
rospy.on_shutdown(shutdown_turtlebot)
control = Twist()
rate = rospy.Rate(1)

def handleMessage(topic, payload):
    duration = 4
    print("Received a new message: ")
    print(payload)
    print("from topic: ")
    print(topic)
    print("--------------\n\n")
    payload = json.loads(payload)
    x = 0
    z = 0
    if payload["control"] == "forward":
        x = 0.1
    if payload["control"] == "stop":
        x = 0
        z = 0
    if payload["control"] == "backward":
        x = -0.1
    if payload["control"] == "left":
        z = pi*0.8/4/duration
    if payload["control"] == "right":
        z = -(pi*0.8/4/duration)
    control.linear.x = x
    control.angular.z = z

# AWS IoT MQTT Client connection configuration
mqtt_connection = mqtt_connection_builder.mtls_from_path(
        endpoint=host,
        port=port,
        cert_filepath=certificatePath,
        pri_key_filepath=privateKeyPath,
        ca_filepath=rootCAPath,
        client_id=thingsName,
        clean_session=False,
        keep_alive_secs=30)

# Connect to AWS IoT
connect_future = mqtt_connection.connect()

# Waits until a result is available
connect_future.result()
print("Connected to AWS IoT!")

# Subscribe to AWS IoT
subscribe_future, packet_id = mqtt_connection.subscribe(
        topic=topic,
        qos=mqtt.QoS.AT_LEAST_ONCE,
        callback=handleMessage)
subscribe_result = subscribe_future.result()
print("Subscribed with {}".format(str(subscribe_result['qos'])))

while not rospy.is_shutdown():
    try:
        cmd_vel_pub.publish(control)
        rate.sleep()
    except ROSInterruptException:
        rospy.loginfo('Finish')

python3 main.py

{
  "control": "stop"
}