Quality of service setting missing and laser scan (/scan) on ground level

[Fabulani]

Our robot uses quality of service 'RELIABILITY=VOLATILE' for the laser scan, but it needs to be changed to 'RELIABLE' to work with Unity. I couldn't find anywhere to configure it in Unity. Then, when it works, the laser scan is on ground-level. It should be a bit above it.

The global and local costmaps also don't align. This, plus the laser scan issue, makes me think it might be a problem with the /tf.

When I run the Nav2-SLAM-Example, everything is aligned and properly positioned (with the data from Unity's simulated robot).

Environment:

• Unity Version: 2021.3.14f1
• Unity machine OS + version: Ubuntu
• ROS machine OS + version: Docker image running ROS-galactic (osrf/ros:galactic-desktop)
• ROS–Unity communication: Docker container running ROS-TCP-Endpoint

In the following image, pink is the floor on Y=-1, laser scan are the colored dots, white dots are the point cloud (unrelated), and the costmap is the white+black-ink square (also looks weird).

Nav2-SLAM-Example has maps and laserscan properly aligned and positioned:

[jankolkmeier]

FIY, I just ran into the same issue, tried to work around it by changing the QoS in ros_tcp_endpoint/subscriber.py to reliability=ReliabilityPolicy.BEST_EFFORT. While that fixed the issue, paradoxically, it also fixed it when using the default ros_tcp_endpoint, so I'm not sure if it is really related to any QoS settings.

[chwu-rwth]

@jankolkmeier Hi, I am having the issue where there is incompatibility issue with Unity and ROS. The laser scanner driver that we are using uses BEST EFFORT, but unity apparently only supports RELIABLE. I tried looking into the subscriber.py to change the QoS, but i cant seem to find the line of code of:
reliability=ReliabilityPolicy

Do you mind double checking if that is still a valid solution?

[KingKiger]

Change the qos_profile in ros_tcp_endpoint/subscriber.py like this:
qos_profile = QoSProfile(depth=queue_size, reliability=QoSReliabilityPolicy.BEST_EFFORT)

Hope this helps.

[chwu-rwth]

@KingKiger This is the subscriber.py script that is from Unity-Technologies/ROS-TCP-Endpoint repo, unless I am missing something or looking at the wrong place, i do not see the where is qos_profile that you mentioned above. Or is this something i have to add somewhere?

#  Copyright 2020 Unity Technologies
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

import rospy
import socket
import re

from .communication import RosReceiver
from .client import ClientThread


class RosSubscriber(RosReceiver):
    """
    Class to send messages outside of ROS network
    """

    def __init__(self, topic, message_class, tcp_server, queue_size=10):
        """

        Args:
            topic:         Topic name to publish messages to
            message_class: The message class in catkin workspace
            queue_size:    Max number of entries to maintain in an outgoing queue
        """
        strippedTopic = re.sub("[^A-Za-z0-9_]+", "", topic)
        self.node_name = "{}_RosSubscriber".format(strippedTopic)
        RosReceiver.__init__(self, self.node_name)
        self.topic = topic
        self.msg = message_class
        self.tcp_server = tcp_server
        self.queue_size = queue_size

        # Start Subscriber listener function
        self.sub = rospy.Subscriber(self.topic, self.msg, self.send)

    def send(self, data):
        """
        Connect to TCP endpoint on client and pass along message
        Args:
            data: message data to send outside of ROS network

        Returns:
            self.msg: The deserialize message

        """
        self.tcp_server.send_unity_message(self.topic, data)
        return self.msg

    def unregister(self):
        """

        Returns:

        """
        if not self.sub is None:
            self.sub.unregister()