david.c.liebman's profile - activity

I have created my own msg files and would now like to use them in python. One line trips me up over and over.

from my_package.msg import *

I get an error like this:

ImportError: No module named my_package

I do believe I have written the '.msg' files correctly, and I have executed 'catkin_make' successfully on the workspace I'm using for ros development. I also believe I've edited the CMakeLists.txt file correctly.

cmake_minimum_required(VERSION 2.8.3)
project(my_package)


find_package(catkin REQUIRED COMPONENTS
  geometry_msgs
  roscpp
  rospy
  std_msgs
  message_generation
  map_store
)

add_message_files(
  FILES
  MapListEntryList.msg
  MapListElement.msg
#   Message2.msg
)

generate_messages(
  DEPENDENCIES
  #my_package
#  MapListEntryList  
#   geometry_msgs#   std_msgs
)

catkin_package(
#  INCLUDE_DIRS include
  LIBRARIES my_package map_store
  CATKIN_DEPENDS message_runtime geometry_msgs roscpp rospy std_msgs
#  DEPENDS system_lib
)

include_directories(
  ${catkin_INCLUDE_DIRS}
)

 install(PROGRAMS
   scripts/turtlebot_listen.py
   scripts/turtlebot_map.py
   DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
 )

The two .msg files are trivial:

# MapListEntryList.msg
# num of available maps/ num of maps in list
int8 len

# list of available map_id objects
my_package/MapListElement[] list

and

# MapListElement.msg

string name
string id

I can use rosmsg to look at both messages. If anyone can point out what I'm doing wrong, I'd be grateful.

I'm trying to use amcl on the turtlebot robot. My amcl launch file is modified from the android app_manager amcl launcher. I have authored several of my own rapp files, and that part seems to work for now. I am able to load amcl and a map file, and then once one is loaded I can try to programmatically designate start (/initialpose) and stop (/move_base_simple/goal) coordinates. After doing so I even observe a small blue line on rviz that covers what I expect would be the path of the robot, BUT the robot doesn't move. I get the following two errors. The first on I get on the rviz computer. The second one I get on the Turtlebot computer.

[ERROR] [1394045389.663173820]: TF_NAN_INPUT: Ignoring transform for child_frame_id "odom" from authority "/app_manager/application/amcl" because of a nan value in the transform (-nan -nan nan) (-nan -nan -nan -nan)

[ERROR] [1394045392.583904722]: You must specify at least three points for the robot footprint, reverting to previous footprint.

EDIT 1: This is my launcher file. It comes almost directly from the android example. BTW I would like to get rid of the functionality that sends images to the android phone. I'm actually using a rosbridge server interface to control the robot and I don't need to see images from the kinect. Maybe I don't need the optimization code too. Also I'm using hydro on an ubuntu 12.04 system.

<launch>
  <include file="$(find turtlebot_bringup)/launch/minimal.launch"/>
  <include file="$(find tele_presence)/launch/minimal.launch"/>

  <!-- *********************** Teleoperation ********************** -->
  <param name="camera/rgb/image_color/compressed/jpeg_quality" value="22"/>

  <include file="$(find turtlebot_bringup)/launch/3dsensor.launch">
    <arg name="rgb_processing" value="true" />
    <arg name="depth_registration" value="false" />
    <arg name="depth_processing" value="false" />
  </include>

  <!-- Make a slower camera feed available. -->
  <node pkg="topic_tools" type="throttle" name="camera_throttle" args="messages camera/rgb/image_color/compressed 5"/>

  <node pkg="nodelet" type="nodelet" name="teleop_velocity_smoother"
        args="load yocs_velocity_smoother/VelocitySmootherNodelet /mobile_base_nodelet_manager">
    <rosparam file="$(find turtlebot_bringup)/param/defaults/smoother.yaml" command="load"/>
    <remap from="teleop_velocity_smoother/raw_cmd_vel" to="android/virtual_joystick/cmd_vel"/>
    <remap from="teleop_velocity_smoother/smooth_cmd_vel" to="/cmd_vel_mux/input/teleop"/>

    <!-- Robot velocity feedbacks; use the one configured as base default -->
    <remap from="teleop_velocity_smoother/odometry" to="/odom"/>
    <remap from="teleop_velocity_smoother/robot_cmd_vel" to="/mobile_base/commands/velocity"/>
  </node>

  <!-- *********************** Optimisation *********************** -->
  <node pkg="tf" type="tf_change_notifier" name="tf_throttle_for_android_gui">
    <param name="polling_frequency" value="5"/>
    <param name="translational_update_distance" value="-1"/>
    <param name="angular_update_distance" value="-1"/>
    <rosparam param="frame_pairs">
      - {source_frame: base_footprint, target_frame: map}
      - {source_frame: camera_depth_frame, target_frame: map}
    </rosparam>
  </node>


  <!-- *************************** Navi *************************** -->
  <include file="$(find turtlebot_navigation)/launch/includes/move_base.launch.xml">
    <arg name="odom_topic" value ="/odom" />
  </include>
  <include file="$(find turtlebot_navigation)/launch/includes/amcl.launch.xml">
    <arg name="use_map_topic" value ="true"/>
  </include>


  <!-- *************************** Maps *************************** -->
  <!-- this launcher lets me use some map_store services -->

    <include file="$(find tele_presence)/launch/manage_map.launch"/>
</launch>

How do I specify the robot footprint? Will doing so help at all with the TF amcl error?

I am having some trouble. I have found a resource online for the 'android_map_manager', for example.

http://wiki.ros.org/android_map_manager

I have figured out how to start the app from my program. Now I would like to use some of the services that the online resource says are available to me. I cannot see them (they are services) when I type 'rossrv list' and when I try to access them from my program I get a message like this:

[ERROR] [WallTime: 1391876649.155091] [Client 0] [id: call_service:/android/list_maps:31] call_service InvalidServiceException: Service /android/list_maps does not exist

I feel though that this should work, as I know the app manager is running. I have this in my logs:

[WARN] [WallTime: 1391877076.029768] App Manager : an app is already running [turtlebot_core_apps/android_map_manager]

If I could find out how to list the maps, I could figure out how to rename, delete, etc. My next goals are to implement services in the 'android_make_a_map' rapp and possibly the nav rapp too. I did notice that the map_store package is being started by the launcher. Is the map_store package working independently of the map_manager? The launcher that I'm using is a slightly modified version of the 'minimal_with_appmanager.launch' file. Thanks.

On the turtlebot I am trying to launch the amcl demo after launching the gmapping demo, but without shutting down all of ros.

Usually I can get the gmapping to work (that's the first demo I test) and then the amcl will partially work. I can load a map using 'map_store' and then see the map on the rviz screen. I also can usually see the turtlebot on the rviz screen. I have trouble directing the turtlebot, though, and I don't exactly know why.

When I look at the RobotModel listing under the 'Displays' box in rviz it's red, and the cause is that the tf's from all the components are red. (base_footprint, base_link, etc., all red). They all say 'No transform from [base_footprint] to [map]'. When I execute view_frames and look at the pdf it says "no tf data received". When I type rostopic list '/tf' comes up as one of my topics. Is there something I can start that will restart the tf data in the turtlebot?

If I don't start gmapping first I can usually load a map and direct the turtlebot with /initialpose, etc.

I am working on a project where I want to be able to launch the turtlebot gmapping demo immediately after the amcl demo. I do not want to add to a map that I've already been navigating, instead I want to clear the map that was used by the amcl navigation demo and start a new one. The problem I have is that the /map topic seems to hold the values that the navigating demo was using. I don't want to quit ros and start it over again. What I was hoping was that there was some way to clear the map and proceed from there.

How does one clear a topic to the state of emptyness or the state of not being published at all? Can this be done programmatically? Does this make sense?

what does ROI mean? Can someone link me to something that points out how this is used? I see it has an OccupancyGrid in it. I'm looking for a little direction. Any help would be appreciated. Thanks.

I'm trying to make a single app that controls a turtlebot robot. I would like to be able to run the gmapping software that makes a map at one point and then switch to the software that navigates the map, all from the interface of my program. I am under the impression that these elements don't work well together, so I want to be able to start one node that does the gmapping and then stop that node and start the node that does the navigating -- all from my program.

I was searching on line and I found that there used to be software called rosspawn. (I'm not even sure if this would do what I want) anyway I don't think it's part of hydro???

So what I'm looking for is a master node that allows me to configure several other nodes at startup and then allows me to start and stop these other nodes either by service or through some topic publishing scheme. Any help would be appreciated.

How do I publish this test data to the /map topic. I would like to use this routine to test other things I'm working on. I think I'm doing it right but when I type 'rostopic echo /map' I see nothing. If I run the script at the command prompt after typing 'roscore' in another terminal I see the test OccupancyGrid on the screen. I don't know what I'm doing wrong.

#!/usr/bin/env python

import rospy
import sys


from nav_msgs.msg import *
from std_msgs.msg import *

def map_stuff():
    rospy.init_node('turtlebot_map', anonymous=True)
    if not rospy.is_shutdown():
        create_map()
        rospy.spin()

def create_map( ):
    test_map = OccupancyGrid()
    test_map.info.resolution = 1.0 
    test_map.info.width = 10
    test_map.info.height = 10
    test_map.info.origin.position.x = 0.0 
    test_map.info.origin.position.y = 1.0 
    test_map.info.origin.position.z = 2.0 
    test_map.info.origin.orientation.x = 3.0 
    test_map.info.origin.orientation.y = 4.0 
    test_map.info.origin.orientation.z = 5.0 
    test_map.info.origin.orientation.w = 6.0 
    test_map.data = []
    for i in range(0, 100):
        test_map.data.append(i)
    print test_map
    map_pub = rospy.Publisher('/map', OccupancyGrid)
    map_pub.publish(test_map);
    return 

if __name__ == '__main__':
    try:
        map_stuff()
    except rospy.ROSInterruptException:
        pass

I followed online tutorials as closely as I could. Any help would be appreciated.

Is it possible to make a ros python node that has more than one subscriber and more than one publisher? Are there examples of this?

I'm working on a kinect project. I'm trying to write a pair of files that test out the PointCloud2 sensor message. I don't know how to make the 'listener' python script read the value that I have created in the 'talktest' script. I am using the class defined here:

sensor_msgs/point_cloud2.py (I could not post a link)

This is my code. These are my includes. I use them pretty much the same in both files.

#!/usr/bin/env python
import rospy
import sensor_msgs.point_cloud2 as pc2
from sensor_msgs.msg import PointCloud2, PointField

This is the 'talktest' code.

#talktest
def test():
    rospy.init_node('talktest', anonymous=True)
    pub_cloud = rospy.Publisher("camera/depth_registered/points", PointCloud2)
    while not rospy.is_shutdown():
        pcloud = PointCloud2()
        # make point cloud
        cloud = [[33,22,11],[55,33,22],[33,22,11]]
        pcloud = pc2.create_cloud_xyz32(pcloud.header, cloud)
        pub_cloud.publish(pcloud)
        rospy.loginfo(pcloud)
        rospy.sleep(1.0)

if __name__ == '__main__':
    try:
        test()
    except rospy.ROSInterruptException:
        pass

Then I have written a script that listens for point cloud data. It always throws a AttributeError.

#listener
def listen():
    rospy.init_node('listen', anonymous=True)
    rospy.Subscriber("camera/depth_registered/points", PointCloud2, callback_kinect)

def callback_kinect(data) :
    # pick a height
    height =  int (data.height / 2)
    # pick x coords near front and center
    middle_x = int (data.width / 2)
    # examine point
    middle = read_depth (middle_x, height, data)
    # do stuff with middle


def read_depth(width, height, data) :
    # read function
    if (height >= data.height) or (width >= data.width) :
        return -1
    data_out = pc2.read_points(data, field_names=None, skip_nans=False, uvs=[width, height])
    int_data = next(data_out)
    rospy.loginfo("int_data " + str(int_data))
    return int_data


if __name__ == '__main__':
    try:
        listen()
    except rospy.ROSInterruptException:
        pass

I always get this error:

[ERROR] [WallTime: 1389040976.560028] bad callback: <function callback_kinect="" at="" 0x2a51b18=""> Traceback (most recent call last):
File "/opt/ros/hydro/lib/python2.7/dist-packages/rospy/topics.py", line 681, in _invoke_callback cb(msg) File "./turtlebot_listen.py", line 98, in callback_kinect left = read_depth (left_x, height, data) File "./turtlebot_listen.py", line 126, in read_depth int_data = next(data_out) File "/opt/ros/hydro/lib/python2.7/dist-packages/sensor_msgs/point_cloud2.py", line 74, in read_points assert isinstance(cloud, roslib.message.Message) and cloud._type == 'sensor_msgs/PointCloud2', 'cloud is not a sensor_msgs.msg.PointCloud2' AttributeError: 'module' object has no attribute 'message'

Can anyone tell me how to use this library correctly?