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2019-08-09 17:06:50 -0500 marked best answer Extracting compressed image data from bag file results in doubled up or dropped frames

Hi,

I'm trying to extract compressed images from a bag file. Here is my launch file:

<launch>   
  <!-- Play Bag File -->   
  <node pkg="rosbag" type="play" name="rosbag" required="true" args="-r
  0.2 /media/nick/Samsung\ USB/bag_files/_2018-07-20-16-30-09.bag"/>

  <!-- Uncompress images -->   
  <node pkg="image_transport" type="republish" name="decompress_node" args="compressed in:=/webcam1/image out:=/webcam1/image" />

  <!-- Extract images -->
  <node name="extract" pkg="image_view" type="extract_images" respawn="false" required="true" output="screen" cwd="ROS_HOME">
    <remap from="image" to="/webcam1/image"/>
  </node>
</launch>

This results in some frames not being saved and some frames being saves multiple times. Also a lot of frames are saved out of order so the video I make out of the frames is really choppy.

2019-05-20 02:20:09 -0500 marked best answer Waypoint specific yaw_goal_tolerance for move base

Is there any way to specify a yaw_goal_tolerance for each waypoint you send to move_base? Sometimes I care which direction it ends up in and other times I don't care. And using dynamic reconfigure sounds overly complicated and would result in much less readable code and would be harder to debug.

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2019-03-08 15:31:08 -0500 asked a question AMCL Time-based updating

AMCL Time-based updating Hi, I am using an Rover Robotics OpenRover to run AMCL on a robot and I see that AMCL updates

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2019-02-07 16:56:02 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:54:21 -0500 commented answer ROS2 Debugging Techniques

Ah okay. I have tried to update my CMakesLists.txt and package.xml but am still getting an error. I have updated my ques

2019-02-07 16:42:12 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:41:11 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:40:30 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:40:06 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:36:32 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:36:00 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:35:12 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:33:56 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:32:55 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:30:48 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:29:36 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 16:24:04 -0500 edited question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-02-07 15:52:57 -0500 asked a question ROS2 Debugging Techniques

ROS2 Debugging Techniques I'm just getting started learning ROS2 and I'm going through the tutorials. I am trying to cre

2019-01-29 10:36:43 -0500 marked best answer Static global map updating

Hi,
I have the ROS navigation stack running on a robot. I can choose a point in RVIZ for the robot to navigate to and it is working well, except for sometimes the robot will start doing clearing rotations because it can't find a route through the global map. I then check the global map and see that obstacles have been put into it even though I have it set to be a static map.

Also in RVIZ the global map sometimes doesn't update until I toggle it off and back on again.

Here is my global_costmap_params.yaml

global_costmap:
  global_frame: /map
  robot_base_frame: base_link
  update_frequency: 5.0
  static_map: true

And here is the part of my launch files that loads move_base

<node pkg="move_base" type="move_base" name="move_base" >
    <rosparam file="$(find goose_chaser_main)/move_base_config/costmap_common_params.yaml" command="load" ns="global_costmap" />
    <rosparam file="$(find goose_chaser_main)/move_base_config/costmap_common_params.yaml" command="load" ns="local_costmap" />
    <rosparam file="$(find goose_chaser_main)/move_base_config/local_costmap_params.yaml" command="load" />
    <rosparam file="$(find goose_chaser_main)/move_base_config/global_costmap_params.yaml" command="load" />
    <rosparam file="$(find goose_chaser_main)/move_base_config/base_local_planner_params.yaml" command="load" />
</node>

Also is there a way to verify that my .yaml file is being loaded?

Update:
I verified that the .yaml file is indeed being loaded by running

rosparam get /move_base/global_costmap/static_map

Which returned: true

Update 2

I am running move_base with the default recovery behavior which includes clear_costmap_recovery, so I'm confused at why this recovery isn't working

Here is a picture of a situation where my robot failed to find a valid plan image description

Update 3

Here are my config files:

base_local_planner_params.yaml
local_costmap_params.yaml
global_costmap_params.yaml
costmap_common_params.yaml

2019-01-25 16:26:35 -0500 commented answer How to start a ROS node on startup??

I've started using systemctl instead of upstart. Seems like that's the way the linux community is going. In order to do

2019-01-09 07:29:14 -0500 marked best answer ROS Logging Display Node Name

Hi,

I'm very sorry if this is a repeat question, but I'm using robot_upstart which dumps all logging output into the single file /var/log/upstart/foo.log. This makes it really hard to tell which node is talking. I'm currently getting the generic error "Failed to open port" and I'm not sure how to figure out where this message is coming from.

Is there a way to get ROS logging to display to node name?

2018-12-14 16:54:28 -0500 marked best answer ROS Unreliable Cell Signal

Hi,

I am using ROS to control robots that are many miles away. Each robot has a cell modem to connect to the internet. I use my laptop and tinc VPN to access the robots.

I need the ability to drive the robots around manually from inside the office. I find it easiest to plug an Xbox controller into my laptop and run the ROS Joy node. I also want to be able to drive the robot with my phone or tablet if I run out to the field to check on something.

image description

Lost signal problem
Currently if I lose cell signal the robot keeps doing the last command it was told.

Re-connection problem
When the robot reconnects it starts doing old commands

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2018-11-30 12:41:47 -0500 marked best answer The impact of installing packages via apt-get or source on portability

I am wondering if the choice one makes between installing packages via apt-get or from source has any impact on how easy it then becomes to install on another computer. It seems to me that since apt-get installs packages in the opt folder, that you would have to install all of those packages on the new computer before running your code. That would be a major hassle if you have dozens of packages. But from what I've read it seems like people prefer apt-get to building from source because its easier. Is this just because people generally aren't transferring their code, or am I missing something? Please be specific with answers.

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2018-09-13 03:53:27 -0500 marked best answer Multiple nodelets in the same package

I am trying to create a package that performs multiple computer vision tasks. I want to nodeletize both tasks to take advantage of zero-copying of the images. Working off the examples below I have been able to create a single nodelet successfully, but am running into naming issues when trying to catkin_make my package with a second nodelet.

http://www.clearpathrobotics.com/asse...
https://github.com/ros/common_tutoria...
http://wiki.ros.org/nodelet/Tutorials
http://wiki.ros.org/usb_cam

I was surprised that I couldn't find any examples of packages with multiple nodelets to reference. Is this because its bad practice?

If not does anyone have an example of what the CMakeLists.txt and nodelets.xml files should look like for multiple nodelets?

2018-09-12 09:22:42 -0500 marked best answer mapviz - missing multi-res-image and tile-map plugins

I'm trying to use mapviz to plot the location of a robot on a geo-referenced map. The multi-res-image plugin for mapviz seems perfect for my application but when I click add the options are missing for multi-res-image and tile map.

I installed using apt-get like so sudo apt-get install ros-indigo-mapviz ros-indigo-mapviz-plugins I'm using ROS Indigo on Ubuntu 14.04.

Should I try installing from source?

2018-08-29 16:05:39 -0500 asked a question Multiple nodelets in the same package

Multiple nodelets in the same package I am trying to create a package that performs multiple computer vision tasks. I wa

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2018-08-08 01:21:53 -0500 marked best answer rosdep basic usage

Hi,

I have a couple packages that depend on python libraries ( one depends on rtklib and the other on mxnet)

My first question is do these belong in my package.yml file

  <build_depend>rtklib</build_depend>  
  <run_depend>rtklib</run_depend>

and

  <build_depend>mxnet</build_depend>  
  <run_depend>mxnet</run_depend>

I'm trying to get the hang of rosdep by doing a simpler example with pygame. I included

 <run_depend>pygame</run_depend>

in my package.yml and then ran rosdep install <my-package>

but I get the error:

ERROR: the following packages/stacks could not have their rosdep keys resolved to system dependencies: rosdep_tutorial: Cannot locate rosdep definition for [pygame]

I also tried python_pygame but that did not work either

UPDATE:
Okay, I got my pygame example working by using python-pygame because I found out that rosdep is using the apt package manager. Now I'm stuck because neither rtklib or mxnet are able to be install via apt. How should these be installed?

2018-08-03 17:22:29 -0500 commented answer robot rotation in place speed lower then minimum

Are you saying your solution was to change the source code? That seems like a hokey fix, the parameter should be loaded

2018-07-30 08:48:47 -0500 marked best answer Wheel Odometry Covariance

Hi,

I am using robot_localization. I'm using the typical setup

EKF1 fuses encoders + IMU
EKF2 fuses encoders + IMU + GPS

My question is about encoder covariances. The robot_localization documentation says

  • If the odometry provides both position and linear velocity, fuse the linear velocity.
  • If the odometry provides both orientation and angular velocity, fuse the orientation.

Following this advice I am fusing the orientation that the wheel encoders report, but I don't know what to set the encoders pose covariance to. Logically I would think the pose covariance should grow every time you move. It would just keep growing and growing without bound. But when I look at the example pose covariance diagonals of the diff_drive_contoller package it says to use static values

pose_covariance_diagonal: [0.001, 0.001, 1000000.0, 1000000.0, 1000000.0, 0.03]

I'm very confused because diff_drive_controller seems like a commonly used package but those covariances don't make sense to me.