Lolita390's profile - activity

I replied in EDIT1.

Hello,

I am trying to use a quadrotor with ROS moveit! The driver node of the quadrotor publishes a tf tree, which contains odom, base, frontcam and bottomcam, where odom is the parent frame of base and base is the parent frame of frontcam and bottom cam. Besides this diver I am running a Slam algorithm, which publishes another tf tree, which contains two frames, map and sensor.

When setting up moveit with a urdf model, I create a virtual link between the map frame from the slam algorithm and the base link of the quadrotor. When I launch the resulting demo.launch I get the following warn messages:

[ WARN] [1448659454.360465559]: Unable to transform object from frame 'ardrone_base_frontcam' to planning frame 'Map' (Could not find a connection between 'Map' and 'ardrone_base_frontcam' because they are not part of the same tree.Tf has two or more unconnected trees.) 
[ WARN] [1448659454.360597000]: Unable to transform object from frame 'ardrone_base_link' to planning frame 'Map' (Could not find a connection between 'Map' and 'ardrone_base_link' because they are not part of the same tree.Tf has two or more unconnected trees.) 
[ WARN] [1448659454.360687375]: Unable to transform object from frame 'ardrone_base_bottomcam' to planning frame 'Map' (Could not find a connection between 'Map' and 'ardrone_base_bottomcam' because they are not part of the same tree.Tf has two or more unconnected trees.) 
[ WARN] [1448659454.360741781]: No transform available between frame 'odom' and planning frame 'Map' (Could not find a connection between 'Map' and 'odom' because they are not part of the same tree.Tf has two or more unconnected trees.)

Apparently I need to publish transforms to connect the trees and have only one. I see the following problem: on one tree odometry is being published from the IMU. I am not interested in this data, I only wish to represent the pose of the urdf model in rviz with the data from the Slam algorithm. I would like the base of the quadrotor to share the pose output from the sensor frame.

Any help is appreciated. Thanks

EDIT1: I cannot provide the tf frames right now because I do not have the quadrotor with me, for now, I can give a brief explanation of this. I am using visual slam Ptam so in one tree I have map and sensor, where map is the fixed frame. In the other tf tree I have odom followed by base and the two children of base are frontcam and bottomcam. In this post ( [ http://answers.ros.org/question/21682... ] I read that there would have to be a static transform between world and odom. I have found no files for parameter configuration.

What could the problem be?

I cannot launch octomap. The following warning comes up : "Nothing to publish, octree is empty". The frame I write in the launch file is the same as the fixed frame in rviz, which is "world". No transform is required, since the slam algorithm outputs the point cloud already in the world frame

Hello,

I do not understand why I get the following message when launching octomap: "Nothing to publish, octree is empty". I have remapped "cloud_in" topic to the according pointcloud topic and the fixed frame in the launch file corresponds to the fixed frame in rviz. I have checked my launch file for typos, but the input topic and frame_id are written correctly. I ran "rostopic echo points2" (points2 is my remapped input pointcloud topic) and I verified that the pointcloud is indeed being published to this topic. What could the problem be?

Thanks.

<launch>
<node pkg="octomap_server" type="octomap_server_node" name="octomap_server" output="screen" >
    <param name="resolution" value="0.05" />

    <!-- fixed map frame (set to 'map' if SLAM or localization running!) -->
    <param name="frame_id" type="string" value="World" />

    <!-- maximum range to integrate (speedup!) -->
    <param name="sensor_model/max_range" value="5.0" />

    <!-- data source to integrate (PointCloud2) -->
    <remap from="cloud_in" to="points2" />


</node>

</launch>

Hello,

I am receiving a sparse point cloud from a monocular slam algorithm. My question is if octomap_mapping is suitable for obstacle detection if my input pointcloud is sparse and I do not use a laser as sensor? If so, what changes would have to be made to octomap?

EDIT: Thanks for the reply. I configured the launch file of octomap and remapped it to the right point cloud topic, but nothing occurs. I checked the publisher topics of octomap, but I get the message that the topics have not been published yet. What could be the cause of this? Could you give me any hint about this please.Also I was not sure about the configuration of the following line in the launch file: param name="sensor_model/max_range" value="5.0"

In this particular case I am dealing with a world frame, which is the origin of the world, and a robot position which is the target frame. The frame_id of my marker is the world frame. Could you please give me a little more detail of what I should do to correct this. Thanks.

Sorry. Aparrently with tf::createQuaternionMsgFromYaw(yaw) function, the marker does not even rotate. When I use tf::createQuaternionMsgFromRollPitchYaw(0.0,yaw,0.0) function rotation of the marker ocurrs, but still on the undesired axes. In this particular case I am dealing with a world frame, which is the origin of the world, and a robot position which is the target frame. The frame_id of my marker is the world frame. Could you please give me a little more detail of what I should do to correct this. Thanks.

Hello,

From a downloaded project I have access to a marker in rviz which is defined by position and orientation(quaternion). However, I would like to create a marker at the same position and with only the yaw as orientation. This means that roll and pitch should be zero and even though the original marker were to have roll and pitch, the second marker should only rotate when there is a variation in yaw. In this way the marker I create should only move on a 2D plane. I used the following function to create the quaternion for my marker: q = tf::createQuaternionMsgFromYaw(yaw); where q is a geometry_msgs::qauternion. Then I pass q.x, q.y, q.z and q.w to my marker.

tf::Matrix3x3(transform.getRotation()).getRPY(pitch, yaw, roll);
geometry_msgs::Quaternion q;
q = tf::createQuaternionMsgFromYaw(yaw);
oPose_msg.orientation.x = q.x;
oPose_msg.orientation.y = q.y;
oPose_msg.orientation.z = q.z;
oPose_msg.orientation.w = q.w;

However when observing in Rviz my marker still tilts in roll and pitch as the original marker does. Why is this and what could I change to achieve the output I desire?

Note: I obtain roll, pitch and yaw from a rotation matrix. These are in this order to be consistent with the designated angles. I have the same problem when using q = tf::createQuaternionMsgFromRollPitchYaw(0.0,yaw,0.0); instead of q = tf::createQuaternionMsgFromYaw(yaw);