obotic's profile - activity

Recording bag files over network with shared timestamp I have 3 machines that are networked together with one serving as

I am running a tile map plugin for mapviz. As I move my mouse on the map I can see the GPS coordinates changing on the ui interface. I also used the swri_transform_util to give my robot a lat/lon xy origin. Now I am trying to use the point click publisher to get lat/lon coordinates when a place on the map is clicked. I am not sure what the tile map frame is however. I can get my robot's local xy position when I click on the map, but not sure how to transform it to the lat/lon coordinate.

I have a set of gps navsatfix points that are recorded within a visible physical boundary when viewed on a google satellite image. I am using rviz_satellite to view the utm points on the satellite image, but I noticed that my trajectory is drifting south over time. Based on the answer given below regarding rviz float32 precision:

http://answers.ros.org/question/33624...

I changed my tf transform to:

tf::Transform transform;
transform.setOrigin( tf::Vector3( (utmpoint.easting-easting_ref), (utmpoint.northing-northing_ref), utmpoint.altitude ));
tf::Quaternion q;
q.setRPY(0, 0, 0);
transform.setRotation(q);
br.sendTransform(tf::StampedTransform(transform, msg->header.stamp, frame_fix_origin, frame_robot));

where ref_easting and ref_northing are utm points captured from my first incoming gps message, therefore now my first tf x,y coordinate starts at (0,0). On rviz Fixed Frame is set to frame_fix_origin and Robot frame(from rviz_satellite package) is set to frame_robot, but I still see the drift happening.

If I use another mapping visualization tool called mapviz(which has its own lat long to local xy coordinate system) and feed it my gps coordinates(using same maptile URI source) everything is displayed correctly, there is no drift. So I think my raw /fix coordinates are fine. Either I'm doing the transformation wrong when giving it to rviz or maybe the rviz_satellite is not projecting the satellite images correctly or it's something else.

I guess my question is has anyone used rviz_satellite and been able to plot their utm points without seeing this drift?

Well I still don't know why the drift happens, but I started to do the navsatfix to local coordinate transformation simi

utm points drifting on rviz over time I have a set of gps navsatfix points that are recorded within a visible physical b

utm points drifting on rviz over time I have a set of gps navsatfix points that are recorded within a visible physical b

As I was looking in some of the other swri packages there is a function called Wgs84FromLocalXy in package swri_transfor

Thanks Geoff, I forgot about that utility. I saw that there was no frame from the tile map which then made me realize ma

mapviz - transforming local xy coordinate frame to tile map lat/lon coordinate frame I am running a tile map plugin for

Thanks I think this may be the solution to our problem, I will test it out and post an update.

Ok I think I understand what you are saying, but let's say my imu was mounted 40deg in the positive yaw relative to /base_link. Now if the imu sees a roll, the /base_link needs to interpret the imu's roll as a combination of pitch and yaw. I know the yaw is 40(I think) but how would I know the pitch

Sorry I meant to say "(new_roll,new_pitch,new_yaw) to be (80,100,120)" not (80,90,120)

Hello, I have two frames on my robot, /base_link and /frame_imu. The imu is positioned 90deg in the positive yaw direction relative to the robot center(or /base_link). So basically a roll in the imu's coordinate frame would correspond to a pitch in the robot's coordinate frame. From what I understand I should be able to use TF's transform_broadcaster to broadcast this transformation:

  tf::Transform transform;
  transform.setOrigin( tf::Vector3(0.0, 0.0, 0.0) );
  transform.setRotation( tf::createQuaternionFromRPY(0,0,M_PI/2) );
  tf_broadcast->sendTransform(tf::StampedTransform(transform, ros::Time::now(), "/base_link", "imu_frame"));

At first I thought if I just use TF's lookupTransform I could get the correct transformation between frames(my imu's frame_id is set to /imu_frame):

void imuCallback(const sensor_msgs::Imu::ConstPtr& msg){
tf::StampedTransform transform;

listener->waitForTransform("/base_link",
                                    msg->header.frame_id,
                                    msg->header.stamp,
                                    ros::Duration(3.0));

listener->lookupTransform("/base_link",
                                  msg->header.frame_id,
                                  msg->header.stamp,
                                  transform);

That just gives me the transformation (0,0,M_PI/2), then I could use TF's transformQuaternion to actually perform the rotation from the imu's frame to the robot's frame:

geometry_msgs::QuaternionStamped imu_quat = geometry_msgs::QuaternionStamped();
imu_quat.header = msg->header;
imu_quat.quaternion = msg->orientation;
geometry_msgs::QuaternionStamped q_robot;
listener->transformQuaternion("base_link",msg->header.stamp,imu_quat, imu_quat.header.frame_id, q_robot);
tf::Quaternion quatquat;
tf::quaternionMsgToTF(q_robot.quaternion,quatquat);
tf::Matrix3x3(quatquat).getEulerYPR(new_yaw,new_pitch,new_roll);

What happens is if my imu reads a (Yaw,Pitch,Roll) of say (80,10,120) I would expect my (new_roll,new_pitch,new_yaw) to be (80,90,120) but instead I get (170,10,120) so it just adds the yaw factor. Is trasnformQuaternion the right method for what I want to achieve? Any help to point me in the right direction would be greatly appreciated.

EDIT/UPDATE:

Well I don't think the twists really made a difference. I imagined that if my frame transformation setup is:

  tf::Transform transform;
  transform.setOrigin( tf::Vector3(0.0, 0.0, 0.0) );
  transform.setRotation( tf::createQuaternionFromRPY(0,0,M_PI/2) );
  tf_broadcast->sendTransform(tf::StampedTransform(transform, ros::Time::now(), "/base_link", "imu_frame"));

And I have the twists set up like so:

        geometry_msgs::Twist robot_twist;
        listener.lookupTwist("/imu_frame","/base_link",ros::Time(0),ros::Duration(3.0),robot_twist);

Then if I perform a roll on my /imu_frame, I should see an angular velocity increase on the pitch(robot_twist.angular.y) of my /base_link , but I still see the angular velocity of roll(robot_twist.angular.x) increasing on /base_link . It may be that I am not doing the broadcast of frame transforms correctly