choog's profile - activity

Hello,

Does anyone know if there is a function that lets you read a specific tf frame such as:

.readFrame("/base_link" , time(latest info published), //frame reference);

I need to be able to read a specific frame. I know you can do: tf::StampedTransform transform; .lookUpTransform("target frame", "original frame" , time , transform);

The reason why I don't want a lookUpTransform is because I am actually not trying to take the transform of anything here. Unless I am not understanding something here, I would appreciate some feed back here.

This is what I have so far. Please give me some feed back on the frames that I am using. Because to my understanding The "base_link" frame should be transformed to the "map" frame, If I have a .yaml map file running on top of the navigation stack right?

  #include <ros/ros.h>
#include <geometry_msgs/Twist.h>
#include <geometry_msgs/TransformStamped.h>
#include <tf/transform_listener.h>
#include <tf/transform_broadcaster.h>
#include <tf/transform_broadcaster.h>

using namespace std;

int main(int argc, char** argv) {
    ros::init(argc, argv, "readTFframe");
    ros::NodeHandle nh;
        tf::Transform leader_base_link;
    tf::Quaternion q;
    tf::Vector3 v;  
    tf::TransformListener listener;
    geometry_msgs::TransformStamped transformConverter;

    ros::Time current_time, last_time;
        current_time = ros::Time::now();
        last_time = ros::Time::now();

    ros::Publisher pub = nh.advertise<geometry_msgs::TransformStamped>("/leader/tf", 1);

    static tf::TransformBroadcaster br;

    double yaw; 


ros::Rate loopRate(10);
while(ros::ok()){
    tf::StampedTransform transform;
    current_time = ros::Time::now();


    try {
                        listener.waitForTransform("base_link", "base_footprint", ros::Time(0), ros::Duration(10.0));
            listener.lookupTransform("base_link", "base_footprint", ros::Time(0), transform);
        }
        catch (tf::TransformException &ex) {
            ROS_ERROR("%s",ex.what());
        }
    yaw =   tf::getYaw(transform.getRotation()); 
        v.setValue(transform.getOrigin().x() , transform.getOrigin().y() , transform.getOrigin().z());

    leader_base_link.setOrigin(v);
    q.setRPY(0.0, 0.0, yaw);
    leader_base_link.setRotation(q );
    br.sendTransform(tf::StampedTransform(leader_base_link, ros::Time::now(), "base_footprint", "leader_base_link"));

/*
    ROS_INFO_STREAM("X pose " <<  transform.getOrigin().x() );
    ROS_INFO_STREAM("Y pose " << transform.getOrigin().y() );
    ROS_INFO_STREAM("Z pose " << transform.getOrigin().z() );
    ROS_INFO_STREAM("Yaw "<< yaw );
*/  
double th = yaw;
 geometry_msgs::Quaternion odom_quat = tf::createQuaternionMsgFromYaw(th);
    transformConverter.header.stamp = current_time; 
    transformConverter.header.frame_id = "base_footprint";
    transformConverter.child_frame_id = "base_link";
    transformConverter.transform.translation.x = transform.getOrigin().x();
    transformConverter.transform.translation.y = transform.getOrigin().y();
    transformConverter.transform.translation.z = transform.getOrigin().z();
    transformConverter.transform.rotation = odom_quat;
    ROS_INFO_STREAM("X pose " <<  transformConverter.transform.translation.x );
    ROS_INFO_STREAM("Y pose " << transformConverter.transform.translation.y);
    ROS_INFO_STREAM("Z pose " << transformConverter.transform.translation.z );
    ROS_INFO_STREAM("Yaw "<< yaw );

    loopRate.sleep();
}

    return 0;
}

This is my current code when I run it I can see that the values are being passed to the transformConverter transform that is converting the desired transform from tf::StampedTransform to geometry_msgs::TransformStamped . This way it can be published on the topic /leader/tf. The only thing is I can see the values are passed through ROS_INFO. But they are not being published now on the topic.

Hello, I am getting this error:

In function ‘int main(int, char**)’: /home/turtlebot/catkin_ws/src/turtlebot_formation/src/readTFframe.cpp:70:24: error: no match for call to ‘(ros::Publisher) (geometry_msgs::TransformStamped&)’

I can clear see that the two types are compatible but for some reason cmake is telling me that no match all to (geometry_msgs::TransformStamped&) exists. If anyone can help me solve this issue it would be greatly appreciated.

#include <ros/ros.h>
#include <geometry_msgs/Twist.h>
#include <geometry_msgs/TransformStamped.h>
#include <tf/transform_listener.h>
#include <tf/transform_broadcaster.h>
#include <tf/transform_broadcaster.h>

using namespace std;

int main(int argc, char** argv) {
    ros::init(argc, argv, "readTFframe");
    ros::NodeHandle nh;
        tf::Transform leader_base_link;
    tf::Quaternion q;
    tf::Vector3 v;  
    tf::TransformListener listener;
    geometry_msgs::TransformStamped transformConverter;

    ros::Time current_time, last_time;
        current_time = ros::Time::now();
        last_time = ros::Time::now();

    ros::Publisher pub = nh.advertise<geometry_msgs::TransformStamped>("/leader/tf", 1000); //error because of this

    static tf::TransformBroadcaster br;

    double yaw; 


ros::Rate loopRate(10);
while(ros::ok()){
    tf::StampedTransform transform;
    current_time = ros::Time::now();


    try {
                        listener.waitForTransform("base_link", "base_footprint", ros::Time(0), ros::Duration(10.0));
            listener.lookupTransform("base_link", "base_footprint", ros::Time(0), transform);
        }
        catch (tf::TransformException &ex) {
            ROS_ERROR("%s",ex.what());
        }
    yaw =   tf::getYaw(transform.getRotation()); 
        v.setValue(transform.getOrigin().x() , transform.getOrigin().y() , transform.getOrigin().z());

    leader_base_link.setOrigin(v);
    q.setRPY(0.0, 0.0, yaw);
    leader_base_link.setRotation(q );
    br.sendTransform(tf::StampedTransform(leader_base_link,     ros::Time::now(), "base_footprint", "leader_base_link"));

    double th = yaw;
    geometry_msgs::Quaternion odom_quat = tf::createQuaternionMsgFromYaw(th);
    transformConverter.header.stamp = current_time; 
    transformConverter.header.frame_id = "base_footprint";
        transformConverter.child_frame_id = "base_link";
    transformConverter.transform.translation.x = transform.getOrigin().x();
    transformConverter.transform.translation.y = transform.getOrigin().y();
    transformConverter.transform.translation.z = transform.getOrigin().z();
    transformConverter.transform.rotation = odom_quat;
    ROS_INFO_STREAM("X pose " <<  transformConverter.transform.translation.x );
    ROS_INFO_STREAM("Y pose " << transformConverter.transform.translation.y);
    ROS_INFO_STREAM("Z pose " << transformConverter.transform.translation.z );
    ROS_INFO_STREAM("Yaw "<< yaw );
    pub(transformConverter);  //error here
    loopRate.sleep();
}

    return 0;
}

The only problem with that logic is that we had a total of 4 that were in storage for a while and there is only 2 that have this battery issue. I did some research on the model of asus laptop that was shipped to us and other people had lemons. Therefore it leads to a defective conclusion.

Hello,

I am having an issue with some of the equipment that my organization purchased through I Heart Engineering. Apparently I Heart Engineering has closed down and I am having a hard time getting in contact with them for warranty and support.

Is anyone else having this issue? What did you do to get in contact with them? Or does anyone have any suggestions for me?

The problem was not user error, the devices we ordered and received came with Asus x200 laptops. Those laptops have defective batteries, we didn't know they didn't work because we neglected to test them 6 months ago when we received them for the first time.We took the equipment out last week for a test drive to come and find out the batteries don't work. So now we have about two laptops without batteries that came through I Heart Engineering.

Thank you.

That worked. I figured that is what you meant and it tried. Thanks a lot.

listener.waitForTransform( "map","base_footprint", ros::Time(0), ros::Duration(10.0)); listener.lookupTransform( "map", "base_footprint",ros::Time(0), transformOdom);

as such?

HI, I am trying to log some data. The code works like intended except I am receiving the Relative Position instead of the Position.

tf::StampedTransform transformOdom;
current_time = ros::Time::now();

try {
        listener.waitForTransform( "odom","base_footprint", ros::Time(0), ros::Duration(10.0));
    listener.lookupTransform( "odom", "base_footprint",ros::Time(0), transformOdom);
    }
    catch (tf::TransformException &ex) {
        ROS_ERROR("%s",ex.what());
    }

//For debugging purposes
ROS_INFO_STREAM("X pose " <<  transformOdom.getOrigin().x() );
ROS_INFO_STREAM("Y pose " << transformOdom.getOrigin().y());

fileToWrite.open ("log.txt", ios_base::app);
fileToWrite << "X: " << transformOdom.getOrigin().x() << " Y: " << transformOdom.getOrigin().y()<< "\n";
fileToWrite.close();

Does anyone know how to get the position of the robot instead of the relative position?

Thanks, choog

Thank you that actually fixed the problem. Now time for the Odom frame.

and so is the orientation. The top picture is what goes wrong when the robot turns.