unicornair's profile - activity

 <launch>
<rosparam file="$(find turtlesim_launch)/launch.yaml" command="load" />
<node name="turtlesim_node" pkg="turtlesim" type="turtlesim_node" respawn="false" output="screen" />
<rosparam file="$(find turtlesim_launch)/launch.yaml" command="load" />
</launch>

and my launch.yaml is

background_r: 0
background_g: 0
background_b: 0

I also use rosservice call /clear but it does not work

I stay well with eclipse，I can build run and debug，but I can not stop it from jerking off！eg I code `

ros::init(argc,argv,"turtle_move");

eclipse told me

:Invalid arguments ' Candidates are: void init(const ? &, const ? &, ?) void init(int &, char * *, const ? &, ?) '

I code

ros::Publisher pub=Nh.advertise<geometry_msgs::twist>("/turtle1/cmd_vel",10);

eclipse told me

Multiple markers at this line
    - Invalid arguments ' Candidates are: ros::Publisher advertise(const ? &, ?, bool) ros::Publisher advertise(ros::AdvertiseOptions 
     &) ros::Publisher advertise(const ? &, ?, const ? &, const ? &, const ? &, bool) '
    - Symbol 'advertise' could not be resolved

uncountable situations like this，omfg

yes,I used image_view to subscribe the /camera/rgb/image_raw topic,then I got the video stream,but when I subscribed to the /camera/depth_registered/image-_raw,I can't get any data

when i run roslaunch freenect_launch freenect-registered-xyzrgb.launch I got following errors,and I run rosrun image_view image_view image:=/camera/ depth_registered /image_rect the window break down at once,but I can use rgb camera without any errors,Thanks everyone who is willing to help me!

 **[ INFO] [1446808989.401577431]: Starting a 3s RGB and Depth stream flush.              
[ INFO] [1446808989.401989802]: Opened 'Xbox NUI Camera' on bus 0:0 with serial number 'A22596705403327A'       
 [ WARN] [1446808989.616986731]: Could not find any compatible depth output mode for 1. Falling back to default depth         output mode 1.        
[ INFO] [1446808989.635605723]: rgb_frame_id = 'camera_rgb_optical_frame'       
[ INFO] [1446808989.635924353]: depth_frame_id = 'camera_depth_optical_frame'          
 [ WARN] [1446808989.651085845]: Camera calibration file /home/unicorn/.ros/camera_info/rgb_A22596705403327A.yaml not found.            
 [ WARN] [1446808989.651150401]: Using default parameters for RGB camera calibration. 
[ WARN] [1446808989.651205748]: Camera calibration file /home/unicorn/.ros/camera_info       /depth_A22596705403327A.yaml not found.            
 [ WARN] [1446808989.651243210]: Using default parameters for IR camera calibration. 
 [ INFO] [1446808992.402965026]: Stopping device RGB and Depth stream flush.**

I can not open my depth camera on my Kinect when I use freenect package,and I got errors like follwing,could you help me ?

[ INFO] [1446804753.661709266]: Starting a 3s RGB and Depth stream flush.
[ INFO] [1446804753.661829291]: Opened 'Xbox NUI Camera' on bus 0:0 with serial number 'A22596705403327A'
[ WARN] [1446804754.800842567]: Could not find any compatible depth output mode for 1. Falling back to default depth output mode 1.
[ INFO] [1446804754.815870621]: rgb_frame_id = 'camera_rgb_optical_frame'
[ INFO] [1446804754.815933870]: depth_frame_id = 'camera_depth_optical_frame'
[ WARN] [1446804754.830528673]: Camera calibration file /home/unicorn/.ros/camera_info/rgb_A22596705403327A.yaml not found.
[ WARN] [1446804754.830604644]: Using default parameters for RGB camera calibration. 
[ WARN] [1446804754.830654848]: Camera calibration file /home/unicorn/.ros/camera_info/depth_A22596705403327A.yaml not found.
[ WARN] [1446804754.830695204]: Using default parameters for IR camera calibration. 
[ INFO] [1446804757.091943001]: Stopping device RGB and Depth stream flush.

I have already finished learning TF,but roscpp makes me puzzled,I have cognition for it

I don't know the C++ syntax and roscpp APIs,like these transformPoint(const tf::TransformListener& listener) ros::Timer timer = n.createTimer(ros::Duration(1.0), boost::bind(&transformPoint, boost::ref(listener)) I think I have already grasped the TF but here it's a new puzzled me

sorry for that, here I changed

Thanks for your detail answer,It helps me out

I got trouble in this code coz I just know python,Is there any one that could help me recode this in python?I'm very grateful!

 #include <ros/ros.h>
#include <geometry_msgs/PointStamped.h>
#include <tf/transform_listener.h>

void transformPoint(const tf::TransformListener& listener){
  //we'll create a point in the base_laser frame that we'd like to transform to the base_link frame
  geometry_msgs::PointStamped laser_point;
  laser_point.header.frame_id = "base_laser";

  //we'll just use the most recent transform available for our simple example
  laser_point.header.stamp = ros::Time();

  //just an arbitrary point in space
  laser_point.point.x = 1.0;
  laser_point.point.y = 0.2;
  laser_point.point.z = 0.0;

  try{
    geometry_msgs::PointStamped base_point;
    listener.transformPoint("base_link", laser_point, base_point);

    ROS_INFO("base_laser: (%.2f, %.2f. %.2f) -----> base_link: (%.2f, %.2f, %.2f) at time %.2f",
        laser_point.point.x, laser_point.point.y, laser_point.point.z,
        base_point.point.x, base_point.point.y, base_point.point.z, base_point.header.stamp.toSec());
  }
  catch(tf::TransformException& ex){
    ROS_ERROR("Received an exception trying to transform a point from \"base_laser\" to \"base_link\": %s", ex.what());
  }
}

int main(int argc, char** argv){
  ros::init(argc, argv, "robot_tf_listener");
  ros::NodeHandle n;

  tf::TransformListener listener(ros::Duration(10));

  //we'll transform a point once every second
  ros::Timer timer = n.createTimer(ros::Duration(1.0), boost::bind(&transformPoint, boost::ref(listener)));

  ros::spin();

}

Hi,you, I'm a clown boy and the following params puzzled me,can you make a description for me? My questions are: first:I don't understand "the translation of the transformtion as a tuple (x, y, z)",It seems that translation is equal to transformtion,they has same means unexpectedly! And what do "msg.x" , "msg.y" and "0" actually mean in robot pose? Can i comprehend like this:msg.x and msg.y are Coordinate value where 0 means z=0?

second:param rotation: the rotation of the transformation as a tuple (x, y, z, w),what does (0, 0, msg.theta) mean in robot pose?And what are the relations between rotation and translation?

sendTransform((msg.x,msg.y,0),
                        tf.transformations.quaternion_from_euler(0, 0, msg.theta),
                        rospy.Time.now(),
                        turtlename,
                        "world")

Hi,all, I'm a ROS pupil.I downloaded the kinect driver from https://github.com/avin2/SensorKinect but I don't know how to install it,could you give me some detailed instructions?Thanks

Thank you,I have already solved this with your help.^_^

Hi,everybody I'm a chinese student,because of the greatwall firewall,I can not get enough and explicit documentations except for wiki.ros.I'm so sorry to interrupt you for asking these silly questions,if you would share your valuable time to dispel my doubts,I am deeply grateful. Here are the baffle puzzled me: 1.what is the "lookupTransform" method below,what type of date does it return? I can not find any descriptions against it. 2.I'm fairly puzzled with traslation and transformation,they belong to the same description in chinese.And i get trouble with euler and quaternion,I don't understand what the arguments x,y,z,w refer to,I'm hoping for a nice boy to solve my problems,if you'd like to introduce more msg in ros detailed,nice of you!!!!^_^

The following is the unsolved code:

listener = tf.TransformListener()
 rospy.wait_for_service('spawn')
spawner = rospy.ServiceProxy('spawn', turtlesim.srv.Spawn)
spawner(4, 2, 0, 'turtle2')

turtle_vel = rospy.Publisher('turtle2/cmd_vel', geometry_msgs.msg.Twist,queue_size=1)

rate = rospy.Rate(10.0)
while not rospy.is_shutdown():
    try:
        (trans,rot) = listener.lookupTransform('/turtle2', '/turtle1', rospy.Time(0))
    except (tf.LookupException, tf.ConnectivityException, tf.ExtrapolationException):
        continue

    angular = 4 * math.atan2(trans[1], trans[0])
    linear = 0.5 * math.sqrt(trans[0] ** 2 + trans[1] ** 2)
    cmd = geometry_msgs.msg.Twist()
    cmd.linear.x = linear
    cmd.angular.z = angular
    turtle_vel.publish(cmd)

    rate.sleep()