philippp625's profile - activity

I just realized that my problem only exists if I use a tf::MessageFilter when subscribing. Nevertheless, I don't understand why the messages are not processed in the order of their time stamps, since they all have the same frame_id, so the transforms should be available for older messages first.

I have a single publisher that publishes messages at high frequency (1800 Hz), and a subscriber in another node. I realized that the messages are not always processed sequentially. I verified this by doing the following: in the callback function, I output a warning every time the seq number of the processed message is lower than the seq number of the message processed in the previous call of the callback.

My question: is there a way to force a subscriber to process the incoming messages exactly in the order of the seq numbers in their header? (up to now I thought this would be the case by default with a single subscriber/publisher system, but apparently it isn't...)

Any help is greatly appreciated!

I did the following:

in the file vslam_system/src/nodes/stereo_vslam_node.cpp

go to line 159 and replace "if (0)" by "if (1)"

(then do a rosmake vslam_system)

Hi,

I have the following problem: I'm running a node on one computer which publishes nav_msgs::Odometry messages (ROS master running on this machine). Another computer is connected via Wi-Fi, and there's a node which subscribes to the odometry topic. Now, when the Wi-Fi connection is interrupted, the publisher node freezes. It starts publishing again when the connection is re-established.

The strange thing is that it only happens with Odometry messages. Below is a simple example node with two publishers which I used to reproduce the problem. Now if I run this on one machine and on the other I do a "rostopic echo chatter2", then disconnect the Wi-Fi, the publisher node shuts down. However, if I do a "rostopic echo chatter1" and disconnect the Wi-Fi, nothing happens.

Does anyone have an idea how I can avoid the publishing node hanging when the subscriber is disconnected?

#!/usr/bin/env python
import roslib; roslib.load_manifest('pub_sub_test')
import rospy
from std_msgs.msg import String
from nav_msgs.msg import Odometry
def talker():
    pub1 = rospy.Publisher('chatter1', String)
    pub2 = rospy.Publisher('chatter2', Odometry)
    rospy.init_node('talker')
    while not rospy.is_shutdown():
        str = "hello world %s"%rospy.get_time()
        rospy.loginfo(str)
        odom = Odometry()
        pub1.publish(String(str))
        pub2.publish(odom)
        rospy.sleep(0.1)
if __name__ == '__main__':
    try:
        talker()
    except rospy.ROSInterruptException: pass