dottant's profile - activity

Hi guys, I'm developing on Ubuntu 20 with ROS Noetic full desktop completely updated but I'm struggling with an error I get if I try to run (but it also happens if I run rqt and later I use the TF plugin)

rosrun rqt_tf_tree rqt_tf_tree

The error is:

"dot" with args ['-Tdot', '/tmp/tmp93jif2d2'] returned code: 1

stdout, stderr:
 b''
b"Error: /tmp/tmp93jif2d2: syntax error in line 6 near ':'\n"

PluginHandlerDirect._restore_settings() plugin "rqt_tf_tree/RosTfTree#0" raised an exception:
Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/qt_gui/plugin_handler_direct.py", line 121, in _restore_settings
    self._plugin.restore_settings(plugin_settings_plugin, instance_settings_plugin)
  File "/opt/ros/noetic/lib/python3/dist-packages/rqt_tf_tree/tf_tree.py", line 131, in restore_settings
    self._refresh_tf_graph()
  File "/opt/ros/noetic/lib/python3/dist-packages/rqt_tf_tree/tf_tree.py", line 143, in _refresh_tf_graph
    self._update_graph_view(self._generate_dotcode())
  File "/opt/ros/noetic/lib/python3/dist-packages/rqt_tf_tree/tf_tree.py", line 150, in _generate_dotcode
    return self.dotcode_generator.generate_dotcode(dotcode_factory=self.dotcode_factory,
  File "/opt/ros/noetic/lib/python3/dist-packages/rqt_tf_tree/dotcode_tf.py", line 98, in generate_dotcode
    self.dotcode = self.dotcode_factory.create_dot(self.graph)
  File "/opt/ros/noetic/lib/python3/dist-packages/qt_dotgraph/pydotfactory.py", line 175, in create_dot
    dot = graph.create_dot()
  File "/usr/lib/python3/dist-packages/pydot.py", line 1726, in new_method
    return self.create(
  File "/usr/lib/python3/dist-packages/pydot.py", line 1953, in create
    assert process.returncode == 0, process.returncode
AssertionError: 1

I tried to find something useful on the ROS Answer and on the web, I've seen some open ticket about error related to mine, but I've found just a couple of suggestions that for some people worked, for ex run on a terminal

sudo dot -c

or uninstall pyyaml which it's not possible to do, I get

Found existing installation: PyYAML 5.3.1
Not uninstalling pyyaml at /usr/lib/python3/dist-packages, outside environment /usr
Can't uninstall 'PyYAML'. No files were found to uninstall.

No one worked for me. Can you help me? I really need to debug the TF tree in a proper way for a project
Thank you

Great job, thanks, it works!

Yes, sorry, but for me a symlink is a file which points to another file and in that folder I have the ones i wrote about

Yes, sorry, but for me a symlink is a file which points to another file and in that folder I have the ones i wrote about

I have a link to python2 as shared library and a link to python3 as executable

Can't run rqt_tf_tree on Noetic, dot error Hi guys, I'm developing on Ubuntu 20 with ROS Noetic full desktop freshly upd

Unable to use rqt_tf_tree in Noetic, dot error Hi guys, I'm developing on Ubuntu 20 with ROS Noetic full desktop complet

Updated with new code lines and pics

Occupancy grid creation Hi guys, I'm trying to implement my own controller in ROS1 Melodic for a mobile robot and now I'

Occupancy grid creation Hi guys, I'm trying to implement my own controller in ROS1 Melodic for a mobile robot and now I'

thank you so much. I updated the question before your answer. It would be great if you have a look thanks

Occupancy grid creation Hi guys, I'm trying to implement my own controller in ROS1 Melodic for a mobile robot and now I'

Occupancy grid creation Hi guys, I'm trying to implement my own controller in ROS1 Melodic for a mobile robot and now I'

Thanks for the answer. The other solution can't be right cause the cell index must be related to the robot position

Occupancy grid creation Hi guys, I'm trying to implement my own controller in ROS1 Melodic for a mobile robot and now I'

Occupancy grid creation Hi guys, I'm trying to implement my own controller in ROS1 Melodic for a mobile robot and now I'

Occupancy grid creation Hi guys, I'm trying to implementing my own controller in ROS1 Melodic for a mobile robot and now

@gvdhoom sure, I wrote it in my answer, I know that the link points to Galactic and I tried to find it within the Foxy s

Thank you guys. I investigated and unfortunately I didn't find anything on the official DOC and repo about the accessibi

ROS2 official parameter monitor example doesn't compile Hi, I tried on two different Ubuntu 20 machines with ROS2 Galact

ROS2 parameters monitor compile fails Hi, I tried on two different Ubuntu 20 machines with ROS2 Galactic and Foxy full d

Be sure to not miss in your "polygon_plugins" CMakeLists the line pluginlib_export_plugin_description_file(polygon_bas

It's ok, it returns a rclcpp::node_interfaces::NodeBaseInterface::SharedPtr needed by the spin_until_future_complete fun

It's ok, it returns a rclcpp::node_interfaces::NodeBaseInterface::SharedPtr needed by the spin_until_future_complete fun

Hi all, I have a problem to compute odometry from wheel encoders, I mean, i don't have a real problem, I just don't understand a step.
I get the ticks from the encoders (they are about 2626 ticks for a full wheel rotation) and I perform the odometry calculation in the following way(of course this is in a loop...i paste just the important lines about the odometry calculation)

current_time = ros::Time::now();
double DistancePerCount = (3.14159265 * 0.13) / 2626;
double lengthBetweenTwoWheels = 0.25;

// extract the wheel velocities from the tick signals count
deltaLeft = tick_x - _PreviousLeftEncoderCounts;
deltaRight = tick_y - _PreviousRightEncoderCounts;

omega_left = (deltaLeft * DistancePerCount) / (current_time - last_time).toSec();
omega_right = (deltaRight * DistancePerCount) / (current_time - last_time).toSec();

v_left = omega_left * 0.065; //radius
v_right = omega_right * 0.065;

vx = ((v_right + v_left) / 2)*10;
vy = 0;
vth = ((v_right - v_left)/lengthBetweenTwoWheels)*10;

double dt = (current_time - last_time).toSec();
double delta_x = (vx * cos(th)) * dt;
double delta_y = (vx * sin(th)) * dt;
double delta_th = vth * dt;

x += delta_x;
y += delta_y;
th += delta_th;

geometry_msgs::Quaternion odom_quat = tf::createQuaternionMsgFromYaw(th);

geometry_msgs::TransformStamped odom_trans;
odom_trans.header.stamp = current_time;
odom_trans.header.frame_id = "odom";
odom_trans.child_frame_id = "base_link";

odom_trans.transform.translation.x = x;
odom_trans.transform.translation.y = y;
odom_trans.transform.translation.z = 0.0;
odom_trans.transform.rotation = odom_quat;

// send the transform
odom_broadcaster.sendTransform(odom_trans);

// Odometry message
nav_msgs::Odometry odom;
odom.header.stamp = current_time;
odom.header.frame_id = "odom";

// set the position
odom.pose.pose.position.x = x;
odom.pose.pose.position.y = y;
odom.pose.pose.position.z = 0.0;
odom.pose.pose.orientation = odom_quat;

// set the velocity
odom.child_frame_id = "base_link";
odom.twist.twist.linear.x = vx;
odom.twist.twist.linear.y = vy;
odom.twist.twist.angular.z = vth;

// publish the message
odom_pub.publish(odom);
_PreviousLeftEncoderCounts = tick_x;
_PreviousRightEncoderCounts = tick_y;

last_time = current_time;

The thing that I don't understand is why i have to multiply vx and vth for 10 (it is a value that i set randomly and seems to work) to make the odometry consistent with the movements of the robot (if i dont multply, the odometry will change very slowly compared to what the robot does in terms of meters done).
Maybe I'm doing some errors calculating the velocities.
An help would be very very appreciated, thank you.

Hi all
Anyone knows how to use the sound_play action_lib client request c++ version?
I've see that only a python test file is available.
Thank you so much

This topic is old, there's no need to perform that, the formula was wrong cause I had to fix some hardware issue related

Hi all, anyone can get the depth stream from this 3D camera over ROS? For me it works perfect using the original Intel library tools/example, but in ROS i just can get the RGB stream using this package
https://github.com/BlazingForests/realsense_camera
Im using ROS indigo on Ubuntu 14.04.4 4.2 kernel
Thank you.