ros | operating system | Robotics library
kandi X-RAY | ros Summary
kandi X-RAY | ros Summary
Robot Operating System (ROS).
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Top functions reviewed by kandi - BETA
- Run a test
- Create test results
- Start coverage tests
- Return the path to the XML results file
- Read test results
- Main entry point
- Generate summary output
- Recursively build a package
- Returns the dependencies of a package
- Load a package
- Load message definitions from a string
- Create a summary summary summary
- Generate coverage reports
- Return the full path to the test results file
- Creates a test suite
- Entry point for RosPack
- Reads results from the test results directory
- Creates test results
- Compute the full text of the dependencies
- Resolve a type
- Kill a process
- Run the build loop
- Read test result
- Load messages from a string
- Read a ROS handshake header from the socket
- Find the location of a ROS location
- Purge files from the system
- Load dependencies for a given package
ros Key Features
ros Examples and Code Snippets
Community Discussions
Trending Discussions on ros
QUESTION
I am trying to read left and right camera images from a vehicle to do some image processing. I am unsure of how to use the same callback function to process each image. I have seen examples where the data type was different, but not where both are of the same type, such as images. In this example, separate callbacks were used.
Here is my current attempt:
...ANSWER
Answered 2022-Apr-04 at 09:17Each node needs to initialize itself first before it can interact with the ROS network using rospy.init_node()
.
Also, you need to provide two message_filter.Subscriber
instead of rospy.Subscriber
to the message_filter.ApproximateTimeSynchronizer
.
Finally, instead of setting the callback for each subscriber you should set it once for the ApproximateTimeSynchronizer
using registerCallback
.
Here is a working example:
QUESTION
I have limited experience in drake and currently trying to learn and implement some simple algorithms. The code I have is based on an example from the Underactuated Robotics course by R. Tedrake. The code is a slightly modified version of this example here, where the goal is to design a Lyapanuv Control Function for the unicycle robot model.
To simulate the robot model, an instance of SymbolicVectorSystem from drake is used.
As I understand this is just a building block for the "prototyping" and designing a suitable controller, is this correct?, is SymbolicVectorSystem still needed if there is a real robot?.
Now that I am happy with the controller, I would like to deploy this controller to a ROS2 robot. For that, I have written a simple script that subscribes to the current robot states from the localization system that I have. I am not really sure how to proceed from here, I think I need to connect the received robot state messages to the input of the controller, then publish the output of the controller back to the robot. The problem is I couldn't find any examples that suit this use case.
An approach I think of, could be that I create another class that inherits from VectorSystem, and this class wraps the ros stuff to subscribe publish ROS messages. In overridden DoCalcVectorOutput function of my wrapper class, I assign/retrieve the I/O and publish retrieved control commands. Finally, I connect the I/O of controller and wrapper classes with a DiagramBuilder
I am not sure if this will work, or if this is will be the recommended approach, I will appreciate your help.
Here is what the current code looks like;
...ANSWER
Answered 2022-Apr-03 at 16:02The code is a slightly modified version of this example here [...]
Unfortunately, this is not accessible to me (I'm not sure if this is your drive, or if the transition to DeepNote changed things). Can you post a link directly to the course notes? e.g. http://underactuated.csail.mit.edu/acrobot.html#cart_pole
As I understand this is just a building block for the "prototyping" and designing a suitable controller, is this correct?, is SymbolicVectorSystem still needed if there is a real robot?.
The choice is ultimately up to you and your application. SymbolicVectorSystem
may express what you need initially, but your needs may extend beyond what it can (easily) express.
Now that I am happy with the controller, I would like to deploy this controller to a ROS2 robot. [...]
There are a few examples of this using the Systems Framework, some in Drake proper, others in downstream projects, but understandably it may be hard to locate them.
Some examples in Drake itself, though using LCM, not ROS2, though:
- https://github.com/RobotLocomotion/drake/tree/v1.1.0/examples/manipulation_station - most notably, see
manipulation_station_hardware_interface.cc
- https://github.com/RobotLocomotion/drake/tree/v1.1.0/examples/kuka_iiwa_arm
Some examples in downstream projects; also primarily using LCM:
- From DAIR Lab
- From Dexai
- https://github.com/DexaiRobotics/drake-franka-driver/tree/cf3b20ef - this is moreso the "lower level" driver, but with very advanced features for robot arm control
As a small side note, some of us at TRI, w/ help from OpenRobotics, are (slowly) developing some ROS2 interfaces for Drake; you can see some of the progress here: https://github.com/RobotLocomotion/drake-ros/tree/develop
Some caveats:
- This is very experimental and has not yet been vetted (to any extent) on our side.
- Our primary customer is ourselves in this case, so it may not fit your use case well at this point in time.
QUESTION
ANSWER
Answered 2021-Dec-08 at 13:20I was able to solve it (after a few days of suffering) using precompiled Boost 1.74 and by changing the boost/python related parts of cv_bridge/CMakeLists.txt to:
QUESTION
I facing an issue while running a .cpp file, cleaner_bot.cpp (shown below) through ros run. Here are the following details:
...ANSWER
Answered 2022-Mar-15 at 09:42You should not (ros)run the source files of your project but rather the executable created by catkin_make
.
For example:
QUESTION
So I am learning ROS and I am having an issue in writing a simple service client code.
The srv_server.cpp is:
...ANSWER
Answered 2022-Mar-07 at 14:33Since it is a uint8
on the ROS side, it's actually being saved as a char
when it hits c++ code. This means you're trying to print out the ASCII value of of your age
field. Instead you should convert the value directly to an int when printing like:
QUESTION
Im new to Concurrency and parallelism programming in C/C++ so I need some help woth my project.
I want to run multiple process using POSIX and Semaphores in C++. So the structure of the program should be the following one. First I Open Serial port (Serial communication of the Raspberry PI 4). While the Serial is Open Two processes are running
First one, the main one run automatically and do the following: The thread ask for ODOM Updates(Pressure and IMU from the microcontroller) and Publish them. Also every 0.3 seconds check the modem inbox and if something new it publish.
The other one only on DEMAND from ROS Services detect that there is new message in the modem inbox do HALT( on the first main Process) and execute (publish) on the serial Port. Then the first process resume with normal work
So I trying to do first some pseudo C++ code that looks like these But I need help as Im new to Concurrency and parallelism. Here it is
...ANSWER
Answered 2022-Feb-22 at 11:43Fortunately, ROS lets you decide what threading model you want to use (http://wiki.ros.org/roscpp/Overview/Callbacks%20and%20Spinning).
You could use the ros::AsyncSpinner
for that:
Your main thread starts the AsyncSpinner that runs in the background, listens to ROS messages, and calls your ROS callback functions in its own threads.
Then, your main thread cares about your serial port connection and forwards/publishes messages. In pseudo-code, it could look as follows:
QUESTION
When I run
...ANSWER
Answered 2022-Jan-24 at 10:49I use this method, from https://answers.ros.org/question/354808/error-running-turtlesim-noetic/.
The key point is to be sure to find the location of your libQtCore, and don't copy others' answers directly.
You could try:
QUESTION
I have built a yocto image (just for reference see the end of this question) when I try to run it with runqemu I get the following error:
...ANSWER
Answered 2022-Jan-25 at 08:44this is actually complaining about the "ip" command not being found, not your IP address, you need to install it.
Depending on your distribution the package name may change, but for Ubuntu/Debian the package you need is iproute2
QUESTION
I am working with Turtlebots and ROS, and using a camera to find the pixel positions of a marker in the camera. I've moved over from simulations to a physical system. The issue I'm having is that the pixel positions in my physical system did not match the pixel positions in the physical system despite the marker and everything else being in the same position as in the simulations. There was a shift in the vertical pixel position by about 40 pixels when everything else like the height between the camera and marker, the marker position, and the distance between the marker and camera were the same in both the physical and simulated system. The simulated system does not need a camera calibration matrix, it is assumed to be ideal.
The resolution I'm using is 640x480, so the center pixels should be cx=320 and cy=240, but what I noticed in the camera calibration matrix I was using in the physical system was that the cx was around 318, which is pretty accurate, but the cy was around 202, which is far from what it should be. This also made me think that the shift in pixel positions in the vertical direction is shifted with about the same amount of pixels that I'm getting as an error.
So is it right to assume that the error in the center pixel in the calibration could be causing the error in the pixel positions?
I have been trying to calibrate a USB camera (Logitech C920 I think) and I've been using the camera_calibrator ROS package found here http://wiki.ros.org/camera_calibration to calibrate the camera. I think the camera calibration did not go that well, seeing as I always have a pretty big error in either cx or cy. Here are the calibration matrices.
First calibration matrix, used 15x10 vertices with size 0.25
Recalibrated but did not actually use this yet, calibrated with 8x6 size 0.25
Same as previous, some difference between the two
The checkerboards were on A4 papers.
Thanks in advance.
...ANSWER
Answered 2022-Jan-21 at 23:46I believe the answer to your question is to answer how to perform a better camera calibration.
Quoting from Calib.io enter link description here:
- Choose the right size calibration target.
- Perform calibration at the approximate working distance (WD) of your final application.
- The target should have a high feature count.
- Collect images from different areas and tilts.
- Use good lighting.
- Calibration is only as accurate as the calibration target used. Use laser or inkjet printed targets only to validate and test.
- Per sample, proper mounting of calibration target and camera.
- Remove bad observations. Carefully inspect reprojection errors.
- Obtaining a low re-projection error does not equal a good camera calibration. Be careful of over fitting.
QUESTION
I want to create a ROS node that is able to listen to a topic without knowing its message type. In python, this is possible as can be seen here:
https://schulz-m.github.io/2016/07/18/rospy-subscribe-to-any-msg-type/
I tried that and it works like a charm. However, I want to avoid copying the whole message; thus, i need that functionality in a roscpp nodelet.
...ANSWER
Answered 2022-Jan-19 at 15:06By nature, this sort of problem is very pythonic and much harder to work around in c++. That being said, there is one (sort of) solution out there already. Take a look at the ros_msg_parser.
The syntax isn't pretty, and I'm not even sure if it's a good idea, but it will let you generate generic subscribers. Example from the linked repo:
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Install ros
You can use ros like any standard Python library. You will need to make sure that you have a development environment consisting of a Python distribution including header files, a compiler, pip, and git installed. Make sure that your pip, setuptools, and wheel are up to date. When using pip it is generally recommended to install packages in a virtual environment to avoid changes to the system.
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