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2018-03-26 20:14:19 -0500 received badge  Notable Question (source)
2017-03-31 23:20:27 -0500 asked a question Can we build rviz using ogre 2.1

Rviz uses ogre graphics engine for delivering its functionalities. Rviz provides terrific functionalities for robotics community but is not as polished as current open source technologies are. Rviz is not that fast. When will prebuilt Rviz ship with ros distros that has been compiled either using ogre 2.1 or open scene graph because these two are very fast. Rviz even in ros kinetic seems to be built using ogre 1.9 which is not the best open source graphics engine out there. Can users expect ros developers to improve rviz in a future release like lunar or is there a hack however involved they can try to obtain an optimized Rviz. My main complaints are the markers are not well implemented as screen hangs after running animation for long times. Also the animations themselves appear a bit flaky. There maybe parameters that need optimization i don't know of. But after running animations in V-rep etc. it does not feel that rviz should have much difficulty giving fast and better graphics.

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2016-10-31 16:59:44 -0500 asked a question player/Stage for 2D schematic simulation of multiple robots

I was wondering should i use rviz for a 2D schematic simulation of multiple robots. Robots are only represented as circles and swarm robotics algorithms are implemented. But I wanted to use player/Stage. Is that obsolete nowadays or people still use it? Which is the best 2D option under ROS?

I know for 3D there are good options like gazebo but i am only interested in 2D. Gazebo is an overkill.

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2016-09-11 00:10:25 -0500 asked a question Make ROS talk between two programs

I am asking a general question to which general answers would suffice. As part of a project, I am working on a MATLAB program that does some data analysis on some pre-stored data and outputs numbers. These numbers have to be used by a C++ program to do further processing. The Matlab code works and so does the C++ code.

Now we want to use ROS to allow them to talk in real-time: Matlab sends data to C++ as it is produced on which C++ acts and outputs final result in a specified manner. Can someone please direct me to a coding source where ROS has been used to make a Matlab code talk to C++ code. I am using Ubuntu 16.04 and Matlab R16a.

If someone could chart out a communication architecture and give programming tips to implement it, that would be very helpful. But online references should work too.

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2015-06-05 11:31:13 -0500 asked a question How to interpret Baxter forces

I want to keep moving the baxter mounted with a 2 parallel jaw gripper into a flat table and stop motion when i sense that force exerted on the baxter gripper due to table contact is increasing beyond certain limit. For this purpose, I want to get the force exerted by Baxter along gripper axis when its gripper is thrust into a flat table. Logically there should be a force in z-axis.

So I use the command:

rostopic echo /robot/limb/right/endpoint_state

Part of the output it gives me is:

    x: 0.000755130895413
    y: -0.922724783421
    z: 0.56328082085
    x: 1.53568863869
    y: -0.00801796652377
    z: 0.366737604141

It gives me different force values arbitrarily and sometimes close to zero even when there is tight contact between gripper and table. Even when Baxter end-effector gripper is in mid-air then also it gives me a non-zero force in z-axis. I cannot understand how to get the force along the gripper axis using ROS in baxter in a way that makes sense, eg. when baxter is in mid-air force should be zero at the end-effector, right? Is there no such force sensing capability in baxter?

2015-02-05 06:28:49 -0500 received badge  Notable Question (source)
2015-02-04 09:21:01 -0500 commented question Using data from a ROS node in a separate C++/Python program

Yes, I think i should combine my code to a subscriber code and it should work.

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2015-02-03 08:48:08 -0500 commented question Using data from a ROS node in a separate C++/Python program

yes. i have a c++ function and the node is reading sensor data and processing it. i need the outputted data from this node as input for my c++ function. will subscribing to the topic to which this node publishes work? i amn't sure.

2015-02-02 22:39:46 -0500 received badge  Notable Question (source)
2015-02-02 17:16:26 -0500 commented answer Baxter Installation on ROS groovy

I just skipped that error-ridden step and proceeded with other steps and things worked out. I have not yet rationalised why it should be so. Still things worked out!

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2015-02-02 17:12:34 -0500 asked a question Using data from a ROS node in a separate C++/Python program

Suppose there is a user-defined ROS node. I make it publish to a topic. Now i want to use this data published to the topic as input to a C++/Python program. So how do I

  1. make the node publish to a topic?
  2. route the data from the topic as input to another separate C++/Python program?

Any reference/tutorial with concrete coding examples is sought.

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2014-10-24 16:23:23 -0500 asked a question Sensor_msgs libraary in ros indigo installation has no CvBridge declaration.

I wish to Write a Simple Image Subscriber (C++). I have installed ROS indigo in Ubuntu 14.04. When i run the standard example on ROS website to do the same, I run into the following error:

~/image_transport_ws/src/learning_image_transport/src/my_publisher.cpp:15:1: error: ‘CvBridge’ is not a member of ‘sensor_msgs’
 sensor_msgs::CvBridge bridge;

So naturally i checked the line numbers which gave the error:-

sensor_msgs::ImagePtr msg = sensor_msgs::CvBridge::cvToImgMsg(image.Ipl(), "bgr8");

Then i also cheked my sensor_msgs library and searched the entire document but Cvbridge was not declared there. How can i make my publisher code work?

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2014-09-30 12:41:00 -0500 commented answer How to Correct wrong Environment setup?

Thanks. That solved my problem.

2014-09-30 11:14:23 -0500 commented answer How to Correct wrong Environment setup?

Where is ~/.bashrc located?

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2014-09-30 10:48:45 -0500 asked a question How to Correct wrong Environment setup?

I was trying to set up my environment variables and typed in the following code:

echo "source /opt/ros/electric/setup.bash" >> ~/.bashrc
source ~/.bashrc

Later i realised i only had groovy, so i changed electric in above to groovy but whenever i try to run ros or baxter, always this message gets displayed that

bash: /opt/ros/electric/setup.bash: No such file or directory

My question is how to get the wrong environment set-up command disabled so that the irritating message is not displayed again and again? Thanks in advance.

2014-09-23 17:08:49 -0500 received badge  Popular Question (source)
2014-09-22 09:49:32 -0500 asked a question Baxter Installation on ROS groovy

I am trying to install Baxter on ROS groovy from catkin workspace where the SDK resides, and use wstool to install and update. This is waht i am supposed to do:-

    $ cd ~/ros_ws/src
    $ git clone
    $ cd baxter_simulator
    $ git checkout early_interface_dev
    $ cd ..
    $ wstool init # need to do this only if this is a new workspace where this command was not executed before.
    $ wstool merge baxter_simulator/baxter_simulator.rosinstall
    $ wstool update

But after i type in <git checkout="" early_interface_dev=""> i get this error message. please explain the reason and solution.

sa@svs-FX6860:~/catkin_ws/src/baxter_simulator$ git checkout early_interface_dev
error: pathspec 'early_interface_dev' did not match any file(s) known to git.