nc61's profile - activity

I want to implement my own local planner that adheres to base_local_planner for use with move_base. I need to make a planner that does not allow for rotation in place (car-like steering). I have tried going through all the documentation and reading the source on Github, but it's a bit overwhelming. Can anyone point to kind of a minimal example that would adhere to the interface, or maybe give some points on how I could modify either base_local_planner or dwa_local_planner to fit my needs?

Thanks in advance.

I'm new to using the navigation stack, and I have a robot with Ackermann steering. When I simulate the robot, any 2D Nav Goal set behind it will cause the robot to freeze up, publishing angular cmd_vel values which it cannot realize. I'm looking to tweak the local planner so that I can match the capabilities of my robot. The docs say that dwa_local_planner is more modular, so I plan to use it (unless there is a reason I should use the regular base_local_planner). I know this is probably really simple, but I can't find anything in the documents that goes through this process.

Thanks in advance.

I'm pretty new to networking concepts. I'm looking to control my robot with a custom Android app. I have written a client that can write to a server on a given IP address/port.

Is there any way I can manually send messages into the ROS Master from my phone by opening a socket connection to port 11311? If so, what protocol would I have to follow and how would I go about doing it. I would prefer not to run an unnecessary server on my robot.

I'm honestly not interested in using the pre-made ROS Android packages because it is something I want to learn anyway. Any help would be appreciated, thanks.

If I have a launch file that runs my main nodes on my embedded computer. I want to see the messages on my laptop which is connected to the embedded computer via wifi. If I were to run rqt, would it run on the master node (set to my laptop) or would it try (and fail) to run it on my embedded computer?

That's what I'm doing now, but it's not as convenient. For example, when my left IR reaches a certain threshold, I want to pivot my robot to the right until the reading is an acceptable value. Right now I have to make a while(reading != whatever){ ros::spinOnce(); } and update the value in my callback. However, then I have to put in extra logic to my callback function so it doesnt interfere with this process and put me in a different state.

I'm making a simple robot which will avoid obstacles and perform a basic task. My plan is to have the main program use Spin() to update global variables to which my main loop (state machine) will respond. For example: each time it spins, my leftIR midIR and rightIR global variables are updated. Using that, I will check to see if threshold values are met and go into mode = OBS_AVOID or something similar.

First of all, is this good practice? Is there a more efficient way to do this? Secondly, how do I spin constantly while still executing a main loop? Currently I am just running Spin() as I need it, but it gets messy and confusing. I was thinking it would be possible to use multi-threading, either through multithreadedspin or regular C++ libraries. If anyone has information that could lead me in the right direction I would appreciate it.

I'm making a simple robot which will avoid obstacles and perform a basic task. My plan is to have the main program use Spin() to update global variables to which my main loop (state machine) will respond. For example: each time it spins, my leftIR midIR and rightIR global variables are updated. Using that, I will check to see if threshold values are met and go into mode = OBS_AVOID or something similar. First of all, is this good practice? Is there a more efficient way to do this? Secondly, how do I spin constantly while still executing a main loop? I was thinking it would be possible to use multi-threading, either through multithreadedspin or regular C++ libraries. If anyone has information that could lead me in the right direction I would appreciate it.

I'm making a pretty basic robot powered by a single board Linux computer. It will communicate serially with one servo controller and one microcontroller. It takes in sensor data from both and outputs commands back (there is also a camera, and I will be doing onboard image processing). I want to learn ROS, but I'm not sure how to use it effectively in this situation. Is the normal procedure to make a node that repeatedly reads sensor data and publishes it to a node that reacts to this data and sends it back out? Is there a more effective way to use ROS? How do I know that multiple nodes using serial ports won't 'overlap' and cause errors?