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2016-11-16 08:17:54 -0500 answered a question Apply angular velocity to wheel via plugin

Have a look at https://github.com/gmsanchez/gazebo_stuff/tree/master/WheelSpeedPlugin It is a plugin that applies each of the two wheels of a differential drive robot a velocity received on vel_cmd topic. The code has two standalone programs to test if it works. You can also check the differential_drive.world model where it was tested. Cheers!

2016-11-11 09:00:29 -0500 received badge  Editor (source)
2016-11-11 08:59:30 -0500 commented answer Wheeled mobile robot with GPS, accelerometer, magnetometer and odometry

Sensor noise: I wrote a plugin that captures IMU data and then publish two topics (https://github.com/gmsanchez/gazebo_plugins/tree/master/imu_noise_plugin). The other sensors do not make it easy to do the same. I started writing the plugins but soon I realized that I was duplicating too much code. I think the best approach would be to rewrite the sensor files directly. How can I help and modify the sensor files? I forked Gazebo project but I can't get the CMakeFile to work. Any help?

2016-11-11 08:53:21 -0500 answered a question Wheeled mobile robot with GPS, accelerometer, magnetometer and odometry

Thanks for the response, it was very helpful.

Wheel position & Chassis position

Soon I will write a plugin to filter these messages, let's hope it's easy to filter the wheel position in degrees or radians.

Sensor noise

I managed to write a plugin that captures the IMU data and then publish two topics. You can see it on https://github.com/gmsanchez/gazebo_plugins/tree/master/imu_noise_plugin.

As you mention in the issue request, the other sensors do not make it easy to do the same. I started writing the plugins but soon I realized that I was duplicating too much of the sensor code in order to have the measurements with and without noise. Then, I think the best approach would be to rewrite the sensor files directly.

For now, I will attach two of each sensors to the chassis, one with noise and one without noise in the SDF file. Do you think there will be any problem with the number of sensors?

How can I help and modify the sensor files directly? I already forked Gazebo project on my Bitbucket account, but I can't get a working CMakeFile to compile the sensors. Any help or advise in that topic would be great.

Thanks!

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2016-11-08 11:55:59 -0500 asked a question Wheeled mobile robot with GPS, accelerometer, magnetometer and odometry

I came across Gazebo a week ago and I think it's just great. I would like to use for my project, where I need to estimate the position and control a wheeled mobile robot. For that, I would like to have measurements from a GPS, accelerometer, magnetometer and wheel position in order to estimate the robot position and orientation using the different sensors.

So far I followed the tutorial on how to build a differential drive robot [1] and the noisy IMU [2]. I added GPS and magnetometer measurements to the IMU successfully and then, following [3], attached the sensor to the differential drive robot. All the sensors topics are published correctly. Finally, I added the DifferentialDrive plugin to the robot and I was able to send linear and angular velocities.

How can I measure the wheel position?

How can I get the simulator to send me the sensor measurements without noise in order to have the "real" measurement and the noisy one?

How can I get the real position and orientation of the robot chassis?

Since I am using Python and I only need to get the noisy measurements and the real values, what would you describe it would be the best approach?

I tried using PyGazebo, so far I was able to subscribe to the sensor topics and send controls with the DifferentialDrive plugin. Should I stick with PyGazebo or try to connect via TCP/IP? Is there any benefit of using ROS on top of Gazebo?

Thanks in advance for any help.

[1] http://gazebosim.org/tutorials?tut=bu...

[2] http://gazebosim.org/tutorials?tut=se...

[3] http://gazebosim.org/tutorials?tut=ad...