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Wheeled mobile robot with GPS, accelerometer, magnetometer and odometry

asked 2016-11-08 11:23:50 -0500

guido_sanchez gravatar image

updated 2016-11-11 09:00:29 -0500

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...

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answered 2016-11-09 10:17:57 -0500

nkoenig gravatar image

Wheel position & Chassis position

You have a couple options to get the position of objects in simulation.

  1. Subscribe to the /gazebo/default/pose/info topic and filter the messages on the desired links.
  2. Write a ModelPlugin for your robot that publishes wheel/chassis position.

Sensor noise

You can write a sensor plugin that outputs sensor data without noise, then apply noise and output it on a different topic. I like the idea of a simulation setting that makes it possible to output both data sources (noisy and noise-free) without writing a special plugin. Here is an issue to track this feature.

ROS

Ros is useful when you want to control a robot. There are numerous packages for localization, planning, motion control, etc. Whether you should use it or not depends on what you need to get done.

Hope this helps.

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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?

guido_sanchez gravatar imageguido_sanchez ( 2016-11-11 08:59:30 -0500 )edit

How can i attach this plugin (https://github.com/gmsanchez/gazebo_plugins/tree/master/imu_noise_plugin) with my cat-vehicle in gazebo using autoware .

Asif gravatar imageAsif ( 2018-01-23 05:59:45 -0500 )edit
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Asked: 2016-11-08 11:23:50 -0500

Seen: 937 times

Last updated: Nov 11 '16