Dynamic Time Warping (DTW) is a method to align two sequences under certain constraints. For instance, two trajectories that are very similar but one of them performed in a longer time. The alignment should be is such way that minimizes the distance between these two sequences. Here I have done DTW between two-time series with python. I found a […]
ROS packages for Dynamic Time Warping Read More »
I found a really good code at GitHub for fitting a Gaussian Mixture Model (GMM) with Expectation Maximization (EM) for ROS. There are so many parameters that you can change. Some of the most important ones are:
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// minimum number of gaussians #define PARAM_NAME_GAUSSIAN_COUNT_MIN "gaussian_count_min" #define PARAM_DEFAULT_GAUSSIAN_COUNT_MIN 1 // search will terminate when the gaussian count reaches this #define PARAM_NAME_GAUSSIAN_COUNT_MAX "gaussian_count_max" #define PARAM_DEFAULT_GAUSSIAN_COUNT_MAX 10 |
To find the optimal number of components, it uses Bayesian information criterion (BIC). There are other methods to find
Expectation Maximization algorithm to obtain Gaussian mixture models for ROS Read More »
Most of the wheeled robots in ROS use move_base to move the robot. move_base geometry model is based on differential drive which basically transforms a velocity command (twist message) into a command for rotating the left and the right wheels at a different speed which enable the car to turn into the right or left or goes straight. But cars
Ackermann steering car robot model with simulation in Gazebo Read More »
Two wheels differential drive robot (with two caster wheels). List of installed sensors: • Velodyne VLP-16. • Velodyne HDL-32E. • Hokuyo Laser scanner. • IMU. • Microsoft Kinect/Asus Xtion Pro. • RGB Camera. You can manually control the robot with Joystick controller for mapping robot environment. Autonomous navigation is possible by setting goal pose.
Autonomous navigation of two wheels differential drive robot in Gazebo Read More »
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#include <sensor_msgs/point_cloud_conversion.h> sensor_msgs::PointCloud2 point_cloud2; sensor_msgs::PointCloud point_cloud; sensor_msgs::convertPointCloudToPointCloud2(point_cloud, point_cloud2); sensor_msgs::convertPointCloud2ToPointCloud(point_cloud2, point_cloud); |
Converting sensor_msgs::PCLPointCloud2 to sensor_msgs::PointCloud and reverse Read More »
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#include <pcl/conversions.h> |
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pcl::PCLPointCloud2 point_cloud2; pcl::PointCloud<pcl::PointXYZ> point_cloud; pcl::fromPCLPointCloud2( point_cloud2, point_cloud); pcl::toPCLPointCloud2(point_cloud, point_cloud2); |
more about pcl point cloud and conversion
Converting pcl::PCLPointCloud2 to pcl::PointCloud and reverse Read More »
For this work, first I loaded the RRBot in Gazebo and launched Its joints controller, then I sent a periodic signal to the robot such that the laser scanner mounted on the robot swings. In the following, I assembled the incoming laser scans with the transformation from tf and created PCL point cloud. Install the necessary
Assembling Laser scans into PCL point cloud Using Gazebo and ROS Read More »
In other tutorials, I showed how to get access to the joystick and how to code with that. In this tutorial, I’m going to show you how to do that without writing any line of code. First, install the required packages:
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sudo apt-get install ros-noetic-teleop-twist-joy ros-noetic-joy ros-noetic-joy-teleop |
Now call the following
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rosrun joy joy_node dev:=/dev/input/js0 |
This will publish the topic “/joy_node” which
Control your robot with a joystick in ROS Read More »
First install the liburdfdom-tools
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sudo apt-get install liburdfdom-tools |
Then
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urdf_to_graphiz <robot_model.urdf> |
How to create hierarchical graph from your robot model (URDF) Read More »
First, install the necessary package:
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sudo apt-get install ros-indigo-joy |
make sure your joystick is working:
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sudo jstest /dev/input/js0 |
also, make sure your controller has correct permissions:
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ls -l /dev/input/js0 |
The permission on the last column must be rw, if it “–” like this:
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crw-rw-r--+ 1 root root 13, 0 May 18 12:12 /dev/input/js0 |
then correct the permission:
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sudo chmod a+rw /dev/input/js0 |
run the Joy node and roscore:
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roscore rosparam set joy_node/dev "/dev/input/js0" rosrun joy joy_node |
The joystick data are being published under
Controlling your robot with joystick and reading data from it Read More »
