Using Transforms to Robot Base View

Motivation

One approach is to transform odometry results to a robot base. This would leave use with a speed in the robot's x direction and an angular z component. If the x speed is positive, the robot is moving forward. This simplifies reasoning. This page documents investigations. The investigation of this path is not completed.

Not currently successful

ROS Transforms

This is a dead end. ROS transforms tell us where we the robot base is in our map space but does not transform to robot space.

ROS Transform References

• Writing a tf Listener

My Code

 #include <tf/transform_listener.h>

And added the following to the main loop:

   while (ros::ok()) {
       ros::spinOnce();
       loop_rate.sleep();

tf::StampedTransform transform; geometry_msgs::Twist t; try { // tf_listener.lookupTransform("/odom", "/base_link", // ros::Time(0), transform); tf_listener.lookupTwist("/base_link", "/odom", ros::Time(0), ros::Duration(0.1), t);

       }

catch (tf::TransformException ex){ ROS_ERROR("%s", ex.what()); ros::Duration(1.0).sleep(); }

// ROS_INFO ("x %.2f, y %.2f", transform.getOrigin().x(), transform.getOrigin().y()); ROS_INFO ("x %.2f, y %.2f", t.linear.x, t.linear.y);