AndyZe

Thanks! One more question-- The checkerboard will be mounted on the end effector. How does `robot_calibration` know the checkerboard is attached to the end effector? And how does it know...

Given this setup: ``` free_frames: - name: checkerboard x: true y: true z: true roll: false pitch: true yaw: true free_frames_initial_values: # what frame is this in? Is it the...

This is a good reason to get the Ruckig smoothing PR merged: https://github.com/ros-controls/ros2_controllers/pull/324 You can actually get infinite vels/accels right now, with the spline interpolation algorithm.

I don't completely understand the loop rate issue. Maybe it would be smart to reject incoming commands if `time_since_previous_command` is less than 0.8x the control period? Or something like that.

Thank you for the reality check @gavanderhoorn :+1:

> Why would control engineers choose this then to write their control systems with if they don't start with the assumption that it isn't going to be deterministic. Some robot...

I suspect it would be easier to do the yaml inside xacro option (Option 2). Mainly because C++ isn't great at parsing, but that macro Lovro wrote looks very simple/readable....

I guess I'm not clear on where the data gets stored for Option 1. Would it go in `x_robot.ros2_control.xacro`?

Another thing to consider is switching from simulation to hardware easily. Something like a launch parameter (sim:=true) in ROS1 would be great. I saw there's now a separate hardware plug-in...

Here's an even worse example of 3 messages being declared and even resized inside `update()`. Pointed out by @jbeck28 https://github.com/ros-controls/ros2_controllers/blob/b9ccf04aa95203e37077f297ddcf9f933ef464fa/joint_trajectory_controller/src/joint_trajectory_controller.cpp#L144 ``` JointTrajectoryPoint state_current, state_desired, state_error; const auto joint_num = joint_names_.size();...