[JTC] Add Parameter to Toggle State Setting on Activation (#1231)

* [JTC] Add param to setting last command interface value as state on activation

* [JTC] add a note about set_last_command_interface_value_as_state_on_activation to release_notes. Updated the parameters.yaml description to match the same wording.

---------

Co-authored-by: Bence Magyar <[email protected]>
Co-authored-by: Christoph Fröhlich <[email protected]>

Author: 3 people

doc/release_notes.rst

@@ -48,6 +48,8 @@ joint_trajectory_controller
      * -1 - The tolerance is "erased".  If there was a default, the joint will be
             allowed to move without restriction.
 
+* Add the boolean parameter ``set_last_command_interface_value_as_state_on_activation``. When set to ``true``, the last command interface value is used as both the current state and the last commanded state upon activation. When set to ``false``, the current state is used for both (`#1231 <https://github.com/ros-controls/ros2_controllers/pull/1231>`_).
+
 pid_controller
 ************************
 * 🚀 The PID controller was added 🎉 (`#434 <https://github.com/ros-controls/ros2_controllers/pull/434>`_).

joint_trajectory_controller/src/joint_trajectory_controller.cpp

@@ -924,7 +924,9 @@ controller_interface::CallbackReturn JointTrajectoryController::on_activate(
   // running already)
   trajectory_msgs::msg::JointTrajectoryPoint state;
   resize_joint_trajectory_point(state, dof_);
-  if (read_state_from_command_interfaces(state))
+  if (
+    params_.set_last_command_interface_value_as_state_on_activation &&
+    read_state_from_command_interfaces(state))
   {
     state_current_ = state;
     last_commanded_state_ = state;

joint_trajectory_controller/src/joint_trajectory_controller_parameters.yaml

@@ -64,6 +64,11 @@ joint_trajectory_controller:
     default_value: false,
     description: "Allow integration in goal trajectories to accept goals without position or velocity specified",
   }
+  set_last_command_interface_value_as_state_on_activation: {
+    type: bool,
+    default_value: true,
+    description: "When set to true, the last command interface value is used as both the current state and the last commanded state upon activation. When set to false, the current state is used for both.",
+  }
   action_monitor_rate: {
     type: double,
     default_value: 20.0,