[JTC] Rename open_loop_control parameter and slightly change its scope

joint_trajectory_controller/doc/parameters_context.yaml

@@ -2,8 +2,6 @@ constraints:
     Default values for tolerances if no explicit values are set in the ``JointTrajectory`` message.
 
 gains: |
-  Only relevant, if ``open_loop_control`` is not set.
-
   If ``velocity`` is the only command interface for all joints or an ``effort`` command interface is configured, PID controllers are used for every joint.
   This structure contains the controller gains for every joint with the control law
 
@@ -16,3 +14,6 @@ gains: |
   i.e., the shortest rotation to the target position is the desired motion.
   Otherwise  :math:`e = s_d - s` is used, with the desired position :math:`s_d` and the measured
   position :math:`s` from the state interface.
+
+  If you want to turn of the PIDs (open loop control), set the gains to zero.
+

joint_trajectory_controller/doc/userdoc.rst

@@ -97,7 +97,7 @@ A yaml file for using it could be:
           action_monitor_rate: 20.0
 
           allow_partial_joints_goal: false
-          open_loop_control: true
+          interpolate_from_desired_state: true
           constraints:
             stopped_velocity_tolerance: 0.01
             goal_time: 0.0

joint_trajectory_controller/src/joint_trajectory_controller.cpp

@@ -192,7 +192,7 @@ controller_interface::return_type JointTrajectoryController::update(
     if (!traj_external_point_ptr_->is_sampled_already())
     {
       first_sample = true;
-      if (params_.open_loop_control)
+      if (params_.interpolate_from_desired_state)
       {
         traj_external_point_ptr_->set_point_before_trajectory_msg(
           time, last_commanded_state_, joints_angle_wraparound_);
@@ -719,8 +719,7 @@ controller_interface::CallbackReturn JointTrajectoryController::on_configure(
   // if there is only velocity or if there is effort command interface
   // then use also PID adapter
   use_closed_loop_pid_adapter_ =
-    (has_velocity_command_interface_ && params_.command_interfaces.size() == 1 &&
-     !params_.open_loop_control) ||
+    (has_velocity_command_interface_ && params_.command_interfaces.size() == 1) ||
     has_effort_command_interface_;
 
   if (use_closed_loop_pid_adapter_)

joint_trajectory_controller/src/joint_trajectory_controller_parameters.yaml

@@ -44,15 +44,15 @@ joint_trajectory_controller:
     default_value: false,
     description: "Allow joint goals defining trajectory for only some joints.",
   }
-  open_loop_control: {
+  interpolate_from_desired_state: {
     type: bool,
-    default_value: false,
-    description: "Use controller in open-loop control mode
+    default_value: true,
+    description: "Interpolate from the current desired state when receiving a new trajectory.
       \n\n
       * The controller ignores the states provided by hardware interface but using last commands as states for starting the trajectory interpolation.\n
-      * It deactivates the feedback control, see the ``gains`` structure.
       \n\n
       This is useful if hardware states are not following commands, i.e., an offset between those (typical for hydraulic manipulators).
+      Furthermore, it is necessary if you have a reference trajectory that you send over multiple messages (e.g. for MPC-style trajectory planning).
       \n\n
       If this flag is set, the controller tries to read the values from the command interfaces on activation.
       If they have real numeric values, those will be used instead of state interfaces.

joint_trajectory_controller/test/test_trajectory_controller.cpp

@@ -1005,8 +1005,7 @@ TEST_P(TrajectoryControllerTestParameterized, use_closed_loop_pid)
     (traj_controller_->has_velocity_command_interface() &&
      !traj_controller_->has_position_command_interface() &&
      !traj_controller_->has_effort_command_interface() &&
-     !traj_controller_->has_acceleration_command_interface() &&
-     !traj_controller_->is_open_loop()) ||
+     !traj_controller_->has_acceleration_command_interface()) ||
     traj_controller_->has_effort_command_interface())
   {
     EXPECT_TRUE(traj_controller_->use_closed_loop_pid_adapter());
@@ -1685,8 +1684,8 @@ TEST_P(TrajectoryControllerTestParameterized, test_jump_when_state_tracking_erro
 {
   rclcpp::executors::SingleThreadedExecutor executor;
   // default if false so it will not be actually set parameter
-  rclcpp::Parameter is_open_loop_parameters("open_loop_control", false);
-  SetUpAndActivateTrajectoryController(executor, {is_open_loop_parameters}, true);
+  rclcpp::Parameter interp_desired_state_parameter("interpolate_from_desired_state", false);
+  SetUpAndActivateTrajectoryController(executor, {interp_desired_state_parameter}, true);
 
   if (traj_controller_->has_position_command_interface() == false)
   {
@@ -1790,10 +1789,10 @@ TEST_P(TrajectoryControllerTestParameterized, test_no_jump_when_state_tracking_e
 {
   rclcpp::executors::SingleThreadedExecutor executor;
   // set open loop to true, this should change behavior from above
-  rclcpp::Parameter is_open_loop_parameters("open_loop_control", true);
+  rclcpp::Parameter interp_desired_state_parameter("interpolate_from_desired_state", true);
   rclcpp::Parameter update_rate_param("update_rate", 100);
   SetUpAndActivateTrajectoryController(
-    executor, {is_open_loop_parameters, update_rate_param}, true);
+    executor, {interp_desired_state_parameter, update_rate_param}, true);
 
   if (traj_controller_->has_position_command_interface() == false)
   {
@@ -1893,15 +1892,15 @@ TEST_P(TrajectoryControllerTestParameterized, test_no_jump_when_state_tracking_e
 TEST_P(TrajectoryControllerTestParameterized, test_hw_states_has_offset_first_controller_start)
 {
   rclcpp::executors::SingleThreadedExecutor executor;
-  rclcpp::Parameter is_open_loop_parameters("open_loop_control", true);
+  rclcpp::Parameter interp_desired_state_parameter("interpolate_from_desired_state", true);
 
   // set command values to NaN
   std::vector<double> initial_pos_cmd{3, std::numeric_limits<double>::quiet_NaN()};
   std::vector<double> initial_vel_cmd{3, std::numeric_limits<double>::quiet_NaN()};
   std::vector<double> initial_acc_cmd{3, std::numeric_limits<double>::quiet_NaN()};
 
   SetUpAndActivateTrajectoryController(
-    executor, {is_open_loop_parameters}, true, 0., 1., initial_pos_cmd, initial_vel_cmd,
+    executor, {interp_desired_state_parameter}, true, 0., 1., initial_pos_cmd, initial_vel_cmd,
     initial_acc_cmd);
 
   // no call of update method, so the values should be read from state interfaces
@@ -1934,7 +1933,7 @@ TEST_P(TrajectoryControllerTestParameterized, test_hw_states_has_offset_first_co
 TEST_P(TrajectoryControllerTestParameterized, test_hw_states_has_offset_later_controller_start)
 {
   rclcpp::executors::SingleThreadedExecutor executor;
-  rclcpp::Parameter is_open_loop_parameters("open_loop_control", true);
+  rclcpp::Parameter interp_desired_state_parameter("interpolate_from_desired_state", true);
 
   // set command values to arbitrary values
   std::vector<double> initial_pos_cmd, initial_vel_cmd, initial_acc_cmd;
@@ -1945,7 +1944,7 @@ TEST_P(TrajectoryControllerTestParameterized, test_hw_states_has_offset_later_co
     initial_acc_cmd.push_back(0.02 + static_cast<double>(i) / 10.0);
   }
   SetUpAndActivateTrajectoryController(
-    executor, {is_open_loop_parameters}, true, 0., 1., initial_pos_cmd, initial_vel_cmd,
+    executor, {interp_desired_state_parameter}, true, 0., 1., initial_pos_cmd, initial_vel_cmd,
     initial_acc_cmd);
 
   // no call of update method, so the values should be read from command interfaces

joint_trajectory_controller/test/test_trajectory_controller_utils.hpp

@@ -167,8 +167,6 @@ class TestableJointTrajectoryController
 
   bool use_closed_loop_pid_adapter() const { return use_closed_loop_pid_adapter_; }
 
-  bool is_open_loop() const { return params_.open_loop_control; }
-
   joint_trajectory_controller::SegmentTolerances get_active_tolerances()
   {
     return *(active_tolerances_.readFromRT());