Revert "SJTC: Correctly handle an unset update rate (#1886)"

This reverts commit 383c18a.

Author: urfeex

ur_bringup/config/ur_controllers.yaml

@@ -86,7 +86,6 @@ joint_trajectory_controller:
       $(var tf_prefix)wrist_1_joint: { trajectory: 0.2, goal: 0.1 }
       $(var tf_prefix)wrist_2_joint: { trajectory: 0.2, goal: 0.1 }
       $(var tf_prefix)wrist_3_joint: { trajectory: 0.2, goal: 0.1 }
-    update_rate: $(var update_rate)
 
 
 scaled_joint_trajectory_controller:

ur_controllers/src/scaled_joint_trajectory_controller.cpp

@@ -74,16 +74,7 @@ controller_interface::InterfaceConfiguration ScaledJointTrajectoryController::st
 
 controller_interface::CallbackReturn ScaledJointTrajectoryController::on_configure(const rclcpp_lifecycle::State& state)
 {
-  auto update_rate = get_update_rate();
-
-  if (update_rate == 0) {
-    RCLCPP_WARN(get_node()->get_logger(), "Controller's update_rate is 0. Please configure a non-zero update_rate for "
-                                          "the controller to work properly. Falling back to sampling trajectory at "
-                                          "current_time + last period.");
-    update_period_ = rclcpp::Duration(0, 0);
-  } else {
-    update_period_ = rclcpp::Duration(0, static_cast<uint32_t>(1.0e9 / static_cast<double>(get_update_rate())));
-  }
+  update_period_ = rclcpp::Duration(0.0, static_cast<uint32_t>(1.0e9 / static_cast<double>(get_update_rate())));
 
   return JointTrajectoryController::on_configure(state);
 }
@@ -194,10 +185,8 @@ controller_interface::return_type ScaledJointTrajectoryController::update(const
                                      end_segment_itr);
     state_desired_.time_from_start = traj_time_ - traj_external_point_ptr_->time_from_start();
 
-    // find segment for current timestamp. Look controller period ahead, fallback to last cycle's
-    // period if no update rate is configured.
-    const auto& sample_period = update_period_.seconds() == 0.0 ? period : update_period_;
-    const bool valid_point = traj_external_point_ptr_->sample(traj_time_ + sample_period, interpolation_method_,
+    // find segment for current timestamp
+    const bool valid_point = traj_external_point_ptr_->sample(traj_time_ + update_period_, interpolation_method_,
                                                               command_next_, start_segment_itr, end_segment_itr);
     state_current_.time_from_start = time - traj_external_point_ptr_->time_from_start();
 

ur_robot_driver/config/ur_controllers.yaml

@@ -133,7 +133,6 @@ scaled_joint_trajectory_controller:
       $(var tf_prefix)wrist_2_joint: { trajectory: 0.2, goal: 0.1 }
       $(var tf_prefix)wrist_3_joint: { trajectory: 0.2, goal: 0.1 }
     speed_scaling_interface_name: $(var tf_prefix)speed_scaling/speed_scaling_factor
-    update_rate: $(var update_rate)
 
 passthrough_trajectory_controller:
   ros__parameters:

ur_robot_driver/launch/ur_control.launch.py

@@ -29,8 +29,6 @@
 #
 # Author: Denis Stogl
 
-import yaml
-
 from launch_ros.actions import Node
 from launch_ros.parameter_descriptions import ParameterFile, ParameterValue
 from launch_ros.substitutions import FindPackagePrefix, FindPackageShare
@@ -230,13 +228,6 @@ def launch_setup(context, *args, **kwargs):
         ]
     )
 
-    # Expose the controller_manager update_rate as a launch configuration so
-    # that '$(var update_rate)' substitutions inside controller config yaml
-    # resolve to the correct rate for this ur_type.
-    with open(update_rate_config_file.perform(context)) as f:
-        update_rate = yaml.safe_load(f)["controller_manager"]["ros__parameters"]["update_rate"]
-    context.launch_configurations["update_rate"] = str(update_rate)
-
     control_node = Node(
         package="controller_manager",
         executable="ros2_control_node",