Reset PID controllers on activation and add save_iterm parameter

doc/release_notes.rst

@@ -60,6 +60,7 @@ mecanum_drive_controller
 pid_controller
 ************************
 * 🚀 The PID controller was added 🎉 (`#434 <https://github.com/ros-controls/ros2_controllers/pull/434>`_).
+* Add ``save_iterm`` parameter to control retention of integral state after re-activation (`#1507 <https://github.com/ros-controls/ros2_controllers/pull/1507>`_).
 
 steering_controllers_library
 ********************************

pid_controller/src/pid_controller.cpp

@@ -440,6 +440,11 @@ controller_interface::CallbackReturn PidController::on_activate(
   measured_state_values_.assign(
     measured_state_values_.size(), std::numeric_limits<double>::quiet_NaN());
 
+  // prefixed save_iterm parameter is read from ROS parameters
+  for (auto & pid : pids_)
+  {
+    pid->reset();
+  }
   return controller_interface::CallbackReturn::SUCCESS;
 }
 

pid_controller/src/pid_controller.yaml

@@ -89,3 +89,8 @@ pid_controller:
         description: "For joints that wrap around (i.e., are continuous).
           Normalizes position-error to -pi to pi."
       }
+      save_iterm: {
+        type: bool,
+        default_value: true,
+        description: "Indicating if integral term is retained after re-activation"
+      }