Implemented Sail Class With Tests

src/controller/controller/common/constants.py

@@ -1 +1,18 @@
 """Constants used across the controller package."""
+
+# meters, trim tab chord width is not included
+CHORD_WIDTH_MAIN_SAIL = 0.23
+
+# {m^2 / s at 10degC} and air density at 1.225 {kg / m^3}
+KINEMATIC_VISCOSITY = 0.000014207
+
+# lookup_table (List[List[Scalar]]): A list of lists or NDArray containing x-y
+# data points for interpolation. Shape should be (n, 2).
+# x units is reynolds number, y units is degrees
+REYNOLDS_NUMBER_ALPHA_TABLE = [
+ [50000, 5.75],
+ [100000, 6.75],
+ [200000, 7],
+ [500000, 9.25],
+ [1000000, 10],
+]

src/controller/controller/wingsail/controllers.py

@@ -0,0 +1,78 @@
+import math
+
+from controller.common.lut import LUT
+
+
+class WingsailController:
+ """
+ The controller class for computing trim tab angles for controlling the mainsail.
+
+ Args:
+ - chord_width_main_sail (float): The chord width of the main sail.
+ - kinematic_viscosity (float): The kinematic viscosity of the fluid.
+ - lut (LUT): A lookup table containing Reynolds numbers and corresponding desired angles of
+ attack.
+ """
+
+ def __init__(self, chord_width_main_sail: float, kinematic_viscosity: float, lut: LUT):
+ self.chord_width_main_sail = chord_width_main_sail
+ self.kinematic_viscosity = kinematic_viscosity
+ self.lut: LUT = lut
+
+ def _compute_reynolds_number(self, apparent_wind_speed: float) -> float:
+ """
+ Computes the Reynolds number for the main sail.
+
+ Args:
+ - apparent_wind_speed (float): The apparent wind speed in meters per second.
+
+ Returns:
+ - reynolds_number (float): The computed Reynolds number for the main sail.
+ """
+ reynolds_number: float = (
+ apparent_wind_speed * self.chord_width_main_sail
+ ) / self.kinematic_viscosity
+ return reynolds_number
+
+ def _compute_trim_tab_angle(
+ self, reynolds_number: float, apparent_wind_direction: float
+ ) -> float:
+ """
+ Computes the trim tab angle based on Reynolds number and apparent wind direction.
+
+ Args:
+ - reynolds_number (float): The Reynolds number.
+ - apparent_wind_direction (float): The absolute bearing (true heading) of the wind.
+ Degrees, 0° means the apparent wind is blowing from the bow to the stern of the boat,
+ increase CW
+ Range: -180 < direction <= 180 for symmetry
+
+ Returns:
+ - trim_tab_angle (float): The computed trim tab angle based on the provided
+ Reynolds number and apparent wind direction.
+ """
+ desired_alpha: float = self.lut(reynolds_number) # Using __call__ method
+ # If the controller convention seems reversed, flip the sign of this return statement
+ # EN, AE - 2024/03/16
+ return math.copysign(desired_alpha, apparent_wind_direction)
+
+ def get_trim_tab_angle(
+ self, apparent_wind_speed: float, apparent_wind_direction: float
+ ) -> float:
+ """
+ Computes and returns the final trim tab angle.
+
+ Range: -180 < direction <= 180 for symmetry
+
+ Args:
+ - apparent_wind_speed (float): The apparent wind speed in meters per second.
+ - apparent_wind_direction (float): The apparent wind direction in degrees.
+
+ Returns:
+ - trim_tab_angle (float): The computed trim tab angle.
+ """
+ reynolds_number: float = self._compute_reynolds_number(apparent_wind_speed)
+ trim_tab_angle: float = self._compute_trim_tab_angle(
+ reynolds_number, apparent_wind_direction
+ )
+ return trim_tab_angle

src/controller/controller/wingsail/wingsail_ctrl_node.py

@@ -7,6 +7,14 @@
 from custom_interfaces.msg import GPS, SailCmd, WindSensor
 from rclpy.node import Node
 
+from controller.common.constants import (
+ CHORD_WIDTH_MAIN_SAIL,
+ KINEMATIC_VISCOSITY,
+ REYNOLDS_NUMBER_ALPHA_TABLE,
+)
+from controller.common.lut import LUT
+from controller.wingsail.controllers import WingsailController
+
 
 def main(args=None):
  rclpy.init(args=args)
@@ -47,8 +55,14 @@ def __init_private_attributes(self):
  during the initialization process.
  """
  self.__trim_tab_angle = 0.0
- self.__filtered_wind_sensor = None
- self.__gps = None
+ self.__filtered_wind_sensor = WindSensor()
+ self.__gps = GPS()
+ # pull hardcoded table from the right place later...
+ # right location should be config.py
+ lut = LUT(REYNOLDS_NUMBER_ALPHA_TABLE)
+ self.__wingsailController = WingsailController(
+ CHORD_WIDTH_MAIN_SAIL, KINEMATIC_VISCOSITY, lut
+ )
 
  def __declare_ros_parameters(self):
  """Declares ROS parameters from the global configuration file that will be used in this
@@ -124,11 +138,20 @@ def __init_timer_callbacks(self):
  def __publish(self):
  """Publishes a SailCmd message with the trim tab angle using the designated publisher.
  It also logs information about the publication to the logger."""
-
  msg = SailCmd()
- msg.trim_tab_angle_degrees = 0.0
+
+ self.__trim_tab_angle = self.__wingsailController.get_trim_tab_angle(
+ self.__filtered_wind_sensor.speed.speed, self.__filtered_wind_sensor.direction
+ )
+
+ msg.trim_tab_angle_degrees = self.__trim_tab_angle
+
  self.__trim_tab_angle_pub.publish(msg)
- self.get_logger().info(f"Published to {self.__trim_tab_angle_pub.topic}")
+
+ self.get_logger().info(
+ f"Published to {self.__trim_tab_angle_pub.topic} \
+ the following angle: {msg.trim_tab_angle_degrees}"
+ )
 
  @property
  def pub_period(self) -> float:

src/controller/tests/unit/wingsail/test_controllers.py

@@ -0,0 +1,107 @@
+import numpy as np
+import pytest
+
+from controller.common.constants import CHORD_WIDTH_MAIN_SAIL, KINEMATIC_VISCOSITY
+from controller.common.lut import LUT
+from controller.wingsail.controllers import WingsailController
+
+# Define test data
+test_lut_data = np.array(
+ [[50000, 5.75], [100000, 6.75], [200000, 7], [500000, 9.25], [1000000, 10]]
+)
+test_lut = LUT(test_lut_data)
+test_chord_width = CHORD_WIDTH_MAIN_SAIL
+test_kinematic_viscosity = KINEMATIC_VISCOSITY
+
+
+class TestWingsailController:
+ """
+ Tests the functionality of the WingsailController class.
+ """
+
+ @pytest.fixture
+ def wingsail_controller(self):
+ """
+ Fixture to create an instance of WingsailController for testing.
+ """
+ return WingsailController(test_chord_width, test_kinematic_viscosity, test_lut)
+
+ @pytest.mark.parametrize(
+ "apparent_wind_speed, expected_reynolds_number",
+ [
+ (0, 0),
+ (3, 3 * CHORD_WIDTH_MAIN_SAIL / KINEMATIC_VISCOSITY),
+ (5, 5 * CHORD_WIDTH_MAIN_SAIL / KINEMATIC_VISCOSITY),
+ (10, 10 * CHORD_WIDTH_MAIN_SAIL / KINEMATIC_VISCOSITY),
+ (20, 20 * CHORD_WIDTH_MAIN_SAIL / KINEMATIC_VISCOSITY),
+ ],
+ )
+ def test_compute_reynolds_number(
+ self, wingsail_controller, apparent_wind_speed, expected_reynolds_number
+ ):
+ """
+ Tests the computation of Reynolds number.
+
+ Args:
+ wingsail_controller: Instance of WingsailController.
+ """
+ computed_reynolds_number = wingsail_controller._compute_reynolds_number(
+ apparent_wind_speed
+ )
+ assert np.isclose(computed_reynolds_number, expected_reynolds_number)
+
+ @pytest.mark.parametrize(
+ "reynolds_number, apparent_wind_direction, expected_trim_tab_angle",
+ [
+ (1250, 45.0, 5.75),
+ (15388, -90.0, -5.75),
+ (210945, 170.0, 7.0820875),
+ (824000, -120.0, -9.736),
+ (2000000, 0, 10.0),
+ ],
+ )
+ def test_compute_trim_tab_angle(
+ self,
+ wingsail_controller,
+ reynolds_number,
+ apparent_wind_direction,
+ expected_trim_tab_angle,
+ ):
+ """
+ Tests the computation of trim tab angle.
+
+ Args:
+ wingsail_controller: Instance of WingsailController.
+ """
+ computed_trim_tab_angle = wingsail_controller._compute_trim_tab_angle(
+ reynolds_number, apparent_wind_direction
+ )
+ assert np.isclose(computed_trim_tab_angle, expected_trim_tab_angle)
+
+ @pytest.mark.parametrize(
+ "apparent_wind_speed, apparent_wind_direction, expected_trim_tab_angle",
+ [
+ (10.0, 0, 6.9047300626451),
+ (4.0, 90.0, 6.045136200464),
+ (10.0, 180.0, 6.904730062645),
+ (15.0, -50.0, -7.3212852819032),
+ (20.0, -120.0, -7.928380375871),
+ ],
+ )
+ def test_get_trim_tab_angle(
+ self,
+ wingsail_controller,
+ apparent_wind_speed,
+ apparent_wind_direction,
+ expected_trim_tab_angle,
+ ):
+ """
+ Tests the computation of final trim tab angle.
+
+ Args:
+ wingsail_controller: Instance of WingsailController.
+ """
+ computed_trim_tab_angle = wingsail_controller.get_trim_tab_angle(
+ apparent_wind_speed, apparent_wind_direction
+ )
+ assert np.isclose(computed_trim_tab_angle, expected_trim_tab_angle)

src/custom_interfaces/msg/SailCmd.msg

@@ -1,4 +1,4 @@
 # Angle to rotate the trim tab relative to the mailsail
-# Unit: degrees, 0° is the neutral position, Increases CW
+# Unit: degrees, 0° is the neutral position, Increases CCW
 # Range: -40° <= angle <= 40°
 float32 trim_tab_angle_degrees