within Requirements; model StabilityRequirement "SR-WIND-02: The UAS shall maintain lateral and yaw stability under wind disturbance and recover within limits" // ---- System-level parameters (traceable to SR-WIND-02) ---- parameter Real hoverTolerance = 2.5 "Maximum allowed lateral deviation during hover [m]"; parameter Real yawTolerance = 5 "Maximum allowed yaw error [deg]"; parameter Real recoveryBand = 0.5 "Position error band for recovery after disturbance [m]"; parameter Real recoveryTime = 3 "Time to remain within recovery band [s]"; // ---- Inputs from the system ---- Modelica.Blocks.Interfaces.RealInput posX "Measured X position [m]" annotation( Placement(transformation(extent={{120,40},{80,80}}))); Modelica.Blocks.Interfaces.RealInput posY "Measured Y position [m]" annotation( Placement(transformation(extent={{120,-80},{80,-40}}))); Modelica.Blocks.Interfaces.RealInput yaw "Measured yaw angle [deg]" annotation( Placement(transformation(extent={{120,-10},{80,30}}))); Modelica.Blocks.Interfaces.RealInput DronePositionConsign[3] "Commanded reference position [m]" annotation( Placement(transformation(extent={{-20,120},{20,80}}, rotation=-90))); Modelica.Blocks.Interfaces.RealInput yawConsign "Commanded yaw angle [deg]" annotation( Placement(transformation(extent={{-60,120},{-20,80}}, rotation=-90))); // ---- Outputs for monitoring ---- Modelica.Blocks.Interfaces.RealOutput lateralError "2D lateral position error magnitude [m]" annotation( Placement(transformation(extent={{-90,50},{-110,70}}))); Modelica.Blocks.Interfaces.RealOutput yawError "Yaw error magnitude [deg]" annotation( Placement(transformation(extent={{-90,20},{-110,40}}))); Modelica.Blocks.Interfaces.BooleanOutput withinHoverLimit "true if lateralError < hoverTolerance" annotation( Placement(visible = true, transformation(extent = {{-110, -10}, {-90, 10}}, rotation = 0), iconTransformation(origin = {-100, 0}, extent = {{10, -10}, {-10, 10}}, rotation = 0))); Modelica.Blocks.Interfaces.BooleanOutput withinYawLimit "true if yawError < yawTolerance" annotation( Placement(visible = true, transformation(extent = {{-110, -40}, {-90, -20}}, rotation = 0), iconTransformation(origin = {-100, -30}, extent = {{10, -10}, {-10, 10}}, rotation = 0))); Modelica.Blocks.Interfaces.BooleanOutput recovered "true if position remains within recoveryBand for recoveryTime" annotation( Placement(visible = true, transformation(extent = {{-110, -70}, {-90, -50}}, rotation = 0), iconTransformation(origin = {-100, -60}, extent = {{10, -10}, {-10, 10}}, rotation = 0))); Modelica.Blocks.Interfaces.BooleanOutput pass "true if all criteria are satisfied" annotation( Placement(visible = true, transformation(extent = {{-110, -100}, {-90, -80}}, rotation = 0), iconTransformation(origin = {-100, -90}, extent = {{10, -10}, {-10, 10}}, rotation = 0))); protected Real t_within(start=0) "Timer for recovery criterion"; equation // --- Lateral and yaw errors --- lateralError = sqrt((posX - DronePositionConsign[1])^2 + (posY - DronePositionConsign[2])^2); yawError = abs(yaw - yawConsign); withinHoverLimit = lateralError < hoverTolerance; withinYawLimit = yawError < yawTolerance; // --- Recovery logic (after gust disturbance) --- der(t_within) = if lateralError < recoveryBand then 1 else 0; // Reset timer whenever the drone leaves the recovery band when lateralError > recoveryBand then reinit(t_within, 0); end when; recovered = t_within >= recoveryTime; // --- Overall requirement pass flag --- //pass = withinHoverLimit and withinYawLimit and recovered; pass = withinHoverLimit and withinYawLimit; annotation( Documentation(info="

SR-WIND-02 – Performance in Wind

Source: EASA Means of Compliance Light-UAS.2512, ISO 21384-3 (Clause 10 – Operational limitations).

Requirement:
Under a steady 8 m/s wind with 12 m/s gusts, the UAS shall:

Simulation Inputs: Connect to AIDA_System position, yaw, and reference signals.

"), uses(Modelica(version="3.2.2")), Icon(graphics = {Text(extent = {{-100, 100}, {100, -100}}, textString = "SR-WIND-02"), Rectangle(extent = {{-104, -2}, {-104, -2}}), Rectangle(origin = {0, -1}, extent = {{-100, 101}, {100, -99}})}, coordinateSystem(initialScale = 0.1))); end StabilityRequirement;