uavWindGust

Generate wind gust for UAV platform

Since R2024a

Description

The uavWindGust object generates a wind gust of the standard “1-cosine” shape for a UAV platform. For more information on the gust shape, see 1-Cosine Gust Shape. To simulate a wind gust in a UAV scenario:

1. Create the uavWindGust object and set its properties.

2. Attach the wind model to a UAV platform by using the addWind function.

3. Obtain the wind velocity from the UAV scenario by using the windVelocity function while the UAV scenario is running.

Note

Simulating a UAV scenario that contains a uavWindGust object requires Aerospace Toolbox.

Creation

Syntax

gustWind = uavWindGust

gustWind = uavWindGust(Name=Value)

Description

gustWind = uavWindGust creates a wind gust object with default property values.

gustWind = uavWindGust(Name=Value) specifies properties using one or more name-value arguments. For example, uavWindGust(StartTime=10) sets the wind start time to 10 seconds.

Properties

You can modify these properties before you add the uavWindGust object to the UAV platform using the addWind function.

GustAmplitude — Gust amplitude

[3.5 3.5 3] (default) | vector of the form [v_x v_y v_z]

Gust amplitude in the UAV platform body frame, specified as a vector of the form [ v_x v_y v_z]. The values of v_x, v_y, and v_z are the wind velocity amplitudes in the positive x-, y-, and z-axes, respectively. Units are in m/s.

Example: [1 0 0]

Data Types: double

GustLength — Gust length

[120 120 80] (default) | vector of form [d_x d_v d_z]

The length over which the gust builds up in each axis of the UAV platform body frame, specified as a vector of the form [d_x d_y d_z], where d_x d_y d_z are gust length in the x-, y-, and z-axes, respectively. Units are in meters.

Example: [1 0 0]

Data Types: double

StartTime — Wind start time

0 (default) | nonnegative scalar

Wind start time, specified as a nonnegative scalar. This value is relative to the simulation start time of the UAV scenario. Units are in seconds.

Example: 2

Data Types: double

StopTime — Wind stop time

Inf (default) | nonnegative scalar

Wind stop time, specified as a nonnegative scalar. This value is relative to the simulation start time of the UAV scenario. If specified as inf, the wind gust continues until the UAV scenario simulation ends. Units are in seconds.

Example: 5

Data Types: double

Examples

Generate Wind Gust in UAV Scenario

Create a UAV scenario with default properties.

scene = uavScenario;

Create a UAV platform. Specify a trajectory to fly the platform 80 meters north of the scenario origin in 80 seconds.

distance = 80;
duration = 80;
platformTrajectory = waypointTrajectory([0 0 -50; distance 0 -50],[0 duration]);
platform = uavPlatform("UAV",scene,Trajectory=platformTrajectory);

Create a wind gust object. Specify the amplitude as 5 m/s on the z-axis, with a gust length of 80 meters. Add the wind object to the UAV platform.

gustWind = uavWindGust(GustAmplitude=[0 0 5],GustLength=[80 80 80]);
addWind(platform,gustWind)

Set up the scenario.

setup(scene)

% initialize arrays of zeros to store the vertical wind velocity and x-position of the UAV
wv = zeros(scene.UpdateRate*duration,1);
xpos = zeros(scene.UpdateRate*duration,1);

% Start a counter index
idx = 1;

Run the scenario. Obtain the vertical wind velocity at each time step.

while scene.CurrentTime <= duration
    % Obtain resultant wind velocity
    vel = windVelocity(platform);
    
    % Obtain UAV position
    [motion,lla] = read(platform);
    
    % Obtain UAV x-position
    xpos(idx) = motion(1);

    % Obtain vertical wind velocity
    wv(idx) = vel(3);

    % Increment counter index
    idx = idx + 1;

    % Advance the scenario time step
    advance(scene);
end

Plot the vertical wind velocity against distance.

plot(xpos,wv)
title("Vertical Wind Velocity")
xlabel("Distance (m)")
ylabel("Vertical Wind Velocity (m/s)")

More About

1-Cosine Gust Shape

This figure shows the shape of a gust with a start time of zero. This diagram shows the impact of gust length and gust amplitude on the shape of the gust.

To assess the response of a UAV to large wind disturbances, you can use one or more discrete gust objects for a single platform.

The mathematical representation of the discrete gust is:

$$V_{wind}=\{\begin{array}{lll}0,\hfill & x<0\hfill & \hfill \\ \frac{V_m}{2}\left(1-\cos \left(\frac{\pi x}{d_m}\right)\right),\hfill & 0\le x\le d_m\hfill & \hfill \\ V_m,\hfill & x>d_m\hfill & \hfill \end{array}$$

where V_m is the gust amplitude, d_m is the gust length, x is the distance traveled, and V_wind is the resultant wind velocity in the UAV platform body frame.

Version History

Introduced in R2024a