Aerospace Blockset™

6DoF Wind (Wind Angles)

Implement wind angle representation of six-degrees-of-freedom equations of motion

Library

Equations of Motion/6DoF

Description

For a description of the coordinate system employed and the translational dynamics, see the block description for the 6DoF Wind (Quaternion) block.

The relationship between the wind angles, [ ]^T, can be determined by resolving the wind rates into the wind-fixed coordinate frame.

Inverting then gives the required relationship to determine the wind rate vector.

The body-fixed angular rates are related to the wind-fixed angular rate by the following equation.

Using this relationship in the wind rate vector equations, gives the relationship between the wind rate vector and the body-fixed angular rates.

Dialog Box

Units

Specifies the input and output units:

Units	Forces	Moment	Acceleration	Velocity	Position	Mass	Inertia
Metric (MKS)	Newton	Newton meter	Meters per second squared	Meters per second	Meters	Kilogram	Kilogram meter squared
English (Velocity in ft/s)	Pound	Foot pound	Feet per second squared	Feet per second	Feet	Slug	Slug foot squared
English (Velocity in kts)	Pound	Foot pound	Feet per second squared	Knots	Feet	Slug	Slug foot squared

Mass type

Select the type of mass to use:

Fixed	Mass is constant throughout the simulation.
Simple Variable	Mass and inertia vary linearly as a function of mass rate.
Custom Variable	Mass and inertia variations are customizable.

The Fixed selection conforms to the previously described equations of motion.

Representation

Select the representation to use:

Wind Angles	Use wind angles within equations of motion.
Quaternion	Use quaternions within equations of motion.

The Wind Angles selection conforms to the previously described equations of motion.

Initial position in inertial axes

The three-element vector for the initial location of the body in the Earth-fixed reference frame.

Initial airspeed, angle of attack, and sideslip angle

The three-element vector containing the initial airspeed, initial angle of attack and initial sideslip angle.

Initial wind orientation

The three-element vector containing the initial wind angles [bank, flight path, and heading], in radians.

Initial body rotation rates

The three-element vector for the initial body-fixed angular rates, in radians per second.

Initial mass

The mass of the rigid body.

Inertia

The 3-by-3 inertia tensor matrix , in body-fixed axes.

Inputs and Outputs

Assumptions and Limitations

The block assumes that the applied forces are acting at the center of gravity of the body, and that the mass and inertia are constant.

Reference

Stevens, B. L., and F. L. Lewis, Aircraft Control and Simulation, John Wiley & Sons, New York, 1992.

See Also

6DoF (Euler Angles)

6DoF (Quaternion)

6DoF ECEF (Quaternion)

6DoF Wind (Quaternion)

6th Order Point Mass (Coordinated Flight)

Custom Variable Mass 6DoF (Euler Angles)

Custom Variable Mass 6DoF (Quaternion)

Custom Variable Mass 6DoF ECEF (Quaternion)

Custom Variable Mass 6DoF Wind (Quaternion)

Custom Variable Mass 6DoF Wind (Wind Angles)

Simple Variable Mass 6DoF (Euler Angles)

Simple Variable Mass 6DoF (Quaternion)

Simple Variable Mass 6DoF ECEF (Quaternion)

Simple Variable Mass 6DoF Wind (Quaternion)

Simple Variable Mass 6DoF Wind (Wind Angles)

6DoF Wind (Quaternion)

6th Order Point Mass (Coordinated Flight)