3DOF Angular Acceleration

Compute pitch or angular acceleration of body in three-degrees-of-freedom motion

Since R2025a

• 

Libraries:
Aerospace Blockset / Equations of Motion / Acceleration

Description

The 3DOF Angular Acceleration block computes the pitch or angular acceleration of a body in six-degrees-of-freedom motion with respect to body-fixed coordinate frame and inertial (flat Earth) coordinate frame.

To compute the angular acceleration for equations of motions blocks:

• Select Output mass properties for acceleration computation.

• Feed signals from the matching output ports of the associated 3DOF equation of motion block into the associated input ports of 3DOF Angular Acceleration.

Tip

Match all the parameter values for 3DOF Angular Acceleration and the 3DOF equations of motion blocks.

Ports

Input

q — Pitch angular rate

scalar

Pitch angular rate, specified as a scalar, in radians per second.

Data Types: double

I — Inertia tensor

scalar

Inertia tensor, specified as a scalar, in the units selected in Units.

Data Types: double

dI/dt coeff — Rate of change of inertia tensor matrix coefficient

3-by-3 matrix

Rate of change of inertia tensor matrix coefficient, specified as a 3-by-3 matrix, in m².

Dependencies

To enable this port, set Mass type to Simple Variable.

Data Types: double

M — Applied pitching moment

scalar

Applied pitching moment, specified as a scalar, in the units selected in Units.

Data Types: double

dm/dt — Rate of change of mass

scalar

Rate of change of mass (positive if accreted, negative if ablated), specified as a scalar, in the units selected in Units.

Dependencies

To enable this port, set Mass type to Simple Variable.

Data Types: double

dI/dt — Rate of change of inertia tensor

scalar

Rate of change of inertia tensor, I_yy, specified as scalar, in the units selected in Units.

Dependencies

To enable this port, set Mass type to Custom Variable.

Data Types: double

Output

dq/dt — Pitch angular acceleration

scalar

Pitch angular acceleration, returned as a scalar, in radians per second squared.

Data Types: double

Parameters

To edit block parameters interactively, use the Property Inspector. From the Simulink^® Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Units — Input and output units

Metric (MKS) (default) | English (Velocity in ft/s) | English (Velocity in kts)

Input and output units, specified as Metric (MKS), English (Velocity in ft/s), or English (Velocity in kts).

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

Programmatic Use

Block Parameter: units

Type: character vector

Values: Metric (MKS) | English (Velocity in ft/s) | English (Velocity in kts)

Default: Metric (MKS)

Mass type — Mass type

Fixed (default) | Simple Variable | Custom Variable

Mass type, specified according to the following table.

Mass Type	Description	Default for
Fixed	Mass is constant throughout the simulation.	3DOF (Body Axes) 3DOF (Wind Axes)
Simple Variable	Mass and inertia vary linearly as a function of mass rate.	Simple Variable Mass 3DOF (Body Axes) Simple Variable Mass 3DOF (Wind Axes)
Custom Variable	Mass and inertia variations are customizable.	Custom Variable Mass 3DOF (Body Axes) Custom Variable Mass 3DOF (Wind Axes)

Programmatic Use

Block Parameter: mtype

Type: character vector

Values: Fixed | Simple Variable | Custom Variable

Default: 'Fixed'

Version History

Introduced in R2025a