WOLFRAM SYSTEM MODELER

LongitudinalMotion

State space representation of longitudinal motion

Diagram

Wolfram Language

In[1]:=
SystemModel["Aircraft.StateSpace.FixedWing.Blocks.LongitudinalMotion"]
Out[1]:=

Information

This model compiles the linearized state space representation of the longitudinal motion (in body frame) of an aircraft. The linearization is done over the reference flight conditions that are inputs from the subRefFlightSignalBus connector, and the states, inputs and outputs are perturbations from the reference flight conditions.

Other inputs to this model are the perturbations to the control actuators: DeltaeIn (Δδe) for elevator deflection perturbation and DdeltaTIn (ΔδT) for throttle position perturbation. Additionally, the longitudinal stability and control derivatives are inputs through the longdervsIn connector. The output from this model is the output vector yvec through the subLongMotSignalBus bus port.

The state space representation of the longitudinal motion is in the following form

where x is the state vector and η is the control vector consisting of different perturbation components that are described in Table 1. The matrices A and B contain the stability and control derivatives, respectively. The output vector y consists of the three first components of x in Table 1. [1]

Table 1: Perturbation components of state and control vectors in state space representation of longitudinal motion.

Vector Perturbation component
x Δu     axial velocity
Δw     normal velocity
Δq     pitch rate
Δθ     pitch angle
η Δδe   elevator deflection
ΔδT   throttle position
References

[1]  Nelson, R. C. (1998) Flight Stability and Automatic Control. 2nd ed. McGraw-Hill.
      Available at: http://home.eng.iastate.edu/~shermanp/AERE355/lectures/Flight_Stability_and_Automatic_Control_N.pdf.

Parameters (1)

nEng

Value:

Type: Integer

Description: Number of engines

Connectors (5)

DdeltaeIn

Type: RealInput

Description: Elevator deflection perturbation input

DdeltaTIn

Type: RealInput

Description: Throttle perturbation input

longdervsIn

Type: RealVectorInput[14]

Description: Input vector of longitudinal derivatives

subLongMotSignalBus

Type: MotionSignalBus

Description: Bus port for output vector output

subRefFlightSignalBus

Type: RefFlightSignalBus

Description: Bus port for reference flight conditions input

Components (3)

DuExpr

Type: RealExpression

Description: Set output signal to a time varying Real expression

DwExpr

Type: RealExpression

Description: Set output signal to a time varying Real expression

DqExpr

Type: RealExpression

Description: Set output signal to a time varying Real expression

Used in Components (1)

DefaultAircraft

Aircraft.StateSpace.FixedWing

Aircraft model using state-space representation