Version 4

New In Version 4.0

Overview of New Features
Real-Time Wind Data from NOAA
Newtonian Aerodynamics from a CAD Model
Airship Stability and Control Derivatives
Parametric Aircraft Point Mass Model
Change List

Overview of New Features

Several new demos
Updated help pages and demos integrated into Matlab help system
New CAD models and utilities in Common module
Real-Time Wind Data from NOAA
Newtonian Aerodynamics from a CAD Model
Airship Stability and Control Derivatives
Parametric Aircraft Point Mass Model

New Examples

Real-Time Wind Data from NOAA

This example uses the NOAAWindData function to obtain real-time winds aloft data from the NOAA website. The data is available for several geographic regions in the United States, at altitudes from 3,000 to 53,000 ft. The plot to the right shows a vector wind field for a large region of the midwest. Real-time winds aloft data can be used to plan flight trajectories, especially for launch vehicles and airships, whose performance can be greatly impacted by wind. Run NOAAWindDemo for the demo.

Newtonian Aerodynamics from a CAD Model

Aerodynamic forces and torques on different surfaces of a vehicle can now be quickly computed using our new tools. Load a .obj or other supported format into Matlab with LoadCAD, then pass the data structure to NewtonianForceAndTorqueFromCAD along with the flight condition. Articulation of control surfaces is also supported. The image below shows is a CAD model of a missile 3rd stage. It shows the visual highlighting of surfaces in the airstream during reentry. This example is taken from the LiftAndDragForMissile demo, which is provided with the Launch Vehicle Toolbox.

Airship Stability and Control Derivatives

We always strive to provide excellent technical support to our customers. When a recent customer asked how they could use ACT to compute stability and control derivatives for their airship model, we delivered a new function to do just that. The file "AirshipStabConDerivatives" computes the trim controls for a given airship model at a given flight condition, perturbs the states and controls one by one, and computes the change in aerodynamic forces and moments. A built-in demo is provided and produces the following data for the longitudinal stability derivatives:

        X_V: -0.00977380458639986
        Z_V: -0.00427690148323265
        M_V: -0.000159112668746186
    X_alpha: -9.84182392115935
    Z_alpha: -6.33410804101002
    M_alpha: -0.021393644565374
        X_q: 0
        Z_q: 0
        M_q: -5.75519022581117e-05
      X_elv: 0
      Z_elv: -1.04596407536638
      M_elv: -0.0389127821079408

Parametric Aircraft Point Mass Model

ACT now includes a non-dimensional point mass model of a standard aircraft model. A simulation of the open loop dynamics with nonlinear dynamic inversion for feedback control is implemented in AircraftPointMassCLPSim.m. An example of how to use this simulation with a simple set of commands is provided in the AircraftTrajectoryControlSim demo. The plots below, taken from this demo, show the tracked velocity and the control input histories. The desired closed-loop dynamics for velocity is a second order system, and the control inputs are normalized lift, bank angle, and and normalized excess thrust.