As shown, SURVEY is set up to make calculations based on the 12 x 12 Fmodel and 12 x 7 Gmodel produced by FLIGHT, with the generic business jet model trimmed for flight at V = 102 m/s and h = 3,050 m. The flags are set to generate a fourth-order, body-axis, lateral-directional model from the data set; to calculate eigenvalues, eigenvectors, and the transfer function from aileron to roll rate; and to show the Bode plot, Nyquist plot, and Nichols chart for the transfer function. Asymptotes of the Bode plot are shown using the function asymp.m, which can be downloaded at https://www.mathworks.com/matlabcentral/fileexchange/10183-bode-plot-with-asymptotes.
LonLatDir accepts stability and control-effect matrices for combined longitudinal and lateral-directional dynamics as input and either passes the matrices unchanged, re-orders elements of the matrices, or generates a selected reduced-order model from them. It presents matrices for body, stability, or hybrid axes, for longitudinal or lateral-directional partitions, and for fourth- or sixth-order computations. As shown, there are twelve original state elements, four longitudinal controls, and three lateral-directional controls
Trans calculates and plots transient response to an arbitrary array of initial conditions and step control inputs, calling the MATLAB function lsim to perform the simulation.
Static computes static control and command response for fourth-order systems with no disturbances and two control inputs (elevator and throttle in the longitudinal case, aileron and rudder for the lateral-directional model). Static control equilibrium does not exist for the higher-order models presented here because the stability matrix is singular.
The matrix rank tests described in Chapter 4 are performed by calling the MATLAB functions ctrb and obsv in ConObs.
NatFreq presents eigenvalues sorted in descending order and natural frequencies, damping ratios, and real roots using the MATLAB functions esort and damp.
StabMode presents eigenvalues and eigenvectors, as well as amplitudes of the eigenvector components for both original and velocity-weighted sets.