F18 Analysis Folder Description
This file explains the contents and objectives of each of the F18 Analysis folders that are provided here.
NOTE: Users who are not interested in model development and formulation can skip folders 1 and 2. They can use the plants given in folder 3 and proceed with the analysis in folders 4-6.
Contents
Folder 1: 1_F18FullModel
Description:
This folder contains a detailed and full 6 degree-of-freedom 9 State description of the F/A-18 aircraft, including the aerodynamic equations and physical parameters of the aircraft.
USAGE:
Run runf18full.m to generate initial condition response of the F/A-18 aircraft.
Files:
NOTE: This model has been reduced further to perform all the analyses. We have not used this model for any of the analyses /results presented here. This model is given only for completeness. None of the analyses have been performed on this full model.
f18full.m This file describes a 6 DoF / 9 state F/A-18 nonlinear model. This also includes the aerodynamic data and physical parameters of the aircraft.
runf18full.m: This file simulates initial condition response of the F/A-18 model described in f18full.m.
Folder 2: 2_F18ReducedModel
This folder formulates and develops the reduced order model for analysis. The models generated from this folder have been included in Folder 3: F18 Analysis Plants. This section can be skipped if model formulation is not of interest.
Folder 2a: Nonlinear Model
Description:
This folder contains multiple files. Each file will be described below. The subsequent analysis compares the stability properties of two different control laws: (i) Baseline , and (ii) Revised control law. This file generates cubic order reduced models for the F/A-18 open loop plant and for the closed-loop systems with the baseline and revised controllers.
USAGE:
(a) Run F18CubicNL_BaseLine.m to generate Cubic Degree Polynomial Closed Loop Baseline model.
(b) Run F18CubicNL_Revised.m to generate Cubic Degree Polynomial Closed Loop Revised model.
Files:
NOTE : The following files require the Multipoly toolbox.
F18CubicNL_OLoop.m: This file generates a polynomial open loop nonlinear F/A-18 model.
F18CubicNL_BaseLine.m: This file generates the Baseline Closed Loop cubic order F/A-18 Model.
LS_xcldot_BaseLine.m: This file is being used by the F18Clp_BaseLine.m file to perform the least square approximation.
F18CubicNL_Revised.m: This file generates the Revised Closed Loop cubic order F/A-18 Model.
LS_xcldot_Revised.m: This file is being used by the F18Clp_Revised.m file to perform the least square approximation.
f18_data.m: This file contains all the physical parameters of the F/A-18. The Velocity state which assumed to be constant is also included there.
AeroApprox.m: This file contains approximation of some of the aerodynamic coefficients.
Folder 2b: LinearModel
Description:
This folder contains multiple files. Each files will be described below. This folder generates the open loop linear model for the F/A-18 aircraft.
USAGE:
(a) Run Lin_F18.m to generate open loop linear F/A-18 plant for flight condition described inside this file.
Files:
Lin_F18.m: This file will trim & generate the open loop linear model for F/A-18 aircraft. The trimming and linearization is done based on the nonlinear plant 'F18Reduced_OLoop.m' described in the "2_F18ReducedModel /NonlinearModel" Folder.
f18_plant.m: This file contains the nonlinear plant 'F18CubicNL_OLoop.m' described in the "2_F18ReducedModel /NonlinearModel" Folder. This file can be used to simulate open loop response.
f18_sfcn.m: This is a S-function for performing trimming. This file is being used in the Lin_F18.m file.
f18_trim.mdl: This is a Simulink file, also used for trimming. This file is being used in the Lin_F18.m file.
Folder 3: 3_F18AnalysisPlants
Description:
This folder contains all the linear and nonlinear plants for analysis. For detailed description on how these models have been generated refer to Folder 2 and its subfolders.
Files:
F18BaselineCubic.MAT: This MAT file contains the cubic order F/A-18 baseline closed loop model. This will be used for nonlinear analysis.
F18RevisedCubic.MAT: This MAT file contains the cubic order F/A-18 revised closed loop model. This will be used for nonlinear analysis.
LinF18OLoop---.MAT: These MAT files (starting with 'LinF18OLoop...' ) contain two open loop linear plants. The difference in these two linear plants are in the output equation (y = Cx + Du), as each control law uses different feedback channels. The plant named "Pss_Baseline" will be used to construct the baseline model whereas plant "Pss_Revised" is used for building up the revised model.
Folder 4: 4_LinearAnalysis
Description:
This folder generates the closed loop linear (i) baseline, (ii) revised models. Then, linear robustness analysis have been performed on these two plants.
USAGE:
(a) Run F18_Lin_Analysis.m: to perform linear analysis on both the linearized baseline and revised model. This file generates the linear closed loop plants and perform all the robustness analysis.
Files:
F18_Lin_Analysis.m: Run this file to performs linear robustness analysis on the two closed loop linear models specified above.
Gen_LinF18Clps.m: This file generates closed loop F/A-18 models given the open loop plants. The open loop plant(s) should be named in the following way : Pdata.Pss_Baseline Pdata.Pss_Revised
*NOTE:* Use "2_F18ReducedModel/LinearModel/Lin_f18.m"
for generating both (i) baseline (ii) revised open loop linear
models with correct ordering of state, input and output.Gen_LinF18ClpPlants.m: This file generates both (i) baseline and (ii) revised closed loop linear models for all the linear plants provided in the "3_F18AnalysisPlants" folder as |LinF18OLoop.MAT:| files.
Folder 5: 5_MonteCarlo
Description:
This folder contains files that will run Monte Carlo simulation on the closed loop nonlinear plants provided in the "3_F18AnalysisPlants" Folder.
USAGE:
Both the files can be executed to perform the tasks mentioned below.
Files:
Search4UnstableTraj.m: This file solves the following via Monte Carlo min x0'*N*x0 ( N := shape factor) subject to: dx/dt = f(x) diverges from the initial condition x0.
Search4VdotPos.m: This file attempts to solve via Monte Carlo search: min x0'*N*x0 subject to: dV/dt = grad(V)(x)*f(x) >0
Folder 6: 6_ROAAnalysis
Description:
This folder contains files that will perform the region-of-attraction analysis on the cubic order polynomial models described in the Folder 1-3.
USAGE:
Both the files can be executed to perform the tasks mentioned below.
Files:
ROA1_F18_LinearizedLyap.m: This file computes an estimate of the region of attraction for the F/A-18 using the Lyapunov function obtained via linearization.
ROA2_F18_VSIteration.m: This file computes an estimate of the region of attraction for F/A-18 using the V-S Iteration.