Move uncertain model design into uav_model and add more design parameter

1 files changed, 107 insertions, 0 deletions

diff --git a/uav.m b/uav.m
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+% Copyright (c) 2024, Naoki Sean Pross, ETH Zürich
+%
+% Controller design for a ducted fan VTOL micro-UAV.
+
+%  ------------------------------------------------------------------------
+% Clear environment and generate parameters
+
+clear; clc; close all; s = tf('s');
+params = uav_params();
+
+% ------------------------------------------------------------------------
+% Define performance requirements
+
+% Mechanically, flaps are constrained to a max of 20~25 degrees,
+% and they have a maximal angular speed
+alpha_max = params.actuators.ServoAbsMaxAngle;
+alpha_dot_max = params.actuators.ServoNominalAngularVelocity;
+
+W_Palpha = (s + 100 * alpha_dot_max) / (s + alpha_dot_max);
+W_Palpha = alpha_max * W_Palpha / dcgain(W_Palpha); % adjust gain
+
+% Mechanically we have a maximal angular velocity for the propeller in the
+% thruster, also there are a lot of unmodelled dynamics in the thruster
+omega_max = params.actuators.TurbineMaxSpeed;
+W_Pomega = (s + 50 * omega_max) / (s + omega_max);
+
+% We want a nice and smooth movements
+v_xy_max = params.performance.MaxHorizontalSpeed;
+v_z_max = params.performance.MaxVerticalSpeed;
+
+W_Pxy = 1 / (s + 1 / v_xy_max);
+W_Pz = 1 / (s + 1 / v_z_max);
+
+% Bode plots of performance requirements
+figure; hold on;
+
+bodemag(1/W_Palpha);
+bodemag(1/W_Pomega);
+bodemag(1/W_Pxy);
+bodemag(1/W_Pz);
+
+grid on;
+legend('$W_{P,\alpha}$', '$W_{P,\omega}$', ...
+  '$W_{P,xy}$', '$W_{P,z}$', ...
+  'interpreter', 'latex', 'fontSize', 8);
+title('Performance requirements');
+
+% Step response of position requirements
+figure; hold on;
+step(W_Pxy); step(W_Pz);
+grid on;
+legend('$W_{P,xy}$', '$W_{P,z}$', 'interpreter', 'latex', 'fontSize', 8);
+title('Step responses of position performance requirements');
+
+% Construct performance for position vector by combining xy and z
+W_PP = blkdiag(W_Pxy * eye(2), W_Pz);
+
+perf = struct(...
+  'FlapAngle', W_Palpha * eye(4), ...
+  'Thrust', W_Pomega, ...
+  'PositionAccuracy', W_PP);
+
+%  ------------------------------------------------------------------------
+% Define stability requirements
+
+W_malpha = tf(1,1);
+W_momega = tf(1,1);
+W_mTheta = tf(1,1);
+W_mOmega = tf(1,1);
+
+figure; hold on;
+
+bodemag(W_malpha);
+bodemag(W_momega);
+bodemag(W_mTheta);
+bodemag(W_mOmega);
+
+grid on;
+legend('$W_{m,\alpha}$', '$W_{m,\omega}$', ...
+  '$W_{m,\Theta}$', '$W_{m,\Omega}$', ...
+  'interpreter', 'latex', 'fontSize', 8);
+title('Uncertainties')
+
+uncert = struct(...
+  'FlapAngle', W_malpha * eye(4), ...
+  'Thrust', W_momega, ...
+  'EulerAnglesApprox', W_mTheta * eye(3), ...
+  'AngularRateApprox', W_mOmega * eye(3));
+  
+% ------------------------------------------------------------------------
+% Create UAV model
+
+model = uav_model(params, perf, uncert);
+
+% ------------------------------------------------------------------------
+% Perform H-infinity design
+
+Gnom = model.linear.StateSpace;
+G = model.uncertain.StateSpace;
+
+%  ------------------------------------------------------------------------
+% Verify performance satisfaction
+
+%  ------------------------------------------------------------------------
+% Perform mu-Analysis & DK iteration
+
+% vim: ts=2 sw=2 et: