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%CALC_THRUST_CONSTANT
% Calculates the thrust constant (Kt) given experimental data. The thrust
% constant is described in detail in sections 4.2.1.1 and 5.5.1 of
% "Model development, system identification, and control of a quadrotor
% helicopter" by Matt Rich.
% Input Arguments:
% data: experimental data
% Convert RPM to angular speed of each rotor.
rotor_speed_0 = data.(2) * (pi/30);
rotor_speed_1 = data.(3) * (pi/30);
rotor_speed_2 = data.(4) * (pi/30);
rotor_speed_3 = data.(5) * (pi/30);
% Define the A matrix as the sum of each rotors speed squared.
A = (rotor_speed_0.^2 + rotor_speed_1.^2 + rotor_speed_2.^2 + rotor_speed_3.^2);
% Convert weight (g) to thrust force (N) by converting grams to kilograms and
% multiplying by the acceleration of gravity.
T = (data.Scale_g_/1000)*9.8;
% Calculate the thrust constant (Kt) through the following
% equation: Kt = (A'A)^-1.*A'.*T as defined on page 65 of "Model
% development, system identification, and control of a quadrotor
% helicopter" (Matt Rich's Thesis).
Kt = ((A'*A)^(-1))*(A'*T)
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