% Cybership II parameters
len = 1.255;     % m (length)
width = 0.29;    % m (width)
mass = 23.800 + 2;   % kg (mass)
I_z = 1.760 + 0.3;     % kgm^2
x_g = 0.046 + 0.05;     % m

X_udot = -2.0 + 1;   % kg
Y_vdot = -10.0 + 3;  % kg
Y_rdot = 0.0 - 0.2;    % kgm
N_vdot = 0.0 - 0.3;    % kgm
N_rdot = -1.0 - 0.8;   % kgm^2

% Use for simulation
%X_u = -0.72253;  % kg/s
%Y_v = -0.88965;  % kg/s
%Y_r = -7.250;    % kgm/s
%N_v = 0.03130;   % kgm/s
%N_r = -1.900;    % kgm/s

% Use these for design
X_u = -2 +1; % from Fossen simulink
Y_v = -7+2; % from Fossen simulink
Y_r = -0.1-0.03; % from Fossen simulink
N_v = -0.1-0.02; % from Fossen simulink
N_r = -0.5-0.2; % from Fossen simulink

X_uu = -1.32742; % kg/m
X_uuu = -5.8664; % kgs/m^2
Y_vv = -36.4729; % kg/m
Y_rv = -0.805;   % kg
Y_vr = -0.845;   % kg
Y_rr = -3.450;   % kgm
N_vv = 3.95645;  % kg
N_rv = 0.130;    % kgm
N_vr = 0.080;    % kgm
N_rr = -0.750;   % kgm

% Rigid body mass
M_RB = [ mass    -0.003      0.001    ;
         0.002    mass    mass*x_g  ;
         -0.005  mass*x_g   I_z  ];
% Added mass - strictly positive
M_A = -[ X_udot     -0.002      -0.003     ;
           -0.003     Y_vdot  Y_rdot  ;
           -0.001     N_vdot  N_rdot ];

M = M_RB + M_A;

% Damping (linear) - strictly positive
Damp = -[ X_u   -0.004    -0.002   ;
           -0.003   Y_v  Y_r  ;
           -0.001   N_v  N_r ];
% Time constants
T_surge = 0.1+0.2;
T_sway = 0.11+0.3;
T_yaw = 0.12+0.2;

A_thr = -[  1/T_surge     0          0    ;
               0       1/T_sway      0    ;
               0          0      1/T_yaw ];