stuck in a small issue related to implementation of an aircraft trim condition code with cost function: error is "TOO MANY INPUT ARGUMENTS"

% TRIM.m
clear; clc; close all;
global x u gamma;
x(1) = 170;
x(5) = 0;
gamma = 0;
name = input('Name of Cost function file? : ','s');
cg= 0.25; land=1; % 0 = clean 1=gear+flaps;
u = [0.1 -10 cg land];
x(2)= .1; % Alpha, initial guess
x(3)=x(2) + gamma; % Theta
x(4)=0; % Pitch rate
x(6)=0;
s0=[u(1) u(2) x(2)];
% Now initialize any other states and get initial cost
disp(['Initial cost= ', num2str(feval(name,s0))]);
[s,fval]= fminsearch(name,s0);
x(2) = s(3) ; x(3) = s(3)+ gamma;
u(l)=s(1); u(2)=s(2);
disp(['minimizing vector= ',num2str(feval)]);
disp(['minimum cost vector= ',num2str(s)]);
temp=[length(x), length(u),x,u];
name= input('Name of output file? : ',' s');
dlmwrite(name,temp);
% Medium-sized transport aircraft, longitudinal dynamics
time = 0.0;
function[xd] = transp(time,x,u)
%Aircraft Data
S=2170.0; CBAR=17.5; MASS=5.0E3; IYY= 4.1E6;
TSTAT=6.0E4; DTDV =-38.0; ZE = 2.0; CDCLS= .042;
CLA = .085; CMA = -.022; CMDE =-.016; % per degree
CMQ =-16.0; CMADOT= -6.0; CLADOT= 0.0; % per radian
RTOD = 57.29578; GD=32.17;
% defining input parameters
THTL = u(1);
ELEV = u(2);
XCG = u(3);
LAND = u(4);
VT = x(1);
ALPHA= RTOD*x(2);
THETA= x(3);
Q = x(4);
H = x(5);
QBAR = 34.34;   %0.5 * (2.377E-3) * VT^2;
QS = QBAR*S;
SALP= sin (x(2));
GAM = THETA - x(2); SGAM = sin(GAM); CGAM = cos(GAM);
if LAND == 0
    CLO= .20; CDO= .016;
    CMO= .05; DCDG= 0.0; DCMG= 0.0;
elseif LAND == 1 % LANDING FLAPS ON & GEAR DOWN
    CLO= 1.0;
    CMO= -.20; DCDG= 0.02; DCMG= -0.05;
else
    disp('Landing Gear and Flaps ?')
end
THR= (TSTAT+VT*DTDV)*max(THTL,0); % THRUST
CL=CLO+CLA*ALPHA; % NONDIM. LIFT
CM=DCMG+CMO+CMA*ALPHA+CMDE*ELEV+CL*(XCG-.25); % MOMENT
CD = DCDG+CDO+(CDCLS*CL*CL); % DRAG POLAR
% State EQUATIONS NEXT
xd(1) = (THR*CALP) - (QS*CD)/ MASS - (GD*SGAM);
xd(2)= (-THR*SALP-QS*CL+MASS*((VT*Q)+(GD*CGAM)))/(MASS*VT+QS*CLADOT);
xd(3)= Q;
xd(5)= VT*SGAM; % Verticle Speed
xd(6)= VT*CGAM; % Horizonal Speed
D = .5*CBAR*(CMQ*Q+CMADOT*xd(2))/VT; % PITCH DAMPING
xd(4)= (QS*CBAR*(CM + D) + THR*ZE)/ IYY; % Q-DOT
end

%% COST FUNCTION
function[f]=cost_func(s)
global x u
u(1) = 0.1;
u(2) = -10;
x(2) = 0;
x(3) = x(2);
u(1)=s(1); u(2)=s(2);
x(2) = s(3);
s0=[u(1) u(2) x(2)];
time = 0.0;
[xd] = transp(time,x,u);
f= xd(1)^2 + 100*xd(2)^2 + 10*xd(4)^2;
end

[Dyuman Joshi]

What is the input provided to the input() call?

And where do you get the error? Share the full error message i.e. all of the red text.

[John]

Error using transp

Too many input arguments.

Error in trim (line 21)

disp(['Initial cost= ', num2str(feval(name,s0))]);

[John]

the transp function here defines three input arguments: time, x, and u.... Dont know how to get over with this error.....

Answer 1

[VBBV]

Few syntax and typo errors that are persistent in your code need to checked.

% TRIM.m
clear; clc; close all;
% x u gamma;
x = zeros(1,6);  % define x
u = zeros(1,4);  % define u

x(1) = 170;
x(5) = 0;
gamma = 0;
name = 'cost_func' %input('Name of Cost function file? : ','s');

name = 'cost_func'

cg= 0.25; 
land=1; % 0 = clean 1=gear+flaps;
u = [0.1 -10 cg land];
x(2)= .1; % Alpha, initial guess
x(3)=x(2) + gamma; % Theta
x(4)=0; % Pitch rate
x(6)=0;
s0=[u(1) u(2) x(2)];

% Now initialize any other states and get initial cost
disp(['Initial cost= ', num2str(feval(name,x,u,s0))]);

Initial cost= 2.3959

[s,fval]= fminsearch(@cost_func,s0); % syntax error while using fminsearch
x(2) = s(3) ; x(3) = s(3)+ gamma;
u(1)=s(1);  % typo error  
u(2)=s(2);
disp(['minimizing vector= ',num2str(fval)]);  % typo error

minimizing vector= 1.3641

disp(['minimum cost vector= ',num2str(s)]);

minimum cost vector= 3677.669497      175148.1444     -1989.451985

temp=[length(x), length(u),x,u];
% name= input('Name of output file? : ',' s');
% dlmwrite(name,temp);
% Medium-sized transport aircraft, longitudinal dynamics
time = 0.0;

%% COST FUNCTION
function[f]=cost_func(x,u,s)
% global x u
u(1) = 0.1;
u(2) = -10;
x(2) = 0;
x(3) = x(2);
x(4) = 0;
x(5) = 0; x(6) = 0;
% u(1)=s(1); 
% u(2)=s(2);
% x(2) = s(3);
s0=[u(1) u(2) x(2)];
time = 0.0;
[xd] = transp(time,x);
f = xd(1)^2 + 100*xd(2)^2 + 10*xd(4)^2;
end

function[xd] = transp(time,x)
%Aircraft Data
S=2170.0; CBAR=17.5; MASS=5.0E3; IYY= 4.1E6;
TSTAT=6.0E4; DTDV =-38.0; ZE = 2.0; CDCLS= .042;
CLA = .085; CMA = -.022; CMDE =-.016; % per degree
CMQ =-16.0; CMADOT= -6.0; CLADOT= 0.0; % per radian
RTOD = 57.29578; GD=32.17;

cg= 0.25; 
land=1; % 0 = clean 1=gear+flaps;
u = [0.1 -10 cg land];
% x = zeros(1,6);
% defining input parameters
THTL = u(1);
ELEV = u(2);
XCG = u(3);
LAND = u(4);
VT = x(1);
ALPHA= RTOD*x(2);
THETA= x(3);
Q = x(4);
H = x(5);
QBAR = 34.34;   %0.5 * (2.377E-3) * VT^2;
QS = QBAR*S;
SALP= sin (x(2));
GAM = THETA - x(2);
SGAM = sin(GAM); 
CGAM = cos(GAM);

THR= (TSTAT+VT*DTDV)*max(THTL,0); % THRUST

if LAND == 0
    CLO= .20; CDO = .016;
    CMO= .05; DCDG= 0.0; DCMG= 0.0;
   
    CL=CLO+CLA*ALPHA; % NONDIM. LIFT
    CM=DCMG+CMO+CMA*ALPHA+CMDE*ELEV+CL*(XCG-.25); % MOMENT
    CD = DCDG+CDO+(CDCLS*CL*CL); % DRAG POLAR

elseif LAND == 1 % LANDING FLAPS ON & GEAR DOWN
    CLO= 1.0;
    CMO= -.20; DCDG= 0.02; DCMG= -0.05;
    CDO = .016;
    
    CL=CLO+CLA*ALPHA; % NONDIM. LIFT
    CM=DCMG+CMO+CMA*ALPHA+CMDE*ELEV+CL*(XCG-.25); % MOMENT
    CD = DCDG+CDO+(CDCLS*CL*CL); % DRAG POLAR
    % 
else
    disp('Landing Gear and Flaps ?')
end
% State EQUATIONS NEXT
xd(1) = (THR*SALP) - (QS*CD)/ MASS - (GD*SGAM);
xd(2)= (-THR*SALP-QS*CL+MASS*((VT*Q)+(GD*CGAM)))/(MASS*VT+QS*CLADOT);
xd(3)= Q;
xd(5)= VT*SGAM; % Verticle Speed
xd(6)= VT*CGAM; % Horizonal Speed
D = .5*CBAR*(CMQ*Q+CMADOT*xd(2))/VT; % PITCH DAMPING
xd(4)= (QS*CBAR*(CM + D) + THR*ZE)/ IYY; % Q-DOT
end

[John]

great work!!!! lovely......

Answer 2

[Matthew Sisson]

Your error might be related to user input on the following line.

name = input('Name of Cost function file? : ','s');

I assume you are entering "cost_func" as shown:

--> Name of Cost function file? : cost_func

[John]

yes exactly i am entering "cost func" once it asks for name of cost function