Check for missing argument or incorrect argument data type in call to function 'ilaplace'.

syms t s
num = [0 0 1 2 1]
den = [1 2 2 2 0]
sys=tf(num,den)
h=matlabFunction(ilaplace(sys))
t=1:0.01:20
plot(t,h(t))
xlabel('Time [sec]')
ylabel('y(t)')

I am trying to plot the inverse laplace of sys. But I can't solve the error, please help!!

Answer 1

[Ameer Hamza]

tf() is from the control system toolbox, which is not directly compatible with the symbolic toolbox—following shows how to solve it using both approaches.

Using ilaplace (symbolic toolbox)

syms t s
num = [0 0 1 2 1];
den = [1 2 2 2 0];

hs = poly2sym(num, s)/poly2sym(den, s);
ht = ilaplace(hs);

tv = 0:0.01:20;
Hv = subs(ht, t, tv);

plot(tv, Hv);

Using control toolbox

num = [0 0 1 2 1];
den = [1 2 2 2 0];

sys = tf(num, den);
impulse(sys);

Output for both codes

[Lim Wei Jie]

Thank you, Ameer!!!

[Ameer Hamza]

I am glad to be of help!

Answer 2

[vissia volpe]

I run my program, but i have a problem instruction ilaplace .

"Check for missing argument or incorrect argument data type in call to function 'ilaplace'.

Error in s229562_Es1 (line 56)

Y=ilaplace(g)"

the program is:

a=2;

b=2;

c=7;

d=9;

e=6;

f=2;

syms s tau1 tau2 k1 k2

tau= a+b+c+d+e+f

K= a+b+c+d*0.1+e*0.01+f*0.001

k1=1/(1+K*tau)

k2=1/(1+K*tau)

tau1=tau/(1+K*tau)

tau2=tau/(1+K*tau)

num=[k1*k2];

den=[tau1*tau2,tau1+tau2, 1];

disp("QUESTA E' LA FUNZIONE DI TRASFERIMENTO:")

G=tf(num, den)

disp("ZERI DELLA MIA FDT:")

zero(G)

disp("POLI DELLA MIA FDT:")

p=pole (G)

disp("GUADAGNO STATICO DELLA MIA FDT:")

z=dcgain(G)

%PUNTO_3 DISEGNO DEL GRAFICO DELLA RISPOSTA

A=-1; %ampiezza della mia variazione a gradino

disp('FDT SOGGETTA AD UN DISTURBO A GRADINO DI AMPIEZZA A=-1:')

g=G*A

step(g)

title('RISPOSTA AD UN IMPULSO A GRADINO DI AMPIEZZA A=-1')

%calcolo dell'antitrasformata

disp("ANTITRASFORMATA DI LAPLACE:")

Y=ilaplace(g)

Answer 3

[seniha yildirim]

function [a,b] = dft(x)

N= length(x);

n=1:N-1;

t = 2 * pi * (0:(n-1))/N;

for k=1:N

n=1:N-1;

fa= x(n) .* cos(2*pi*n/N);

fb =x(n) .* sin(2*pi*n/N);

a(k) = (2/N) * symsum (fa, n, 0, N-1);

b(k) = (2/N) * symsum (fb, n, 0, N-1);

x = @(t)a/2 + symsum((ak*cos(2*pi*k*n/N))+(bk*cos(2*pi*k*n/N)),k,1:k);

end

end

Can you help me please, it gives error of 'Check for incorrect argument data type or missing argument in call to function

'symsum'.

Error in dft (line 9)

a(k) = (2/N) * symsum (fa, n, 0, N-1);'

[Image Analyst]

I suggest you start your own discussion thread for this.

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