how to solve the program?

Question

prajith samraj 2022-7-18

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此问题的直接链接

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编辑： prajith samraj 2022-7-26

Unrecognized function or variable 'e1'.
s1=x3.^2+x1*x3+x1.^2;
s2=x1.^4+x1.^3*x3+x1.^2*x3.^2 +x1.^2*x3.^2+x1*x3.^3 + x3.^4;
%s1=x2.^2+x1*x2+x1.^2;
%s2=x1.^4+x1.^3*x2+x1.^2*x2.^2 +x1.^2*x2.^3 + x2.^4;
%u1 = -e1-e2;
%u2 = beta*e1*k1 +gamma*e1*k2+omegaf*e1-ff2*cos(W2*t)+ff1*cos(W1*t);
u1 = -e2-e1;
u2 = beta*e1*s1 + gamma*e1*s2+omegaf*e1-ff2*cos(W2*t)+ff1*cos(W1*t);
%sys-I
dx1=x2;
dx2=-alpha*x2-omegaf*x1-beta*x1.^3- gamma*x1.^5+ff1*cos(W1*t);
%sys -II
dx3=x4+u1;
dx4=-alpha*x4-omegaf*x3-beta*x3.^3- gamma*x3.^5+ff2*cos(W2*t)+u2;
de1=dx3-dx1;
de2=dx4-dx2;
e1 = x3-x1;   
e2= x4-x2;
de1=e2+u1;
de2=-alpha*e2-omegaf*e1-beta*e1*s1- gamma*e1*s2+ff2*cos(W2*t)-ff1*cos(W1*t)+u2;
 dy = [dx1; dx2; dx3; dx4];
end

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prajith samraj 2022-7-18

i need e1 and e2 graph. what can i do?

Lateef Adewale Kareem 2022-7-19

在 MATLAB Online 中打开

e1 = y(:,3)-y(:,1); 
e2= y(:,4)-y(:,2); 

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Answer 1

Sam Chak 2022-7-19

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1762965-how-to-solve-the-program#answer_1010530

在 MATLAB Online 中打开

Hi @prajith samraj

Try manipulating the parameters to get different results.

% Solver

tspan = [0 20];

x10 = 0.11;

x20 = 0.1;

x30 = 0.21;

x40 = 0.2;

y0 = [x10; x20; x30; x40];

[t, y] = ode45(@(t, y) f(t, y), tspan, y0);

% Plots

e1 = y(:, 3) - y(:, 1);

e2 = y(:, 4) - y(:, 2);

subplot(2,1,1)

plot(t, e1), grid on, xlabel('t'), ylabel('e_{1}')

subplot(2,1,2)

plot(t, e2), grid on, xlabel('t'), ylabel('e_{2}')

function dy = f(t, y)

% parameters

alpha = 0.5;

omegaf = -1;

beta = 0.8790;

gamma = 0.3000;

W1 = 1.4450;

ff1 = 0.5381;

W2 = 1.4450;

ff2 = 0.5381;

% assignment

x1 = y(1);

x2 = y(2);

x3 = y(3);

x4 = y(4);

e1 = x3 - x1;

e2 = x4 - x2;

s1 = x3^2 + x1*x3 + x1^2;

s2 = x1^4 + (x1^3)*x3 + (x1^2)*(x3^2) + (x1^2)*(x3^2) + x1*(x3^3) + x3^4;

u1 = - e2 - e1;

u2 = beta*e1*s1 + gamma*e1*s2 + omegaf*e1 - ff2*cos(W2*t) + ff1*cos(W1*t);

% sys I

dx1 = x2;

dx2 = - alpha*x2 - omegaf*x1 - beta*x1^3 - gamma*x1^5 + ff1*cos(W1*t);

% sys II

dx3 = x4 + u1;

dx4 = - alpha*x4 - omegaf*x3 - beta*x3^3 - gamma*x3^5 + ff2*cos(W2*t) + u2;

de1 = dx3 - dx1;

de2 = dx4 - dx2;

dy = [dx1; dx2; dx3; dx4];

end

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prajith samraj 2022-7-19

i need the value of e1dot and e2 dot graph

Sam Chak 2022-7-19

@prajith samraj, I'm a little confused now. In your comment, you clearly mentioned that you need e1 and e2 graph. Perhaps, you unintentionally confused yourself with e1dot and e2dot?

Please edit the title of your question for clarity...

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