简单的一维自适应控制算法，目的是画出信号x的图像，但是dsolve一直报错！

Question

Zhou guoLi 2022-12-2

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1869257-x-dsolve

回答： Dheeraj 2023-9-20

x1.m文件：

function x1=x1(theta,phi,g,u)

x1=theta'*phi+g*u;

end

代码如下：

>> syms x(t) thetah(t) u e

yd=sin(t);

phi=cos(x);

gamma=6;

theta=1;

g=2;

e=x-yd;

c=2;

yd1=diff(yd);

eq1=diff(thetah)==gamma*phi*e;

cond=(thetah(0)==0);

thetah=dsolve(eq1,cond);

u=(-c*e-thetah*phi+yd1)/g;

eq2=diff(x)==x1(theta,phi,g,u);

cond=x(0)==0;

x=dsolve(eq2,cond);

plot(t,x)

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Answer 1

Dheeraj 2023-9-20

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1869257-x-dsolve#answer_1313767

Hi,

I understand you’re encountering an error using “dsolve” to solve your equations generated.

It is because “dsolve” function only solves ordinary differential equations, but equation-2 of the differential equation has an unsolved integral expression on the right-hand side of it. I.e.

Hence, MATLAB throws an error to provide an ordinary differential equation as function argument. You can re write the "thetah" equation then "dsolve" will give an output of solved expression rather than an unsolved integral.

You can refer to the below MATLAB’s documentation for better understanding of “dsolve”’s capabilities.

https://mathworks.com/help/symbolic/dsolve.html

Hope this helps!