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dso​lve一直报错！

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)

Answer 1

[Dheeraj]

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!