Questions about the inverted pendulum function.

I wrote the following functions using a nonlinear model. Myfun is a function that creates an inverted pendulum model, and the drawcartpend function is a function that draws a pendulum.

At this time, the following problems occur in each function, and I want to get an answer for them.

myfun function

>>>Myfun

function dx = myfun(x, M, m, L, g, b, u)

Sx = sin(x)(3));

Cx = cos(x(3));

dx(1,1) = x(2);

dx(2,1) = 1/(M+m-m*Cx*Cx)*(-b*x(2)+m*g*Cx*Sx+M*x(4)*Sx+u);

dx(3,1) = x(4);

dx(4,1) = -g/L*Sx-Cx/((M+m-m*Cx*Cx)*L*(-b*x2)+m*g*Cx*Sx*M*x(4)*Sx+u);

M = 3;

m = 1;

L = 2;

g = 10;

b = 0.5;

u = 0;

tspan = 0:.1:15;

x0 = [2*pi/3; .5];

[t,x] =ode45 (@(t,x)pend(x,m,L,g,b),tspan,x0);

>>error

Insufficient input arguments.

Value entered for variables M and u is not used.

It is not possible to verify that the variables t and x are interpolated.

drawcartpend function

>>>Drawcartpend

function drawcartpend(x,L)

th = x(3); %theta

% draw the horizontal line

plot([-10 10],[0 0]',w','LineWidth',2)

Axis equal

hold on

% draw the pendulum line

x = L*sin(th);

y = -L*cos(th);

plot([0 x],[0 y]'w','LineWidth',2)

% draw the circle ball

bsize = 0.4; %ball dimeter

viscircles ([x, y], bsize/2);

% defined limits and colors

xlim([-5 5]);

ylim([-2.5 2.5]);

set (gca'Color',[0 0 0]', XColor,'w','YColor','w')

% box off

Drawnow

hold off

for k=1:length(t)

drawcartpend(x(k,:), L);

pause (0.01)

End

>>error

Insufficient input arguments.

Please reply as soon as possible.

Answer 1

[Nikhil Sonavane]

From what I understand, you have declared input variables to their values inside the function itself. If they are just some constants there is not need of putting them into input arguments of the function. You may refer to function for more information on functions.