MATLAB: Please tell me how to use ode45 code

controltheory

num=134;
den=[1 16 134];
x=tf(num,den)
subplot(1,2,1)
step(x)
title('(a)')

I want to express this code as ode45, how do I do it?

Best Answer

Following is one way of using ode45 to solve this

[t, y] = ode45(@odeFun, [0 1], [0; 0]);
plot(t, y(:,1), 'o-')
function dydt = odeFun(t, y)
    % transfer function is equivalent to following ODE
    % y'' = -16y'-124y+134u
    u = 1; % step input
    dydt = zeros(2, 1);
    dydt(1) = y(2);
    dydt(2) = -16*y(2)-124*y(1)+134*u;
end

Related Solutions

MATLAB: Please tell how

Try this

num=[303 4848 0];
den=[1 16 164];
ea=tf(num,den);
subplot(1,2,1)
step(ea)
[t, y] = ode45(@odeFun, [0 1], [303; 0]);
subplot(1,2,2)
plot(t, y(:,1), '-')
function dydt = odeFun(t, y)
    % transfer function is equivalent to following ODE
    % y'' = -16y'-164y+303u''+4848u'
    u = 1; % step input
    du = 0;
    ddu = 0;
    dydt = zeros(2, 1);
    dydt(1) = y(2);
    dydt(2) = -16*y(2)-164*y(1)+303*ddu+4848*du+134*u;
end

MATLAB: I want to add

Based on your comment on other question for expression of ea(t): https://www.mathworks.com/matlabcentral/answers/541922-please-tell-me-how-to-use-ode45-code#comment_883106 the following shows how to use ode45 to solve this ODE with input saturation

[t, y] = ode45(@odeFun, [0 1], [0; 0]);
plot(t, y(:,1), 'o-')
function dxdt = odeFun(t, x)
    % transfer function is equivalent to following ODE
    % x'' = 4/9(-16x'+ea(t))
    ea = (1-x(1))*303;
    if ea > 100
        ea = 100;
    elseif ea < -100
        ea = -100;
    end
    dxdt = zeros(2, 1);
    dxdt(1) = x(2);
    dxdt(2) = 4/9*(-16*x(2)+ea);
end

Best Answer

Related Solutions

MATLAB: Please tell how

MATLAB: I want to add

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