Having trouble with ODE45 and a System of Ordinary Differential Equations
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For a class project, I am trying to solve for an automobile’s vertical and pitching motions as a function of time. I have the equations of motion describing the vehicle and I am trying to use ODE45. However, I keep getting the error Not enough input arguments. I have tried to fiddle with each variable but I am getting nowhere. If anyone could help me it would be greatly appreciated.
Main Code:
[t,z] = ode45(@ode, [0 10], [8 0]);
plot(t,z(:,5),'-o')
plot(t,z(:,7),'-o')
title('Automobiles Vertical and Pitching Motions');
xlabel('time t');
ylabel('displacement (m)');
Function Code:
function zdot = ode(t,z)
Mv = 1500;
Jg = 1000;
Mw = 20;
kc = 200000;
kt = 350000;
l1 = 2;
l2 = 2.5;
w = 100;
zdot = zeros(1,8);
zdot(1) = z(2)
zdot(2) = (1/Mw)*(.01*cos(w*t)+kc*x(3)-(kt+kc)*x(2)-kc*l1*theta)
zdot(3) = z(4)
zdot(4) = (1/Mw)*(.01*cost(w*t)+kc*x(3)+kc*l2*theta-(kt+kc)*x(2))
zdot(5) = z(6)
zdot(6) = (1/Mv)*(kc*l1*theta+kc*x1+kc*x2-kc*l2*theta-2*kc*x3)
zdot(7) = z(8)
zdot(8) = (1/Jg)*(kc*l1*x3-kc*((l2^2)+(l1^2))*theta-kc*l1*x1-kc*l2*x3+kc*l2*x2)
%zdot = [z(2) , (1/Mw)*(.01*cos(w*t)+kc*x(3)-(kt+kc)*x(2)-kc*l1*theta) , z(4) , (1/Mw)*(.01*cost(w*t)+kc*x(3)+kc*l2*theta-(kt+kc)*x(2)) , z(6) , (1/Mv)*(kc*l1*theta+kc*x1+kc*x2-kc*l2*theta-2*kc*x3) , z(8) , (1/Jg)*(kc*l1*x3-kc*((l2^2)+(l1^2))*theta-kc*l1*x1-kc*l2*x3+kc*l2*x2)];
end
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Respuestas (2)
Stephan
el 4 de Dic. de 2019
For every equation you have to input an initial condition. You have 8 but only give 2 initial conditions to ode45.
Also your function should return a column vector.
And where is x?
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