4th oder runge kutta with 2 2nd order ode

2 次查看（过去 30 天）
Noel Lou
Noel Lou 2016-3-3
Hi There!
MX''=Fn(sin θ - uCos θ )
MZ''=Fn(cos θ + uSin θ ) - Mg
Fn,M,θ,u is constant
fn/M = 0.866
M = 6000
θ = 30
u = 0.5774
i split my motion equation into 2 individual 1st ode,
X' = Vx
Z' = Vz
Vx'=[fn*(sin θ - uCos θ )]/M
Vz'={[fn(cos θ + uSin θ )]/M} - g
After trying many tutorials i still don't understand how to implement my motion equation into matlab, i tried to do the following for Vz' motion but it seems wrong, my right hand side of the equation does not have t or y. please help !
clc; % Clears the screen
clear all;
h=0.1; % step size
thete=30;
g=9.81;
x = 0:h:3; % Calculates upto y(3)
y = zeros(1,length(x));
y(1) = 5; % initial condition
F_z = @(t,y) 0.866*(cos(thete)+0.5774*(sin(thete)))-g; % function
for i=1:(length(x)-1) % calculation loop
k_1 = F_z(x(i),y(i));
k_2 = F_z(x(i)+0.5*h,y(i)+0.5*h*k_1);
k_3 = F_z((x(i)+0.5*h),(y(i)+0.5*h*k_2));
k_4 = F_z((x(i)+h),(y(i)+k_3*h));
y(i+1) = y(i) + (1/6)*(k_1+2*k_2+2*k_3+k_4)*h; % main equation
end
hold on %Plot graph
plot(x,y,'+-', 'Linewidth', 1.5, 'color', 'blue')
xlabel('x')
ylabel('y')
legend('RK4')

请先登录，再回答此问题。

回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Numerical Integration and Differential Equations 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by