pendulum animation

%Calling a function pendulum

function [dtheta_dt] = pendulum_ode(t, theta,g,l,m)

w = g/(l*m);

theta1 = theta(1);

theta2 = theta(2);

dtheta1_dt = theta2;

dtheta2_dt = -w*w*sin(theta1);

dtheta_dt = [dtheta1_dt;dtheta2_dt];

end

% main program

clear all

close all

clc

% inputs

g = 9.81;

l = 1.5;

m = 0.5;

%Initial conditions

theta0 = [0;6.5];

t_span = linspace(0,1,500);

%Solving the ODE

[t, results] = ode45(@(t,theta) pendulum_ode(t, theta,g,l,m), t_span, theta0);

angular_disp = results(:,1);

%Animation

ct = 1;

for i = 1:length(t_span);

THETA = angular_disp(i);

%Coordinates for pendulum

x0 = 0;

y0 = 0;

x1 = 1.5*sin(THETA);

y1 = -1.5*cos(THETA);

%Plotting for animation

plot([-0.5 0.5],[0 0],[-0.5 -0.5],[0 0.08],[-0.5 0.5],[0.08 0.08],[0.5 0.5],[0.08 0], 'color','b','linewidth',3);

hold on

plot([x0 x1],[y0 y1], 'color', 'k', 'linewidth', 5)

plot(x1,y1,'-o','markers',23,'markerfacecolor','b','color','y')

hold off

axis([-2 2 -3 0.5])

P(ct) = getframe(gcf);

ct = ct + 1;

end

%Movie

movie(P);

videofile = VideoWriter('iSIMPLE_PENDULUM.avi','Uncompressed AVI');

open(videofile);

writeVideo(videofile, P);

close(videofile);