ANIMATION OF PENDULUM AND ODE SOLUTION

SOLUTION OF ODE

clear all
close all
clc

b=0.05;
g=9.81;
l=1;
m=0.1;

%intial conditions
thetha_0=[0,5];

% time points
t_span=linspace(0,50,500);

% solve  ODE 
[t,results] =ode45(@(t,thetha) ode_func(t,thetha,b,g,l,m),t_span,thetha_0); 

plot(t,results(:,1))
hold on
plot(t,results(:,2))
ylabel(\'plot\')
xlabel(\'time\')

ANIMATION CODE

clear all
close all
clc

b=0.05;
g=9.81;
l=1;
m=0.1;

%intial conditions
thetha_0=[0,3];

% time points
t_span=linspace(0,20,500);

% solve  ODE 
[t,results] =ode45(@(t,thetha) ode_func(t,thetha,b,g,l,m),t_span,thetha_0);
subplot(5,4,[13,14,17,18]);
plot(t,results(:,1),\'color\',\'b\');
hold on;
plot(t,results(:,2),\'color\',\'r\');
hold off;
subplot(5,4,[15,16,19,20]);
plot(results(:,1),results(:,2));


ylabel(\'positions-radians\')
xlabel(\'angular velocity\')

ct=1;
for i=1:length(results(:,1));
    x0=1;
    y0=0;
    x1=1*sin(results(i,1));
     y1=-1*cos(results(i,1));
     subplot(5,4,[1,2,3,4,5,6,7,8,9,10,11,12])
     plot([-1 1],[0 0],\'linewidth\',4,\'color\',\'r\');
     hold on
     line([x0 x1],[y0 y1],\'linewidth\',2,\'color\',\'b\');
     hold on;
     
     %r=0.75 %plotting the circle and mapping the center to the string
     %cir_deg=linspace(0.2*pi,1000);
     %xc=r*cos(cir_deg);
     %yc=r*sin(cir_deg);
     %plot(x1+xc,y1+yc,\'linewidth\',2);
     %hold off;
     plot(x1,y1,\'-o\',\'markers\',20,\'markerfacecolor\',\'r\');%plotting the bob using marker and facecolor
     
     %r=0.25;%plot a curved rectangle and color its inner
%rectangle(\'position\',[(x1-(r/2),(y1-r/2),r,r],\'curvature\',[1
%1],\'Facecolor\',\'r\',\'linewidth\',3]
grid on;
axis(  [-1.5 1.5 -1.5 0.5]);
pause(0.0003);
hold off
 q(ct)=getframe(gcf);
text=fprintf(\'pendulum%d.png\',ct);

ct=ct+1;
end

movie(q)
videofile=Videowriter(\'Pendulum_damped.avi\',\'uncompressed avi\')
open(videofile)
writeVideo(videofile,g)
close(videofile)