MATLAB by rudra pratap

6. 7 Animation
225
Example 3: A bar pendulum swings in 2-D
Here is a slightly more complicated example. It involves animation of the motion of
a bar pendulum governed by the ODE B +sin B = 0. Now that you are comfortable
with defining graphics objects and using their handles to change their position, etc.,
the added complication of solving a differential equation should not be too hard.
%----- script file to animate a bar pendulum --------------
elf
data = [0 0; -1 .5 0] ;
phi = 0;
R = [cos (phi) -sin (phi) ;
data = R*data;
axis([ - 2 2 -2 2] )
axis('equal ')
% clear figure and stuff
% coordinates of endpoints of the bar
% initial orientation
sin (phi) cos(phi) ];
% rotation matrix
% set axis limits
%-----define the obj ects called bar , hinge , and path .
bar = line('xdata' ,data(1, :), 'ydata' ,data (2 , :), ...
' linewidth' ,3, 'erase' , 'xor ') ;
hinge = line ('xdata' ,O, 'ydata' ,O, 'marker ' , 'o' , 'markersize ' , [10] ) ;
path = line('xdata' ,[] ,'ydat a' ,
[] ,'marker' ,' .','erasemode' , 'none ');
theta = pi -pi/ 1000;
thetadot = 0·
'
t = 0;
dt = .2;
tfinal = 50 ;
% initial angle
% initial angular speed
% initial time
% time step
% final time
%------Euler 's method for numerical integration
while (t