EE443: MATLAB PENDULUM SIMULATION

This example shows how MATLAB commands can be used to simulate a pendulum using the discrete-time approximation of the nonlinear model.

%
% Filename: example3.m
%
% Description:  This m-file demonstrates how matlab can be used to perform
%               the discrete-time simulation of the nonlinear pendulum model.
%

clear; clf;				% clear matlab memory and figure

m = 5.0; l = 0.5; g = 9.81; b = 1.3;   	% define system parameters

x0 = [-0.2; 0.1];			% initial conditions
tmax = 5;				% maximum time in simulation

xk = x0; T = 0.01;			% define initial conditions & time step
plot(0,xk(1),'o');			% plot initial condition
hold;

for k = 1:tmax/T,			% perform 'disc-time' simulation
   Torque = sin(pi*k*T);
   xk(1) = xk(1) + T*xk(2);
   xk(2) = xk(2) + T/(m*l*l)*(Torque - b*xk(2) - m*g*l*sin(xk(1)));
   plot(k*T,xk(1),'o');
end;
hold;

xlabel('t ');
ylabel('y[k] = theta[k]');
title('Pendulum Position for Sinusoidal Input');
grid;