Project3 Main Page

Project 3: Fun with Pendulums

Dylan Kilpatrick, Wonjun Lee, and Donnelly Phillips

Part 1: Simple Damped Pendulum

We were first asked to look at a simple pendulum. The only forces acting on it were gravity and a damping factor (eg. air resistance). The pendulum was modeled with the following equations:

Damped Pendulum

h = .005, Initial Angle: π/2

h = .01, Initial Angle: π/2

For this set of initial conditions, the distance the pendulum
travels decreases as time goes on. The pendulum travels roughly half
the distance each time. Each set of initial conditions end up
reapeating the periodic behavior, so only 1 video is included.

Since the damping force always occurs against the direction
the pendulum travels, there is a consistant decline in the pendulum's
angle. At small angles, these differences can seem to be the same size,
but observing the angle size when the pendulum reaches it's maximum
height, we can quantitatively say that isn't true. The larger step size
(h = .01) accounts for the quicker movement of the pendulum.


FORCE DAMPED PENDULUM DESCRIPTION
The forced damped pendulum was modeled by the following equations:

Forced Damped Pendulum
Wonjun's Site


DAMPED DOUBLE PENDULUM DESCRIPTION
The damped double pendulum was modeled by the following equations:

Damped Double Pendulum

Tame Behavior: Angle 1: 5pi/6 Angle 2: 5pi/6

Chaotic Behavior: Angle 1: 5pi/6 Angle 2: pi/4

Here, the motion of the double pendulum is partially periodic.
In general, through a single swing, the first pendulum's velocity
will slow down to zero half way through, then pick up again,
while the second pendulum will make a single fast swing. This
particular test does not completely demonstrate this phenomenon.

Here, the double pendulum's behavior can hardly be described
as periodic. The full revolutions of both rods generate severely chaotic
turns.


Here's Something Interesting...


LIST OF MATLAB CODE:
Simple Damped Pendulum
Damped Double Pendulum
Forced Damped Pendulum 1
Forced Damped Pendulum 2
Forced Damped Pendulum 3

Credit Dylan: Simple Damped Pendulum, Website, Equation Images
Credit Wonjun: Force Damped Pendulum, (problems 5,6,7)
Credit Don: Double Pendulum, Implementing Polar Graphs, Debugging, Having Graph Paper to Organize the Labor