Readme for this folder

'no_force_input.mp4' shows the behavior of the system if there is no control input. This shows that the physics of the simulator is correct.
'pid.mp4' shows the behavior of the system if a PID controller is used
'lqr.mp4' shows the behavior of the system if a PID controller is used
'inverted_pendulum.py' is the code
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Readme for 'inverted_pendulum.py'

This code uses the following libraries:
numpy, cv2, math, time, matplotlib and control (https://pypi.python.org/pypi/control/0.7.0)

To install the control library please run the following:
>> pip install slycot
(If this gives an error like 'fortran compiler not found', please run >> sudo apt-get install gfortran)
>> pip install control

Usage: python inverted_pendulum.py <controller_used>
Options for <controller_used> = "lqr","pid"
Example: python inverted_pendulum.py lqr

Running the code will show a simulation of the system. The simulation runs for 30 seconds but this can be changed in the main() function. 
When the simulation ends, 4 graphs are shown which show the:
- error vs time, 
- theta value (of the pendulum) vs time,
- force input vs time, and 
- X position of the cart vs time. 
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