Implementation of discrete PID on Inverted pendulum

The objective here is to implement the discrete PID on pendulum. The idea is to balance an Inverted pendulum electro-mechanically using Proportional Integral Differential (PID) Control. The heart of the system is a PIC micro-controller (PIC18F4520). Controller commands the motor through PWM signal, which drives the cart to balance the pendulum in an inverted position. Pendulum´s angular position is fed back by an incremental encoder mounted on its base, which is read by controller. Controller then calculates error and runs the PID algorithm to generate a new command signal. The exact position of pendulum with the value of its gains are sent to the attached Personal Computer (PC) using RS-232 protocol. The front panel is built in LabVIEW software.