Introduction

Inverted Pendulum is one of the most famous laboratory equipment to test different control algorithms. It is used as a bench mark to test control schemes like fuzzy control, non-linear control, PID, robust control etc. The simplest realization of inverted pendulum can be though as balancing a broom on one’s hand. In this project, work pendulum was done from hardware design to implementation of robust control algorithms.

Hardware

Our setup was similar to cart pulley system. Choice of this structure was to avoid the complexities of mathematical modeling. The motor is attached with the pulley. Belt is used as a source of connection between cart and pulley. With to and fro rotation of pulley cart moves to and fro and can be used to balance the pendulum in upward direction. This hardware was designed in PIEAS mechanical workshop.

Two PCB’s were designed i.e. motor drive card and control card. Microcontroller that we opt in our project was PIC18f4431 because of its built in QEI and PWM modules, which also simplify our PCBdesign. OMRON Optical encoders were used to extract linear position of cart and angular position of pole. The above mention cards were designed in PIEAS control system lab.

Control

Classical physics was used to extract mathematical model of inverted pendulum. Simulation of different robust control strategies were done in Simulink MATLAB for this setup. H-infinity, loop synthesis, LQG and PID controllers were designed and simulated.

Software

MPLAB was the compiler used to write codes on PIC18f4431. Proteus was used for testing validity of different codes written for PIC18f4431. And GUI was designed using Matlab GUIDE toolbox.

Useful Links

http://sdrv.ms/Q6XLXI

http://www.youtube.com/watch?v=7FVDxNI3NAg

Contacts

1. Dr. Muhammad Abid (mabid@pieas.edu.pk)

2. Engr. Arsalan Tahir (Arsal05@hotmail.com )