Dual-axis light tracker

Abstract

With an ever growing dependence on technology and intelligent systems, automatic control and microcontroller based systems play an increasingly important role in our daily lives. Feedback control systems have been extremely popular over the past few decades, providing elegant solutions to complicated control problems in applications ranging from climate control systems in automobiles to high precision systems in space vehicle control. This project involved the design and implementation of a dual axis light tracker which is able to locate a source of light in both the panning and tilting axis of rotation. This was achieved through the use of four light sensors strategically placed around a cross-shaped shade in such a way that all sensors receive equal light when the system directly faces the light source. A digital control algorithm based on proportional, integral and derivative control was implemented on an Arduino microcontroller driving two servo motors, one for each axis of rotation. Gain scheduling was applied to the system. This is a technique used for achieving reliable and repeatable performance for different system conditions, in this case, varying ambient light intensities needed to be considered. Integral anti-windup techniques were also explored. The results are compared to a simple yet widely used algorithm for light tracking.