My thesis presented in the followings discusses the design and creation of a control system termed "Ball and plate system". The name is self-explanatory: the aim is to balance the ball on an inclined plate (with an even surface), which is a well-known problem in control theory.
The plate can be tilted in two independent directions through the aid of a remote servo motor.
The hardware unit contains the ball itself, a plate with an even surface, the mechanism moving the plate, a digital camera and an FGPA based logic board, in which the image processing code and the controller algorithm run.
The plate is mounted on the output shafts of the electric motors which enables tilting it about its central axis by applying an electrical control signal to the servo motors. The position of the ball on the plate can be measured using the digital camera. The aim of the control process is to move the ball to any desired position on the plate by changing the angle of inclinaition of the plate. The task is rendered highly complicated by the fact that the ball does not remain stationary in one positionon, but moves with an acceleration proportional to the angle of the plate. In control technology the system is can be considerd open loop unstable because the system output (the ball position) increases without limit for a fixed not zero input (plate X,Y angle). Feedback control must be used to keep the ball in a desired position on the plate.
My thesis begins with a brief summary of the invovled literature. Than it summarizeses the process of the development of the mechanical, electronical and software parts. After that it describes the simulation and the design of a PD controller. Finally the test results are compared to the simulations.