Design and Control of an Air Levitation Ball System for Mechatronics Education and Research

This paper presents a variable PID control prototype designed to showcase automation and control for systems using hand gestures. The prototype utilizes a simple physical model to demonstrate ball levitation and illustrate the effectiveness of PID control. PID controllers are widely used in automation and control engineering due to their versatility and compatibility with different controllers. The goal of this work is to elucidate PID control techniques and their practical applications. The system features a single input, single output (SISO), non-linear nature, necessitating a detailed physical examination for accurate mathematical modeling. All operations are conducted digitally, with the Arduino generating the control voltage and transmitting the output through the PWM interface. The implementation of the theoretical PID control law involves the summation of three discrete time instant computations. The performance of the system and the effectiveness of PID control rely on the tuning of its gains. Through testing and evaluation, it is noted that the prototype takes approximately 10s to reach the reference level of 50% and showed commendable results having an error % of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 5 \%$</tex>. The step response of the system exhibits a rise time of approximately 10 seconds with the overshoot being minimal. The system experiences oscillations with a maximum amplitude of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 2$</tex> cm and for a period of approximately 4 seconds until equilibrium has been attained with the oscillations decreasing in amplitude eventually. Approximately 10 seconds after the step excitation, the system is in a steady state, with fluctuations within <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 5 \%$</tex> of the reference value of 50 % thereby making the system stable and in effective control of PID parameters.