# Neural Network Based on Orthogonal Polynomials Applied in Magnetic Levitation System Control

## Authors

• Miroslav B. Milovanovic University of Niš, Faculty of Electronic Engineering, Aleksandra Medvedeva 14, Niš, Serbia
• Dragan S. Antic University of Niš, Faculty of Electronic Engineering, Aleksandra Medvedeva 14, Niš, Serbia
• Sasa S. Nikolic University of Niš, Faculty of Electronic Engineering, Aleksandra Medvedeva 14, Niš, Serbia
• Stanisa Lj. Peric University of Niš, Faculty of Electronic Engineering, Aleksandra Medvedeva 14, Niš, Serbia
• Marko T. Milojkovic University of Niš, Faculty of Electronic Engineering, Aleksandra Medvedeva 14, Niš, Serbia
• Miodrag D. Spasic University of Niš, Faculty of Electronic Engineering, Aleksandra Medvedeva 14, Niš, Serbia

## Keywords:

Activation function, magnetic levitation system, neural networks, orthogonal polynomials

## Abstract

This paper presents a new approach for improving performances of magnetic levitation system. Controlled parameter is the amplitude which levitated object achieves during movement from one levitation position to another. Two position levitation with improved amplitude performances is obtained by implementing orthogonal neural network in standard levitation control logic. Proposed network is a nonlinear autoregressive neural network with newly developed activation function based on orthogonal polynomials. Performed experiments on a system with default control logic showed that it could not provide stable two position levitation when specified amplitude of the levitation object is greater than 10-4 m. Artificial network was trained using real experimental data and it was based on standard tangent and sigmoid activation functions. Default activation functions were then substituted with a newly developed orthogonal polynomial functions. The amplitude 10-3 m was achieved with stable two position levitation after parameter optimization. It is proven that simple control logic with nonlinear autoregressive neural network and proper activation function can provide improved amplitude performances.

2017-07-13

## How to Cite

Milovanovic, M. B., Antic, D. S., Nikolic, S. S., Peric, S. L., Milojkovic, M. T., & Spasic, M. D. (2017). Neural Network Based on Orthogonal Polynomials Applied in Magnetic Levitation System Control. Elektronika Ir Elektrotechnika, 23(3), 24-29. https://doi.org/10.5755/j01.eie.23.3.13167

## Section

ELECTRICAL ENGINEERING