1. Department of Mechatronics, Silesian University of Technology, Akademicka 2A, 44-100 Gliwice, Poland
2. Department of Electrical, Electronics and Informatics Engineering, University of Catania, Viale Andrea Doria, 6, 95125 Catania, Italy
3. Department of Theoretical and Applied Mechanics, Silesian University of Technology, Konarskiego 18A, 44-100 Gliwice, Poland
4. ENEA, C.R. Frascati, Via E.Fermi 45, 00044 Frascati, Italy