1. Post Doctoral Researcher, Dept. of Electromechanical Engineering, Center for Mechanical and Aerospace Sciences and Technology (C-MAST), Univ. of Beira Interior, R. Mq.s D’Ávila e Bolama, 6201-001 Covilhã, Portugal (corresponding author).
2. Professor, Dept. of Electromechanical Engineering, Univ. of Beira Interior, 6201-001 Covilhã, Portugal.
3. Professor, DISMI—Dipartimento di Scienze e Metodi dell’Ingegneria, Università degli Studi di Modena e Reggio Emilia, Via Amendola 2, Pad. Morselli, 42122 Reggio Emilia, Italy.