1. IDMEC Instituto Superior Técnico, Universidade de Lisboa Av. Rovisco Pais , Lisbon 1049-001, Portugal
2. Department of Mechanical Engineering, School of Engineering and Design, Technical University of Munich , Boltzmannstr. 15, Garching 85748, Germany
3. IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais , Lisbon 1049-001, Portugal