1. Department of BioMechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
2. Atlas Copco Airpower NV, Boomsesteenweg 957, B-2610 Wilrijk, Belgium; Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300B, 3001 Heverlee, Belgium