1. Department of Product and Systems Design Engineering, University of the Aegean, Ermoupolis 84100, Greece e-mail:
2. Robotics Group, Department of Mechanical Engineering and Aeronautics, University of Patras, Patras 26504, Greece e-mail:
3. Professor Robotics Group, Department of Mechanical Engineering and Aeronautics, University of Patras, Patras 26504, Greece e-mail: