1. a Department of Mechatronic Technology, National Taiwan Normal University, 162 He-ping East Road, Section 1, Taipei, Taiwan 10610, ROC;, Email: chenct@ntnu.edu.tw
2. b Department of Mechanical and Automation Engineering, Da Yeh University, 112 Shan Jiau Road, Da Tsuen, Changhwa, Taiwan 51591, ROC