1. School of Printing, Packaging Engineering and Digital Media Technology, Xi’an University of Technology 1 , Xi’an 710054, China
2. Shaanxi Key Laboratory of Advanced Manufacturing and Evaluation of Robot Key Components, Baoji University of Arts and Sciences 2 , 721016 Baoji, China
3. School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology 3 , Xi’an 710048, China