1. Center for Complex Systems,
School of Mechano-Electronic Engineering,
Xidian University,
Xi'an 710071, China;School of Automation Science
and Electrical Engineering,
Beihang University,
Beijing 100191, China
e-mail: yongkuiliu@163.com
2. Fellow ASME
Department of Mechanical Engineering,
The University of Auckland,
Auckland 1142, New Zealand
e-mail: xun.xu@auckland.ac.nz
3. School of Automation Science
and Electrical Engineering,
Beihang University,
Beijing 100191, China;Engineering Research Center of Complex
Product Advanced Manufacturing Systems,
Ministry of Education,
Beihang University,
Beijing 100191, China
e-mail: johnlin9999@163.com
4. School of Automation Science
and Electrical Engineering,
Beihang University,
Beijing 100191, China
e-mail: ftao@buaa.edu.cn