中文摘要：

Liu Yuzhe, born in 1990. He has been a candidate of doctoral research since 2012 in Mechanical Engineering Department of Tsinghua University. He received his B.S. degree in Mechanical Science and Engineering School of Huazhong University of Science and Technology in 2012. His current research interests include parallel mechanisms and accuracy assurance. To whom correspondence should be addressed. E-mail： jhwu@ mail. tsinghua, edu. cn