Affiliations: [a] Ningbo Institute of Technology, Zhejiang University,
Ningbo, China | [b] School of Electrical and Electronic Engineering,
Nanyang Technological University, Singapore
Correspondence:
[*]
Corresponding author: Dr. Chi Zhang, PhD, School of Information
Science and Engineering, Ningbo Institute of Technology, Zhejiang University,
Ningbo City, China, 315100, Tel.: +86 574 88130028; Fax: +86 574 88229505;
E-mail: zhangchi@pmail.ntu.edu.sg
Abstract: This paper presents a three-link direct drive robot arm for wafer
handling application. This robot arm is directly driven by three permanent
magnet synchronous motors which are designed with flat structures and large
rated torques. The mechanical structures of the presented robot arm and the PM
motors are introduced and their dynamic models are derived. The frequency
responses obtained from experimental tests reveal serious coupling effect of
the system. A decoupling method based on computed torque control is proposed
and the test results validate the effectiveness of this method. Robust SISO
controllers are developed to control the PM motors after the decoupling. The
experimental results demonstrate satisfying dynamic, settling and static
performances with the proposed robust decoupling control.
