Self-tuning Position Control for the Linear Long-stroke, Compound Switched Reluctance Conveyance Machine

Abstract

This paper proposes a long-stroke linear switched reluctance machine (LSRM) with a primary and a secondary translator for industrial conveyance applications. The secondary one can translate according to the primary one so that linear compound motions can be achieved. Considering the fact that either one translator imposes a time-variant, nonlinear disturbance onto the other, the self-tuning position controllers are implemented for the compound machine and experimental results demonstrate that the absolute steady-state error values can fall into 0.03 mm and 0.05 mm for the secondary and primary translator, respectively. A composite absolute precision of less than 0.6 mm can be achieved under the proposed control strategy. Keyword:Compound motion LSRM Self-tuning control Copyright ©2017 Institute of Advanced Engineering and Science.All rights reserved. Corresponding Author:Li Qiu, Laboratory of Space Collaborative Manipulation Technology, Shenzhen University, Fundamental Building Phase II, Southern Campus of Shenzhen University, 3688 Nanhai Road, Shenzhen University, China. Email: qiuli@szu.edu.cn INTRODUCTIONIn modern manufacturing and assembly industry, electrical or mechanical components or parts rely on conveyance systems to transport them to arrive at proper positionsfor furtherprocessing. For linear transportations, rotary machines with synchronous belts are sometimes involved to realize conveyance systems. Due to wear and aging of the belts and other mechanical parts, the precision of the entire conveyance system is often hard to be guaranteed [1]. The traditional method of rotary machines and belts can be replaced by direct-drive, linear machines, which have the advantages of fast response, high-precision and speed [2]. For linear conveyance systems nowadays, the speed of the moving part should often be kept at specified values for sequenced processing of the components or parts [4]. Two or more transportation tasks can rarely be handled at the same time.If any secondary moving part (or translator) can be embedded onto the linear conveyance system and the moving part makes relative motions according to the primary conveyance one at the same time, then the efficiency ofthe entire components transportationtask can be increased.As shown in Figure 1 the concept of a direct-drive, compound linear conveyance system, the stationary part propels the conveyance track(primary part) along the x axis, and the manipulator is responsible to transport the components to a certain work station along the y direction. The secondary part is embedded onto the conveyance track and it is capable of translationalong the conveyance track. It can be seen that the secondary part can work simultaneously as the conveyance track translates. Thus, the processing time can be reduced with increased component conveyance efficiency. Meanwhile, the entire positioning precision of the linear conveyance system can be improved, if both the conveyance track and the secondary part can work coordinately.