Title: Combining full and semi closed loop synchronous control for dual mechanically coupled ball screw system

Authors: Min-Fu Hsieh; Wei-Che Chang

Addresses: Department of Systems and Naval Mechatronic Engineering, National Cheng Kung University, 1 University Road, Tainan City, 701, Taiwan. ' Department of Systems and Naval Mechatronic Engineering, National Cheng Kung University, 1 University Road, Tainan City, 701, Taiwan

Abstract: The paper presents a synchronous control scheme for a mechanically coupled dual ball screw system applied to wave makers driven by multiple servomotor/ball screw units or machine tools such as those of the gantry type. The hardware system is first established and modelled using a system identification approach. The controller is then designed with pseudo derivative feedback feedforward (PDFF) control. Full and semi-closed-loop controls are analysed and compared in terms of dynamic stiffness, responses and steady-state errors. A hybrid control scheme is then proposed for the investigated system with only one linear scale (i.e., one drive unit is full- and the other semi-closed-loop control). Experiments are conducted to verify the performance by comparing with three conventional synchronous control schemes. The results show that the proposed approach has a much smaller pull-and-drag effect. Also, the positioning accuracy of the system, as well as the synchronous error between the two units is satisfactory.

Keywords: synchronous control; ball screws; gantry machine tools; wave makers; modelling; system identification; controller design; pseudo derivative feedback feedforward control; PDFF control; dynamic stiffness; steady-state errors; hybrid control.

DOI: 10.1504/IJCAT.2012.050702

International Journal of Computer Applications in Technology, 2012 Vol.45 No.2/3, pp.139 - 147

Available online: 30 Nov 2012 *

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