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Nonlinear control algorithm for improving settling time in systems with friction

Bucci, BA and Cole, DG and Ludwick, SJ and Vipperman, JS (2013) Nonlinear control algorithm for improving settling time in systems with friction. IEEE Transactions on Control Systems Technology, 21 (4). 1365 - 1373. ISSN 1063-6536

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A nonlinear control algorithm that greatly reduces settling time in precision instruments with rolling element bearings is proposed. Reductions of 80.5%-87.4% in settling time were achieved when settling to within 3-100 nm of the commanded position. Final settling of such systems is typically impacted by the nonlinearity in the pre-rolling friction regime, which manifests as a hysteretic stiffness. Consequently, the integral term in the controller can take a long time to respond. In this paper, a nonlinear integral action settling algorithm is presented. The nonlinear integral gain takes the form of a Dahl friction model. Since the integral gain mimics hysteretic stiffness, the output of the integral control term is instantaneously set to a large value after each direction change, greatly improving settling response. A nearly first-order error dynamic results, which has a user-definable time constant. Before the algorithm can be implemented, the Coulomb friction and initial contact stiffness in the Dahl model must be experimentally determined for the stage. A sensitivity study is performed on the initial contact stiffness, which was found in other works to dictate the stability of the algorithm. © 1993-2012 IEEE.


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Item Type: Article
Status: Published
CreatorsEmailPitt UsernameORCID
Bucci, BA
Cole, DGdgcole@pitt.eduDGCOLE0000-0001-9541-3198
Ludwick, SJsludwick@pitt.eduSLUDWICK0000-0002-2638-7640
Vipperman, JSjsv@pitt.eduJSV0000-0001-5585-954X
Date: 1 January 2013
Date Type: Publication
Journal or Publication Title: IEEE Transactions on Control Systems Technology
Volume: 21
Number: 4
Page Range: 1365 - 1373
DOI or Unique Handle: 10.1109/tcst.2012.2206812
Schools and Programs: Swanson School of Engineering > Mechanical Engineering and Materials Science
Refereed: Yes
ISSN: 1063-6536
Date Deposited: 10 Oct 2018 13:46
Last Modified: 01 Mar 2019 17:55


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