Variable gain motion control for transient performance improvement

To deal with performance trade-offs in the control of motion systems, a method is developed for designing variablegain feedback controllers. The idea is to select a piecewise affine controller structure and, subsequently, to find the nonlinear controller parameter values of this structure by data-driven performance optimization. Herein an H2 performance objective is minimized. As a result, variable-gain controllers are synthesized using techniques from the field of learning and optimization. The method is applied to a wafer stage simulation model.

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“…, and x(1) = 0, it then follows that (9) can be represented in the following discretized and lifted form:…”

Section: Lur'e System Descriptionmentioning

confidence: 99%

“…In the wafer scanning industry [4] variable-gain control is used to deal with performance trade-offs otherwise occurring under linear feedback; see also [9], [12], [13], [20]. The rationale is that low-frequency vibrations induced by the motion set-points of wafer scanners are better suppressed under high-gain feedback.…”

Section: Introductionmentioning

confidence: 99%

Learning in the synthesis of data-driven variable-gain controllers

Heertjes

Hunnekens

Wouw

et al. 2013

2013 American Control Conference

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“…The motion system under study consists of a noncollocated motor-load system, which resembles a realistic industrial motion control setting where sensors and actuators are typically placed at different locations. In addition, the system is subject to an external force disturbance, which motivates the use of integral control in order to obtain a zero steady-state error, see e.g., [10].…”

Section: Simulation Examplementioning

confidence: 99%

“…In this paper, we aim to achieve the same objective by our newly proposed variant/extension to the SPAN filter. Furthermore, we would like to emphasize that, similarly as in [10], the linear components of our proposed controller configuration can be designed using well-known loop-shaping techniques, which enhances the applicability to real-life control problems.…”

Section: Introductionmentioning

confidence: 99%

“…In [9], potential benefits of hybrid control for linear systems have been discussed, and in particular, it has been shown that a switched integral controller can improve the transient performance. Another concept is variable gain integral control [10], which limits the integral action if the error exceeds a certain threshold, thereby limiting, in turn, the amount of overshoot. A similar objective is achieved in [11], in which a sliding mode controller with saturated integrator is studied.…”

Section: Introductionmentioning

confidence: 99%

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Transient performance improvement of linear systems using a split-path nonlinear integrator

Loon

Hunnekens

Heemels

et al. 2014

2014 American Control Conference

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In this paper, we introduce the split-path nonlinear integrator (SPANI) as a novel nonlinear filter designed to improve the transient performance of linear systems in terms of overshoot. In particular, this nonlinear controller targets the well-known trade-off induced by integral action, which removes steady-state errors due to constant external disturbances, but deteriorates transient performance in terms of increased overshoot. The rationale behind the proposed SPANI filter is to ensure that the integral action has, at all times, the same sign as the closed-loop error signal, which, as we will show, enables a reduction in overshoot (i.e., improves transient performance). The resulting closed-loop dynamics can be described by a continuous-time switched dynamical system, for which we will provide sufficient conditions for stability. Furthermore, we illustrate the effectiveness, the design and the tuning of the proposed controller in simulation examples.

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