Showing papers by "OH Okko Bosgra published in 2006"
TL;DR: In this paper, an extension to higher-order describing functions is realized by introducing the concept of the harmonics generator, which relates the magnitude and phase of the higher harmonics of the periodic response of the system to the magnitude of a sinusoidal excitation.
100 citations
14 Jun 2006
TL;DR: The presented approach is successful in suppression of residual vibrations with a minimized maximum command amplitude in point-to-point motions, based on iterative learning control.
Abstract: In this paper, we present a new approach for reduction of residual vibrations in point-to-point motions, based on iterative learning control (ILC). The approach is to add a signal to the command input during the point-to-point motion, chosen such as to compensate for the residual vibration. A special form of ILC with separate actuation and observation time windows is shown to find the required input. Optimal suppression is obtained by iteratively updating the command signal, using the measured residual vibrations and a newly designed control strategy. This strategy incorporates 1) robustness to model uncertainties and unmodeled dynamics and 2) the capability of shaping the command signal to limit the command amplitude. In an application on a flexible system, we show that the presented approach is successful in suppression of residual vibrations with a minimized maximum command amplitude.
41 citations
01 Dec 2006
TL;DR: It is proved that systems with certain properties have the additional freedom to manipulate the signal form of the command signal and an actuation and observation time window is introduced in the ILC controlled system, making it possible to capture nonstandard ILC problems within a single general framework.
Abstract: In this paper, we analyse the trial domain stabilizability of Iterative Learning Control (ILC) for linear time varying systems. We prove that a system can only be made asymptotically stable in trial domain if the number of trial domain integrators does not exceed the rank of the convolutive i/o system map. Based on this statement, a general ILC control structure is formulated in which asymptotic stability and optimal performance can be obtained by separate components in the controller. Furthermore, we prove that systems with certain properties have the additional freedom to manipulate the signal form of the command signal. Subsequently, we introduce an actuation and observation time window in the ILC controlled system, making it possible to capture nonstandard ILC problems within a single general framework. The effect of these time windows on the ILC controlled system and the design freedom of the ILC controller is discussed, and illustrated by five applications.
5 citations
TL;DR: The need of high performance non-linear model based control, optimization, monitoring and soft sensing applications and the cost driven necessity of reuse of models and results of earlier engineering effort will be explained to be the drivers for the current and future industrial challenges in (hybrid) modelling and system identification.
4 citations
01 Jan 2006
TL;DR: Two control strategies for Hankel ILC are derived to ensure asymptotic stability of the controlled system resulting in the suppression of residual vibrations and minimizing the weighted variance of the command signal, resulting in an analytical expression for the Hanke ILC controller.
Abstract: Two control strategies for Hankel ILC are derived. Both strategies are first designed to ensure asymptotic stability of the controlled system resulting in the suppression of residual vibrations. The first control strategy is further designed to shape the command signal by minimizing the maximum amplitude of the command signal, using Linear Programming. The second strategy aims at minimizing the weighted variance of the command signal, resulting in an analytical expression for the Hankel ILC controller.