Tesi: "Disturbance attenuation"

1

Yamamoto, Kaoru. "Disturbance Attenuation in Mass Chains with Passive Interconnection". Thesis, University of Cambridge, 2016. https://www.repository.cam.ac.uk/handle/1810/279020.

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This thesis is concerned with disturbance amplification in interconnected systems which may consist of a large number of elements. The main focus is on passive control of a chain of interconnected masses where a single point is subject to an external disturbance. The problem arises in the design of multi-storey buildings subjected to earthquake disturbances, but applies in other situations such as bidirectional control of vehicle platoons. It is shown that the scalar transfer functions from the disturbance to a given intermass displacement can be represented as a complex iterative map. This description is used to establish uniform boundedness of the H∞-norm of these transfer functions for certain choices of interconnection impedance. A graphical method for selecting an impedance such that the H∞-norm is no greater than a prescribed value for an arbitrary length of the mass chain is given. A design methodology for a fixed length of the mass chain is also provided. A case study for a 10-storey building model demonstrates the validity of this method.

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2

Lin, Haomin. "Disturbance attenuation in precise hexapod pointing control using positive force feedback". Laramie, Wyo. : University of Wyoming, 2005. http://proquest.umi.com/pqdweb?did=990288531&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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3

Niziolomski, Joanna. "Optimising soil disturbance and mulch attenuation for erosion and runoff control in asparagus crops". Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9209.

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Exposure of bare soil for long periods and onsite compaction create soil and water problems in asparagus production. This project aims to develop a cost effective and practical runoff and soil erosion management system. Two field trials (Phase 1 running from April - July 2012 and Phase 2 running from May - November 2013) tested different combinations of shallow soil disturbance (SSD) and mulch (straw and compost) application for soil erosion control. Cranfield University’s soil bin was used to test the effect of different tine configurations on soil disturbance. The results of this research corroborated observations that asparagus production can result in levels of unsustainable soil loss that will contribute to the degradation of the existing soil resource. The field trials demonstrated that a straw mulch applied at 6 t ha- 1 significantly improved key performance indicators (KPIs, i.e. runoff initiation, volume and rate; total soil loss; sediment concentration; total oxides of nitrogen; orthophosphate-P; and sediment-bound P) as compared with the Non-SSD Control. In general, SSD (irrespective of tine configuration) was ineffective at improving key performance indicators as compared with the Non-SSD Control. In the soil bin work, different tine configurations generated varying degrees and extent of SSD, with the modified para-plough giving the greatest soil disturbance for the least draught force. However, the differences in SSD observed in the soil bin had no effect on the KPI’s tested in the Phase 2 field trial. The effective treatments observed in the field trials only yielded cost savings to the farmer/grower when a high level of soil loss occurred. This research highlights the need to develop erosion control measures in asparagus fields, with wider implications to other row crops. However caution is needed, given the observed variation in effectiveness and reliability of in-field mitigation measures, especially during ‘extreme’ rainfall events.

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4

Hatlevik, Edvin. "Heave disturbance attenuation in managed pressure drilling from a floating platform using model predictive control". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25958.

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Since a large part of the Norwegian oil shelf has been active for over a generation, many fields begin to be depleted and the drilling operations requires tight down hole pressure margins. And by improving the pressure control for the drilling operations former undrillable wells becomes drillable. Which will make the the oilfields more profitable, and extend their life expectancy. It will also make drilling operations safer by preventing kicks and preventing environmental damages caused by mud leaking into the pore space.\\\\One of the most critical phases when drilling from a floating drilling rig in terms of down hole, is pipe connection. During this procedure the conventional heave compensation is not operational as the drill string is climbed to the drill floor. Consequently the drill bit functions as a piston creating large pressure variations in the drill bit pressure. To control this pressure and create disturbance attention a linear model predictive controller with feedback linearisztion is created using feedback linearization. This controller shows promising results when feedforward with future predictions is applied. Without future predictions the results are the same as for an MPC without feedforward. Because only the topside pressure is known the rest of the states are estimated using a Kalman filter, which shows good results on the state estimations. To make the system more applicable in real life applications an efficient linear model predictive controller implementation was created for a PLC with great results, both in terms of calculation time and memory usage.

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5

CHEN, YU. "ADAPTIVE CONTROL FOR TRACKING AND DISTURBANCE ATTENUATION FOR SISO LINEAR SYSTEMS WITH REPEATED NOISY MEASUREMENTS". University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1070579983.

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6

Foo, Jong Teck. "Selection of controller gains for an electromagnetic suspension system". Ohio : Ohio University, 1993. http://www.ohiolink.edu/etd/view.cgi?ohiou1175287253.

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7

Motaghedi, Pejmun. "Attenuation of disturbances on an earth observing satellite". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/49614.

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8

Vivek, Venugopal. "The efficacy of mindfulness-based meditation in attenuating sleep disturbances among high trait ruminators". Thesis, Kent State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3618844.

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Negative affect is widely recognized as a common precipitant of both subjective and objective sleep disturbances (Vandekerckhove & Cluydts, 2010). Since repetitive thought forms such as rumination can sustain negative affect states, they may play a critical role in the etiology of sleep impairment. However, extant research suffers from a number of methodological shortcomings, including a lack of objective sleep assessment and 'first-night' effects. Further, this literature has yet to adequately address the treatment implications of the association between rumination and sleep. Mindfulness-based meditation has emerged as a favorable candidate for such an intervention in recent years (Carney & Segal, 2005). Therefore, the present studies aimed to investigate the association between rumination and sleep outcomes using a multi-method approach to sleep assessment. The efficacy of mindfulness-based meditation in extinguishing rumination and improving sleep was also explored.

A sample of 42 university students who scored high on a trait-level measure of rumination participated in two, week-long studies. Participants provided informed consent, received an actiwatch, and were randomly assigned to either a mindfulness or distraction group before the studies began. During Study 1, participants in both groups completed brief, electronic questionnaires assessing daily levels of rumination just prior to bedtime. Immediately after waking, participants reported the duration and quality of sleep they experienced the previous night. Analyses revealed that daily rumination (z = 2.44; p < .05) was significantly associated with actigraphy-based sleep-onset latency (SOL), but not with total sleep time (TST) or sleep efficiency (SE). Daily rumination was also significantly associated with self-reported SOL (z = 3.18; p < .01) and SQ (z = 2.39; p < .01), but not with TST.

During Study 2, participants in the mindfulness and distraction groups partook respectively in a mindfulness- or distraction-induction task immediately after the nightly questionnaires. A significant effect emerged between group membership and actigraphy-based SOL (z = - 2.13; p < .05), diary-based TST (z = 2.38; p < .05), and diary-based SQ (z = - 2.88; p < .05), with the mindfulness group reporting better sleep outcomes. With respect to within-person effects over the course of the two studies, the mindfulness group exhibited shorter actigraphy-based SOL (z = - 2.30; p < .05), higher actigraphy-based SE (z = 6.54; p < .01), and higher diary-based SQ (z = - 2.22, p < .05) during Study 2 than during Study 1. There were no significant differences in any sleep outcome between Studies 1 and 2 for the distraction group.

These data suggest that rumination is associated with both subjective and objective sleep impairment, and that mindfulness-based meditation can help attenuate this effect. Implications for current behavioral treatments for insomnia are discussed.

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9

Vivek, Venugopal. "THE EFFICACY OF MINDFULNESS-BASED MEDITATION IN ATTENUATING SLEEP DISTURBANCES AMONG HIGH TRAIT RUMINATORS". Kent State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1373384909.

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10

Jiang, Wei. "Contrôle de la formation et du confinement variable dans le temps et entièrement distribué pour les systèmes multi-agents/ multi-robots". Thesis, Ecole centrale de Lille, 2018. http://www.theses.fr/2018ECLI0016/document.

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Cette thése traite du contrôle de la formation et du confinement variant dans le temps pour les systèmes multi-agents linéaires invariants avec hétérogénéité en tenant compte des délais d’entrée / sortie constants / variables dans le temps et des perturbations adaptées / incompatibles sous topologie de communication dirigée et fixe. De nouveaux formats de formes de formation variables dans le temps pour des systèmes homogènes et hétérogènes sont proposés. Les contrôleurs, conçus sur la base de techniques prédictives et adaptatives avec une technique d’observation, sont entièrement distribués et peuvent être appliqués à des systèmes à grande échelle. L’application sur les systèmes robotisés multi hétérogènes linéarisés est vérifiée
This thesis deals with the time-varying formation and containment control for linear time-invariant multi-agent systems with heterogeneity considering constant / time-varying input / output delays and matched / mismatched disturbances under directed and fixed communication topology. New formats of time-varying formation shapes for homogeneous and heterogeneous systems are proposed. The controllers, which are designed based on predictive and adaptive techniques with observer technique, are fully distributed and can be applied to large-scale systems. The application on linearized heterogeneous multi mobile robot systems is verified

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11

Fan, Kai-Hsiang, e 范凱翔. "PID Controller Design for Disturbance Attenuation". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/07633201356436439921.

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碩士
國立高雄應用科技大學
電機工程系碩士班
94
In analysis of control systems, the effect caused by disturbance to systems is always concerned. The objective of this thesis aims at eliminating the disturbance effect. To do this, the system frequency response for first-order and second-order with time-delay systems is first derived and is in terms of a combination of the transient part and the steady-state part. And then the transient response is considered as the system error function to be minimized. To design the optimal parameters of PID controllers, the integral-squared error, which is evaluated by Residue theorem, is defined as the performance index and the genetic algorithm is used to solve optimal parameters. As shown in the presented examples, the high frequency disturbance effect can be more effectively eliminated than the low frequency one.

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12

張宏榮. "Disturbance attenuation by compensated dynamic matrix control". Thesis, 1990. http://ndltd.ncl.edu.tw/handle/03280556435497394323.

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13

PHONG, VU VAN, e 宇文鋒. "The Disturbance Attenuation Analysis of T-S Fuzzy Models". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/07030949327080209165.

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碩士
南台科技大學
電機工程系
98
Fuzzy systems models are playing an increasingly important role in control system design. In particular, the Takagi-Sugeno model (T-S fuzzy model) provides piecewise linear, regional representations of many nonlinear systems. Unlike their linear counterparts of whom many control issues have long been resolved, the control of nonlinear systems is usually much more challenging. Via the representation in Takagi- Sugeno model, many nonlinear plants now can be expressed by linear sub-models in different state regions. Parallel distributed compensation (PDC) is a standard controller choice for T-S models. However, better results can be obtained by using non-PDC controllers which are generally nonlinear. In this thesis we present a new method to construct the composite controller for Takagi-Sugeno fuzzy system which is based on composite quadratic Lyapunov functions. By adopting this new choice of Lyapunov function and taking into account the information of the membership function of the fuzzy variables, the disturbance attenuation problem was turned into an optimizing problem which can be resolved by solving the corresponding BMIs (Bilinear Matrix Inequalities). It was clearly shown in our simulations that controllers thus designed lead to significantly better disturbance rejection performances.

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14

JIAN, QIU-MING, e 簡秋明. "Equivalent disturbance attenuation design method for control systems with large parameter variations". Thesis, 1991. http://ndltd.ncl.edu.tw/handle/37795337765500210128.

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15

Kuppuswamy, Seshadri. "Comparison of active and passive dancers for periodic tension disturbance attenuation in web processing lines". 2004. http://digital.library.okstate.edu/etd/umi-okstate-1181.pdf.

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16

Nkomo, Lihle Immaculate. "Overall vehicle stability for a non-linear multi-varied suspension aimed at disturbance attenuation, energy efficiency and robustness". Thesis, 2020. https://hdl.handle.net/10539/31105.

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A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering, 2020
This dissertation presents the design and implementation of a half-car active suspension system with a pre-disturbance detection algorithm that aims at reducing driver experienced vibrations. The first research contribution is slack-based state constrained optimal control which is used to address the limitations of the penalty function methodology. The performance index is designed so that it optimises for the control actuation energy and the driver’s ride comfort. The optimal control results demonstrate displacement attenuation of 97.5 % and acceleration of up to 80 %, which is practically feasible if high performance sensors and actuators are utilised to enable a fast and efficient response of the active suspension system. The second research contribution is derived from extending the slack variable state constrained optimal control to the linearised half-car suspension system by addressing the limitations of input output feedback linearisation as the state transformation often results in hidden state dynamics. The results from the completely linearised controller show a displacement attenuation of up to 81.82 %. The third research contribution is through the application of an adaptive sliding backstepping controller to the con-structed test-rig, that ensures robust control on non-smooth road surfaces consisting of white noise. The results from the adaptive sliding backstepping demonstrate improved attenuated displacement and smoother accelerations of up to 71.3 % and 60 % respectively. Although the adaptive sliding backstepping trade-offs disturbance attenuation performance, it demonstrates adaptive properties when tested on rough road surfaces. To achieve overall vehicle stability, the use of these controllers can be integrated to benefit from the targeted performances such as robustness
CK2021

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17

Huang, Ho-Chih, e 黃河智. "Robust Stability for Uncertain Discrete-Time Genetic Regulatory Networks with Disturbance Attenuation and Infinite-Distributed Interval Time-Varying Delays". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/97171847821608365536.

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碩士
國立彰化師範大學
工業教育與技術學系
100
This thesis presents the complete study the robust stability problem for uncertain discrete-time genetic regulatory networks with disturbance attenuation and infinite-distributed interval time-varying delays. The time-varying delays are assumed to be with both upper bound and lower bound in the discrete-time domain, and the uncertain parameters are norm-bounded. By using a Lyapunov-Krasovskii functional method and linear matrix inequality (LMI) techniques with the combination of the Hybrid Taguchi-genetic algorithm (HTGA), we can tackle the disturbance attenuation H-infinity stability problem such that with the specified performance is minimized for the system under disturbance attenuation. For the infinite-distributed time-varying delays problem, a sufficient condition is established that guarantees the robust stability for discrete-time uncertain genetic regulatory networks with infinite-distributed delays. An important feature of the results lies in that the robust stability conditions are dependent on the lower and upper bounds of the delays, which are made possible by using improved bounding to the technique to reduce the conservatism of the criterion due free weighting matrices are induced. Finally, some illustrative examples are provided in order to illustrate the applicability and effectiveness of the proposed theoretical results.

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18

Halim, Dunant. "Vibration Analysis and Control of Smart Structures". Thesis, 2003. http://hdl.handle.net/1959.13/24886.

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This thesis represents the work that has been done by the author in the area of vibration analysis and control of smart structures during his PhD candidature. The research was concentrated on flexible structures, using piezoelectric materials as actuators and sensors. The thesis consists of four major parts. The first part (Chapter 2) is the modelling of piezoelectric laminate structures using modal analysis and finite element methods. The second part (Chapter 4) involves the model correction of pointwise and spatial models of resonant systems. The model correction solution compensates for the errors associated with the truncation of high frequency modes. The third part (Chapter 5) is the optimal placement methodology for general actuators and sensors. In particular, optimal placement of piezoelectric actuators and sensors over a thin plate are considered and implemented in the laboratory. The last part (Chapters 6 to 8) deals with vibration control of smart structures. Several different approaches for vibration control are considered. Vibration control using resonant, spatial H-2 and H-infinity control is proposed and implemented on real systems experimentally. It is possible, for certain modes, to obtain the very satisfactory result of up to 30 dB vibration reduction.
PhD Doctorate

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19

Halim, Dunant. "Vibration Analysis and Control of Smart Structures". 2003. http://hdl.handle.net/1959.13/24886.

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Abstract (sommario):

This thesis represents the work that has been done by the author in the area of vibration analysis and control of smart structures during his PhD candidature. The research was concentrated on flexible structures, using piezoelectric materials as actuators and sensors. The thesis consists of four major parts. The first part (Chapter 2) is the modelling of piezoelectric laminate structures using modal analysis and finite element methods. The second part (Chapter 4) involves the model correction of pointwise and spatial models of resonant systems. The model correction solution compensates for the errors associated with the truncation of high frequency modes. The third part (Chapter 5) is the optimal placement methodology for general actuators and sensors. In particular, optimal placement of piezoelectric actuators and sensors over a thin plate are considered and implemented in the laboratory. The last part (Chapters 6 to 8) deals with vibration control of smart structures. Several different approaches for vibration control are considered. Vibration control using resonant, spatial H-2 and H-infinity control is proposed and implemented on real systems experimentally. It is possible, for certain modes, to obtain the very satisfactory result of up to 30 dB vibration reduction.
PhD Doctorate

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Tesi sul tema "Disturbance attenuation"

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