检索结果-内蒙古大学图书馆

Performance behavior of prediction filters for respiratory motion compensation in radiotherapy

Current Directions in Biomedical engineering 2017年第2期3卷 429-432页

作者： Jöhl, Alexander Berdou, Yannick Guckenberger, Matthias Klöck, Stephan Meboldt, Mirko Zeilinger, Melanie Tanadini-Lang, Stephanie Daners, Marianne Schmid Product Development Group Zurich Department of Mechanical and Process Engineering ETH Zurich Tannenstrasse 3 Zurich 8092 Switzerland Institute for Dynamic Systems and Control Department of Mechanical and Process Engineering ETH Zurich Switzerland Department of Radiation Oncology University Hospital Zurich University of Zurich Switzerland

Introduction: In radiotherapy, tumors may move due to the patient’s respiration, which decreases treatment accuracy. Some motion mitigation methods require measuring the tumor position during treatment. Current available sensors often suffer from time delays, which degrade the motion mitigation performance. However, the tumor motion is often periodic and continuous, which allows predicting the motion ahead. Method and Materials: A couch tracking system was simulated in MATLAB and five prediction filters selected from literature were implemented and tested on 51 respiration signals (median length: 103 s). The five filters were the linear filter (LF), the local regression (LOESS), the neural network (NN), the support vector regression (SVR), and the wavelet least mean squares (wLMS). The time delay to compensate was 320 ms. The normalized root mean square error (nRMSE) was calculated for all prediction filters and respiration signals. The correlation coefficients between the nRMSE of the prediction filters were computed. Results: The prediction filters were grouped into a low and a high nRMSE group. The low nRMSE group consisted of the LF, the NN, and the wLMS with a median nRMSE of 0.14, 0.15, and 0.14, respectively. The high nRMSE group consisted of the LOESS and the SVR with both a median nRMSE of 0.34. The correlations between the low nRMSE filters were above 0.87 and between the high nRMSE filters it was 0.64. Conclusion: The low nRMSE prediction filters not only have similar median nRMSEs but also similar nRMSEs for the same respiration signals as the high correlation shows. Therefore, good prediction filters perform similarly for identical respiration patterns, which might indicate a minimally achievable nRMSE for a given respiration pattern. © 2017 Alexander Jöhl et al., published by De Gruyter.

关键词： Time delay

来源：评论

学校读者我要写书评

暂无评论

Stabilization of discrete-time switched linear systems: Lyapunov-Metzler inequalities versus S-procedure characterizations

引用

IFAC-PapersOnLine 2017年第1期50卷 3412-3417页

作者： Kundu A. Daafouz J. Heemels W.P.M.H. Robert Bosch Centre for Cyber-Physical Systems Indian Institute of Science Bangalore India Centre for Research in Automatic Control of Nancy University of Lorraine France Control Systems Technology Group Department of Mechanical Engineering Eindhoven University of Technology Netherlands

In this paper we study connections between Lyapunov-Metzler inequalities and S-procedure characterizations in the context of stabilizing discrete-time switched linear systems using min-switching strategies. We propose two generalized versions of S-procedure characterization along the lines of the generalized versions of Lyapunov-Metzler inequalities recently proposed in the literature. It is shown that the existence of a solution to the generalized version(s) of Lyapunov-Metzler inequalities is equivalent to the existence of a solution to the generalized version(s) of S-procedure characterization with a restricted choice of the scalar quantities involved in the latter. This recovers some of our earlier works on the classical Lyapunov-Metzler inequalities as a special case. We also highlight and discuss an open question of whether the generalized versions of S-procedure characterization are strictly less conservative than the generalized versions of Lyapunov-Metzler inequalities, which in turn are equivalent to periodic stabilizability as was recently shown. © 2017

关键词： Discrete-time switched linear systems Lyapunov-Metzler inequalities matrix inequalities min-switching strategy S-procedure characterizations stabilizability

来源：评论

学校读者我要写书评

暂无评论

Constrained iterative feedback tuning for robust high-precision motion control 19

Constrained iterative feedback tuning for robust high-precis...

引用

19th IFAC World Congress on International Federation of Automatic control, IFAC 2014

作者： Van Der Velden, Bart J.C.H. Oomen, Tom Heertjes, Marcel F. Control Systems Technology Group Department of Mechanical Engineering Eindhoven University of Technology Eindhoven Netherlands Mechatronics Technology Development ASML Veldhoven Netherlands

ISBN: (纸本)9783902823625

The aim of this paper is to extend iterative feedback tuning (IFT), which is a data-based approach for controller tuning, with robustness constraints. Hereto a constrained IFT problem is formulated that is solved by introducing a penalty function. Essentially, the gradient estimates decompose into (a) the well-known IFT gradients and (b) the gradients with respect to this penalty function. Experimental results obtained from the motion control systems of an industrial wafer scanner confirm enhanced performance with guaranteed robustness properties. © IFAC.

关键词：

来源：评论

学校读者我要写书评

暂无评论

HOW LEARNING control SUPPORTS INDUSTRY 4.0 IN SEMICONDUCTOR MANUFACTURING 6

HOW LEARNING CONTROL SUPPORTS INDUSTRY 4.0 IN SEMICONDUCTOR ...

引用

6th ASPE Spring Topical Meeting on Design and control of Precision Mechatronic systems

作者： Veen, Gijs Van Der Stokkermans, Joep Mooren, Noud Oomen, Tom Equipment & Automation Technologies Nexperia Nijmegen Netherlands Department Of Mechanical Engineering Control Systems Technology Group Eindhoven University Of Technology Eindhoven Netherlands

来源：评论

学校读者我要写书评

暂无评论

Use of real time creep force estimation data for assessment of low adhesion in the wheel/rail contact

Use of real time creep force estimation data for assessment ...

引用

5th IET Conference on Railway Condition Monitoring and Non-Destructive Testing, RCM 2011

作者： Ward, C.P. Goodall, R.M. Dixon, R. Charles, G. Control Systems Group School of Electronic Loughborough University United Kingdom Department of Mechanical Materials and Manufacturing Engineering University of Nottingham United Kingdom

ISBN: (纸本)9781849195584

Low adhesion in railway vehicle wheel/rail contact can create large cost and punctuality issues for train operators and users. There is currently a lack of real time knowledge of the running conditions on networks, therefore the work reported here proposes a method of detecting dynamically the adhesion conditions underneath a rail vehicle using modest cost sensors and advanced model based monitoring of the creep forces. The estimated creep forces are then post processed to give an estimation of the current adhesion condition.

关键词： Adhesion

来源：评论

学校读者我要写书评

暂无评论

One-sided control of surge in a centrifugal compressor system

One-sided control of surge in a centrifugal compressor syste...

引用

ASME Turbo Expo 2000: Power for Land, Sea, and Air, GT 2000

作者： Willems, Frank De Jager, Bram Eindhoven University of Technology Faculty of Mechanical Engineering Systems and Control Group P.O. Box 513 EindhovenMB5600 Netherlands

ISBN: (纸本)9780791878545

Active surge control is studied in a centrifugal compressor system. To stabilize surge, a bleed valve is applied which is nominally closed and only opens to stabilize the system around the desired operating point. This bleed valve is controlled using a linear output feedback controller based on plenum pressure measurements. In this study, the practical limitations of this one-sided surge controller are examined. Experiments show that the performance of the controller is affected by measurement noise and the desired equilibrium point in the controller, which is not accurately known in the unstable operating region. Fully-developed surge is stabilized with relatively small stationary bleed valve mass flow using the proposed controller in combination with a small band-pass filter. Measurements are compared with the results of the Greitzer model. This model shows qualitative agreement with experiments. For the examined compressor system, a 3.5% extension of the stable operating region is obtained using the one-sided surge controller. Copyright © 2000 by ASME.

关键词： Centrifugal compressors

来源：评论

学校读者我要写书评

暂无评论

Exact plant inversion of flexible motion systems with a time-varying state-to-output map

Exact plant inversion of flexible motion systems with a time...

引用

European control Conference

作者： Yanin Kasemsinsup Marcel Heertjes Hans Butler Siep Weiland Control Systems Group Department of Electrical Engineering Control Systems Technology Group Department of Mechanical Engineering

ISBN: (纸本)9781509025923

Many high-accuracy positioning systems have a target performance location that varies with time and position. A typical example is given by wafer stage positioning systems in the lithographic industry. The design of feedforward compensators for such a class of systems, i.e. flexible motion systems having Linear Time Invariant (LTI) state dynamics with Linear Time-Varying (LTV) state-to-output map, can be considerably enhanced if such time or position-varying characteristics of the systems are taken into account. In this work, a strategy to construct a feedforward controller that exactly matches the time-dependent inverse of such a system is investigated. Analysis and simulation on a simplified model show the potential performance improvement obtained with such a strategy.

关键词： Exact plant inversion flexible motion systems time-varying state-to-output map

来源：评论

学校读者我要写书评

暂无评论

Estimation of fingertip force from surface EMG a multivariate Bayesian mixture of experts approach 8

Estimation of fingertip force from surface EMG a multivariat...

引用

8th International Conference on Bio-Inspired systems and Signal Processing, BIOSIGNALS 2015

作者： Baldacchino, Tara Jacobs, William Anderson, Sean R. Worden, Keith Rowson, Jennifer Dynamics Research Group Department of Mechanical Engineering University of Sheffield Sheffield United Kingdom Department of Automatic Control and Systems Engineering University of Sheffield Sheffield United Kingdom

ISBN: (纸本)9789897580697

Improving the dexterity of active prostheses is a major research area amalgamating machine learning algorithms and biosignals. A recent research niche has emerged from this-providing proportional control to a prosthetic hand by modelling the force applied at the fingertips using surface electromyography (sEMG). The publicly released NinaPro database contains sEMG recording for 6 degree-of-freedom force activations for 40 intact subjects. In this preliminary study the authors successfully perform multivariate force regression using Bayesian mixture of experts (MoE). The accuracy of the model is compared to the benchmark set by the authors of NinaPro;comparable performance is achieved, however in this work a lower dimensional feature extraction representation obtains the best modelling accuracies, hence reducing training time. Inherent to the Bayesian framework is the inclusion of uncertainty in the model structure, providing a natural step in obtaining confidence bounds on the predictions. The MoE model used in this paper provides a powerful method for modelling force regression with application to actively controlling prosthetic and robotic arms for rehabilitation purposes, resulting in highly refined movements.

关键词： Learning algorithms

来源：评论

学校读者我要写书评

暂无评论

H/sub ∞/ control of an experimental inverted pendulum with dry friction

引用

IEEE control systems 1993年第4期13卷 44-50页

作者： G.-W. van der Linden P.F. Lambrechts Mechanical Engineering Systems and Control Group Delft University of Technnology Delft Netherlands

The incorporation of dry friction in a standard plant setting and the application of H/sub ∞/ optimal control design to find a controller that is insensitive to dry friction are discussed. The approach is applied to an inverted penulum setup, to show that a significant improvement of behavior can be obtained. It is shown that the application of an H/sub ∞/ optimal controller does not result in a satisfactory behaviour if dry friction is not taken into account and cart position reference error minimization is demanded. The effect of dry friction is considered in developing a controller that is insensitive to this effect but has no reference tracking property. The trade-off between the tracking objective and the insensitivity of dry friction is reviewed, resulting in a controller with good behavior in both respects. This behavior has been validated by implementation on a laboratory setup.

关键词： H infinity control Friction control systems Optimal control control design Measurement standards Error correction mechanical systems Testing Design methodology

来源：评论

学校读者我要写书评

暂无评论

LabVIEW as a teaching aid for control engineering 6

LabVIEW as a teaching aid for control engineering

引用

6th IFAC Symposium on Advances in control Education, ACE 2003

作者： Aradi, Petra Lipovszki, Gyorgy Systems and Control Engineering Group Department of Information Engineering Faculty of Mechanical Engineering Budapest University of Technology and Economics Goldmann Gy. ter 3 BudapestH-1111 Hungary

LabVIEW-based simulation programs help staff and students in various systems and control engineering courses at BUTE. This paper reports on the development and application of two LabVIEW-based simulation systems TUBSIM and .:PSim:. The importance of interactive, modifiable simulation programs lies both in coursework and in individual study. The courses taught, theses written and defended during the last years have proven grounds to this kind ofapplied simulation. Copyright © IFAC Advances in control Education Oulu, Finland, 2003

关键词： Curricula

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：