检索结果-内蒙古大学图书馆

Closed-loop diesel engine combustion phasing control based on crankshaft torque measurements

CONTROL ENGINEERING PRACTICE 2014年 33卷 115-124页

作者： Thor, Mikael Egardt, Bo McKelvey, Tomas Andersson, Ingemar Chalmers Univ Technol Dept Signals & Syst SE-41296 Gothenburg Sweden

Methods for closed-loop combustion phasing control in a diesel engine, based on measurements of crankshaft torque, are developed and evaluated. A model-based method for estimation of cylinder individual torque contributions from the crankshaft torque measurements is explained and a novel approach for identification of crankshaft dynamics is proposed. The use of the combustion net torque concept for combustion phasing estimation in the torque domain is also described. Two different control schemes, one for individual cylinder control and one for average cylinder control, are studied. The proposed methods are experimentally evaluated using a light-duty diesel engine equipped with a crankshaft integrated torque sensor. The results indicate that it is possible to estimate and control on a cylinder individual basis using the measurements from the crankshaft torque sensor. Combustion phasing is estimated with bias levels of less than 0.5 crank angle degrees (CAD) and cycle-to-cycle standard deviations of less than 0.7 CAD for all cylinders and the implemented combustion phasing controllers manage to accurately counteract disturbances in both fuel injection timing and EGR fraction. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Internal combustion engines Engine control Engine management estimation algorithms

来源：评论

学校读者我要写书评

暂无评论

Backstepping based Visual Servoing for Transport Aircraft Automatic Landing

Backstepping based Visual Servoing for Transport Aircraft Au...

引用

IEEE Conference on Control Applications (CCA)

作者： Burlion, Laurent de Plinval, Henry Mouyon, Philippe Off Natl Etud & Rech Aerosp French Aerosp Lab F-31055 Toulouse France

ISBN: (纸本)9781479974092

In this paper we propose a vision based flight control law for the automatic landing of an aircraft. Newly defined visual features obtained by a 2D-video camera embed the needed information about the relative pose between the aircraft and the runway. To cope with their dependence on the unknown distance to the ground, a depth estimation algorithm is proposed. With these elements, several nonlinear and adaptive control backstepping laws are derived depending on our knowledge of the runway width. Closed-loop stability proofs are also provided. Simulation results show the effectiveness of the approach.

关键词： Nonlinear control Visual motion estimation algorithms

来源：评论

学校读者我要写书评

暂无评论

Nonlinear estimation of a Parsimonious Wiener Model for the Neuromuscular Blockade in Closed-loop Anesthesia

引用

IFAC Proceedings Volumes 2014年第3期47卷 9258-9264页

作者： Olov Rosén Margarida M. Silva Alexander Medvedev Department of Information Technology Uppsala University SE-751 05 Uppsala Sweden Departamento de Matemática Faculdade de Ciências da Universidade do Porto Rua do Campo Alegre 4169-007 Porto Portugal and Center for Research and Development in Mathematics and Applications (CIDMA) Campus Universitário de Santiago 3810-193 Aveiro Portugal

The recursive identification of a parsimonious nonlinear Wiener model for the neuromuscular blockade in closed-loop anesthesia is considered. The performance of two popular nonlinear estimation techniques, namely the extended Kalman filter (EKF) and the particle filter (PF), is evaluated on synthetic and clinical data. The parameter estimates obtained with the PF, that does not rely on model linearization, exhibit less bias and shorter settling time than the ones produced by the EKF. This behavior persists when the parameter tracking capabilities of both estimation algorithms are assessed for the model in hand. Taking advantage of the model parameters that were recursively estimated from clinical data, it is demonstrated that the main source of intra-patient variability lies in the nonlinear pharmacodynamic part of the model. The distance to a bifurcation phenomenon leading to nonlinear oscillations of the Wiener model under PID feedback is also evaluated.

关键词： Biomedical control Dynamical systems estimation algorithms Parameter estimation Nonlinear oscillations

来源：评论

学校读者我要写书评

暂无评论

An Online estimation of Rotational Velocity of Flying Ball via Aerodynamics

引用

IFAC Proceedings Volumes 2014年第3期47卷 7176-7181页

作者： Akira Nakashima Takeshi Okamoto Yoshikazu Hayakawa Mechanical Science and Engineering Graduate School of Engineering Nagoya University Furo-cho Chikusa-ku Nagoya Japan

We propose a novel estimation method of the rotational velocity of a flying ball as well as its position and translational velocity via aerodynamics model by measuring the ball trajectory using the middle speed cameras for table tennis system. The aerodynamics model is complex nonlinear and the measured data of the ball trajectory has quantization errors because the size of the ball is very small in the field of view of the middle speed cameras. Then, we consider the estimation by minimizing the difference between the trajectories which are measured by the cameras and numerically solved by integrating the aerodynamics model respectively. Since the difference is not analytical function, the minimization is solved by the downhill simplex method, where some modification is introduced for improving the converge speed. The effectiveness of the method is verified by numerical simulations.

关键词： Optimal estimation estimation algorithms State estimation Robotics Model-based recognition Physical models Table tennis system Online estimation

来源：评论

学校读者我要写书评

暂无评论

Methodology for Handling Missing Data in Nonlinear Mixed Effects Modelling

Methodology for Handling Missing Data in Nonlinear Mixed Eff...

引用

作者： ASA M. JOHANSSON Uppsala University

学位级别：博士

To obtain a better understanding of the pharmacokinetic and/or pharmacodynamic characteristics of an investigated treatment, clinical data is often analysed with nonlinear mixed effects modelling. The developed models can be used to design future clinical trials or to guide individualised drug treatment. Missing data is a frequently encountered problem in analyses of clinical data, and to not venture the predictability of the developed model, it is of great importance that the method chosen to handle the missing data is adequate for its purpose. The overall aim of this thesis was to develop methods for handling missing data in the context of nonlinear mixed effects models and to compare strategies for handling missing data in order to provide guidance for efficient handling and consequences of inappropriate handling of missing data. In accordance with missing data theory, all missing data can be divided into three categories; missing completely at random (MCAR), missing at random (MAR) and missing not at random (MNAR). When data are MCAR, the underlying missing data mechanism does not depend on any observed or unobserved data; when data are MAR, the underlying missing data mechanism depends on observed data but not on unobserved data; when data are MNAR, the underlying missing data mechanism depends on the unobserved data itself. Strategies and methods for handling missing observation data and missing covariate data were evaluated. These evaluations showed that the most frequently used estimation algorithm in nonlinear mixed effects modelling (first-order conditional estimation), resulted in biased parameter estimates independent on missing data mechanism. However, expectation maximization (EM) algorithms (e. g. importance sampling) resulted in unbiased and precise parameter estimates as long as data were MCAR or MAR. When the observation data are MNAR, a proper method for handling the missing data has to be applied to obtain unbiased and precise parameter estimates

关键词： Pharmacometrics population models censored observations missing covariates missing dependent variable missing data mechanism missing completely at random (MCAR) missing at random (MAR) missing not at random (MNAR) estimation algorithms

来源：评论

学校读者我要写书评

暂无评论

Correct algebras over estimation algorithms in the set of regular recognition problems with nonoverlapping classes

引用

COMPUTATIONAL MATHEMATICS AND MATHEMATICAL PHYSICS 2009年第7期49卷 1264-1275页

作者： Maksimov, Yu. V. Moscow Inst Phys & Technol Dolgoprudnyi 141700 Moscow Oblast Russia

Algebras over estimation algorithms in the set of regular problems with nonoverlapping classes are considered. A correctness criterion for the arbitrary degree algebraic closure of the model of estimation algorithms in the classification problems of this type is proposed;this criterion can be efficiently verified. An estimate of the minimal degree of the algebraic closure that is sufficient for constructing a correct classifier in an arbitrary regular problem with nonoverlapping classes is found.

关键词： classification problems algebraic approach estimation algorithms correct algorithms

来源：评论

学校读者我要写书评

暂无评论

An adaptive strategy for Li-ion battery internal state estimation

引用

CONTROL ENGINEERING PRACTICE 2013年第12期21卷 1851-1859页

作者： Di Domenico, Domenico Prada, Eric Creff, Yann IFP Energies Nouvelles F-69360 Solaize France

Further developing a study presented in Di Domenico, Prada, and Creff (2011), this paper presents an extended Kalman filter (EKF) based on an electro-thermal model for the estimation of the internal state of a lithium-ion battery, i.e. state of charge and the cell overpotential. In order to compensate for uncertainties in the model parameters and in the measurements, it is first shown that the filter robustness strongly depends on the State of Charge (SOC) range. Then the filter weights are adapted according to the estimated SOC value. This estimation technique is tested using experimental data collected from a commercial A123 Systems lithium iron phosphate/graphite (LiFePO4/graphite) cell. The filter shows good performance. The estimation of SOC exhibits an average error within 3% range and the overpotential is estimated with a precision higher than 5 mV. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Kalman filters estimation algorithms Nonlinear models Observability Statistical analysis

来源：评论

学校读者我要写书评

暂无评论

A review on speech enhancement algorithms and why to combine with environment classification

引用

INTERNATIONAL JOURNAL OF MODERN PHYSICS C 2014年第10期25卷 1430002-1430002页

作者： Nidhyananthan, S. Selva Kumari, R. Shantha Selva Prakash, A. Arun Mepco Schlenk Engn Coll Dept ECE Sivakasi 626005 India

Speech enhancement has been an intensive research for several decades to enhance the noisy speech that is corrupted by additive noise, multiplicative noise or convolutional noise. Even after decades of research it is still the most challenging problem, because most papers rely on estimating the noise during the nonspeech activity assuming that the background noise is uncorrelated (statistically independent of speech signal), nonstationary and slowly varying, so that the noise characteristics estimated in the absence of speech can be used subsequently in the presence of speech, whereas in a real time environment such assumptions do not hold for all the time. In this paper, we discuss the historical development of approaches that starts from the year 1970 to, the recent, 2013 for enhancing the noisy speech corrupted by additive background noise. Seeing the history, there are algorithms that enhance the noisy speech very well as long as a specific application is concerned such as the In-car noisy environments. It has to be observed that a speech enhancement algorithm performs well with a good estimation of the noise Power Spectral Density (PSD) from the noisy speech. Our idea pops up based on this observation, for online speech enhancement (i.e. in a real time environment) such as mobile phone applications, instead of estimating the noise from the noisy speech alone, the system should be able to monitor an environment continuously and classify it. Based on the current environment of the user, the system should adapt the algorithm (i.e. enhancement or estimation algorithm) for the current environment to enhance the noisy speech.

关键词： Environment classification enhancement algorithms estimation algorithms mobile phone scenario

来源：评论

学校读者我要写书评

暂无评论

Estimating communication costs for distributed XML query processing

引用

IET COMMUNICATIONS 2013年第8期7卷 766-773页

作者： Park, Jong-Hyun Kang, Ji-Hoon Chungnam Natl Univ Dept Comp Sci & Engn Taejon South Korea

In distributed query processing, good estimation algorithms of communication costs are critical for query processing, including distributed XML queries. There are techniques that estimate a communication cost for distributed SQL query processing, and some of techniques are adopted in numerous distributed SQL processors. Therefore adopting the processing techniques for SQL queries for the communication cost-based processing of the distributed XML queries seems natural. Unfortunately, however, the tree-structured XML document is different from the table-shaped relational data. These structural differences make adopting the techniques for SQL queries difficult. This study defines some of the considerations for estimating the communication cost of distributed XML queries, and proposes a method for communication cost-based query processing. The experiments show that the proposed algorithm is reasonable for estimating the communication cost for distributed XML queries.

关键词： distributed processing estimation theory query processing SQL tree data structures XML communication cost-based query processing structural differences table-shaped relational data tree-structured XML document communication cost-based processing processing techniques distributed SQL processors distributed SQL query processing estimation algorithms distributed query processing distributed XML query processing communication cost estimation distributed processing estimation theory query processing SQL tree data structures XML communication cost-based query processing structural differences table-shaped relational data tree-structured XML document communication cost-based processing processing techniques distributed SQL processors distributed SQL query processing estimation algorithms distributed query processing distributed XML query processing communication cost estimation

来源：评论

学校读者我要写书评

暂无评论

Parameter estimation for a flotation process tracking simulator

引用

IFAC Proceedings Volumes 2013年第16期46卷 122-127页

作者： Janne Pietilä Jani Kaartinen Ari-Matti Reinsalo Aalto University Department of Automation and Systems Technology Helsinki Finland

A parameter estimation method for an online flotation process simulator is described. The applications of an online process simulator include soft sensor implementations, process trajectory predictions and advisory feedback to the operator, which have potential to improve the process efficiency and minimize the detrimental effect of disturbances on the process or the environment. The online simulator uses a detailed and dynamic model of an actual industrial flotation process, and therefore accurately corresponds to the process phenomena present at the plant. Parameter estimation is required for the flotation kinetics in order for the simulator to adapt to changes in the process conditions. A relatively generic parameter estimation algorithm is developed and tested with a dual simulator setup. The particular requirements and limitations of adapting an online simulator are discussed, and modifications to well-known estimation algorithms are presented as a possible method of meeting the requirements and overcoming the limitations. The results show that online parameter estimation and simulation model tracking is possible with the chosen method, and point out areas of further development for application when the simulator is used alongside the real process.

关键词： estimation algorithms adaptation process simulators

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：