This paper presents a procedure for quantifying the errors in the estimation of the parameters of systems described by ARMAX models when operating in closed loop. We include stochastic disturbances on the output and c...
详细信息
This paper presents a procedure for quantifying the errors in the estimation of the parameters of systems described by ARMAX models when operating in closed loop. We include stochastic disturbances on the output and consider the case where the true open loop plant is not a member of the chosen set of identifier models. This latter problem is dealt with by considering the impulse response of the undermodelling to be a particular realisation of a random vector with known characteristics but unknown parameters. We show how the parameters which characterize the undermodelling may be estimated from the data using Maximum Likelihood. For the case of Gaussian probability density functions we show how this information may be used to obtain a quasi-Bayesian estimate of the conditional distribution of the true system model. This in turn allows confidence regions to be established which would be suitable for use in robust control system design.
A novel method for generating q-Markov covers for SISO (single-input single-output) discrete-time systems is proposed. It is based on first computing the impulse-response Gramian from the Markov parameters and covaria...
详细信息
A novel method for generating q-Markov covers for SISO (single-input single-output) discrete-time systems is proposed. It is based on first computing the impulse-response Gramian from the Markov parameters and covariances, and then solving the Lyapunov equation inversely to get the system matrices in controllability canonical form. Given the markov parameters and the covariances, exactly two q-Markov covers can be obtained by solving the Lyapunov equation inversely to get the system matrices. The method is illustrated by a numerical example and is shown to be computationally simple.< >
Algebraic necessary and sufficient conditions for the stability analysis of 2-D discrete systems are presented. These conditions are developed based on the frequency-dependent formulation of the Lyapunov equation usin...
详细信息
Algebraic necessary and sufficient conditions for the stability analysis of 2-D discrete systems are presented. These conditions are developed based on the frequency-dependent formulation of the Lyapunov equation using Kronecker products. It is shown that these necessary and sufficient conditions for internal stability of 2-D discrete systems are equivalent to testing the eigenvalues of constant matrices. This is a simplification over earlier tests which require testing the positivity of one or more functions of omega for all omega epsilon (0,2 pi ).< >
The problem of disturbance rejection with simultaneous triangular decoupling via proportional state feedback for linear, time-invariant systems is discussed. The following two major aspects are solved: the necessary a...
详细信息
The problem of disturbance rejection with simultaneous triangular decoupling via proportional state feedback for linear, time-invariant systems is discussed. The following two major aspects are solved: the necessary and sufficient conditions for the problem to have a solution, and the general analytical expressions of the controller matrices.< >
A study is made of the servomechanism problem in unknown stable nonlinear systems. With a neural network as an identifier of the input-output characteristics of the plant, an error-feedback controller that achieves tr...
详细信息
A study is made of the servomechanism problem in unknown stable nonlinear systems. With a neural network as an identifier of the input-output characteristics of the plant, an error-feedback controller that achieves tracking with all states remaining bounded is designed. The controller is applicable to uncertain systems.< >
The necessary and sufficient conditions for the existence of positive definite solutions for the 2-D Lyapunov equation for 2-D discrete, 2-D continuous, and differential-delay systems are presented. It is shown that t...
详细信息
The necessary and sufficient conditions for the existence of positive definite solutions for the 2-D Lyapunov equation for 2-D discrete, 2-D continuous, and differential-delay systems are presented. It is shown that these conditions are related to the strictly positive real and strictly bounded real conditions. The relationship between these conditions and the stability ones is also discussed.< >
作者:
OSTENDORF, DWLEACH, LEHINLEIN, ESXIE, YF1 David W. Ostendorf is an associate professor in the Environmental Engineering Program of the Civil Engineering Department at the University of Massachusetts (Civil Engineering Department
University of Massachusetts Amherst MA 01003). His research interests include unconfined aquifer contamination hazardous waste site remediation and analytical modeling of problems in environmental fluid mechanics. Dr. Ostendorf is a registered professional engineer in Massachusetts and a member of the American Geophysical Union American Society of Civil Engineers Soil Science Society of America Water Pollution Control Federation and Association of Environmental Engineering Professors as well as the National Water Well Association.2 Lowell E. Leach is an environmental engineer with the Robert S. Kerr Environmental Research Laboratory of the U.S. Environmental Protection Agency (RS Kerr Environmental Research Laboratory U.S. EPA P.O. Box 1198 Ada OK74820). Leach received his B.S. ingeological engineering at the University of Oklahoma in 1959 and has been a registered professional engineer in Oklahoma since 1966. With 29 years of experience in field applications of geological engineering he is responsible for developing methodology for sampling ground water and subsurface materials for the Robert S. Kerr Environmental Research Laboratory.3 Erich S. Hinlein is a research assistant in the Environmental Engineering Program of the Civil Engineering Department at the University of Massachusetts (Civil Engineering Department University of Massachusetts Amherst MA 01003). His research interests include ground water pollution hazardous waste site investigation and transport processes in unconfined aquifers. Hinlein graduated with a B.S. in electrical and computer engineering from the University of Massachusetts at Amherst in May 1985 and entered the Environmental Engineering Master's Degree Program in January 1989.4 Yuefeng Xie is a postdoctoral research associate in the Environmental Engineering Program of the Civil E
Two complementary field sampling methods for the determination of residual aviation gasoline content in the contaminated capillary fringe of a fine, uniform, sandy soil were investigated. The first method featured fie...
Two complementary field sampling methods for the determination of residual aviation gasoline content in the contaminated capillary fringe of a fine, uniform, sandy soil were investigated. The first method featured field extrusion of core barrels into pint-size Mason jars, while the second consisted of laboratory partitioning of intact stainless steel core sleeves. The barrel extrusion procedure involved jar headspace sampling in a nitrogen-filled glove box, which delineated the 0.7m thick residually contaminated interval for subsequent core sleeve withdrawal from adjacent boreholes. Soil samples removed from the Mason jars (in the field) and sleeve segments (in the laboratory) were subjected to methylene chloride extraction and gas chromatographic analysis to compare their aviation gasoline content. The barrel extrusion sampling method yielded a vertical profile with 0.10m resolution over an essentially continuous 5.0m interval from the ground surface to the water table. The sleeve segment alternative yielded a more resolved 0.03m vertical profile over a shorter 0.8m interval through the capillary fringe. The two methods delivered precise estimates of the vertically integrated mass of aviation gasoline at a given horizontal location, and a consistent view of the vertical profile as well. In the latter regard, a 0.2m thick lens of maximum contamination was found in the center of the capillary fringe, where moisture filled all voids smaller than the mean pore size. The maximum peak was resolved by the core sleeve data, but was partially obscured by the barrel extrusion observations, so that replicate barrels or a half-pint Mason jar size should be considered for data supporting vertical transport analyses in the absence of sleeve partitions.
Based on the SCARA concept, accepted worldwide, this paper considers the possibility of realizing SCARA with a full circle working area. The basis of the approach is a mechanism with two eccentrically positioned rotat...
详细信息
Based on the SCARA concept, accepted worldwide, this paper considers the possibility of realizing SCARA with a full circle working area. The basis of the approach is a mechanism with two eccentrically positioned rotating discs instead of two joined links. In this way, apart from a circular working area and some other advantages, the installation of several tools (hands) is also facilitated. This paper analyzes the advantages of the proposed solution and the possibilities of its realization.
This paper presents details in the implementation of an adaptive autopilot unit used for ship course keeping and course changing. The control strategy is based on the scheme of self-tuning regulator (STR) in which the...
详细信息
This paper presents details in the implementation of an adaptive autopilot unit used for ship course keeping and course changing. The control strategy is based on the scheme of self-tuning regulator (STR) in which the generalized minimum variance (GMV) control law is combined with an extended least square (ELS) parameter identification technique. A time-varying extended state Kaiman filter (EKF) is designed to estimate the state of the system under disturbances induced by the sea environment and loading conditions. ELS and EKF constitute an adaptive estimator by which both state vector and parameter vector can be estimated properly. A dual microcomputer system using warm standby redundant design is implemented to guarantee the reliability in the control and safety in the steering. The construction principles of hardware and software are discussed. A sophisticated simulation facility is extensively used in the design stage of the autopilot unit. Several sea trials have been performed at “DAQING 232”, a 15000 tdw tanker, the results of which show that the unit reduces the propulsion losses of the ship motion in addition to keeping the course satisfactorily.
Recently, there are many applications of fuzzy controller based on intuition and experience of human operators. The fuzzy controllers are regarded as a set of heuristic decision rules and to be implementec easily in a...
详细信息
暂无评论