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1.
Results for various types of polar compounds in SRC-11 coal-derived liquids and other fuels were obtained by one or more of the three analytical methods: non-aqueous titration, i.r. spectroscopy and h.p.l.c. Practical aspects as well as precision, accuracy and assumptions necessary for effective application of each of the methods are discussed. H.p.l.c. is applicable to the widest variety of compound types, is the most rapid, most sensitive and shows the best promise for increased development and improvement. Application and development of these techniques is a logical step toward improving process monitoring, catalyst development, toxicological screening and general fuel analysis. 相似文献
2.
Necessary and sufficient conditions for the existence of a static state feedback that achieves noninteraction and internal
stability are obtained. This is accomplished by first characterizing the set of all controllability subspaces (distributions)
that can arise as solutions to the noninteracting control problem. This characterization is then used to identify a fixed
internal dynamics that is common to every noninteractive closed loop. The stability properties of this dynamics is shown to
be the key factor in the problem of achieving noninteracting control with internal stability. 相似文献
3.
Grizzle J.W. Di Benedetto M.D. Lamnabhi-Lagarrigue F. 《Automatic Control, IEEE Transactions on》1994,39(9):1782-1794
In the literature, it has been shown that if a single-input single-output analytic nonlinear plant 1) has a well-defined relative degree and 2) is minimum-phase, it is possible to achieve asymptotic tracking for an open set of output trajectories containing the origin in CN [0, ∞), the space of N-times continuously differentiable functions taking values in R. When either of these sufficient conditions is not met, various authors have investigated approximate analytic solutions, discontinuous solutions and solutions for restricted sets of trajectories. In this paper, it is shown that conditions 1) and 2) are necessary for the existence of an analytic compensator which yields asymptotic tracking for an open set of output trajectories. Analogous results are established for multi-input multi-output systems 相似文献
4.
Westervelt E.R. Grizzle J.W. Canudas de Wit C. 《Automatic Control, IEEE Transactions on》2003,48(2):308-312
A companion paper has addressed the problem of designing controllers that induce exponentially stable, periodic walking motions at a fixed walking rate for a planar, biped robot with one degree of underactuation. This note provides two additional control features: 1) the ability to compose such controllers to obtain walking at several discrete walking rates with guaranteed stability during the transitions; and 2) the ability to regulate the average walking rate to a continuum of values. 相似文献
5.
Jeffrey A. Cook Jing Sun Julia H. Buckland Ilya V. Kolmanovsky Huei Peng Jessy W. Grizzle 《Asian journal of control》2006,8(3):237-260
This paper surveys recent and historical publications on automotive powertrain control. Control‐oriented models of gasoline and diesel engines and their aftertreatment systems are reviewed, and challenging control problems for conventional engines, hybrid vehicles and fuel cell powertrains are discussed. Fundamentals are revisited and advancements are highlighted. A comprehensive list of references is provided. 相似文献
6.
A new set of integer invariants of a discrete time nonlinear system is introduced. Following the linear and continuous time nonlinear theory, this set is called the structure at infinity of the system. These integers contain structural information about the system. To support this idea the general block decoupling problem and a special case of the noninteracting control problem are solved in terms of the zeros at infinity.Partially supported by NSF contract ECS-8505318. 相似文献
7.
R Arribas G Capellà S Tórtola L Masramon WE Grizzle M Perucho MA Peinado 《Canadian Metallurgical Quarterly》1997,15(10):3230-3240
PURPOSE: Here we evaluate the prognostic significance of the relative value of genomic damage assessed by DNA fingerprinting in colorectal cancer. MATERIALS AND METHODS: Sixty-three tumor and paired normal mucosa samples were included in the study. Genomic damage was assessed by comparative analysis of paired normal and tumor tissue DNA fingerprints by the arbitrarily primed polymerase chain reaction (AP-PCR). Decreases and increases of intensity in bands were computed and referred to the total number of visualized bands per case. An index reflecting the genomic damage fraction (GDF), with separated values for losses and gains, was obtained for each tumor. This index was used to determine molecular and clinicopathologic correlates after exclusion of eight cases displaying microsatellite instability. RESULTS: Fifty-five cases were considered for the statistical analysis. The average fraction of altered bands per tumor was 0.287+/-0.121. When losses and gains were computed separately, the average fraction of changes was 0.126+/-0.113 and 0.161+/-0.120, respectively. Tumors lacking a ras mutation showed an increased GDF, primarily because of a higher fraction of gains. Tumors that were at advanced Dukes' stages and that were poorly differentiated also displayed a higher GDF. Finally, disease-free survival was significantly diminished in tumors with a GDF greater than 0.314 (P < .001). The prognostic significance of the GDF was independent of Dukes' stage (Cox multivariate analysis, P = .005). CONCLUSION: The degree of genomic damage assessed by unbiased DNA fingerprinting correlates with genotypic, phenotypic, and clinical variables in colorectal carcinoma and may be useful in assessing prognosis in colorectal cancer. 相似文献
8.
Hybrid zero dynamics of planar biped walkers 总被引:2,自引:0,他引:2
Westervelt E.R. Grizzle J.W. Koditschek D.E. 《Automatic Control, IEEE Transactions on》2003,48(1):42-56
Planar, underactuated, biped walkers form an important domain of applications for hybrid dynamical systems. This paper presents the design of exponentially stable walking controllers for general planar bipedal systems that have one degree-of-freedom greater than the number of available actuators. The within-step control action creates an attracting invariant set - a two-dimensional zero dynamics submanifold of the full hybrid model $whose restriction dynamics admits a scalar linear time-invariant return map. Exponentially stable periodic orbits of the zero dynamics correspond to exponentially stabilizable orbits of the full model. A convenient parameterization of the hybrid zero dynamics is imposed through the choice of a class of output functions. Parameter optimization is used to tune the hybrid zero dynamics in order to achieve closed-loop, exponentially stable walking with low energy consumption, while meeting natural kinematic and dynamic constraints. The general theory developed in the paper is illustrated on a five link walker, consisting of a torso and two legs with knees. 相似文献
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10.
Control of semiconductor manufacturing equipment: real-timefeedback control of a reactive ion etcher
Rashap B.A. Elta M.E. Etemad H. Fournier J.P. Freudenberg J.S. Giles M.D. Grizzle J.W. Kabamba P.T. Khargonekar P.P. Lafortune S. Moyne J.R. Teneketzis D. Terry F.L. Jr 《Semiconductor Manufacturing, IEEE Transactions on》1995,8(3):286-297
This paper describes the development of real-time control technology for the improvement of manufacturing characteristics of reactive ion etchers. A general control strategy is presented. The principal ideas are to sense key plasma parameters, develop a dynamic input-output model for the subsystem connecting the equipment inputs to the key plasma variables, and design and implement a multivariable control system to control these variables. Experimental results show that this approach to closed-loop control leads to a much more stable etch rate in the presence of a variety of disturbances as compared to current industrial practice 相似文献