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Characteristics-based model predictive control of selective catalytic reduction in diesel-powered vehicles

JOURNAL OF PROCESS CONTROL 2016年 47卷 98-110页

作者： Pakravesh, H. Aksikas, I. Votsmeier, M. Dubijevic, S. Hayes, R. E. Forbes, F. Univ Alberta Dept Chem & Mat Engn Edmonton AB T6G 2M7 Canada Qatar Univ Dept Math Stat & Phys Doha Qatar Umicore AG & Co KG Hanau Germany

In heavy-duty diesel exhaust systems, selective catalytic reduction (SCR) is used to reduce NOx to nitrogen to meet environmental regulations. Diesel exhaust after-treatment involves a set of components that are best characterized as distributed parameter systems. Thus, the optimal ammonia dosage in the SCR is an important and challenging problem in diesel exhaust treatment. In this work, we propose a method to synthesize an optimal controller for the SCR section of the diesel exhaust after-treatment system, which is based on a system model consisting of coupled hyperbolic and parabolic partial differential equations (PDEs). This results in a boundary control problem;where the control objectives are to reduce the amount of NOx emissions and ammonia slip to the fullest extent possible using the inlet concentration of ammonia as the manipulated variable and assuming that the concentrations of nitric oxide and nitrogen dioxide and ammonia, are measured at the SCR inlet and outlet. The proposed method combines the method of characteristics, spectral decomposition and the model predictive control (MPC) approach. For performance comparison purposes, the open-loop dynamic optimization problem is solved via Direct transcription (DT) to compute the upper performance limit for the optimal SCR problem. The results show that the proposed approach is able to achieve a very high level of control performance in terms of NO and ammonia slip reduction. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Selective catalytic reduction Model predictive control Method of characteristics Spectral decomposition Hyperbolic PDEs Parabolic PDEs distributed parameter system

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Nonlinear control of a reduced-order tubular reactor system

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JOURNAL OF THE CHINESE INSTITUTE OF CHEMICAL ENGINEERS 2002年第5期33卷 529-539页

作者： Wu, W Natl Yunlin Univ Sci & Technol Dept Chem Engn Touliu 640 Yunlin Taiwan

This article deals with the output regulation of distributed reacting systems with a single manipulated variable. Since the coil apparatus for heat removal can be conditionally adopted, the finite difference-based nonlinear model as a class of approximate control systems can be established. Through use of the non-distributed feedback linearization strategy and the successive Lyapunov function design, synthesis of the dynamic feedback controller can ensure asymptotic output regulation. From the practical viewpoint, an extended observer-based control scheme based on the similar Lyapunov-based lineairzation algorithm is developed. Simulations clearly demonstrate that the proposed control methodologies can achieve good tracking performance and are robust against the presence of measurement errors and model mismatch.

关键词： exothermic chemical reaction distributed parameter system Lyapunov-based linearization design observer-based controller synthesis

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ACTUATOR FAILURE-DETECTION IN THE CONTROL OF distributed systemS

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1986年第2期9卷 181-189页

作者： BARUH, H Rutgers University New Brunswick New Jersey

A method is presented for the detection of actuator failures in the control of distributed-parameter systems. The method can be used with any control scheme and is based on identifying the actuator input from the system response by modal analysis. The failure detection can be carried out as an on- or off-line operation. First, the modal excitations are identified. Estimates of the external forces are then synthesized as a linear combination of the modal forces. The identified external forces are compared with the actuator commands to detect the failure and isolate the faulty component(s). The effects of actuator failure on the performance of control systems are investigated, as well as factors that affect the reliability of the failure detection, such as measurement noise and observation spillover. A guideline is proposed to locate the actuators in such a way as to aid the failure detection process. (Author)

关键词： Actuators Control systems distributed parameter system Modal Analysis Mathematical Models Reliability Control Finite Element Method Artificial Intelligence Acceleration Sensors Flexible Structures

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Static and Dynamic Control of Smart Composite Laminates

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AIAA JOURNAL 2014年第9期52卷 1896-1914页

作者： Khandelwal, Ravi Prakash Chakrabarti, Anupam Bhargava, Pradeep Indian Inst Technol Dept Civil Engn Roorkee 247667 Uttar Pradesh India

An efficient C-0 continuous two-dimensional finite-element model has been presented in this paper for the control of laminated composite and sandwich plates embedded/surface-bonded with piezoelectric layers and subjected to mechanical loading as well as electric potential. The problem of modeling of smart laminates involves the coupling between mechanical and electrical fields. The structural component is modeled by an efficient equivalent single-layer plate theory, which ensures interlaminar shear-stress continuity and zero transverse shear-stress conditions at the top and bottom of the plate surfaces. Moreover, this theory contains unknowns defined at the reference plane (i.e., midplane) only. The electric field is modeled using layerwise theory, which contains the unknowns at each layer interfaces. The proposed combine model, which may be called a refined hybrid plate model, is implemented to analyze the coupled problem of piezoelectricity in laminated composites and sandwich plates.

关键词： Smart Composite Laminates Generalized Finite Element Method Transverse Shear Electric Potential Fiber Reinforced Composites Plate Theory distributed parameter system Material Properties Vibration Suppression Control Algorithm

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Vibration control of a flexible aerial refuelling hose with input saturation

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INTERNATIONAL JOURNAL OF systemS SCIENCE 2017年第5期48卷 971-983页

作者： Liu, Zhijie Liu, Jinkun He, Wei Beihang Univ Sch Automat Sci & Elect Engn Beijing Peoples R China Univ Sci & Technol Beijing Sch Automat & Elect Engn Beijing Peoples R China

In this study, we consider a boundary control problem of a flexible aerial refuelling hose in the presence of input saturation. To provide an accurate and concise representation of the hose's behaviour, the flexible hose is modelled as a distributed parameter system described by partial differential equations (PDEs). By using the backstepping method, a boundary control scheme is proposed based on the original PDEs to regulate the hose's vibration. An auxiliary system based on a smooth hyperbolic function and a Nussbaum function is designed to handle the effect of the input saturation. Then based on Lyapunov's directmethod, the state of the system is proven to converge to a small neighbourhood of zero by appropriately choosing design parameters. Finally, the results are illustrated using numerical simulations for control performance verification.

关键词： Flexible hose input saturation backstepping distributed parameter system vibration control

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Lyapunov control law for slew maneuver using time finite element analysis

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2001年第1期24卷 87-94页

作者： Suk, J Boo, S Kim, Y Korea Aerosp Ind Ltd Aerosp Res Ctr Changwon 641600 South Korea Seoul Natl Univ Inst Adv Machinery & Design Dept Aerosp Engn Seoul 151742 South Korea

The Lyapunov control law for the slew maneuver of flexible space structure is designed using a time-domain finite element analysis. Closed-loop dynamics of the hybrid system is analyzed, expanding the results of open-loop dynamics on the spatial propagation of the appendage. Lagrange multipliers are included to guarantee the rest-to-rest maneuver, and the resulting dynamics are solved in the optimization perspective. As a result, the motion of the rigid/flexible modes is governed by the feedback gains. An efficient parameter optimization method is suggested in combination with the time-domain finite element analysis. It serves a concurrent general optimization algorithm that is applicable to partial-state feedback systems. To optimize the gain set of the control system, an energy-based performance index is adopted, and the gradients of the performance index with respect to each gain are derived. several numerical results are shown to demonstrate the result of the integrated modeling-optimization scheme.

关键词： Finite Element Analysis distributed parameter system Space Structures Numerical Integration Optimization Algorithm Control systems Feedback Control system Piezoelectric Sensors Kinetic Energy Vibration Suppression

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SENSITIVITY ANALYSIS OF DISCRETE STRUCTURAL systemS

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AIAA JOURNAL 1986年第5期24卷 823-832页

作者： ADELMAN, HM HAFTKA, RT VIRGINIA POLYTECH INST & STATE UNIV DEPT AEROSP & OCEAN ENGNBLACKSBURGVA 24061

Sensitivity analysis is emerging as a fruitful area of engineering research. The reason for this interest is the recognition of the variety of uses for sensitivity derivatives. In its early stages, sensitivity analysis found its predominant use in assessing the effect of varying parameters in mathematical models of control systems. This article surveys methods for calculating sensitivity derivatives for discrete structural systems and primarily covers literature published during the past two decades. Methods are described for calculating derivatives of static displacements and stresses, eigenvalues and eigenvectors, transient structural response, and derivatives of optimum structural designs with respect to problem parameters.

关键词： Second Order Differential Equations Structural system Finite Element Modeling Numerical Integration Structural Response distributed parameter system Structural Optimization Finite Difference Approximation Structural Sensitivity Analysis Material Derivatives

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WEIGHT MINIMIZATION OF ORTHOTROPIC FLAT PANELS SUBJECTED TO A FLUTTER SPEED CONSTRAINT

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AIAA JOURNAL 1986年第6期24卷 991-997页

作者： LIBRESCU, L BEINER, L Tel-Aviv University Ramat-Aviv Israel

This paper deals with the minimum weight design of orthotropic panels subjected to a supersonic flutter speed constraint and to a system of uniform in-plane loadings. In approaching the problem, use is made of the methods of optimal control theory of distributed parameter systems. This leads to a set of necessary optimality conditions that, together with a supplementary condition ensuring that the flutter speed of the optimal panels coincides with the constrained one, constitute the governing optimality equations of the problem. An alternative form of the optimality equations is derived and a symmetry property of the optimal thickness distribution is placed in evidence. Numerical solutions are obtained via Galerkin’s procedure, providing rough estimates of the optimal panel design. The results also show the influence of some important parameters, such as orthotropy ratio, in-plane loading, aspect ratio, and support conditions. © 1986 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.

关键词： Aspect Ratio distributed parameter system Optimal Control Freestream Mach Number Poisson's Ratio Lagrange Multipliers Supersonic Flow Boundary Value Problems Orthotropic Material Aeroelastic system

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Adaptive Control of a Flexible String system With Input Hysteresis

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IEEE TRANSACTIONS ON CONTROL systemS TECHNOLOGY 2018年第2期26卷 693-700页

作者： He, Wei Meng, Tingting Univ Sci & Technol Beijing Sch Automat & Elect Engn Beijing 100083 Peoples R China Univ Elect Sci & Technol China Sch Automat Engn Chengdu 611731 Sichuan Peoples R China Univ Elect Sci & Technol China Ctr Robot Chengdu 611731 Sichuan Peoples R China

In this brief, a vibration suppression scheme is investigated for a flexible string system with input hysteresis. The input hysteresis is formulated as a linear desired input and a "disturbance-like" term, whose unknown bound is then estimated by an adaptive law. Without constructing a hysteresis inverse, adaptive boundary control is designed to suppress the vibrations of the flexible string, cope with the uncertainties of system parameters, and tackle the hysteresis nonlinearities. Based on the extended LaSalle's invariance principle, asymptotic stability of the closed-loop system is also manifested. Simulations are also provided to show the effectiveness of the designed control.

关键词： Adaptive control boundary control distributed parameter system flexible string input hysteresis vibration control

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SPLINE-BASED distributed system-IDENTIFICATION WITH APPLICATION TO LARGE SPACE ANTENNAS

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1986年第3期9卷 304-311页

作者： BANKS, HT LAMM, PK ARMSTRONG, ES SO METHODIST UNIV DEPT MATHDALLASTX 75275 NASA LANGLEY RES CTRDIV GUIDANCE & CONTROLSPACECRAFT CONTROL BRANCHHAMPTONVA 23665

A parameter and state estimation technique for distributed models is demonstrated through the solution of a problem generic to large space antenna system identification. Assuming the position of the reflective surface of the maypole (hoop/column) antenna to be approximated by the static two-dimensional, stretched-membrane partial differential equation with variable-stiffness coefficient functions, a spline-based approximation procedure is described that estimates the shape and stiffness functions from data set observations. For given stiffness functions, the Galerkin projection with linear spline-based functions is applied to project the distributed problem onto a finite-dimensional subspace wherein algebraic equations exist for determining a static shape (state) prediction. The stiffness functions are then parameterized by cubic splines and the parameters estimated by an output error technique. Numerical results are presented for data descriptive of a 100-m-diameter maypole antenna. (Author)

关键词： distributed parameter system Space Antenna Antennas Space Transportation system Trusses Material Properties Very Long Baseline Interferometry Vibration Suppression Deep Space Network Parallel Computers

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