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Optimizing of selective catalytic reduction urea injection and NOx conversion analysis of diesel engine based on higher-order physical model and sequential quadratic programming algorithm

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ENERGY 2024年 313卷

作者： Liu, Wenlong Gao, Ying You, Yuelin Jiang, Changwen Hua, Taoyi Xia, Bocong Jilin Univ State Key Lab Automot Simulat & Control Changchun 130025 Peoples R China Jilin Univ Coll Automot Engn Changchun 130025 Jilin Peoples R China

In order to maximize the NOx conversion rate and minimize NH3 slip in the diesel selective catalytic reduction (SCR) system, first, the high-order SCR model was simplified and solved using the trapezoidal method and second-order backward difference formula, while the chemical reaction parameters were optimized using the Gauss-Newton method. The results of the engine bench test show that the mean absolute errors of NH3 and NOx concentrations under steady-state operating conditions were 2.67 ppm and 1.72 ppm, respectively, and 5.46 ppm and 42.50 ppm under severe operating conditions. Second, urea injection rate is optimized based on a high-order model combined with the sequential quadratic programming (SQP) algorithm. The change in NOx conversion rate at different temperatures and space velocities is analyzed, and the results show that the NOx conversion is best at 650 K and 29,000 h-1. Third, the experiment validation show that the optimal NH3/NOx ratio is 0.69 at 554 K and 54,200 h-1;0.8;and 1.37 at 746 K and 116,700 h-1. Finally, this paper simulates and analyzes the SCR emission characteristics at different temperatures and space velocities when the upstream NOx concentration is 1000 ppm.

关键词： Diesel engine Selective catalytic reduction NOx conversion rate sequential quadratic programming algorithm Upstream NH 3 /NOx

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Bezier curve-based trajectory planning for autonomous vehicles with collision avoidance

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IET INTELLIGENT TRANSPORT SYSTEMS 2020年第13期14卷 1882-1891页

作者： Zheng, Ling Zeng, Pengyun Yang, Wei Li, Yinong Zhan, Zhenfei Chongqing Univ Coll Automot Engn State Key Lab Mech Transmiss Chongqing 400044 Peoples R China Macro Net Commun Co Ltd Chongqing 400044 Peoples R China

This study proposes an effective trajectory planning algorithm based on the quartic Bezier curve and dangerous potential field for automatic vehicles. To generate collision-free trajectories, potential field functions are introduced to evaluate the collision risk of path candidates. However, many studies on artificial potential field approaches primarily focus on static and straight roads, and attach less importance to more complex driving scenarios, such as curving roads. In this study, a novel method based on the Frenet coordinate system is proposed to address such limitations. Moreover, to balance the driving comfortability and the driving safety of the path candidate, the path-planning problem is converted to an optimisation problem, and sequential quadratic programming algorithm is employed to tackle this task. Another merit of this algorithm is the curvature of the generated path is continuous even at the joints of adjacent sub-trajectories by utilising several specific properties of the Bezier curve. Furthermore, to execute the generated trajectory, a framework of velocity generation is proposed while vehicle dynamic constraints are considered. Some typical traffic scenarios, including lane-changing, lane-keeping, and collision avoidance have been designed to verify the performance of the proposed algorithm, and simulations demonstrate the validity of this method.

关键词： trajectory control road vehicles road safety collision avoidance vehicle dynamics quadratic programming mobile robots path planning road traffic path candidate path-planning problem optimisation problem sequential quadratic programming algorithm generated path adjacent sub-trajectories generated trajectory velocity generation vehicle dynamic constraints typical traffic scenarios collision avoidance Bezier curve-based trajectory autonomous vehicles effective trajectory quartic Bezier curve dangerous potential field automatic vehicles collision-free trajectories potential field functions collision risk artificial potential field static roads straight roads complex driving scenarios curving roads Frenet coordinate system driving comfortability driving safety

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Design and analysis of a graded honeycomb shock absorber for a helicopter seat during a crash condition

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INTERNATIONAL JOURNAL OF CRASHWORTHINESS 2016年第3期21卷 231-241页

作者： Galehdari, S. A. Khodarahmi, H. Islamic Azad Univ Najafabad Branch Dept Mech Engn Fac Engn Najafabad Isfahan Iran Imam Hossein Univ Dept Mech Engn Tehran Iran

An important issue that should be considered in accidents, including car, helicopter, and airplane crashes, is the safety of the human occupants. In this research, graded honeycomb structure is primarily introduced as a shock absorber. The amount of energy absorption, and the applied force and acceleration to the passengers have been calculated through numerical simulation in ABAQUS software. In order to validate numerical results, a low velocity experiment has been conducted on the test sample. Results represent an acceptable agreement with empirical ones. Given the occurrence of an emergency helicopter crash, it is of great importance to avoid any potential injurious loading to the passenger. Hence, according to Joint Aviation Regulations part 27, an optimised seat shock absorber has been designed and analysed for a helicopter in crash condition by the means of Genetic and sequential quadratic programming algorithms. The designed shock absorber, which is of graded honeycomb structure, has satisfied complete standard specifications while being applied in the helicopter crash simulation. The applied design and simulation approach could be extended for any other types of shock absorbers.

关键词： Graded honeycomb structure (GHS) shock absorber banana peel low velocity experimental test helicopter crash passenger genetic algorithm sequential quadratic programming algorithm

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A novel interval linear programming based on probabilistic dominance

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FUZZY SETS AND SYSTEMS 2022年 434卷 20-47页

作者： Qiu, Zhiping Xia, Haijun Beihang Univ Sch Aeronaut Sci & Engn Inst Solid Mech Beijing 100083 Peoples R China

This study investigates a novel interval linear programming based on probabilistic dominance. Firstly, the definition of interval linear programming is briefly reviewed. Then a new interval linear programming model is presented based on probabilistic domi-nance. The probabilistic dominance index treats the intervals as uniformly distributed variables and the interval inequality relation is further defined by probability. To deal with non-linearity in probabilistic dominance index, sequential quadratic programming is used to solve the problem and the performance measure approach is proposed to overcome the convergence difficulties. The deter-mination and sensitivity analysis of the target performance measure are discussed to assess the sequential quadratic programming algorithm. Meanwhile, the extension of the proposed method to fuzzy interval linear programming is discussed. Furthermore, the proposed method is applied to the design of the plane truss structure with interval parameters. Finally, the effectiveness and ratio-nality of the developed method are demonstrated by two mathematical examples and one interval parametric plane truss structure optimization example.(c) 2021 Elsevier B.V. All rights reserved.

关键词： Interval linear programming Probabilistic dominance sequential quadratic programming algorithm Performance measure approach Interval parametric plane truss structure optimization

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Solving quadratic convex bilevel programming problems using a smoothing method

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APPLIED MATHEMATICS AND COMPUTATION 2011年第15期217卷 6680-6690页

作者： Etoa, Jean Bosco Etoa Univ Yaounde II Dept Management & Econ Sci Yaounde Cameroon

In this paper, we present a smoothing sequential quadratic programming to compute a solution of a quadratic convex bilevel programming problem. We use the Karush-Kuhn-Tucker optimality conditions of the lower level problem to obtain a nonsmooth optimization problem known to be a mathematical program with equilibrium constraints;the complementary conditions of the lower level problem are then appended to the upper level objective function with a classical penalty. These complementarity conditions are not relaxed from the constraints and they are reformulated as a system of smooth equations by mean of semismooth equations using Fisher-Burmeister functional. Then, using a quadratic sequential programming method, we solve a series of smooth, regular problems that progressively approximate the nonsmooth problem. Some preliminary computational results are reported, showing that our approach is efficient. (C) 2011 Elsevier Inc. All rights reserved.

关键词： sequential quadratic programming algorithm Convex bilevel problem Complementary constraints Inducible solution Semismooth equations Smoothing method

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Fatigue strength optimisation of friction stir welded A6005-T5 alloy sheets

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SCIENCE AND TECHNOLOGY OF WELDING AND JOINING 2010年第6期15卷 473-478页

作者： Jung, S. P. Park, T. W. Kim, Y. G. Ajou Univ Div Mech Engn Suwon 443749 Gyeonggi Do South Korea Ajou Univ Grad Sch Mech Engn Suwon 443749 Gyeonggi Do South Korea Korea Railrd Res Inst Uiwang City 437757 Kyonggi Do South Korea

In this study, the friction stir welding process is optimised to improve the fatigue strength of the joints of A6005-T5 alloy sheets. The welding speed, rotational speed and tilting angle of the tool tip are chosen as design variables. Fifteen friction stir welding experiments are performed according to the central composite design table. The regression model function is estimated using the response surface analysis method. Using the model function, sensitivity analysis is carried out and the effect of each design variable on the fatigue strength of the joint is discussed. The optimum values of design variables are determined using the sequential quadratic programming algorithm.

关键词： Friction stir welding Central composite design table Regression model function Response surface analysis sequential quadratic programming algorithm

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A Nonlinear Dynamic Optimization algorithm of a Novel Energy Efficient Pneumatic Drive System

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INTERNATIONAL JOURNAL OF CONTROL AUTOMATION AND SYSTEMS 2022年第5期20卷 1593-1604页

作者： Du, Hongwang Xiong, Wei Liu, Wei Dalian Maritime Univ Ship Electromech Equipment Inst Dalian 116026 Peoples R China

A standard pneumatic system is usually controlled by a 5/2 directional control valve in which compressed-air utilization rate is low. To solve the problem, scholars have proposed a bridge pneumatic circuit controlled by four switch valves that uses expansion energy of compressed air to do work. The key to this bridge circuit lies in the accuracy and speed of on-off sequence of the valves. To realize this goal, we study dynamic optimization control of the circuit and establish an optimal valve opening and closing time-sequence control model with a continuous-discrete time differential algebraic equation on the base of the dynamic characteristics of the pneumatic drive system. We use the direct method in modern optimal control theory to solve the problem. Because the model has the characteristics of more equality constraints, lower freedom of variables, and a sparse structure, we use the simplified space sequential quadratic programming algorithm and interior-point methods for computation and analysis so that the process optimization and partial-differential equations are solved simultaneously. To improve the precision and the speed of solving the derivative during the solution-optimization process, the derivative information is obtained with a combination of symbol and numerical automatic differentiation. By analyzing the efficiency of the two algorithms, the interior-point method was proved to be more suitable for use in obtaining the sequence. Finally, the experimental results were realized and showed that our contribution builds a good foundation for the energy-saving research of pneumatic systems.

关键词： Dynamic optimization interior-point method pneumatic bridge pneumatic circuit sequential quadratic programming algorithm

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An approach to construct the relationship between the nonlinear normal mode and forced response of nonlinear systems

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JOURNAL OF VIBRATION AND CONTROL 2016年第14期22卷 3169-3181页

作者： Liao, Haitao Chinese Aeronaut Estab Beijing 100012 Peoples R China

An approach for correlating the given forced response with the nonlinear normal mode utilizing the modal assurance criterion is explored. The problem is transformed into a nonlinear optimization problem with nonlinear constraints. The modal assurance criterion of the Fourier coefficient vectors which indicates the degree of correlation between the nonlinear normal mode and forced response is set as the objective function whereas the nonlinear constraints are built utilizing the harmonic balance method and the Floquet theory. With the aim to make the modal assurance criterion approach to 1, the unknown optimization variables including the Fourier coefficients and the nonlinear frequency are iteratively sought using the sequential quadratic programming algorithm to fit the given periodic solution. Finally, the validity of the proposed method is demonstrated via two numerical case studies. It is illustrated that the proposed approach can be used to construct the relationship between the nonlinear normal mode and forced response. In addition, numerical examples also confirm that resonance forced responses are in the neighborhood of nonlinear normal modes.

关键词： Nonlinear normal mode forced response modal assurance criterion harmonic balance method sequential quadratic programming algorithm

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Optimal utilisation of PMU measurements in power system hybrid state estimators

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IET GENERATION TRANSMISSION & DISTRIBUTION 2019年第21期13卷 4978-4986页

作者： Dubey, Anamika Chakrabarti, Saikat Sharma, Ankush Terzija, Vladimir Indian Inst Technol Kanpur Dept Elect Engn Kanpur Uttar Pradesh India Univ Manchester Sch Elect & Elect Engn Manchester M13 9PL Lancs England

A state estimator provides power system states by minimising the difference between the available measurement set and expected measurements. This minimisation problem is solved using the weighted least squares method or conventional optimisation methods. Most of the optimisation-based conventional methods used for power system state estimation are based on derivative approaches. These traditional methods suffer from problems such as the complication in handling inequality constraints, slow convergence etc. Non-linear constrained optimisation problems can be efficiently solved by the sequential quadratic programming (SQP) algorithm. SQP can be applied to small as well as large-scale non-linear programming problems having a large number of constraints. In the proposed algorithm, hybrid measurement configuration, consisting of measurements from phasor measurement units as well as conventional measurement devices, is used and applied on IEEE 14 bus, IEEE 118 bus test system and Indian northern region power grid-246 bus system.

关键词： quadratic programming state estimation linear programming phasor measurement power system measurement power grids power system state estimation optimisation IEEE standards power system stability optimal utilisation PMU measurements power system hybrid state estimators state estimator power system states available measurement minimisation problem weighted least squares method conventional optimisation methods optimisation-based conventional methods power system state estimation inequality constraints nonlinear constrained optimisation problems sequential quadratic programming algorithm SQP large-scale nonlinear programming problems hybrid measurement configuration phasor measurement units conventional measurement devices IEEE 118 bus test system Indian northern region power grid-246 bus system

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Optimal Design of Friction Stir Welding Process to Improve Tensile Force of the Joint of A6005 Extrusion

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MATERIALS AND MANUFACTURING PROCESSES 2010年第7期25卷 637-643页

作者： Kim, Weon-kyong Goo, Byeong-choon Won, Si-tae Korea Railrd Res Inst Uiwang City 437757 Kyonggi Do South Korea Seoul Natl Univ Technol Dept Die & Mould Engn Seoul South Korea

An aluminum alloy is widely used in various fields of industries such as aerospace, shipbuilding, automotive, and railway vehicles, and gas metal Arc Welding (GMAW) technique has been applied to make the aluminum products. Recently, friction stir welding (FSW) method was developed and known to have many benefits compared to the classical GMAW technique. In this study, three important welding parameters of FSW process including the rotating speed, welding speed, and tilting angle are optimized to increase the tensile force of the joints of friction stir welded A6005 alloy. The objective function is estimated according to the response surface analysis method, and the optimum values of the design parameters are determined by using sequential quadratic programming (SQP) algorithm. The optimization results are verified by comparing the tensile force of FSW specimens before and after optimization.

关键词： Aluminum alloy Friction stir welding Gas metal arc welding Response surface analysis sequential quadratic programming algorithm

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