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MANUFACTURER'S UNIFORM PRICING AND CHANNEL CHOICE WITH A RETAIL PRICE MARKUP COMMITMENT STRATEGY

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Journal of Systems Science and Systems Engineering 2014年第1期23卷 111-126页

作者： Huihui liu Ming Lei xiangdong liu Guanghua School of Management Peking University China Center for International Economic Exchanges

The paper studies channel choice decisions in a multi-channel supply chain under a strategy where there is an ex-ante commitment made on the retail price markup. The market demand is uncertain and dependent on the price and sales efforts. The results show that in any channel structure, when making order decisions the retailer only examines the price ratio and the fluctuation size of random demand, rather than the channel cost and the retailer＇s marketing efficiency. When the retail price rises, the manufacturer is willing to increase inventory quantity for direct sales, because the manufacturer＇s profit margin is higher in direct channel. The increase in demand fluctuation only affects the degree of channel preference but doesn＇t change the manufacturer＇s channel choice. No matter in which level the price ratio is, when the sales efficiency of retail channel is not high or the demand proportion of direct channel is low, the manufacturer and the retailer will be both apt to choose a dual-channel structure. Then adding a direct channel becomes a marketing strategy, rather than a competitor of the retail channel, and helps the supply chain win more market demand.

关键词： Uniform pricing marketing/sales effort channel choice newsvendor model dual channelsupply chain

Study on periodic orbits around the dipole segment model for dumbbell-shaped asteroids

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Science China(Technological Sciences) 2018年第6期61卷 819-829页

作者： ZHANG YongLong ZENG XiangYuan liu xiangdong School of Automation Beijing Institute of Technology Beijing 100081 China

Equilibrium points and periodic orbits in irregular gravitational fields are significant for an understanding of dynamical behaviors around asteroids as well as deep space exploring missions. The dipole segment is a good alternative model to study qualitative dynamical properties near dumbbell-shaped asteroids. In this paper, the dipole segment model and its equilibrium points are simply introduced. The stability of the two triangular equilibrium points of the system is numerically examined. Next, periodic orbits are presented around the dipole segment model in two different cases, in which triangular equilibria are linearly stable and unstable,respectively. New types of periodic orbits are illustrated in detail, including their orbital shapes, periods and the Jacobi *** orbital stability, topological classification and bifurcations of these orbits are also analyzed with numerical continuations.

关键词： dipole segment model equilibrium points periodic orbits topological classification

Disturbance observer based time-varying sliding mode control for uncertain mechanical system

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Journal of Systems Engineering and Electronics 2012年第1期23卷 108-118页

作者： Binglong Cong xiangdong liu Zhen Chen School of Automation Beijing Institute of Technology Beijing 100081 P. R. China Key Laboratory for Intelligent Control ＆ Decision on Complex Systems Beijing Institute of Technology Beijing 100081 P. R. China

It is now well known that the time-varying sliding mode control （TVSMC） is characterized by its global robustness against matched model uncertainties and disturbances. The accurate tracking problem of the mechanical system in the presence of the parametric uncertainty and external disturbance is addressed in the TVSMC framework. Firstly, an exponential TVSMC algorithm is designed and the main features are analyzed. Especially, the control parameter is obtained by solving an optimal problem. Subsequently, the global chattering problem in TVSMC is considered. To reduce the static error resulting from the continuous TVSMC algorithm, a disturbance observer based time-varying sliding mode control （DOTVSMC） algorithm is presented. The detailed design principle and the stability of the closed-loop system under the composite controller are provided. Simulation results verify the effectiveness of the proposed algorithm.

关键词： mechanical system time-varying sliding mode control (TVSMC) global sliding phase global chattering disturbance observer.

Trajectory reshaping based guidance with impact time and angle constraints

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Chinese Journal of Aeronautics 2016年第4期29卷 984-994页

作者： Zhao Yao Sheng Yongzhi liu xiangdong School of Automation Beijing Institute of Technology Key Laboratory for Intelligent Control and Decision of Complex Systems Beijing Institute of Technology

This study presents a novel impact time and angle constrained guidance law for homing missiles. The guidance law is first developed with the prior-assumption of a stationary target, which is followed by the practical extension to a maneuvering target scenario. To derive the closed-form guidance law, the trajectory reshaping technique is utilized and it results in defining a specific polynomial function with two unknown coefficients. These coefficients are determined to satisfy the impact time and angle constraints as well as the zero miss distance. Furthermore, the proposed guidance law has three additional guidance gains as design parameters which make it possible to adjust the guided trajectory according to the operational conditions and missile's capability. Numerical simulations are presented to validate the effectiveness of the proposed guidance law. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

关键词： Guidance Homing missiles Impact angle Impact time Trajectory reshaping

Stochastic maximum principle for partially observed forward-backward stochastic differential equations with jumps and regime switching

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Science China(Information Sciences) 2018年第7期61卷 106-118页

作者： Shuaiqi ZHANG Jie XIONG xiangdong liu School of Economics and Commerce Guangdong University of Technology Department of Mathematics University of Macau Department of Mathematics Southern University of Science and Technology Department of Statistics Jinan University

In this article, we consider the partially observed optimal control problem for forward-backward stochastic systems with Markovian regime switching. A stochastic maximum principle for optimal control is developed using a variational method and filtering technique. Our theoretical results are applied to the motivating example of the risk minimization for portfolio selection.

关键词： partial information Markovian regime-switching stochastic maximum principle forwardbackward stochastic differential equation(FBSDE)

Finite-time sliding mode attitude control for a reentry vehicle with blended aerodynamic surfaces and a reaction control system

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Chinese Journal of Aeronautics 2014年第4期27卷 964-976页

作者： Geng Jie Sheng Yongzhi liu xiangdong Key Laboratory for Intelligent Control&Decision of Complex Systems Beijing Institute of Technology School of Automation Beijing Institute of Technology

This paper proposes a finite-time robust flight controller, targeting for a reentry vehicle with blended aerodynamic surfaces and a reaction control system（RCS）. Firstly, a novel finite-time attitude controller is pointed out with the introduction of a nonsingular finite-time sliding mode manifold. The attitude tracking errors are mathematically proved to converge to zero within finite time which can be estimated. In order to improve the performance, a second-order finite-time sliding mode controller is further developed to effectively alleviate chattering without any deterioration of robustness and accuracy. Moreover, an optimization control allocation algorithm, using linear programming and a pulse-width pulse-frequency（PWPF） modulator, is designed to allocate torque commands for all the aerodynamic surface deflections and on–off switching-states of RCS *** are provided for the reentry vehicle considering uncertain parameters and external disturbances for practical purposes, and the results demonstrate the effectiveness and robustness of the attitude control system.

关键词： Chattering alleviation Control allocation Finite-time convergence Flight control systems Second-order sliding mode Singularity elimination Sliding mode control

Attitude coordination for spacecraft formation with multiple communication delays

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Chinese Journal of Aeronautics 2015年第2期28卷 527-534页

作者： Guo Yaohua Lu Pingli liu xiangdong School of Automation Beijing Institute of Technology

Communication delays are inherently present in information exchange between space- craft and have an effect on the control performance of spacecraft formation. In this work, attitude coordination control of spacecraft formation is addressed, which is in the presence of multiple communication delays between spacecraft. Virtual system-based approach is utilized in case that a constant reference attitude is available to only a part of the spacecraft. The feedback from the virtual systems to the spacecraft formation is introduced to maintain the formation. Using backstepping control method, input torque of each spacecraft is designed such that the attitude of each spacecraft converges asymptotically to the states of its corresponding virtual system. Furthermore, the back- stepping technique and the Lyapunov-Krasovskii method contribute to the control law design when the reference attitude is time-varying and can be obtained by each spacecraft. Finally, effectiveness of the proposed methodology is illustrated by the numerical simulations of a spacecraft formation.

关键词： Attitude coordination Backstepping Delay control systems Formation Lyapunov-Krasovskii

High-order sliding mode attitude controller design for reentry flight

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Journal of Systems Engineering and Electronics 2014年第5期25卷 848-858页

作者： Liang Wang Yongzhi Sheng xiangdong liu School of Automation Beijing Institute of Technology Key Laboratory for Intelligent Control & Decision of Complex Systems Beijing Institute of Technology

A novel high-order sliding mode control strategy is proposed for the attitude control problem of reentry vehicles in the presence of parametric uncertainties and external disturbances, which results in the robust and accurate tracking of the aerodynamic angle commands with the finite time convergence. The proposed control strategy is developed on the basis of integral sliding mode philosophy, which combines conventional sliding mode control and a linear quadratic regulator over a finite time interval with a free-final-state and allows the finite-time establishment of a high-order sliding mode. Firstly, a second-order sliding mode attitude controller is designed in the proposed high-order siding mode control framework. Then, to address the control chattering problem, a virtual control is introduced in the control design and hence a third-order sliding mode attitude controller is developed, leading to the chattering reduction as well as the control accuracy improvement. Finally, simulation examples are given to illustrate the effectiveness of the theoretical results.

关键词： reentry vehicle attitude control high-order sliding mode control integral sliding mode.

Sliding mode control based guidance law with impact angle constraint

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Chinese Journal of Aeronautics 2014年第1期27卷 145-152页

作者： Zhao Yao Sheng Yongzhi liu xiangdong School of Automation Beijing Institute of Technology Key Laboratory for Intelligent Control & Decision of Complex Systems Beijing Institute of Technology

The terminal guidance problem for an unpowered lifting reentry vehicle against a sta- tionary target is considered. In addition to attacking the target with high accuracy, the vehicle is also expected to achieve a desired impact angle. In this paper, a sliding mode control （SMC）-based guidance law is developed to satisfy the terminal angle constraint. Firstly, a specific sliding mode function is designed, and the terminal requirements can be achieved by enforcing both the sliding mode function and its derivative to zero at the end of the flight. Then, a backstepping approach is used to ensure the finite-time reaching phase of the sliding mode and the analytic expression of the control effort can be obtained. The trajectories generated by this method only depend on the initial and terminal conditions of the terminal phase and the instantaneous states of the vehicle. In order to test the performance of the proposed guidance law in practical application, numerical simulations are carried out by taking all the aerodynamic parameters into consideration. The effec- tiveness of the proposed guidance law is verified by the simulation results in various scenarios.

关键词： Backstepping Impact angle Sliding mode control Terminal guidance Unpowered lifting reentryvehicle