Forward-backward Stochastic Differential Equations and Backward Linear Quadratic Stochastic Optimal Control Problem

In this paper, we use the solutions of forward-backward stochastic differential equations to get the optimal control for backward stochastic linear quadratic optimal control problem. And we also give the linear feedback regulator for the optimal control problem by using the solutions of a group of Riccati equations.

A MAXIMUM PRINCIPLE APPROACH TO STOCHASTIC H_2/H_∞ CONTROL WITH RANDOM JUMPS

A necessary maximum principle is given for nonzero-sum stochastic Oltterential games with random jumps. The result is applied to solve the H2/H∞ control problem of stochastic systems with random jumps. A necessary and sufficient condition for the existence of a unique solution to the H2/H∞ control problem is derived. The resulting solution is given by the solution of an uncontrolled forward backward stochastic differential equation with random jumps.

One Kind of Fully Coupled Linear Quadratic Stochastic Control Problem with Random Jumps

有随机的一个种有点线性的二次的随机的控制问题跳被学习。最佳的控制的明确的形式被获得。最佳的控制能被证明唯一。一个种概括 Riccati 方程系统被介绍，它的解决之可能性被讨论。为有随机的最佳的控制问题的线性反馈管理者跳被概括 Riccati 方程系统的解决方案给。

一类线性随机H_∞控制问题的Riccati矩阵微分方程

讨论了一类线性随机H_∞控制问题的解的存在性和相关的Riccati矩阵微分方程的迭代解法.建立了一个算法,利用李雅普诺夫线性矩阵微分方程的解,一致逼近Riccati矩阵微分方程的解.

STOCHASTIC DIFFERENTIAL EQUATIONS AND STOCHASTIC LINEAR QUADRATIC OPTIMAL CONTROL PROBLEM WITH LEVY PROCESSES

In this paper, tile authors first study two kinds of stochastic differential equations （SDEs） with Levy processes as noise source. Based on the existence and uniqueness of the solutions of these SDEs and multi-dimensional backward stochastic differential equations （BSDEs） driven by Levy pro- cesses, the authors proceed to study a stochastic linear quadratic （LQ） optimal control problem with a Levy process, where the cost weighting matrices of the state and control are allowed to be indefinite. One kind of new stochastic Riccati equation that involves equality and inequality constraints is derived from the idea of square completion and its solvability is proved to be sufficient for the well-posedness and the existence of optimal control which can be of either state feedback or open-loop form of the LQ problems. Moreover, the authors obtain the existence and uniqueness of the solution to the Riccati equation for some special cases. Finally, two examples are presented to illustrate these theoretical results.

离散Markov切换系统的随机Nash博弈及H_2/H_∞控制

讨论离散时间Markov切换系统的随机Nash微分博弈问题。通过把单人博弈推广到两人博弈的方法,分别得到了有限时域和无限时域下的离散时间Markov切换系统的随机Nash微分博弈问题的均衡解,证明了均衡解存在的充分必要条件等价于相应的差分(代数)Riccati方程存在解,并给出了最优解的显式形式。最后,将所得结果应用于分析离散时间线性Markov切换系统的随机混合H_2/H_∞鲁棒控制问题。

Linear Quadratic Leader-Follower Stochastic Differential Games:Closed-Loop Solvability

In this paper,a leader-follower stochastic differential game is studied for a linear stochastic differential equation with quadratic cost functionals.The coefficients in the state equation and the weighting matrices in the cost functionals are all deterministic.Closed-loop strategies are introduced,which require to be independent of initial states;and such a nature makes it very useful and convenient in applications.The follower first solves a stochastic linear quadratic optimal control problem,and his optimal closed-loop strategy is characterized by a Riccati equation,together with an adapted solution to a linear backward stochastic differential equation.Then the leader turns to solve a stochastic linear quadratic optimal control problem of a forward-backward stochastic differential equation,necessary conditions for the existence of the optimal closed-loop strategy for the leader is given by a Riccati equation.Some examples are also given.

具有状态依赖噪声的随机H_∞预演控制

为了改善一类系统的H∞控制性能,采用对策论与动态规划相结合的方法,研究具有依赖于状态的乘性噪声连续随机系统H∞预演控制问题,提出了解耦耦合的微分及偏微分方程组的思路,并利用特征线法求解,给出了该问题可解的条件和显式预演控制器,为解决随机时滞系统的控制问题提供新的思路.

求解源于连续H_∞预演控制的偏微分方程组(英文)

通过完全平方的方法研究连续系统的H∞预演控制问题,并以一组耦合的微分方程组(一个微分Riccati方程和两个偏微分方程)的解来刻画所设计的控制器。但是,求解这类方程组或者是给出其数值解都相当困难。这类方程还经常出现在其它时滞系统的控制及估计问题的解的刻画中,通过解耦的方法提供这类方程组的解析解,该方法还为探讨该方程组的数值解提供了思路,也能够求解时滞系统最优控制、H∞控制及估计问题。

带乘性噪声的随机控制系统鲁棒H_2/H_∞控制设计

本文主要研究了状态方程和输出方程均带有多个噪声源的无限时域离散随机控制系统的H_2/H_∞控制器的设计问题。首先给出一个随机有界实引理(SBRL);然后,利用随机有界实引理和系统的精确可观测性,给出了随机控制系统最优解的存在定理。该定理表明随机H_2/H_∞控制设计与四个耦合的广义代数Riccati方程的解的存在性有关。最后,给出了一个仿真实例来说明设计的效用。

Stochastic H_2/H_∞ Control with Random Coefcients

Abstract This paper is concerned with the mixed H2/H∞ control for stochastic systems with random coefficients, which is actually a control combining the H2 optimization with the H∞ robust performance as the name of H2/H∞ reveals. Based on the classical theory of linear-quadratic （LQ, for short） optimal control, the sufficient and necessary conditions for the existence and uniqueness of the solution to the indefinite backward stochastic Riccati equation （BSRE, for short） associated with H∞ robustness are derived. Then the sufficient and necessary conditions for the existence of the H2/H∞ control are given utilizing a pair of coupled stochastic Pdccati equations.

H_2/H_∞ CONTROL PROBLEMS OF BACKWARD STOCHASTIC SYSTEMS

This paper is concerned with the mixed H_2/H_∞ control problem for a new class of stochastic systems with exogenous disturbance signal.The most distinguishing feature,compared with the existing literatures,is that the systems are described by linear backward stochastic differential equations(BSDEs).The solution to this problem is obtained completely and explicitly by using an approach which is based primarily on the completion-of-squares technique.Two equivalent expressions for the H_2/H_∞ control are presented.Contrary to forward deterministic and stochastic cases,the solution to the backward stochastic H_2/H_∞ control is no longer feedback of the current state;rather,it is feedback of the entire history of the state.

一般周期时变系统线性二次型微分对策及H^∞控制问题

讨论了周期时变线性系统的一般线性二次型微分对策 ,即状态方程非齐次且二次型赢得或损失函数包含线性项的一般情况。给出了保性能对策问题和鞍点对策问题可解的充要条件和最优策略的解析构造以及对策值。然后应用对策问题的结果来处理周期时变线性系统的

广义随机系统的多人Nash微分博弈

研究了一类连续时间广义随机系统的多人Nash微分博弈问题.在定义了广义随机系统稳定性的相关概念后,通过一个线性矩阵不等式(linear matrix inequality,LMI)首先给出了系统稳定性的条件.然后,研究了有限时间和无限时间的广义随机系统的多人Nash微分博弈,利用Riccati方程法得到了均衡策略的存在条件等价于耦合的微分或代数Riccati方程存在解,并给出了均衡策略的显式表达及最优性能指标值.最后,将所得的结果应用于现代鲁棒控制中的随机H2/H∞控制问题,得到了鲁棒控制策略的存在条件及显式表达.

Mixed deterministic and random optimal control of linear stochastic systems with quadratic costs

In this paper,we consider the mixed optimal control of a linear stochastic system with a quadratic cost functional,with two controllers—one can choose only deterministic time functions,called the deterministic controller,while the other can choose adapted random processes,called the random controller.The optimal control is shown to exist under suitable assumptions.The optimal control is characterized via a system of fully coupled forward-backward stochastic differential equations(FBSDEs)of mean-field type.We solve the FBSDEs via solutions of two(but decoupled)Riccati equations,and give the respective optimal feedback law for both deterministic and random controllers,using solutions of both Riccati equations.The optimal state satisfies a linear stochastic differential equation(SDE)of mean-field type.Both the singular and infinite time-horizonal cases are also addressed.

Linear quadratic optimal control of conditional McKean-Vlasov equation with random coefficients and applications

We consider the optimal control problem for a linear conditional McKeanVlasov equation with quadratic cost functional.The coefficients of the system and the weighting matrices in the cost functional are allowed to be adapted processes with respect to the common noise filtration.Semi closed-loop strategies are introduced,and following the dynamic programming approach in(Pham and Wei,Dynamic programming for optimal control of stochastic McKean-Vlasov dynamics,2016),we solve the problem and characterize time-consistent optimal control by means of a system of decoupled backward stochastic Riccati differential equations.We present several financial applications with explicit solutions,and revisit,in particular,optimal tracking problems with price impact,and the conditional mean-variance portfolio selection in an incomplete market model.

Mean-field stochastic linear quadratic optimal control problems: closed-loop solvability

An optimal control problem is studied for a linear mean-field stochastic differential equation with a quadratic cost functional.The coefficients and the weighting matrices in the cost functional are all assumed to be deterministic.Closedloop strategies are introduced,which require to be independent of initial states;and such a nature makes it very useful and convenient in applications.In this paper,the existence of an optimal closed-loop strategy for the system(also called the closedloop solvability of the problem)is characterized by the existence of a regular solution to the coupled two(generalized)Riccati equations,together with some constraints on the adapted solution to a linear backward stochastic differential equation and a linear terminal value problem of an ordinary differential equation.

Characterization of optimal feedback for stochastic linear quadratic control problems

One of the fundamental issues in Control Theory is to design feedback controls.It is well-known that,the purpose of introducing Riccati equations in the study of deterministic linear quadratic control problems is exactly to construct the desired feedbacks.To date,the same problem in the stochastic setting is only partially well-understood.In this paper,we establish the equivalence between the existence of optimal feedback controls for the stochastic linear quadratic control problems with random coefficients and the solvability of the corresponding backward stochastic Riccati equations in a suitable sense.We also give a counterexample showing the nonexistence of feedback controls to a solvable stochastic linear quadratic control problem.This is a new phenomenon in the stochastic setting,significantly different from its deterministic counterpart.

随机广义耦合微分Riccati方程解的存在性

本文研究利用奇异值分解方法,获得了随机广义耦合微分Riccati方程解的存在性.另外,作为应用,我们将解的存在性结论应用到了,带马尔可夫跳的线性随机奇异系统最优控制问题,并得到有限时区上的最优控制问题中最优控制的显式表示形式.

离散奇异随机系统的N人Nash博弈

针对It?型离散奇异随机系统的N人线性二次Nash博弈问题,讨论了其在有限时域情形和无限时域情形下的Nash均衡策略.利用配方法,分别得到有限时域和无限时域内,离散奇异随机系统二次线性N人Nash均衡策略存在的条件是相应耦合Riccati差分(代数)方程组存在解.并给出了最优解的显式表达式及最优值函数.借鉴前人研究成果,将所得最优策略应用于随机H2/H∞混合鲁棒控制问题,得到了随机H2/H∞混合鲁棒控制策略.