复杂机动动作最优航迹控制模型及操纵特性分析

为了提高驾驶员对机动动作的控制能力,从驾驶员操纵角度避免机动动作过程中的风险,提出以控制量变化率作为优化参数的机动动作最优航迹控制模型.将机动动作划分为彼此相连的轨迹片段,轨迹片段划分合理,则每个轨迹片段具有相同的控制量变化率,控制量变化率不但能够给出机动动作控制量的输入,更重要的是能够反映机动动作过程中驾驶员操纵的快慢程度.使用小生境稳态遗传算法(niching steady-state genetic algorithm,niching SSGA)对最优航迹控制模型进行求解,求解结果为机动动作最优控制量变化率序列,以该序列对应的控制量作为机动动作的输入,能够实现一个标准的机动动作.仿真实验部分以典型纵向机动动作斤斗及横侧向机动动作桶滚为例进行分析,研究了两类动作的最优控制量变化率序列,并对两类动作的操纵特性进行了分析.     

一种空间飞行器的多目标机动策略模型

为了满足航天器对多目标轨道飞行机动方式和机动策略的要求,在轨道动力学基础上,时机动性能进行分析和解算,对可行的机动轨道进行了评估,提出了针对特定空间区域的轨道机动策略集,提出用控制域作为空间机动平台的导航、制导参考模型.仿真结果表明,该方法简单有效,模型的参考意义强.     

基于高斯过程的多机动扩展目标跟踪

针对杂波环境下多机动扩展目标跟踪问题, 提出一种基于高斯过程的变结构多模型联合概率数据关联方法.首先, 采用期望模型扩展方法构建自适应模型集, 并对各个扩展目标状态进行初始化.其次, 基于高斯过程建立联合跟踪门以选择有效量测, 形成联合关联矩阵.然后, 拆分联合关联矩阵得到可行关联矩阵并求解关联事件概率.最后, 利用联合概率数据关联滤波器更新各个扩展目标的状态和协方差, 并将更新的状态进行融合, 得到最终的状态估计.仿真验证了所提方法的有效性.     

基于超平行空间集员滤波的非线性系统状态估计方法

针对噪声有界但未知条件下的非线性系统状态估计问题,提出基于超平行空间集员滤波算法.利用Stirling矩阵将模型进行一阶展开,基于凸差规划完成线性化误差定界,采用超平行空间表示误差边界和状态可行集,求解下一时刻预测状态可行集超平行体.在更新步将观测值分解为多个带,融入观测值的线性化误差并将带依次与超平行体相交,得到该时刻超平行空间描述下的状态可行集更新情况.所提出算法能够避免在求解线性化误差过程中外包误差集合带来的体积扩充,降低非线性集员滤波算法的保守性,仿真示例验证了所提出算法的可行性和有效性.     

车辆跟随控制策略的状态可达集建模及验证方法

车辆动态行为的不确定性会造成跟随车辆控制的不确定性.传统的车辆跟随控制方法只是针对车辆的单一行为动态的不确定性进行建模,无法遍历车辆所有可能的控制输入,因而,既无法一次性提供跟随策略下完整的可行控制方案,也不足以在理论上保证对策略安全检测的可信性.为此,提出车辆跟随控制策略的状态可达集建模及验证方法.该方法将控制策略转换为能用可达集计算和表征的多级安全判定事件,利用随机可达集的状态遍历特征描述车辆控制输入的不确定性,通过对可达集交集的判断,辨识所有初始条件对应的危险与安全控制行为,为驾驶员提供完整的可选择控制方案;然后利用马尔科夫链逼近可达集,近似表达车辆行为的不确定性,依据驾驶员行为习惯统计验证策略的安全性,实现对控制策略的有效建模分析.实验结果表明,所提出的建模及验证方法不仅可以完备地表征车辆不确定行为,提供交通情形中跟随策略相应的完整控制方案,也可实现对策略安全性的精确验证.     

机动多目标跟踪中的传感器控制策略的研究

针对机动多目标跟踪中的传感器控制问题, 本文提出一种基于信息论的多模型多伯努利滤波器的控制方案. 首先, 基于随机有限集(Random finite set, RFS)方法给出信息论下的传感器控制的一般方法; 其次, 本文给出多模型势均衡多目标多伯努利滤波器的序贯蒙特卡罗实现形式. 此外, 提出一种目标导向的多伯努利概率密度的粒子采样方法, 并借助该方法近似多目标概率密度, 继而利用Bhattacharyya 距离求解最终的控制方案. 典型机动多目标跟踪问题的仿真应用验证了本文传感器控制方法的有效性.     

煤矿掘进多行为协同控制智能决策模型

智能决策支持的掘进多行为协同控制是煤矿掘进工作面智能化的核心之一,掘进多行为协同控制的最优时序规划是智能决策的关键。针对煤矿掘进多行为控制模式单一、固化、协同作业能力差等问题,设计了一种煤矿掘进多行为协同控制智能决策模型,实现了掘进多行为在最优时序下的协同作业。首先,提出了掘进多行为协同控制智能决策方法,确定了掘进多行为可行时序规划集和多目标最优时序规划策略;其次,根据掘进现场的规定和工艺要求,确定了掘进动作事件集,通过对事件集中两两动作事件之间时间关系的分析,求出掘进多行为时间关系约束矩阵;然后,根据时间点关系约束矩阵转换方法,将掘进多行为时间关系约束矩阵转换为时间点关系约束矩阵,再求出掘进多行为可行时序规划集;最后,定义不同掘进目标下的求解函数,求得不同掘进目标的最优时序。实验结果表明,在不同掘进目标下,按照模型决策出的掘进动作最优时序规划结果,掘进机器人可无干涉协同作业,且掘进作业1个工作循环的执行时间与决策模型计算的时间基本一致。     

具有自适应噪声边界的Tube可达集鲁棒预测控制

针对过程噪声设定边界与真实噪声边界失配的有界干扰离散线性不确定系统,提出一种具有自适应噪声边界的Tube可达集鲁棒模型预测控制方法.首先,该算法引入基于MIT规则的自适应集员滤波在线估计系统状态和噪声边界.其次,基于估计值,通过迭代自适应集员滤波的时间更新部分计算出预测时域内闭环不确定系统状态的可达集.最后,用可达集代替不变集并根据Tube鲁棒模型预测控制策略,给出了实际不确定系统的控制律,确保系统状态鲁棒渐近稳定,并收敛于终端干扰不变集.仿真结果验证了该控制方法的有效性.     

时序动作单元感知的开集动作识别

开集动作识别任务要求模型不仅能准确识别训练集中的类别，还能拒绝训练集上未出现的未知类动作.目前，大多数方法都将动作视为一个整体，忽略动作本身可被分解为更细粒度的动作单元.为此，文中提出时序动作单元感知的开集动作识别方法.首先，设计动作单元关系模块，学习细粒度的动作单元特征，得到动作和动作单元的关系模式，并通过已知类动作和未知类动作在动作单元上不同的激活程度识别未知类动作.然后，设计动作单元时序模块，建模动作单元的时序信息，研究动作单元的时序性，进一步区分因为外观相似而被混淆的已知类动作和未知类动作.最后，综合考虑关系模式与动作单元时序信息，使模型具备区分已知类动作和未知类动作的能力.在3个动作识别数据集上的实验表明，文中方法性能较优.     

自动挖掘机的动作规划

针对施工现场有设计目标的挖掘任务,提出自动挖掘机动作规划方法,并同时保证挖掘效率及挖掘任务的精度.首先提供了一种有效的机械几何空间约束的分析方法,继而分析了熟练驾驶员的挖掘动作,并基于以上分析描述了一种有效的自动挖掘机挖掘动作的轨迹规划方法,且对挖掘过程的一系列动作进行规划,最终完成了沟断面挖掘动作的连续动作规划.设计通过实验得到验证,结果为自动挖掘动作的效率可以和熟练驾驶员的动作媲美,且挖掘精度满足设计要求.     

带有运行成本函数的Hamilton-Jacobi可达性分析

水平集方法将可达集表示为Hamilton-Jacobi方程解的零水平集,保存多个不同时间范围的可达集则需要保存Hamilton-Jacobi方程在多个时刻的解,这不仅需要消耗大量的存储空间还为控制律的设计造成了困难.针对这些局限性,提出了一种改进的基于Hamilton-Jacobi方程的可达集表示方法.该方法在Hamilton-Jacobi方程中加入了一项运行成本函数,可以用同一个时刻的解的多个非零水平集表示多个不同时间范围的可达集,极大地节省了存储空间并为控制律的设计提供了便利.为了求解所构造的带有运行成本函数的Hamilton-Jacobi方程,采用了一种基于递归和插值的方法.最后,通过一些数值算例验证了所提出的方法的精确性、在存储空间方面的优越性以及设计的控制律的有效性.     

A proximal characterization of the reachable set

We show that the graph of the reachable set of a control system given by a differential inclusion is uniquely characterized by a Hamilton-Jacobi equation involving proximal normals.     

Overapproximating Reachable Sets by Hamilton-Jacobi Projections

In earlier work, we showed that the set of states which can reach a target set of a continuous dynamic game is the zero sublevel set of the viscosity solution of a time dependent Hamilton-Jacobi-Isaacs (HJI) partial differential equation (PDE). We have developed a numerical tool—based on the level set methods of Osher and Sethian—for computing these sets, and we can accurately calculate them for a range of continuous and hybrid systems in which control inputs are pitted against disturbance inputs. The cost of our algorithm, like that of all convergent numerical schemes, increases exponentially with the dimension of the state space. In this paper, we devise and implement a method that projects the true reachable set of a high dimensional system into a collection of lower dimensional subspaces where computation is less expensive. We formulate a method to evolve the lower dimensional reachable sets such that they are each an overapproximation of the full reachable set, and thus their intersection will also be an overapproximation of the reachable set. The method uses a lower dimensional HJI PDE for each projection with a set of disturbance inputs augmented with the unmodeled dimensions of that projection's subspace. We illustrate our method on two examples in three dimensions using two dimensional projections, and we discuss issues related to the selection of appropriate projection subspaces.     

Autonomous Maneuver Decisions via Transfer Learning Pigeon-Inspired Optimization for UCAVs in Dogfight Engagements

This paper proposes an autonomous maneuver decision method using transfer learning pigeon-inspired optimization (TLPIO) for unmanned combat aerial vehicles (UCAVs) in dogfight engagements. Firstly, a nonlinear F-16 aircraft model and automatic control system are constructed by a MATLAB/Simulink platform. Secondly, a 3-degrees-of-freedom (3-DOF) aircraft model is used as a maneuvering command generator, and the expanded elemental maneuver library is designed, so that the aircraft state reachable set can be obtained. Then, the game matrix is composed with the air combat situation evaluation function calculated according to the angle and range threats. Finally, a key point is that the objective function to be optimized is designed using the game mixed strategy, and the optimal mixed strategy is obtained by TLPIO. Significantly, the proposed TLPIO does not initialize the population randomly, but adopts the transfer learning method based on Kullback-Leibler (KL) divergence to initialize the population, which improves the search accuracy of the optimization algorithm. Besides, the convergence and time complexity of TLPIO are discussed. Comparison analysis with other classical optimization algorithms highlights the advantage of TLPIO. In the simulation of air combat, three initial scenarios are set, namely, opposite, offensive and defensive conditions. The effectiveness performance of the proposed autonomous maneuver decision method is verified by simulation results.      

Properties of the reachable set of control systems

We investigate some properties of the reachable set of a control system. Representing the system as a differential inclusion and using proximal Hamilton–Jacobi equation we describe its graph. We work in infinitely dimensional Hilbert space and use one sided Lipschitz approach. The funnel equation is considered in the last section. That equation describes the reachable set in arbitrary Banach space. We consider also the autonomous case and prove the existence of a limit of the reachable set.     

A time-dependent Hamilton-Jacobi formulation of reachable sets for continuous dynamic games

We describe and implement an algorithm for computing the set of reachable states of a continuous dynamic game. The algorithm is based on a proof that the reachable set is the zero sublevel set of the viscosity solution of a particular time-dependent Hamilton-Jacobi-Isaacs partial differential equation. While alternative techniques for computing the reachable set have been proposed, the differential game formulation allows treatment of nonlinear systems with inputs and uncertain parameters. Because the time-dependent equation's solution is continuous and defined throughout the state space, methods from the level set literature can be used to generate more accurate approximations than are possible for formulations with potentially discontinuous solutions. A numerical implementation of our formulation is described and has been released on the web. Its correctness is verified through a two vehicle, three dimensional collision avoidance example for which an analytic solution is available.     

Simultaneous optimization of the material properties and the topology of functionally graded structures

A level set based method is proposed for the simultaneous optimization of the material properties and the topology of functionally graded structures. The objective of the present study is to determine the optimal material properties (via the material volume fractions) and the structural topology to maximize the performance of the structure in a given application. In the proposed method, the volume fraction and the structural boundary are considered as the design variables, with the former being discretized as a scalar field and the latter being implicitly represented by the level set method. To perform simultaneous optimization, the two design variables are integrated into a common objective functional. Sensitivity analysis is conducted to obtain the descent directions. The optimization process is then expressed as the solution to a coupled Hamilton-Jacobi equation and diffusion partial differential equation. Numerical results are provided for the problem of mean compliance optimization in two dimensions.     

基于三支决策的飞机空战机动决策方法

为了提高战斗机在信息不充足条件下的机动决策能力,提出一种基于三支决策的飞机空战机动决策方法.首先,使用三支决策意图识别模型对目标意图进行识别;其次,将目标的作战意图因素引入到威胁评估中后,结合目标的威胁程度,提出基于三支决策的机动决策权重因子动态调整法;最后,使用模糊逻辑构建机动决策因子评价函数,并利用权值动态调整策略...     

On reachability and minimum cost optimal control

Questions of reachability for continuous and hybrid systems can be formulated as optimal control or game theory problems, whose solution can be characterized using variants of the Hamilton-Jacobi-Bellman or Isaacs partial differential equations. The formal link between the solution to the partial differential equation and the reachability problem is usually established in the framework of viscosity solutions. This paper establishes such a link between reachability, viability and invariance problems and viscosity solutions of a special form of the Hamilton-Jacobi equation. This equation is developed to address optimal control problems where the cost function is the minimum of a function of the state over a specified horizon. The main advantage of the proposed approach is that the properties of the value function (uniform continuity) and the form of the partial differential equation (standard Hamilton-Jacobi form, continuity of the Hamiltonian and simple boundary conditions) make the numerical solution of the problem much simpler than other approaches proposed in the literature. This fact is demonstrated by applying our approach to a reachability problem that arises in flight control and using numerical tools to compute the solution.     

基于水平集方法的软组织图像序列分割

医学图像分割是医学图像处理中的关键问题之一.图像序列的分割操作是医学图像三维重建的必要准备,而软组织图像分割则是医学图像分割中的一大难点.基于曲线演化理论的,借助偏微分方程等数学工具的水平集方法已经被广泛应用于医学图像分割领域.介绍了水平集方法的数学模型,并设计了一种基于窄带水平集方法的,专门针对软组织图像分割的算法.用边界追踪等方法提取第一层图片中的软组织相关轮廓;将它们作为初始水平集曲线,再利用窄带水平集方法进行演化;经过两个阶段的迭代处理,最终自动分割出整个软组织图像序列.实验表明该算法具有较高效率、分割结果精确,所产生的分割结果可以作为三维重建的合适的数据集.