基于非结构网格的分蓄洪区水沙演进数学模型研究

基于非结构三角形网格,采用有限体积算法,建立了分蓄洪区水沙演进数学模型.模型网格能很好适应分蓄洪区复杂的边界条件,应用了DEM数字模型插值技术,能快速获取计算域的地形数据,实现了洪水演进过程中泥沙输移和河床冲淤变形的同步模拟.模型中还对网格划分、数值离散、动边界及干河床处理等关键技术进行了研究,并提供了相应的处理方法....     

论排水管道的检测及评价方法

为规范给排水管道的检测手段及评定方法,总结并研究在天津及周边地区完成的众多管道非开挖修复工程,对排水管道的质量评定参数进行了研究,选取了CCTV电视检测作为最佳检测方法,进行分析、评价归纳出了缺陷类型,建立了管道状况评估模型,包括结构性和功能性缺陷状况的评估。同时对CCTV检测的技术规程进行了探讨,为管道的养管和经济分析提供可靠依据。     

A nonsmooth IMC method for mechanical systems with backlash

This paper proposes a discrete-time nonsmooth internal model control （NSIMC） approach for mechanical transmission systems described by so-called sandwich system with backlash. In this method, a dynamic compensator is introduced to compensate for the effect of the input linear subsystem. Thus, the sandwich systems with backlash can be simplified as a pseudo-Hammerstein system with backlash. The corresponding NSIMC strategy is designed to control this system. The design procedure of the controller is presented based on the analysis on the robust stability by considering the model errors involved with the effect of backlash as well as the compensated error of the input linear subsystem. Moreover, as the model is switched among the different operating zones, the robust filters are proposed to guarantee the robust stability and satisfactory control performance of the system.     

Controllability results for damped second-order impulsive neutral integrodifferential systems with nonlocal conditions

In this paper, we establish a set of sufficient conditions for the controllability of damped second-order impulsive neutral integrodifferential systems with nonlocal initial conditions in Banach spaces. The approach used is the Sadovskii fixed point theorem combined with a noncompact condition on the cosine family of operators. An example is presented to illustrate the result.     

基于非质点模型的纯方位解距离方法

目标距离是战场进行作战决策和武器使用时考虑的一个重要参数.在传统的二维被动跟踪系统基础上,将目标建模为椭圆刚体.论文借鉴修正极坐标(MPC)的思想,利用刚体目标的尺寸参数,建立目标的状态模型和测量模型.采用无迹卡尔曼滤波(UKF)算法进行解距离,为工程实现提供了可能性,并从不同的初始条件下分析了距离误差.Monte-Carlo仿真表明:在新的状态模型下利用UKF算法进行解距离,可以达到较高的精度.其中传感器与目标的相对速度和刚体目标的尺寸对距离解的精度影响较大.     

用栈结构实现二叉树的非递归中序遍历算法

二叉树作为数据结构中的一个重要的部分,有着广泛的应用,其中二叉树的遍历是二叉树操作的根本。文中通过分析二叉树的中序遍历过程,结合栈的先进后出特点,归纳出二叉树的中序遍历非递归算法。     

Development of wheel-less snake robot with two distinct gaits and gait transition capability

Snake robots are mostly designed based on single mode locomotion. However, single mode gait most likely could not work effectively when the robot is subject to an unstructured working environment with different measures of terrain complexity. As a solution, mixed mode locomotion is proposed in this paper by synchronizing two types of gaits known as serpentine and wriggler gaits used for non-constricted and narrow space environments, respectively, but for straight line locomotion only. A gait transition algorithm is developed to efficiently change the gait from one to another. This study includes the investigation on kinematics analysis followed by dynamics analysis while considering related structural constraints for both gaits. The approach utilizes the speed of the serpentine gait for open area locomotion and exploits the narrow space access capability of the wriggler gait. Hence, it can increase motion flexibility in view of the fact that the robot is able to change its mode of locomotion according to the working environment.     

电液伺服试验机系统非周期信号控制策略研究

电液伺服动态试验是一类复杂非线性控制系统,同时材料实验过程中的周围环境,对材料试验的结果造成很大的影响。在材料试验机的检测领域,一项重要的工作就是车辆道路谱的非周期信号进行响应和跟随,经过实验研究表明,普通的PID控制,不能有效的满足实验要求,本文首先对电液伺服试验机进行数学模型的建立,并对数学模型进行简化分析,应用自适应反向控制方法,实现了电液伺服动态实验机的非周期信号的实时控制,实现了系统的实时性、可控性及鲁棒性。     

多闸坝分汊河流的洪水实时模拟和调度

采用一维非恒定水流数学模型耦合闸坝水力学模型,构建了可用于多闸坝分汊河流中场次洪水实时模拟和调度的模型。该模型分别对河流分汊、多闸坝泄水和断流进行处理,增强了模型的实时性和稳定性。基于该模型对北运河杨洼闸以上河道进行洪水模拟和调度,验证结果表明模拟结果令人满意。根据不同重现期场次洪水演进结果提出的调度方案为北运河重要闸坝的调度决策提供了技术支持。