利用Voronoi图解决城市绿化问题

Voronoi图是一种平面分割图,它的剖分结果能够很好地表达点与点之间的邻近关系以及点的影响范围等重要的空间信息.而线段加权Voronoi图是对普通Voronoi图在生成元以及权重两方面加以推广而产生的.本文给出了如何用离散的方法来生成线段加权Voronoi图.针对城市中绿化带选址规划这一城市绿化规划工作中的重要环节,提出了一种基于线段加权Voronoi图的规划方法,更合理地进行绿化场所选址问题.     

应用一级邻近点生成加权Voronoi图的思想

加权Voronoi图是普通Voronoi图的一种扩展形式,在Voronoi图中各Voronoi边是在2个互为一级邻近点的点之间形成的,基于该理论,给出了一种生成加权Voronoi图的思想:用Delaunay三角网先找出各点的一级邻近点,再按加权Voronoi图的性质计算出各点的Voronoi边的数据,最后根据数据画出加权Voronoi图.     

二维Voronoi图删除任意生成点算法研究

针对Voronoi图与Delaunay三角网具有的对偶特性,提出一种二维Voronoi图任意点删除网络更新算法.利用具有拓扑关系的双向链表三角网搜索影响多边形区域,以凸耳消元法为工具重新剖分影响域多边形,通过连接剖分后的三角网中相邻Delaunay三角形外接圆圆心,实现二维Voronoi图的重构.与其它方法相比,该方法具有操作简单、容易理解、计算效率高的优点.     

基于语义信息的虚拟环境路径规划

为了降低虚拟环境下路径规划的计算复杂度,体现路径的合理性与增强算法的适应性,提出一种基于语义信息的层次型路径规划算法。针对目前虚拟人与环境地图建模时只考虑基本的几何信息,提出加入语义信息的建模方法;并在路径搜索算法中加入语义约束,使规划出的路径更符合人体的行为习惯;最后从路径长度、计算时间与扩展结点数三个指标验证算法的有效性,实验结果表明随场景规模的增大算法的计算时间呈线性增长态势。     

基于网络加权Voronoi图的点群选取

传统基于Voronoi图的算法忽略了点与点之间是通过实际网络距离相连这一事实,针对此缺陷,提出一种基于网络加权Voronoi图的点群选取算法. 1）利用网络扩展法构建点群的网络加权Voronoi图;2）计算每个点对应的网络Voronoi多边形面积及扩展弧段总长度,并以此为依据,为点群中所包含的统计、专题、拓扑和度量信息分别选定量化描述因子;3）提出“同心圆”算法,解决点群取舍问题. 实验结果表明,提出的方法顾及了点群权重以及与点群相关联的道路等级、方向及局部密度对选取结果的影响,较好地保持了原始点群的各类信息,选取结果符合实际地理空间特征.     

基于吸引关系的停车场网络连接方法

为研究停车场网络拓扑结构,提出了基于吸引关系的停车场网络连接方法.通过改进现有停车需求预测模型,充分考虑停车利用率、停车周转率、城市中心指数等因素影响,建立了新的停车场需求算法.通过绘制常规Voronoi图,利用断裂点理论的关键性质和常规Voronoi图的物理参数,划分各停车场的影响范围.引入吸引度概念,并对吸引度计算公式中的参数进行了修改和标定.计算停车场网络中每个节点的吸引度和节点间连线的边权,确定了停车场之间的连接情况.对哈尔滨市部分停车场进行吸引关系下的停车场网络模型构建.采用复杂网络参数分析方法对停车场网络进行分析,分别分析了规模赋值计算方法下和进一步通过吸引关系计算下的停车场宏观及微观节点参数.结果表明吸引关系下,停车场网络度分布符合幂律分布,无标度网络特征明显.与全局耦合网络和单边耦合网络对比,吸引关系下停车场网络具有较高聚类系数和全局有效性和较小的平均路径长度,在现有参数评价体系中表现均衡,是一种实用的停车场连接方式.     

既定水池供水区划的Voronoi模型及其算法

山区供水规划常利用山头高地布设水池,针对这种既定水池位置的供水范围区划问题,提出一种基于Voronoi图的空间区域划分模型及算法.以贵州省纳雍县供水工程管网布置为研究对象,首先根据该工程地形确定水池位置,并将水池移入相对坐标中.然后采用Matlab编程语言得到供水区划的Voronoi模型,构建用水点到水池的最短取水路径.最后根据点定位的分层方法,用O(n2)的时间和空间复杂度作预处理,花费O(logn)时间便可定位任意用水点所属的Voronoi区域,实现任意用水点的优化查询.结果表明,将Voronoi模型应用到既定水池供水区划中,能实现既定水池供水范围优化划分,且能达到成本效益管理要求.     

基于改进粒子群算法的无人机路径规划研究

将复杂网络理论应用于粒子群算法改进,提出了一种改进粒子群算法,通过自适应惯性系数方法自动调节惯性系数,增强算法的收敛性能.仿照Voronoi图理论,用可行路径网络结构图表示已知威胁分布情况,采用Dijkstra算法粗略搜索威胁分布图,求得粗略最短路径.在粗略最短路径的基础上,通过改进粒子群算法和最小二乘法拟合求解最优路径.用MATLAB进行了仿真验证,仿真结果表明了算法的有效性和无人机路径规划的合理性.     

变电站定位及供电区域划分的计算几何方法

综合考虑电网规划的经济技术要求和Voronoi图的几何特性，提出了基于V图实现的新增变电站的定位及供电区域划分的计算几何方法；利用V图的影响范围特性、最大空心圆特性和局部动态特性，可以保证变电站住于负荷中心，实现新增变电站的自动优化选址和各变电站供电区域的最佳划分，该计算方法为解决变电站的优化规划问题提供了新的研究思路，算例结果表明，该计算几何方法具有一定的有效性和合理性。     

加权Voronoi图重心在公共设施选址中应用的研究

城市公共设施选址既要充分体现该设施的利用价值,又要减少和避免由于各设施的重复覆盖而造成的资源浪费.为此首先对普通Voronoi图和加权Voronoi图进行了介绍,然后利用层次分析法解决了拥有综合多因素影响的加权Voronoi图的权值确定问题.一般一个平面图形的重心通常被认为是该区域的平衡位置.所以对于每个公共设施的影响区域进行基于综合因素的加权Voronoi区域划分后只要确定出这个区域的重心位置即可确定该公共设施的最佳选址位置.     

Formation control and collision avoidance for multi-UAV systems based on Voronoi partition

This paper deals with the formation control problem of multiple unmanned aerial vehicles(UAVs) with collision avoidance. A distributed formation control and collision avoidance method is proposed based on Voronoi partition and conventional artificial potential field. The collision avoidance is achieved by partitioning the whole space into non-overlapping regions based on Voronoi partition theory, which is taken as the task region to confine the movement of each UAV. The general motion control law is designed based on the conventional artificial potential field. As this often leads to local optimum when two UAVs are going to collide with each other and they may stay still where the repulsive force is adversely equivalent to the attractive force. To address this problem,the destination switch scheme is further proposed to let UAVs switch destinations when they reach the local equilibrium. Finally,the effectiveness of proposed formation control algorithm is validated by simulations and experiments.     

Path planning of the robot assembly based on Voronoi diagram

Based on the concepts of Voronoi diagram that describes geometry information of the robot assembly in C space, the position vector path parameter equation of the assembly movement between the step shaft and two-sided bearing bracket was given. And the path planning strategy of the component initiative assembly was put forward as well. Theoretical analysis proves that using the Voronoi diagram to do the geometry reasoning on the assembly space can evaluate the feasibility of the component assembly, and can present the reference position vector path of the component movement from the initial configuration to the objective configuration, therefore improves the flexibility of the robot initiative assembly.     

Dynamic Path Following Control of a Ground Ackerman Steering Robot to Avoid a Collision

A novel method is proposed to dynamically control the path following of a ground Ackerman steering robot to avoid a collision. The method consists of collision prediction module, collision avoidance module and global path following module. The elliptic repulsive potential field method (ER-PFM) and the enhanced vector polar histogram method (VPH +) based on the Ackerman steering model are proposed to predict the collision in a dynamic environment. The collision avoidance is realized by the proposed cost function and speed control law. The global path following process is achieved by pure pursuit. Experiments show that the robot can fulfill the dynamic path following task safely and efficiently using the proposed method.     

闭式叶轮铣削加工干涉自修正轨迹规划算法

针对目前绝大部分商用CAD/CAM软件在刀具轨迹规划过程中只能检测干涉碰撞的发生、而无法自动生成无干涉碰撞刀具轨迹的问题,提出了一种干涉碰撞自修正算法.该算法提取避让几何体边界,利用配置空间理论把提取的避让几何体边界映射到二维配置空间中,将三维空间中的干涉碰撞问题转化到二维空间中,并利用空间分区二叉树、多边形偏置等算法,解决了自动修正干涉碰撞处刀具姿态的问题.应用该算法生成了闭式叶轮流道的刀具轨迹,从刀具轨迹规划的效果上看,提出的算法确实避免了闭式叶轮刀具轨迹规划过程中干涉碰撞的发生.     

一种基于voronoi图的WMSNs监测路径算法

针对无线多媒体传感器网络在最差覆盖情况下的路径监测能力,通过Voronoi图与图形搜索算法的结合来实现监测路径的搜索。深入探讨了目标在传感器临界密度下最小覆盖路径的择选情况,从而找到网络的薄弱环节,并针对薄弱环节提出网络覆盖增强策略。算法无须复杂计算,容易实现,仿真实验结果验证了算法的可行性和适用性。     

Path planning and stability control of collision avoidance system based on active front steering

Vehicle collision avoidance system is a kind of auxiliary driving system based on vehicle active safety,which can assist the driver to take the initiative to avoid obstacles under certain conditions,so as to effectively improve the driving safety of vehicle.This paper presents a collision avoidance system for an autonomous vehicle based on an active front steering,which mainly consists of a path planner and a robust tracking controller.A path planner is designed based on polynomial parameterization optimized by simulated annealing algorithm,which plans an evasive trajectory to bypass the obstacle and avoid crashes.The dynamic models of the AFS system,vehicle as well as the driver model are established,and based on these,a robust tracking controller is proposed,which controls the system to resist external disturbances and work in accordance with the planning trajectory.The proposed collision avoidance system is testified through CarSim and Simulink combined simulation platform.The simulation results show that it can effectively track the planning trajectory,and improve the steering stability and anti-interference performance of the vehicle.     

Collision avoidance planning in multi-robot system based on improved artificial potential field and rules

For real-time and distributed features of multi-robot system,the strategy of combining the improved artificial potential field method and the rules based on priority is proposed to study the collision avoidance planning in multi-robot systems. The improved artificial potential field based on simulated annealing algorithm satisfactorily overcomes the drawbacks of traditional artificial potential field method,so that robots can find a local collision-free path in the complex environment. According to the movement vector trail of robots,collisions between robots can be detected,thereby the collision avoidance rules can be obtained. Coordination between robots by the priority based rules improves the real-time property of multi-robot system. The combination of these two methods can help a robot to find a collision-free path from a starting point to the goal quickly in an environment with many obstacles. The feasibility of the proposed method is validated in the VC-based simulated environment.     

利用三生成子——顶点对实现VORONOI图

Voronoi图是计算几何的一个重要分支，实现方法很多，大多数算法理论效率高，但数据量和占有内存都比较大，数据结构描述不易实现，给出的算法结构清晰，算法简单,Voronoi图数据结构容易描述，易地实现，最后，用Visual C 编码实现。