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1.
张纪元  牛志纲 《机器人》1999,21(4):256-259
对于含螺旋副(H)的空间连杆机构或机器人机构,无 法用有理化法将其分析与综合方程组化成多项式方程组,因而不能用精确同伦法求解这些 机构的多解问题.本文提出近似同伦法并用该法首次解决了空间7H连杆机构的装配构形问题 .本文方法适用于求解任何含H副的空间连杆机构或机器人机构的多解问题.  相似文献   

2.
用近似同伦法确定空间7H连杆机构的装配构形   总被引:1,自引:0,他引:1  
对于含螺旋副(H)的空间连杆机构或机器人机构,无法用有理化法将其分析与综合方程组化成多项式方程组,因而不能用精确同伦法求解这些机构的多解问题.本文提出近似同伦法并用该法首次解决了空间7H连杆机构的装配构形问题.本文方法适用于求解任何含H副的空间连杆机构或机器人机构的多解问题.  相似文献   

3.
平面四连杆机构近似位姿综合的计算机模拟逼近法   总被引:4,自引:4,他引:4  
平面连杆机构尺寸综合的两个基本工具是几何法和解析法,它们仅适用于规定较少的机构精确位姿数的综合。几何法简单直观,但求解精度低且重复性差;解析法求解精度高且重复性好,但求解复杂、不直观。针对两种方法的缺点,提出一种机构尺寸驱动综合方法,即连杆机构近似位姿综合的计算机模拟逼近法。首先在多个复合精确和近似位姿情况下,用CAD的几何约束和尺寸驱动技术,构造一个基本四连杆模拟机构;再根据函数、轨迹和运动综合的原则,由基本四连杆模拟机构分别构造出函数、轨迹和运动的近似位姿综合模拟机构。计算机模拟结果表明,这种方法不仅具有简捷直观、求解精度高和重复性好的优点,而且可以增加机构综合的规定位置个数,为机构的尺寸综合提供更有效的工具。  相似文献   

4.
平面连杆机构分析与仿真专家系统   总被引:3,自引:1,他引:2  
任意平面连杆机构,在拓扑组成上,可表示为无向图,本文研究了从机构无向图出发建立机械运动生成链和分离可独立求解杆件组,建立规则库自动按照约束性质生成约束方程式和采遥用变异几何方法数值求解机构运动,本文介绍了一个按上述原理实现的任意连杆机构分析仿真专家系统。  相似文献   

5.
用连杆机构几何约束求解   总被引:1,自引:0,他引:1  
高小山  朱长才 《软件学报》2000,11(9):1151-1158
在这篇文章里,我们引入连杆机构作为新的工具,且证明这是完备的,也就是说,所有能构造性描述的图形能被连杆机构作出,这一类包括了所有只含距离约束的约束问题.作为一个应用,我们说明了超出Owen和Hoffmann的三角分解方法之外的最简单的约束图能被转化为纯几何构造形式.为了求解起源于连杆构造的方程,我们提出了一种基于动态轨迹生成的几何方法.  相似文献   

6.
基于免疫计算的机构轨迹综合   总被引:4,自引:1,他引:4  
机构轨迹综合问题本质上可以归结成为一个模式匹配问题.据此给出了机构轨迹综合的模式匹配模型,深入讨论了其实现步骤中涉及到的若干关键技术,如机构轨迹的数字化描述、轨迹曲线的聚类与分类、轨迹模式匹配等.综合运用AINE无监督学习模型、AIRS有监督学习模型和文中给出的阴性选择算法改进模型,提出了基于免疫计算的机构轨迹综合方法.最后,通过一个四杆机构轨迹综合的应用实例证明该方法可以有效地求解机构轨迹综合问题.  相似文献   

7.
针对当前对象族模型在求解拓扑约束时存在的缺陷,提出一种求解拓扑约束的新方法,这种方法在求解拓扑约束时,把拓扑约束映射为布尔约束满足问题,通过用SAT求解器求解布尔约束来求解拓扑约束。实践证明,该方法不仅直接关联与拓扑约束指定的特征的语义,而且当模型中存在大量相交的特征时也是可行的,提高了拓扑约束求解的效率。  相似文献   

8.
提出一种基于GA和SQP求解机械臂最优运动规划问题的混合算法.首先采用B样条函数逼近关节运动轨迹,将最优控制问题转化为有约束的非线性规划问题,然后引入基于种群的GA算法,给出全局最优解的初始估计;最后利用序列二次规划(SQP)得到高精度全局最优解.仿真结果表明该方法优于单纯的GA或SQP方法。  相似文献   

9.
三维几何约束的球面几何求解   总被引:3,自引:1,他引:3  
研究了球面几何学在三维几何约束求解中的应用,提出了球面求解法.该方法建立在姿态约束与位置约束解耦的基础上,并以求解关键的姿态约束为主,一旦姿态约束被解出,则位置约束很容易求解;同时将表征刚体姿态的矢量映射到球平面上的点,将姿态约束映射为球平面上两点的距离,借助球面几何的知识,能够高效、直观地推理出多数情况下姿态约束的解析解,而特殊的情况则结合数值法求解,并很好地解决了数值法的初值问题.  相似文献   

10.
非二元约束满足问题求解   总被引:12,自引:1,他引:12  
孙吉贵  景沈艳 《计算机学报》2003,26(12):1746-1752
在约束满足问题(CSP)的研究中,大部分工作集中在二元约束,但处理实际问题时,常常会遇到非二元约束的情况.该文在概要地讨论了两类求解非二元约束问题方法的基础上,研究了一种将约束传播技术和一般弧相容回溯算法相结合的非二元约束求解方法,并在设计开发的约束求解工具“明月SOLVER1.0”中实现了该方法,以典型例子给出了实现系统的运行结果.  相似文献   

11.
A basic idea of geometric constraint solving (GCS) is to decompose the constraint problem into smaller ones according to some basic configurations. In this paper, we find all spatial basic configurations involving points, lines, and planes containing up to six geometric primitives in an automated way. Many of these basic configurations still resist effective analytical solutions. We propose the locus intersection method (LIM) for GCS, a hybrid method based on geometric computation and numerical search that can be used to find all the solutions for a geometric constraint problem. We show that the LIM can be used to solve all the above basic configurations.  相似文献   

12.
以基本几何约束组合统一表达装配约束,为提高求解效率,研究了姿态约束和位置约束的可解耦情况下位置约束的解析求解.将基本位置约束映射为移动空间并以参数方程表达,通过移动空间的增量解析求交,满足约束;在姿态约束和位置约束的不可解耦情况,联立基本约束进行整体数值法求解.文中方法保持了基本约束表达的独立性,适合于欠约束系统和完整约束系统.  相似文献   

13.
针对数字工业摄影测量中的人工标志点的快速自动匹配问题,根据从物方空间角度描述核线的原理,提出了一种基于空间前方交会的匹配算法。该算法首先通过计算投影线间的最短距离来确定一组初始匹配像点;然后通过双片空间前方交会来确定一组潜在的物方点,并将其按距离分组;最后,将每一个潜在的物方点的坐标残差过大及属于同一张像片的像点剔除,同时通过判断与各物方点对应的像点数来确定同名像点。两组实验均证明,该算法不仅计算速度快,而且具有高匹配率和低误匹配率,能为数字工业摄影测量自检校光束法平差提供高精度的初值。  相似文献   

14.
在支持车路通信的城市车载网络中,路边单元的部署方案影响着整个车载网络的性能,而传统的部署方案采用无线自组织网络中的布点方式,未充分考虑道路网络的拓扑结构和车辆移动的规律性,导致部署成本高和资源浪费.因此,本文提出了一种基于路口优先级和部署均匀性的路边单元部署机制,称为PUD(intersection Priority and deployment Uniformity based roadside unit Deployment scheme),保证其服务能力的同时降低部署成本.PUD以交叉路口作为路边单元的候选部署点,综合车辆移动特性和路网拓扑,以车流密度、连接中心性和公共交通线路数作为主要因素,计算每个交叉路口处部署路边单元的优先级,作为部署位置选择的标准.为了提高部署均匀性,避免路边单元的覆盖范围重叠导致的资源浪费,设置了四条部署约束规则,即位置约束、范围约束、优先级约束和覆盖约束,满足条件的交叉路口可被选择为部署位置.实验表明,与其他路边单元部署方案相比,PUD具有更低的部署成本、更高的覆盖率和车辆覆盖时间比例.  相似文献   

15.
We explore the use of interior point methods in finding feasible solutions to mixed integer programming. As integer solutions are typically in the interior, we use the analytic center cutting plane method to search for integer feasible points within the interior of the feasible set. The algorithm searches along two line segments that connect the weighted analytic center and two extreme points of the linear programming relaxation. Candidate points are rounded and tested for feasibility. Cuts aimed to improve the objective function and restore feasibility are then added to displace the weighted analytic center until a feasible integer solution is found. The algorithm is composed of three phases. In the first, points along the two line segments are rounded gradually to find integer feasible solutions. Then in an attempt to improve the quality of the solutions, the cut related to the bound constraint is updated and a new weighted analytic center is found. Upon failing to find a feasible integer solution, a second phase is started where cuts related to the violated feasibility constraints are added. As a last resort, the algorithm solves a minimum distance problem in a third phase. The heuristic is tested on a set of problems from MIPLIB and CORAL. The algorithm finds good quality feasible solutions in the first two phases and never requires the third phase.  相似文献   

16.
Self-adaptive fitness formulation for constrained optimization   总被引:8,自引:0,他引:8  
A self-adaptive fitness formulation is presented for solving constrained optimization problems. In this method, the dimensionality of the problem is reduced by representing the constraint violations by a single infeasibility measure. The infeasibility measure is used to form a two-stage penalty that is applied to the infeasible solutions. The performance of the method has been examined by its application to a set of eleven test cases from the specialized literature. The results have been compared with previously published results from the literature. It is shown that the method is able to find the optimum solutions. The proposed method requires no parameter tuning and can be used as a fitness evaluator with any evolutionary algorithm. The approach is also robust in its handling of both linear and nonlinear equality and inequality constraint functions. Furthermore, the method does not require an initial feasible solution.  相似文献   

17.
Optimal traffic control synthesis for an isolated intersection   总被引:1,自引:0,他引:1  
A continuous dynamical model of a simplified controlled isolated intersection is derived in order to find and analyze an optimal control policy to minimize total delay. An analytical solution of the optimal control problem with constrained signal light control is presented. The optimal synthesis is found for the four principal control constraint cases. Previous results from the 1960s and 70s are discussed.  相似文献   

18.
郑建国  王翔  刘荣辉 《软件学报》2012,23(9):2374-2387
差分进化(differential evolution,简称DE)算法解决约束优化问题(constrained optimization problems,简称COPs)时通常采用可行解优先的比较规则,但是该方法不能利用种群中不可行解的信息.设计了可以利用不可行解信息的ε-DE算法.该算法通过构造一种比较准则,使得进化过程可以充分利用种群中优秀不可行解的信息.该准则通过引入种群约束允许放松程度的概念,在进化初始阶段使可行域边界上且拥有较优目标函数的不可行解进入种群;随着进化代数增加,种群约束允许放松程度不断减小,使得种群中不可行解数量减少,直到种群约束允许放松程度为0,种群完全由可行解组成.此外,还选择了一种改进的DE算法作为搜索算法,使得进化过程具有较快的收敛性.13个标准Benchmark函数实验仿真的结果表明:ε-DE算法是目前利用DE算法解决COPs问题中效果最好的.  相似文献   

19.
In this paper, a multidimensional 0–1 knapsack model with fuzzy parameters is defuzzified using triangular norm (t-norm) and t-conorm fuzzy relations. In the first part of the paper, the surrogate relaxation models of the defuzzified models are developed, and the use of surrogate constraint normalization rules is proposed as the surrogate multipliers. A methodology is proposed to evaluate some surrogate constraint normalization rules proposed in the literature as well as one rule proposed in this paper. Three distance metrics are used to find the distance of fuzzy objective function from the surrogate models to the distance of fuzzy objective function from the original models. A numerical experiment shows that the rule proposed in this paper dominates the other rules considered in this paper for three distance metrics given the whole assumptions. In the second part of the paper, a methodology is proposed for multi-attribute project portfolio selection, and optimal solutions from the original defuzzified models as well as near-optimal solutions from their surrogate relaxation models are considered as alternatives. The aggregation of evaluation results is managed using a simple yet effective method so-called fuzzy Simple Additive Weighting (SAW) method. Then, the methodology is applied to a hypothetical construction project portfolio selection problem with multiple attributes.  相似文献   

20.
In many real-world multiobjective optimization problems one needs to find solutions or alternatives that provide a fair compromise between different conflicting objective functions—which could be criteria in a multicriteria context, or agent utilities in a multiagent context—while being efficient (i.e. informally, ensuring the greatest possible overall agents' satisfaction). This is typically the case in problems implying human agents, where fairness and efficiency requirements must be met. Preference handling, resource allocation problems are another examples of the need for balanced compromises between several conflicting objectives. A way to characterize good solutions in such problems is to use the leximin preorder to compare the vectors of objective values, and to select the solutions which maximize this preorder. In this article, we describe five algorithms for finding leximin-optimal solutions using constraint programming. Three of these algorithms are original. Other ones are adapted, in constraint programming settings, from existing works. The algorithms are compared experimentally on three benchmark problems.  相似文献   

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