实现经济型CNC系统C刀补的算法研究(上)

提出一种基于直线插补思想的C刀补算法,将三角函数及开方运算转换为加、减运算,算法简单实用,解决了C刀补在单片机开发的经济型CNC系统中的实现问题。     

2π空间发光的理想点光源系统

为获得能在２π空间发光的理想点光源，本文提出了一种特殊光学系统，介绍了这种系统的工作原理、设计方法和设计结果。     

基于柔性多状态开关的主动配电网负荷在线紧急转供策略

配电网故障后,传统基于联络线的负荷转供方法存在停电转供、容易引起非故障线路过负荷等诸多问题。近年来出现的一种配电灵活交流输电(DFACTS)设备——智能软开关为上述问题的解决提供了契机。依托其对多条相连线路功率的柔性调节能力,提出了一种兼顾故障馈线残余负荷以及非故障馈线安全运行约束的负荷快速在线转供策略。首先建立了线路末端功率和各节点电压的关系,设置满足配电网正常运行状态的约束条件;在此基础上,以最大负荷转供量为上层目标函数,以电压偏差最小为下层目标函数,在约束范围内进行求解,获取最优潮流分配方法。最后针对上述最优潮流可能影响非故障馈线的安全运行的特殊场景,提出了在保证正常线路安全运行前提下最大程度保全待转供负荷的紧急切负荷策略和实现方案。依托大江东工程实际拓扑结构,搭建了基于PSCAD-MATLAB的联合仿真平台。结果表明,所提出的方案能够实现负荷的不断电在线转供。     

非接触式激光测量点云数据预处理

作为逆向工程中形状表面数字化应用最广泛的方式,非接触式激光测量具有接触式测量无可比拟的优势。然而激光测量所得的数据点云存在明显缺陷无法直接应用于三维模型重建。本文重点讨论了激光测量所得点云数据的特点,并针对其缺陷提出一些处理方法,使之可以应用于三维模型的重建。     

Path curvature of a geared seven-bar mechanism

This paper presents a graphical technique to locate the center of curvature of the path traced by a coupler point of a planar, single-degree-of-freedom, geared seven-bar mechanism. Since this is an indeterminate mechanism then the pole for the instantaneous motion of the coupler link; i.e., the point coincident with the instantaneous center of zero velocity for this link, cannot be obtained from the Aronhold–Kennedy theorem. The graphical technique that is presented in the first part of the paper to locate the pole is believed to be an important contribution to the kinematics literature. The paper then focuses on the graphical technique to locate the center of curvature of the path traced by an arbitrary coupler point. The technique begins with replacing the seven-bar mechanism by a constrained five-bar linkage whose links are kinematically equivalent to the second-order properties of motion. Then three kinematic inversions are investigated and a four-bar linkage is obtained from each inversion. The motion of the coupler link of the final four-bar linkage is equivalent up to and including the second-order properties of motion of the coupler of the geared seven-bar. Then the center of curvature of the path traced by an arbitrary coupler point can be obtained from existing techniques, such as the Euler–Savary equation. An analytical method, referred to as the method of kinematic coefficients, is presented as an independent check of the graphical technique.     

五坐标数控端铣渐开线螺旋面的刀位计算

介绍五坐标数控端铣加工渐开线螺旋面的刀位 (包括刀心坐标和刀轴矢量 )计算方法 ,并以具有A、B摆头的五坐标数控机床为例 ,将刀轴矢量转换成机床的运动坐标 ,完成编程计算的相关内容     

分布源边界点法在声场全息重建和预测中的应用

提出了以分布源边界点法作为声场的全息变换算法,建立了基于分布源边界点法的声全息重建和预测的数学模型。与基于边界元法的声全息重建和预测模型相比,此法避开了变量插值、数值计算和奇异积分的处理,具有计算速度快、计算精度高、计算稳定性好和简单易懂等优点,因此在工程实践中有着广泛的应用前景。     

λ网络中一种分布式速率分配算法

针对λ网络中的高性能传输问题,提出了一种分布式速率分配算法.该算法基于离散时间系统模型对λ网络进行建模,得到其速率分配问题的数学依赖关系,根据最大-最小公平准则,利用本地信息来分配每个源端和目的端之间的容量,以确保较低期望速率会话的速率最大化,并把剩余容量均匀地分配给全部会话,直至网络被充分利用.结果表明,所提出的分布式速率分配算法能快速收敛到一个最大-最小公平速率分配方式,而且还能实现自适应期望速率的快速变化.     

Glowworm swarm optimization algorithm with topsis for solving multiple objective environmental economic dispatch problem

A new glowworm swarm optimization (GSO) algorithm is proposed to find the optimal solution for multiple objective environmental economic dispatch (MOEED) problem. In this proposed approach, technique for order preference similar to an ideal solution (TOPSIS) is employed as an overall fitness ranking tool to evaluate the multiple objectives simultaneously. In addition, a time varying step size is incorporated in the GSO algorithm to get better performance. Finally, to evaluate the feasibility and effectiveness of the proposed combination of GSO algorithm with TOPSIS (GSO–T) approach is examined in four different test cases. Simulation results have revealed the capabilities of the proposed GSO–T approach to find the optimal solution for MOEED problem. The comparison with own coded weighted sum method incorporated GSO (WGSO) and other methods reported in literatures exhibit the superiority of the proposed GSO–T approach and also the results confirm the potential of the proposed GSO–T approach to solve the MOEED problem.     

Formula of definite point overburden pressure of reservoir layers

Overburden pressure, P_ob, is pressure imposed on layers during the different hydrocarbonic layers operations by the weight of overburden layers. Practically, the geological layers structure varies in matrix and porous media during well head treatment operations such as acidizing, hydraulic fracturing and fluid injection when drilling and completion. So, three structural quantity inter-granular space (IGS), inter-fracture space (IFS) and fracture width (FW) affect fluid conductivity and layers P_ob alternations.Using the petrophysic and geological information and the content of tables under the reservoir conditions, P_ob was formulated for a drilled layer point in various porosity ranges.Since reservoir layers mostly have heterogeneity characterizations, and timely and repeatedly need to control the type of cutting lithology, drilling mud and reservoir pressure by geologists and drillers, the equations derived are effective in wellhead and bottom hole operations for the calculations in which the overburden pressure plays a key role.