基于离散曲线包络的刮削加工仿真数学模型

为实现通用廓形刮削加工过程的分析,提出一种切削刃曲线离散包络的刮削加工仿真数学模型,该模型能够完成任意切削刃廓形的刮削加工廓形与加工误差计算,以及相应的刮削切触运动仿真分析。构建了刮削加工的运动学模型,表述了刀具与工件的结构参数以及刮削设置参数。在刮削加工成型原理的基础上,提出基于切削刃曲线离散运动包络的刮削加工廓形计算原理,并给出相应的计算流程与具体计算方法。在此基础上,通过寻求包络廓形作用点的切削发生关系,借助合理的坐标转换实现了刮削加工过程的切触运动仿真分析,并进一步提出了仿真加工廓形的误差评估算法。采用非规则廓形刀具进行了内刮削廓形的加工计算,并进行了运动仿真和廓形加工误差计算,验证了所提算法的有效性。     

参数α、β和ρ自适应调整的快速蚁群算法

对蚁群算法迭代次数多、收敛速度慢提出了改进。针对蚁群算法前期信息素匮乏而导致收敛速度慢的问题,对信息素和启发式信息的权重参数α和β进行改进,动态调整两种参数;针对迭代后期信息素浓度过高,使得蚁群易陷入局部最优问题,对信息素蒸发系数加以改进,使其成为动态全局自适应参数。通过栅格法进行静态已知环境建模,通过不同规模的路径规划的实验验证了改进后的蚁群算法在寻找最优路径时具有更快的运算速度。     

基于LM算法的多传感器钢轨廓形融合算法研究

运用4个激光轮廓传感器同时采集钢轨断面1/4廓形数据,并利用融合算法拼接得到完整的钢轨廓形,但存在拼接效果差、精度低、误差大等问题。该文通过运用LM算法优化拼接过程中所需变换矩阵H中的旋转角θ、平移量Δx和Δy三个参数,将计算所得的变换矩阵重新用于上述数据的融合,达到了提高精度、提升拼接效果的目的。     

基于调整步长牛顿法的Stewart并联机构位置正解

针对采用牛顿或拟牛顿迭代算法求解Stewart并联机构接近奇异位姿的位置正解时存在计算结果不收敛以及采用牛顿下山迭代算法求解时间较长的问题,提出了将调整步长牛顿法应用于并联机构位置正解。首先设计基于调整步长牛顿法的Stewart并联机构位置正解流程;然后,采用遗传算法以步长矩阵初值及等比参数为变量,以Stewart并联机构64种极限位姿正解所需迭代步数为目标,得到步长矩阵初值及等比参数最优值。通过数值算例,设置机构杆长绝对误差为0.01mm,对64种极限位姿进行正解,牛顿法与拟牛顿法共6种位姿正解不收敛;牛顿下山法10种位姿正解时间大于2.0ms;调整步长牛顿法正解时间均小于2.0ms。调整步长牛顿法为Stewart并联机构位置正解的实时应用提供了理论指导。     

大导程滚珠螺母内滚道接触区磨削分析

针对成形磨削大导程滚珠螺母滚道时磨杆与螺母干涉碰撞的技术问题,基于螺旋面加工原理对砂轮计算截形坏点及滚道廓形误差进行详细分析.在调整安装参数无法满足滚道完整包络成形的前提下,提出了以滚道接触区廓形最大化为目标的精密磨削工艺及相应的砂轮选型与安装参数优化方法.以4040型号大导程滚珠螺母磨削试验为例,验证了该方法可满足大...     

基于压电材料复参数自动测量的算法

本设计为一种压电材料复参数自动测量系统,提出了该测量系统所用的一种快速、精确的自动测量算法—自动迭代算法。其优点是:与常用的Smits迭代法相比,参数初值的选取是与Smits迭代精度接近的Sherrit算法的终值,更加接近真值以减少迭代次数,加快算法速度;频率点的选取遵循一定的规则,以保证迭代的收敛性和测量的自动运行。     

基于正交试验-遗传神经网络的陶瓷球面精密磨削参数优化

针对陶瓷等难加工材料的精密加工要求与特点以及球面磨削传统加工模式,分析了氮化硅陶瓷材料球面廓形工件砂轮法向跟踪精密磨削的方法。采用正交试验法设计试验,运用极差法和方差法综合分析相关磨削工艺参数对工件加工质量与效率的影响规律。考虑到当前磨削加工工艺方案选择与优选的难点,利用遗传神经网络算法建立了工件加工质量与效率和相关磨削工艺参数之间的非线性映射关系,并基于正交试验法的分析结果对遗传神经网络算法进行了改进,实现了相关磨削工艺参数的优化,缩短了氮化硅陶瓷材料球面廓形工件数控磨削工艺制定与操作的时间,提高了磨削加工质量和效率。     

基于模拟退火-粒子群算法优化支持向量机参数的连铸漏钢预报

针对连铸漏钢预报神经网络模型在小样本训练数据情况下难以获得较高预报准确率的问题,提出了一种基于模拟退火-粒子群（SA-PSO）算法优化支持向量机（SVM）参数的连铸漏钢预报算法。将粒子群优化算法引入支持向量机的训练过程中,利用其调整参数少、寻优速度快的优点,有效地提高了漏钢预报模型的寻优速度;利用模拟退火算法对粒子群算法迭代更新后粒子的新位置加以评价,来决定新位置是否被接受,避免了粒子群算法在迭代寻优过程中陷入局部极值的问题。结合某钢厂连铸现场历史数据对提出的连铸漏钢预报算法进行了测试,测试结果表明,所提算法的连铸漏钢预报准确率可达98.8%。     

一种信息素挥发DPSO及其应用研究

以离散状态的信息素编码,对算法迭代公式进行调整,以信息素为依据进行离散状态选择,提出一种新颖的信息素挥发离散微粒群算法.收敛性分析表明,在一定参数条件下微粒轨迹可收敛.基于时延约束的最小能耗路由优化结果显示,该方法具有较好的搜索性能.     

钢轨廓形测量自动对齐技术研究

随着我国铁路发展的高速化，铁路钢轨的形态直接影响列车的运行安全，钢轨廓形是表征钢轨服役形态的重要特征，分析钢轨廓形与基准廓形的偏差是钢轨精细化维护的重要问题，分析钢轨廓形与基准廓形的偏差的基础是廓形对齐，因此，高精度的对齐方法是亟待解决的问题。本文阐述了基于相关性以及DTW（动态时间调整）2种方法实现廓形自动对齐。经过实践表明，本文所述的2种方法能有效提升廓形对齐精度。     

A cutter orientation modification method for five-axis ball-end machining with kinematic constraints

Cutter orientation modification with kinematic constraints is very necessary and effective for five-axis machining especially machining at high speed. It is very helpful for achieving a smooth cutter motion and keeping the process steady. Therefore, a cutter orientation adjustment method is proposed to obtain an optimized tool path which makes best use of the kinematic characteristics of angular feed for five-axis machining. For the given five-axis cutter location path and the feed profile of cutter tip point both expressed by b-spline formats with the same parameterization, the analytic relations of angular feed, angular feed acceleration, and jerk with respect to the geometric and tangential feed parameters of the cutter tip trajectory are first derived. Then, the conditional inequalities of these kinematic constraints used for orientation adjustment are built. Subsequently, the determination method of feasible cutter orientation and detailed algorithm of orientation adjustment are given. Finally, illustrated examples are conducted to validate the proposed orientation adjustment method. The results show that the developed method is effective and can be applied to optimize geometrically complex five-axis tool path by taking the angular feed, angular feed acceleration, and jerk into account.     

Head-cutter for optimal tooth modifications in spiral bevel gears

A method for the determination of optimal tooth modifications in spiral bevel gears based on improved load distribution and reduced maximum tooth contact pressure and transmission errors is presented. The modifications are introduced into the pinion tooth-surface by using a head-cutter with bicircular profile and with optimal diameter. In the optimization of tool parameters the influence of relative position errors of the mating gears is included.By using the computer program developed for load distribution calculation, the influence of head-cutter parameters and relative position errors of the mating gears on tooth contact and transmission errors is investigated. Based on the results obtained, the radii and the position of the circular tool profile arcs and the cutter diameter for pinion teeth finishing were optimized. By applying the optimal tool parameters, the maximum tooth contact pressure is reduced by 45% and the maximum angular position error of the driven gear by 60%, in regard to the spiral bevel gear pair with a pinion manufactured by a cutter of straight-sided profile and of diameter determined by the commonly used methods.     

牛顿插值公式在模具数控编程计算中的应用

越野汽车车身左右侧翼板冲压件模具型面为单曲面，先进行数控工艺分析，计算出形刀具中心轨迹新的离散点，分别用牛顿不等间距插值公式在微机上计算出凸、凹两部分的对应轨变值，编制数控程序单，纸带循体数控加工单曲面成功。     

径向剃齿刀设计与制造过程的虚拟检验

为了验证径向剃齿刀ＣＡＤ系统以及刀具制造系统的正确性,提出了一种基于刀具设计参数,用最小二乘法拟合刀具齿面的建模方法,并计算反射出被剃齿轮齿面,通过与原齿轮参数比较从而达到检验刀具设计制造的正确性的目的。     

弧面分度凸轮的非等径数控加工自动编程

弧面分度凸轮廓形的非等径加工自动编程,能够及时有效地补偿刀具尺寸的变化,保证加工精度,降低刀具费用.文章介绍了在三轴联动数控机床上加工弧面分度凸轮时,非等径加工刀具轴线的确定、编程坐标换算和自动编程应用程序框架,并给出了非等径加工程序实例.     

基于虚拟检验的径向剃齿刀齿面设计与建模

为了虚拟检验径向剃齿刀ＣＡＤ系统的正确性,有必要对刀具齿面进行建模。根据齿轮啮合原理,提出了基于刀具设计参数的径向剃齿刀齿面设计的计算方法,给定剃刀齿面上任意矩形域内点的ｘ,ｙ坐标便可用弦截法计算出该点的ｚ坐标。同时提出了一种用最小二乘法拟合刀具齿面上离散点的齿面建模方法,构造了齿面的简单表达式。该模型可用于虚拟径向剃齿过程,从而生成被剃齿轮齿面,通过与渐开线齿面的比较达到检验刀具设计正确性的目的     

销齿轮齿形设计方法的研究

介绍利用计算机进行销齿轮齿形设计的方法。文中推导了销齿轮齿形的曲线方程并建立了刀具中心轨迹方程，给出了对齿形曲线进行圆弧拟合的方法。     

Modeling and numerical simulation for the machining of helical surface profiles on cutting tools

The classical conjugation and envelope method is very accurate and effective for forward and inverse calculations of grinding helical surfaces. However, this method involves complicated mathematics and requires that the profiles be continuous. It can also result in undercutting or interference to the desired surface profiles. In this paper, a new approach is proposed to simulate the grinding process of helical surfaces on cutting tools. The paper begins with the reconstruction of cutter helicoids from sampled points. Using the recovered helical parameters from the sample points, the cross-sectional profile of the cutter surface is derived using a polynomial curve. A numerical method for calculating the profile of the grinding wheel required for the cutter surface profile is then provided. Finally, an optimization method is presented for solving the problem of inverse calculation to determine the helical surface profile for a given grinding wheel profile and setting parameters. The feasibility of the approach is tested by simulation results, which shows that the proposed approach can eliminate undesired tool-work interferences and undercutting.     

半切顶插齿刀的精确设计和Y7125半切顶角度的调整计算

用平面啮合原理通俗地介绍了目前广泛应用的半切顶插齿刀的设计方法与步骤,导出了半切顶插齿刀主切削刃与半切顶切削刃的交点半径的通用计算公式,从而解决了半切顶插齿刀的精确设计,和半切顶齿形的测量。从Y7125型磨齿机的磨齿原理进行分析,从设计半切顶插齿刀中所获得的两个基圆中,求取磨制半切顶插齿刀的半切顶修整角的调整。     

An Enhanced DFM Model for Shaper Cutters

This paper presents a systematic CAD/CAM based geometric modelling technique for enhancing the manufacturing accuracy of general straight-tooth shaper cutters. The proposed modelling technique systematically computes and improves on the shape of general shaper cutters using a five-step procedure. In the first modelling step, the significant geometric parameters of shaper cutters which including tooth profile, rake and clearance angles, offsets, and backlash are estimated using criteria associated with the practical requirements and the theory of gearing, differential geometry, and motion theory. In the second modelling step, the precise cutting-edge curve model of the shaper cutter is constructed. The theoretical involute or cycloidal cutting-edge curve on the plane perpendicular to the motion axis of the shaper cutter is first computed and is then projected onto the conic surface of the shaper cutter which has both the rake and the clearance angles. In the third modelling step, the convoluted sectional profile of the diskshaped generating cutter required for producing the cuttingedge profile is established using the theory of gearing and the relative motion relationship between the grinder and the cutter in the manufacturing process. In the fourth modelling step, a simple procedure to obtain the profile shift coefficient of the shaper cutters from various given process parameters is presented. Shaper cutters of various shapes can thus be designed and produced. In the last modelling step, a practical working example for producing the precise disk-shaped generating cutter and associated shaper cutter is presented to illustrate the effectiveness of the proposed modelling approach. The results of numerical modelling indicate that the proposed approach is systematic, accurate and reliable for producing shaper cutters of various shapes.