圆盘剪分切工艺有限元仿真研究

基于金属板材圆盘剪分切工艺,应用DEFORM-2D仿真软件建立了金属板材的圆盘剪分切模型,采用Oyane韧性断裂准则仿真研究了304不锈钢板材圆盘剪分切加工过程,探讨了圆盘刀轴向间隙、刃角半径、压板力、板厚等工艺参数对分切断面形貌特征的影响规律。轴向间隙是影响分切断面形貌特征的主要因素,随着轴向间隙的增大,塌角高度增大,剪切带高度减小。刃角半径对断面的塌角高度、剪切带高度影响不大,对毛刺高度影响最大,随着刃角半径增大,毛刺高度增大。压板力对断面的塌角高度、剪切带高度影响很小,对毛刺影响较大,随着压板力增大,毛刺高度有下降趋势。板厚对分切断面塌角和毛刺影响不大,对剪切带高度影响很大,随着板厚的增大,剪切带高度增大。     

基于AMESim的车身高度控制系统仿真研究

车身高度控制系统模型可根据车辆的运行状态,按照设定PID参数,向执行机构适时发出控制指令,可控制车身振动速度和加速度,调节车身高度,提高车身系统的可靠性与灵活性。应用AMESim软件,对1/4车辆模型的车身高度响应进行仿真分析,结果表明,基于AMESim的车身高度控制模型能较精确地反映系统特性,合理的车身高度控制系统模型的PID参数可以控制车身高度、车身振动速度和加速度,有效地降低车身振动,在实现车身高度控制的同时改善车辆的乘坐舒适性。     

多高度小零件视觉测量方法设计

设计一种综合应用激光三角法和二维机器视觉测量技术测量方法,实现对多高度小零件二维几何尺寸的测量。首先在测量高度范围内,利用线结构光进行高度测量标定,采用多项式拟合建立线结构光成像位置与高度的关系;用精密圆形靶标对不同高度平面进行二维尺寸标定,分别考虑不同高度平面坐标系映射到图像坐标系后光学放大率不同和坐标系间的不平行,CCD摄像机阵列垂直方向与水平方向不一定垂直的情况,以及光学镜头畸变等得到不同平面所在高度的二维尺寸测量标定参数,由此建立起各二维尺寸标定参数和高度的函数关系。对具有不同高度的小零件进行测量,并与三坐标测量机结果进行比对,多次测量的高度最大误差小于0.032mm,二维尺寸最大误差均小于0.08mm。     

ECAS客车车身高度的实时跟踪

为实现客车车身高度的精确跟踪,满足空气悬架控制要求,设计出一种基于电感式传感器的车身高度跟踪电路,传感器中的电感与跟踪电路由单片机共同控制,实现对传感器电感的充放电,单片机计算不同电感系数下的时间常数,间接获得实时的客车车身高度。并采用温度补偿电路和低温漂特性元件,适应客车工作环境温度的变化。设计出专用的滤波处理软件,既保证了车身动态高度的准确跟踪,又满足车身高度跟踪实时性的要求。试验表明,设计的车身高度跟踪系统启动后很快达到稳定且跟踪变化值在1 mm左右;当环境温度从30℃上升到80℃的过程中,跟踪高度的相对误差在1.9%左右,跟踪最大误差为5 mm,能够保证车身高度控制的准确性。     

谈倒大双冲天炉的底焦高度

底焦高度对冲天炉熔炼很重要,若底焦高度偏高,则焦耗增加,熔化率降低,若底焦偏低,则铁水温度偏低,而且氧化加剧,元素烧损严重。所以应确定正确的底焦高度,才能保证冲天炉的正常熔炼。而底焦高度应分为初焦高度和熔化时底焦的真实高度两个概念。开炉前装入的底焦高度为初焦     

基于等残留高度的自由曲面加工刀具轨迹规划

对于曲面加工来说,效率和精度是相互矛盾的2个方面。加工时,用等残留高度法生成刀具轨迹,选择待加工曲面最长的1条边界线作为第1条加工的轨迹线,通过控制相邻刀具接触点的距离,使刀具轨迹间的残留高度均匀一致,依据刀具半径和允许的残留高度,迭代生成另一条刀具轨迹线。等残留高度法生成的刀具路径间的残留高度均为设定值,所生成的刀位点数最少,刀具路径长度最短。采用牛顿法作为等残留高度法的刀位点搜索方法,得到等残留高度刀具轨迹的生成过程。     

一种新型机车车钩中心高度测量尺的设计

测量机车车钩中心高度的重要性在于确保铁路运输的安全和稳定。机车车钩中心高度是指连接机车和车辆之间的接触面的高度。机车车钩中心高度不正确会导致车辆之间连接不牢固,可能发生脱轨或脱钩事故,对人员和货物造成严重威胁,准确测量机车车钩中心高度可以保证车辆在行驶过程中的稳定性和平衡性。车钩中心高度不同,车辆在行驶中可能出现偏移、晃动或不平衡的现象,增加了事故发生的风险,并影响行车的舒适性和效率。而正确调整车钩中心高度可以确保车辆在行驶时保持平稳的姿态,减少运输过程中的震动和振动,提高乘员乘坐的舒适度。机车车钩中心高度是行车安全的重要参数之一,为铁路运输部门提供有效的数据支持,帮助保障列车安全行驶。但老式的机车车钩中心高度测量尺在测量过程中存在一定的不足。所设计的新型机车车钩中心高度测量尺的底座滚轮机构设计、限制机构设计、尺身滑动机构设计和通用性棘爪机构设计,解决了老式的机车车钩中心高度测量尺测量的不足,确保了车钩中心高度测量符合相关技术标准,避免因技术不合规造成的纠纷和不必要的损失。     

基于灰色BP神经网络的质心数据处理方法

为减小传感器的随机误差对三点支撑小型农业机质心测试系统质心高度数据的影响,同时提高质心高度的测试效率和安全性,对该类测试系统在有限次、小角度条件下测试获得质心高度的数据处理方法进行了研究。提出灰色GM(1,1)模型与BP神经网络相结合的灰色BP神经网络模型的构建方法,采用该方法构建的预测模型,对质心高度测试获得的数据进行处理可以获得较高精度的质心高度数据,并搭建了小型试验台对预测模型进行验证。结果表明,采用该方法构建的质心高度预测模型得到的质心高度数据相对误差为0.759%。     

L波段雷达探空系统气压测量值与气压反算气压值的误差分析

以锡林浩特和南京探空站为例,用雷达定位信息计算的位势高度和用气压计算的位势高度与GPS导航测风探空仪所测高度进行比较;用雷达高度反算的气压值和GTSI型探空仪用气压传感器直接测量的气压值与GPS导航测风探空仪测量的气压值进行比较。结果表明:用雷达定位信息计算位势高度可以替代用气压计算的位势高度并应用于业务;而用雷达高度反算40hPa的等压面高度以上可以代替探空仪对气压的直接测量。在用L波段雷达的情况下,用高度反算气压的可行性应进一步研究。     

乘用车高度变化对偏置碰撞B柱加速度影响研究

本文旨在研究由质量变化引起的乘用车高度变化对偏置碰撞B柱加速度影响。首先,利用经过验证的丰田Yaris搭建CNCAP偏置碰撞仿真模型,然后构建不同整车高度仿真模型,分析高度变化对B柱加速度的影响。结果表明,当整车高度下降较多时对B柱参考点加速度影响偏大,碰撞仿真中需要考虑质量变化引起的高度变化对碰撞仿真精度的影响.     

BP neural network classification on passenger vehicle type based on GA of feature selection

This paper has concluded six features that belong to passenger vehicle types based on genetic algorithm(GA)of feature selection.We have obtained an optimal feature subset,including length,ratio of width and length,and ratio of height and length.And then we apply this optimal feature subset as well as another feature set,containing length,width and height,to the network input.Back-propagation(BP)neural network and support vector machine(SVM)are applied to classify the passenger vehicle type.There are four passenger vehicle types.This paper selects 400 samples of passenger vehicles,among which 320 samples are used as training set(each class has 80 samples)and the other 80 samples as testing set,taking the feature of the samples as network input and taking four passenger vehicle types as output.For the test,we have applied BP neural network to choose the optimal feature subset as network input,and the results show that the total classification accuracy rate can reach 96%,and the classification accuracy rate of first type can reach 100%.In this condition,we obtain a conclusion that this algorithm is better than the traditional ones[9].     

Fuzzy Sliding Mode Control for the Vehicle Height and Leveling Adjustment System of an Electronic Air Suspension

The accurate control for the vehicle height and leveling adjustment system of an electronic air suspension(EAS) still is a challenging problem that has not been effectively solved in prior researches. This paper proposes a new adaptive controller to control the vehicle height and to adjust the roll and pitch angles of the vehicle body(leveling control) during the vehicle height adjustment procedures by an EAS system. A nonlinear mechanism model of the full?car vehicle height adjustment system is established to reflect the system dynamic behaviors and to derive the system optimal control law. To deal with the nonlinear characters in the vehicle height and leveling adjustment processes, the nonlinear system model is globally linearized through the state feedback method. On this basis, a fuzzy sliding mode controller(FSMC) is designed to improve the control accuracy of the vehicle height adjustment and to reduce the peak values of the roll and pitch angles of the vehicle body. To verify the effectiveness of the proposed control method more accurately, the full?car EAS system model programmed using AMESim is also given. Then, the co?simulation study of the FSMC performance can be conducted. Finally, actual vehicle tests are performed with a city bus, and the test results illustrate that the vehicle height adjustment performance is effectively guaranteed by the FSMC, and the peak values of the roll and pitch angles of the vehicle body during the vehicle height adjustment procedures are also reduced significantly. This research proposes an effective control methodology for the vehicle height and leveling adjustment system of an EAS, which provides a favorable control performance for the system.     

A hybrid approach to modeling and control of vehicle height for electronically controlled air suspension

The control problems associated with vehicle height adjustment of electronically controlled air suspension (ECAS) still pose theoretical challenges for researchers, which manifest themselves in the publications on this subject over the last years. This paper deals with modeling and control of a vehicle height adjustment system for ECAS, which is an example of a hybrid dynamical system due to the coexistence and coupling of continuous variables and discrete events. A mixed logical dynamical (MLD) modeling approach is chosen for capturing enough details of the vehicle height adjustment process. The hybrid dynamic model is constructed on the basis of some assumptions and piecewise linear approximation for components nonlinearities. Then, the on-off statuses of solenoid valves and the piecewise approximation process are described by propositional logic, and the hybrid system is transformed into the set of linear mixed-integer equalities and inequalities, denoted as MLD model, automatically by HYSDEL. Using this model, a hybrid model predictive controller (HMPC) is tuned based on online mixed-integer quadratic optimization (MIQP). Two different scenarios are considered in the simulation, whose results verify the height adjustment effectiveness of the proposed approach. Explicit solutions of the controller are computed to control the vehicle height adjustment system in realtime using an offline multi-parametric programming technology (MPT), thus convert the controller into an equivalent explicit piecewise affine form. Finally, bench experiments for vehicle height lifting, holding and lowering procedures are conducted, which demonstrate that the HMPC can adjust the vehicle height by controlling the on-off statuses of solenoid valves directly. This research proposes a new modeling and control method for vehicle height adjustment of ECAS, which leads to a closed-loop system with favorable dynamical properties.     

车用磁粉离合器起步控制试验研究

阐述了车用磁粉离合器的工作原理,介绍了车用磁粉离合器的控制参数及评价指标,在新型动力试验平台上,对车辆起步工况下车用磁粉离合器的控制进行了试验。试验结果表明：通过控制励磁电流能够使车用磁粉离合器的接合较好地满足不同车辆起步工况的要求;作为新型动力传递部件,车用磁粉离合器具有广阔的应用前景。     

汽车ABS滚筒式惯性检测台架的设计

概述了国内汽车安全检测设备的现状和ABS系统的原理,目前国内的汽车检测设备还无法评价汽车ABS的制动性能。利用物体的动能可以用物体的转动惯量来表示这一原理．设计出一种以模拟汽车的运行状况的滚筒式惯性检测台架。该台架不仅可以评价汽车ABS的制动性能,还可以取代现有的汽车安全检测设备,极大提高汽车安全检测效率,具有很好的应用前景。     

机车车辆称重台现场安装之要点

随着中国铁路的高速发展,各类新型机车和车辆陆续完成并投入使用,为保证机车和车辆的质量及在线路上的安全运营,对计量设备——机车车辆称重台计量性能及检定也提出较高的要求。而为保证机车车辆称重台的顺利检定及投用,现场的安装工作是一个不可小觑的重要环节。本文简单介绍了机车车辆称重台在现场安装时经常会出现的问题及相应的解决措施。     

纯电动桥梁检测维修车在高速铁路桥梁检测维护中的应用

介绍纯电力驱动技术桥梁检测维修车,该车采用C型整车结构,解决了桥梁断面复杂多变的问题,说明纯电动桥梁检测维修车在桥梁检测维修方面的可行性.     

机械式车高自动调平装置的研制

针对现有车高自动调平装置存在的不足,以某轻型客车非独立后悬架作为研制对象,对机械式车高自动调平装置进行了创新设计、样件试制和试验验证;为比较调平悬架和普通悬架的性能差异,在随机和脉冲路面激励下采用时域和频域分析法对两种悬架进行了数学建模和仿真分析,从而初步得出了自动调平悬架的主要性能特点。
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基于油耗及噪声目标的轻型商用车匹配优化研究

介绍了基于油耗噪声目标的轻型商用车在整车成本控制的前提下,对车辆发动机与传动系统匹配优化获得汽车综合性能的一种方法。以某款轻型商用车为例,对车型试验过程中出现的油耗及噪声超出预定目标值的问题开展分析,借助AVL Cruise软件进行动力性及经济性仿真计算,在油耗及噪声目标约束下优化传动系匹配。通过不同方案的样车测试,验证了方案的可行性及油耗、噪声的改善效果,使整车综合性能更加合理。