改进自适应遗传算法在硫化车间调度中的应用

针对轮胎加工生产过程中的瓶颈即硫化工序的生产调度,建立了一个基于改进自适应遗传算法的调度方案.改进自适应遗传算法相对于普通遗传算法,能够更有效收敛于目标,提高运算速度,并通过实例证明了该算法的有效性和可行性.     

柔性车间生产资源与AGV物流资源联合优化调度

柔性车间生产资源与物流资源关联性越来越强,各资源独立调度无法实现系统的高效率运行。针对此问题,提出了基于二维度自适应遗传算法的车间生产资源与物流资源联合调度方法。明确了AGV系统组成、工作模式和分配策略,建立了柔性车间的栅格地图模型;以车间完工时间最小为目标,建立了生产资源与物流资源联合调度模型;从时间和空间2个维度设计自适应算子,提出了基于二维度自适应遗传算法的联合调度方法。经合作企业某车间生产验证,二维度自适应遗传算法联合调度方案的完工时间为68 min,小于遗传算法和自适应遗传算法调度方案;经参数敏感性分析可知,二维度自适应遗传算法鲁棒性好,对不同情况下的车间调度问题都具有较好的性能。     

基于改进自适应遗传算法的柔性作业车间调度问题研究

为了克服遗传算法在解决柔性作业车间调度问题中收敛速度慢、易陷入局部最优的缺陷,根据柔性作业车间调度问题的特点,提出一种具有自适应交叉概率与变异概率的改进自适应遗传算法。将交叉概率与个体适应度值相关,将变异概率同时与个体适度值与进化代数相关,采用有效的编码、解码机制,引入精英保留策略。通过对两个基准问题进行仿真分析,验证了改进自适应遗传算法的有效性。     

改进遗传算法求解同类并行机优化调度问题

研究在给定n个可拆分加工的作业和m台同类不同速加工机器的条件下,考虑同时优化拖期成本和生产能耗的生产调度问题。采用理想点法构建目标函数,建立了考虑拖期成本与能耗的同类并行机排产调度模型。在传统遗传算法基础上,引入多种群、自适应和局部搜索策略以提高搜索效率,并提出个体差异度以改进交叉效果。分别用不同规模的问题进行算例实验,对比改进遗传算法和传统遗传算法性能,求解排产方案。实验结果表明改进算法计算效果优于标准遗传算法,能够求解不同规模该类问题,且具有良好的稳健性。     

基于电量和负载均衡约束的多AGV生产车间调度研究

目前多AGV的使用大大提升了制造企业的生产效率，在调度过程中也产生了诸多问题，其中以AGV负载不均和电量限制所带来的拥堵问题尤为凸显。对此，以最小化生产调度时间和负载均衡偏差为目标，考虑AGV的电池容量、充电次数、充电时间等约束，建立了一种非线性的多目标集成优化模型，基于MFC(Minimum time selection for charged volume constraint,MFC)策略设计了自适应改进遗传算法，并通过与传统遗传算法对比分析，验证了算法的有效性。最后对AGV调度中的相关参数进行分析，得到了AGV在负载均衡时的运行规律。     

基于自适应遗传算法的柔性动态调度研究

提出了柔性生产环境下动态调度系统的框架结构。系统主要由评估模块，动态数据库管理模块以及遗传算法模块组成，它能够在扰动发生后快速提供新的调度计划；而自适应策略保证遗传算法有很好的收敛速度与精度。该方案减少了人为的干预，完全可以在实时生产条件下运行。     

基于改进自适应遗传算法的网格任务调度算法

针对网格环境动态多变性的特点,对网格环境任务调度中的遗传算法进行研究,提出一种改进的自适应遗传算法.通过对影响遗传算法行为和性能的关键参数交叉概率与变异概率进行分析,提出利用自适应思想以及表征调度性能的种群适应度对交叉概率和变异概率合理选取的自适应遗传算法,使交叉概率和变异概率能随种群适应度自动调节、改变.试验结果表明,改进的自适应遗传算法能使网格任务调度具有较好的种群自适应度,从而表明该方法的有效性.     

改进元胞遗传算法求解柔性作业车间调度问题

针对柔性作业车间调度问题(Flexible Job-shop Scheduling Problem,FJSP)中的不同性能指标优化,提出一种改进的元胞遗传算法。结合柔性作业车间调度的特点,设计一种基于工序编码和设备分配的双层编码,在交叉变异时分别对两层编码进行操作,同时在变异时引入贪婪式变异以加快收敛速度。为了克服传统遗传算法早熟和收敛慢的特点,设计了根据邻居个体自适应的选择算子。将该改进的元胞遗传算法求解柔性作业车间调度问题并同其他遗传算法的测试结果进行比较,表明所提出的改进元胞遗传算法在求解柔性作业车间调度问题上的有效性。     

基于改进的单倍体遗传算法生产调度设计

在对车间生产调度进行建模和仿真的基础上,基于改进的单倍体遗传算法设计实现车间生产调度系统.设计实现证明基于改进后的单倍体遗传算法设计的调度系统在算法的寻优速度和收敛精度上有明显提高.     

基于遗传算法与仿真联合的车间调度方案优化

以车间生产系统仿真模型为仿真器，以改进的遗传算法模块为优化器，通过Socket实现联合求解调度优化问题。结果表明，优化的调度方案相比实际完成时间减少19.4%；相比考虑实际因素的仿真时间减少14.3%。通过遗传算法与仿真模型的联合求解，找到了较优的调度方案，实现了生产能力的有效提升。     

胎压无源监测系统的电能发生装置研究

针对目前汽车行业中常用的直接式轮胎压力监测系统的供电问题,以超磁致伸缩材料作为核心元件,利用其磁致伸缩逆效应,设计一种可产生电能的发电装置。利用该装置为汽车轮胎压力监测系统的检测发射模块供电,可改变纽扣电池的供电方式。研究成果为解决汽车轮胎压力监测系统的供电问题提供一种有效方法,对实现压力监测系统的无源化具有一定的推动作用,为超磁致伸缩材料的应用提供一种新途径。     

A study on the fatigue life prediction of tire belt-layers using probabilistic method

Tire belt separation failure is occurred by internal cracks generated in #1 and #2 belt layers and by its growth. And belt failure seriously affects tire endurance. Therefore, to improve the tire endurance, it is necessary to analyze tire crack growth behavior and predict fatigue life. Generally, the prediction of tire endurance is performed by the experimental method using tire test machine. But it takes much cost and time to perform experiment. In this paper, to predict tire fatigue life, we applied deterministic fracture mechanics approach, based on finite element analysis. Also, probabilistic analysis method based on statistics using Monte Carlo simulation is presented. Above mentioned two methods include a global-local finite element analysis to provide the detail necessary to model explicitly an internal crack and calculate the J-integral for tire life prediction.     

基于加速度变化率的轮胎等效侧偏刚度估计方法

等效侧偏刚度精确地反映了轮胎的侧偏特性,是汽车操纵稳定性研究中的重要参数。为此提出了基于加速度变化率的汽车轮胎等效侧偏刚度估计方法。采用三自由度汽车动力学模型,把前后轮侧向力的时间变化率表示为加速度变化率的函数。利用轮胎力学特性理论推导出瞬时等效侧偏刚度的估计公式,在汽车纵向加速度为稳态的条件下,利用轮胎侧向力的时间变化率和轮胎侧偏角的时间变化率来估算轮胎瞬时等效侧偏刚度。通过ADAMS软件的整车常半径转向虚拟试验对估计方法进行了验证。虚拟试验结果表明提出的方法具有较好的估计精度。     

CHARACTERIZATION OF EFFECTIVE TIRE CONTACT AREA FOR VARIOUS TREAD PATTERNS

The effective tire-pavement contact area affects the relative damage of asphalt pavement and should be incorporated in both mechanistic and empirical response analyses of pavements. A new machine called ROTOCOM Wheel Tracker (RCWT) was designed and fabricated to capture the effective tire contact area apart from slab compacting, and conducting simulative laboratory wheel tracking tests. The main focus of this paper is laboratory measurement of effective tire contact areas for various tread patterns. Seven tire treads were selected for the footprint image analyses at five tire loads and four tire inflation pressures. An image processing MATLAB-based program was coded to calculate the contact areas of the 280 imprints obtained from both sides of the RCWT. Factorial analysis indicated significant effects of tire tread, tire load, and inflation pressure on the resulting contact area. Comparison between effective and traditional contact areas indicated that the current pavement design procedure with traditional circular contact area extremely overestimates the actual tire-pavement contact area up to 92%.     

New Method for Monitoring Tire Pressure of Cars Based on the Tire Radial Deformation

Monitoring tire pressure of cars and signaling abnormal conditions is an important means to prevent deadly accidents. Large achievements have been gained, especially in direct tire pressure monitoring system(TPMS). But there has been rarely research on indirect TPMS in the world. In China, the research on indirect TPMS is almost lacking. The international research on the indirect monitoring tire pressure method is mainly based on measuring and comparing the rotating speed of wheels. But it is very difficult to measure wheel rotating speed accurately because of the influence of many random factors. In this paper, the authors propose a new method in which the tire pressure can be monitored indirectly. This method can be used for tire calibration, wheel speed frequency standardization, wheel speed frequency comparison, and abnormal tire pressure determination. The pulse frequencies from wheel speed sensors of ABS are used to indicate tire deformation. Because the frequency has a relationship with tire deformation, the tire deformation reflects the tire pressure. Small sample statistics is used in the new method to increase the accuracy, and the experimental samples using the principle of the new method have been made and tested. The result of vehicle tests on road demonstrates that the method is efficient and accurate to monitor tire pressure. The research has positive potential for developing products.     

Development and comparative study on tire models in the AutoDyn7 program

In this paper, several tire models (Magic formula, Carpet plot, UA tire, DADS tire and STI tire) are implemented and compared. Since the STI (System Technology Inc.) tire model in the AutoDyn7 program is in a good agreement to NADSdyna STI tire model and experiment, it is selected as a reference tire model for the comparison. To compare tire models, input parameters of each tire model are extracted from the STI tire model to preserve the same tire properties. Several simulations are carried out to compare performances of tire models, i. e., bump simulation, lane change simulation, and pulse steering simulation. The performances in vehicle maneuverability are also compared with the four parameter evaluation method.     

汽车动力学仿真中轮胎模型的建模

针对当前车辆动力学模拟与动态控制研究中所采用的经验轮胎模型需要大量实验数据的情况,探讨了利用理论轮胎模型来进行车辆动力学建模与仿真的实现方法,以改善轮胎经验模型对实验数据过于依赖的不足。通过研究,利用MATLAB／Simulink软件实现了Gim理论轮胎模型的模块化建模和动力学仿真分析。仿真结果和实验数据的对比表明：Gim理论轮胎模型的精度高,能准确预测轮胎的力学特性;所建立的Simulink轮胎子模块通用性强,所需参数少,运算快,为车辆动力学的实时仿真提供了很大方便。     

ADAMS在汽车轮胎动力学研究的应用

汽车轮胎的力学特性是优化轮胎设计,提高轮胎性能的重要依据。然而汽车轮胎的行驶条件的复杂多变,给轮胎的力学特性的掌握和计算带来不少困难。将ADAMS应用于汽车轮胎的动力学研究,可以利用软件来模拟汽车轮胎的各种行驶条件,并利用数学模型计算出汽车轮胎在各工况下的力学特性参数。通过这一过程,工程技术人员可以减少汽车轮胎设计过程中试制试验的轮次,从而达到降低轮胎试验成本,并优化轮胎设计的目的。     

轮胎非稳态侧偏特性非线性仿真模型

在稳态指数统一模型的基础上,根据动态过程有效滑移率的微分表达,建立轮胎非稳态侧偏特性非线性仿真模型。在实验中发现当用有效滑移率和准稳态概念来计算回正力臂 Ｄｘ 时,有滑移率超前而回正力臂滞后现象,该现象可以通过一个一阶滤波器来表达。模型的计算结果与实验结果对比,表明该模型可以反映轮胎非线性侧偏特性,可以用于汽车操纵动力学研究。     

高精度车载航位推算温度补偿研究

温度变化会导致轮胎半径变化,对由里程仪作为测程元件的轮式车辆而言,温度变化会引起里程仪的刻度系数变化,需要建立里程仪刻度系数的温度模型来提高里程仪的测距精度。基于Hadekel轮胎下沉量近似计算公式和胎内气体热力学分析,建立轮胎下沉量及轮胎有效半径的温度模型,进而建立里程仪刻度系数的温度及纵坡度模型,利用最小二乘法标定模型系数,进行跑车试验验证模型补偿效果,跑车试验结果表明:里程仪刻度系数经过温度及纵坡度补偿,里程仪测距精度由1.83‰提高到0.13‰,精度提高一个量级,该模型可使里程仪实现高精度测距。