Development of a gap searching program for automotive body assemblies based on a decomposition model representation

Automobiles, aircraft, and ships require tremendously many parts to be assembled. For developing such large assemblies, most companies accelerate the design process by having many design engineers in different functional or sectional design groups working concurrently. However, interferences and gaps can be found when the parts and sub-assemblies of different design groups are to be assembled. These error cause design changes and additional repair processes, resulting in an unexpected increase in costs and time delays. While the interference problem has been resolved by digital mockup and concurrent engineering methodology, many cases of the gap problem in the automotive industry have been covered by temporary treatments when the gaps are small enough to be filled with sealants. This kind of fast fix can cause leakage into the engine chamber and passenger cabin when the gap size is too big for filling or when the sealant gets old, which can turn fatal. With this research, we have developed a program to automatically find gaps between the parts of an assembly so that design engineers can correct their designs before the manufacturing stage begins. By using the method of decomposition model representation, the program can visualize gaps between complex car body parts as well as estimate their volumetric information. It can also automatically define the boundary between a gap and the exterior space. Although we have reviewed the benefits of the program by applying it to car development, it can also be applied to aircraft and ship designs comprising several parts.     

Improved Quality Output through Computer‐Based Training: An Automotive Assembly Field Study

In this article, two field experiments, conducted in an automotive assembly plant, evaluate how computer‐based training of operational sequences and related quality information can support the assembly performance of the operators. The experiments were performed during the launch of a new vehicle. A comparison was made of learning progress and quality performance between a reference group of operators that only had regular training and a test group for which some of the regular training was replaced with individual computer‐based training. Both quantitative measures of the quality output and questionnaires and observations were used to evaluate the effects of computer‐based training. The results show a clear positive difference in learning progress and improvements in quality output for the test group compared with the reference group. This combined with positive attitudes expressed by the operators and their team leaders shows that this type of training is an effective way to train operators during launches of new vehicles in automotive production.     

汽车电控发动机故障诊断专家系统在高职教学中的应用

随着电子控制技术在汽车上的广泛应用,电控发动机的检修日益成为汽车维修的重点和难点,同时,发动机电控系统检修也是高职高专汽车类专业重要的专业课之一。对模糊理论和BP神经网络在故障诊断方面的应用进行了探讨,以BP神经网络为主,采用模糊理论作为有益补充设计了电控发动机故障诊断专家系统,给学生创造接近实际的虚拟学习环境,增强学生的学习积极性,取得了良好的教学效果。     

乘法器复用技术在滑窗FIR滤波处理中的运用

随着超大规模集成电路的飞速发展,FPGA集成的硬件乘法器越来越多,内核时钟越来越快,使得FPGA在实时信号处理中得到广泛应用。介绍了FIR滤波运算的原理与硬件处理结构,通过乘法器的复用技术,解决了实现滑窗FIR滤波处理时,FPGA内部乘法器的高速运算与外部慢速数据率之间的矛盾。     

WCDMA空中接口的物理层测量

本文对空中接口的技术进行了简单的介绍,着重描述了WCDMA空中接口的结构与功能。并从测量可实现的角度出发,给出了对物理层性能指标和过程进行测量的方案,开发设计了测量分析软件。通过测量的结果,对网络的性能进行了分析。     

医用充气式保温毯控制系统设计及仿真

针对医用充气式保温毯的温度控制要求,提出其温度控制闭环系统的结构,系统的硬件电路主要由温度传感器、单片机及RS232通讯模块等组成。采用PWM方法控制晶闸管导通时间的方式来改变加热丝的加热时间、采用自适应模糊PID控制方法实现保温毯气囊出气温度的自动调节与控制。将整个控制过程分为两个阶段:自动调节初始阶段,加热丝加热的占空比为100%;当温度达到一定值后转入自适应模糊PID控制阶段,由相应控制量来决定加热丝加热的占空比,实现气体温度的调节。通过MATLAB仿真分析表明,所采用的自适应模糊PID控制方法优于常规的PID控制,具有良好的适应性和鲁棒性,可明显提高系统的稳态精度。     

超声波测距在汽车停车泊位中的应用

本系统的硬件基于ARM7,软件基于μC／OS—Ⅱ实时多任务操作系统。本文介绍了以ARM7为控制核心的超声波汽车停车泊位检测报警系统,重点分析了超声波测距的原理、超声波收发器与ARM7的连接与实现以及系统的软件流程设计。该系统在汽车电子方面有一定的实用价值。     

Nonlinear vehicle side-slip estimation with friction adaptation

A nonlinear observer for estimation of the longitudinal velocity, lateral velocity, and yaw rate of a vehicle, designed for the purpose of vehicle side-slip estimation, is modified and extended in order to work for different road surface conditions. The observer relies on a road-tire friction model and is therefore sensitive to changes in the adhesion characteristics of the road surface. The friction model is parametrized with a single friction parameter, and an update law is designed. The adaptive observer is proven to be uniformly globally asymptotically stable and uniformly locally exponentially stable under a persistency-of-excitation condition and a set of technical assumptions, using results related to Matrosov's theorem. The observer is tested on recorded data from two test vehicles and shows good results on a range of road surfaces.