【作者】 魏守山；

【导师】 莫以为；

【作者基本信息】 广西大学 ， 机械电子工程， 2008， 硕士

【摘要】 随着我国汽车保有量的急剧增加,对汽车检测及诊断方法要求越来越高,其中双怠速测试法是一种有效的检测手段之一,据此实现汽车排放的自动测试系统有助于减轻人工劳动强度、提高汽车排放检测的精度,从而提升汽车检测及诊断水平。基于双单片机的系统控制器,分别构造了依据K线(Kan总线)和OBDⅡ(在线诊断Ⅱ代)与汽车ECU(电控单元)通讯获取转速的通讯模块、以步进电机和动力传动装置实现的发动机转速控制模块以及与排放分析仪通讯实现检测数据自动采集的采集模块,实现了发动机转速分段恒值调节控制和排放检测数据自动采集功能,研制出基于双怠速法汽车排放自动测试系统的雏型。由于采用通讯方法获得转速反馈信息可能导致速度控制系统存在不确定的延迟。为提高控制质量,对时滞对象的控制进行初步探讨。当延迟时间较短时,采用Smith预估补偿;当延时超大,采用外推法。并利用Matlab做了仿真比较,结果证明这些控制方法是有效的。实验证明该系统运行稳定,能将发动机转速控制在国标规定范围之内,检测时间可精确定位,确保检测结果准确,达到预期设计目标。更多还原

【Abstract】 As the quantity of the automobile increasing rapidly,the test and diagnosis of automobile is becoming more and more important.The method under two-speed idle condition is one of the effective methods.As a result of realizing the automatic test system,it can cut labor intensity,improve the precision of test vehicles exhaust and improve the level of test and diagnosis.The control system bases on double single-chip.Based on the communication between K-line、OBDII and the ECU,the communication module which can acquire the rotate speed is designed.Based on the rotate speed,the rotate speed of engine which is controlled is realized at the same in period of time.The data which is tested form exhaust is acquired automatically by the acquired module.The module of rotate speed controlled is composed of step motor and gearing.The data acquisition is realized by the communication with exhaust gas analyzer.The automatic test system for test vehicles exhaust is developed based on two-speed idle.Because the rotate speed is acquired by communication and it is indeterminacy when the data is transmitted,there is indeterminacy time delay in the control system.In order to improve the control quality,it probes into the control of time-delay system.When the delay time is short,it adopts the Smith predictor;when the delay time is too long,it chooses the extrapolation.Do some simulations by MATLAB,they prove that the control method is very effectively.It is proved the system working stability by the experiment.It can control the rotate speed within Chinese Standard range and keep the test time accurately. The research goal is achieved.更多还原