Research On Automotive Testing System Based On Windows CE

Nowadays, automobile has become a part of people’s life and commutes as anindispensable way of transportation. Along with the wide use of automobiles, more and morepeople concern their car’s performance. Currently, the main approaches for investigatingautomobile performance are computer simulation, laboratory experiment and road test.Computer simulation is performed by computer software with relative automobile and itssubsystem models. In fact, it is difficult to develop a vehicle model with high accuracy.Sometimes the gap between the developed automobile model and actual automobile is distinct.Laboratory experiments for studying automobile performance are usually limited due to thefunction of testing bench. For example, it cannot study the tests of automobile controllabilityand stability. Because road tests are always carried out in the experiment field by the use ofactual automobile, the obtained automobile performance is identical to the one as commonuse. Therefore, road test is the key procedure for studying and analyzing automobileperformance.Now most of the widely used test devices and systems are developed on Windows basedon optical speed sensor. There are many constraints in using them. Firstly, vehicle trajectorycannot be obtained with high accuracy directly. Then, there are many factors that limit itsapplication such as the effect of road environment on speed sensor, low precision,inconvenient use, complicated installation and poor portability. With the development ofelectronic techniques and sensors, global positioning system (GPS) is widely used for testingsystems in various engineering. Because GPS testing system is based on position with highaccuracy, it can be extended as a testing system for automobile performance conveniently.Based on these advantages, the present research combines the characteristics of GPS system,XW-AHRS5100and steering force and angle measuring instrument and develops a portableautomobile testing system based on Windows CE.Firstly, GPS positioning principle and calculation method is briefly introduced The usedGPS coordinate systems and the conversion principle between these coordinate systems areanalyzed in detail. Then, the main testing procedures and the measurement of key vehicledynamic parameters are analyzed in detail. After the illustration of GPS system for trajectoryand speed, XW-AHRS5100for acceleration and angular speed, AM-2012for steering angleand turning effort, the hardware platform (ARM Development board of OK6410) and theircharacteristics, the hardware architecture of testing system for automobile performance isinvestigated and developed. By using the programming platform of Visual Studio and C/C++programming language, the software portion of the test system is coded. The software systemmainly consists of four parts. The first part is serial programming, including GPS and AHRSsignals acquisiting and data analyzing. The next is ADC programming. In this part stream driver program is coded firstly, then the data acquisition of steering force and angle isprogrammed with the application of ADC stream driver. The third is about the display of testdata and dynamic curves in real time and the saving procedure. The last part is the realizationof main testing procedure for automobile performance including the maximum speed, theminimum stable speed test, acceleration performance test, coastdown test, braking test, pyloncourse slalom test, steady static circular test, steering efforts test and steering wheel angle stepinput test.In order to verify the developed automobile testing system, a series of testing proceduresis carried out between the present testing system which is based on Windows CE and thewidely used commercial test system AM2600. It is shown from the comparison and analysisof measured data that the results from the present testing system is more accurate than thatfrom AM2600. In addition, data acquisition, real time data and dynamic curves display, datasaving and human-machine interface are completed well. At the same time, the present testingsystem for automobile performance has many advantages such as low price, convenient using,simple operation, easy transplant, good portability and so on. The results also show that itachieves the desired objectives and requirements and can be further used in engineering.