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The Design Of Vehicle Weigh-in-Moting Instrument Based On Over-Sampling

Posted on:2011-07-23Degree:MasterType:Thesis
Country:ChinaCandidate:Y N HanFull Text:PDF
GTID:2132360305471532Subject:Control theory and control engineering
Abstract/Summary:PDF Full Text Request
The phenomena of overload around the vehicle on road transport is serious, it resulted in the serious damage on the road even breaking the bridge and blocking the traffic. The phenomena of overload around the vehicle given our country's roads and bridges great destruction, increased the coast of road maintenance, resulted in incalculable economic losses. The use of dynamic truck scale weighing can effectively deter acts of overweight vehicles, using the car value of the monitoring results can effectively evaluate the safe state of highway and bridges.The departments can make weight charges accord to the weighing results of dynamic truck scale in order to conduct strictly and effictivly. At home and abroad, a variety of automotive products in the automotive low-speed dynamic weighing <5Km / h ,the precision is high, but when the vehicle speed 20Km / h ~ 30Km / h , the precision still can not meet the requirements.The key technology of dynamic vehicle weighbridge is the weighing instrument, also known as the dynamic weighing system. It is a combination of hardware and sofeware platform and has been developed for many years in our country.The research and development for the key technology of the system which is the weighing instrument has always been paid close attention. For the current dynamic weighing system,the problem on the identifying accuracy and automobile passing speed can't be resolved well all along, for the disturbing factors affecting the WIM are short of systems analysis and the detecting signal isn't processed further.The thesis first analysis and research thorough to the run state and the dynamical characteristic of the car. and get a conclusion: the vibration of the car be the key factor which influences the effect dynamic weigth, if you want to reflect accurately the static weight, it is necessary to minish and avoid effectually the vibration bases the reason of car's vibration.Secondly, analyse to the sample data and choice the valid district of sample data. When dynamic weigthing, in course of the axle pass to the weigthing platform, on account of the interfere that produce by the car drive up and down the weigthing platform and pass to the surface of weigthing platform,cause a part of sample data consumedly deviated the true value of the axle weight.So the data that collected by the system not only had the true axle weight data, but also had the invalid data which is samplinged when axle don't drive completely up to weigthing platform.For the sake of exaltation calculation accuracy, it is necessary to avoid this kind of invalid data.Thirdly, after reference to various projects, the thesis put forward a kind of way which is over-sampling. The precision of AD is increased when making the best of the AD's speed,the over-sampling can reduce the error and gain the equal SNR with high resolving power.In this way,the AD's resolving power increases through improving the effective digitals of metrical data.By choosing sampling signals by the way of the over-sampling, the metrical speed of dynamic automotive metrical can be increased when holding the accuracy of weigh-in-motion within 1%.Finally hardware electric circuit road is designed according to the effective demand.Includes the design of the outer circuit of the single slice machine, the design of data sampling circuit,the design of data communication circuit, the design of display circuit,the design of keyboard circuit and the design of watchdog circuit.And software system is designed which based on the SAMLLRTOS51 embeded operate system,And carry out the over-sampling weigthing arithmetic using C language.
Keywords/Search Tags:weigth-in-motion, effective data, operate system, over-sampling Small RTOS51
PDF Full Text Request
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