Research On Detecting System Of Taximeter Use Error Without Disassembly

With the development of reform and opening in recent years, the market is increasingly prosperous, taxicar profession get a booming development ,that is one of the modern city symbolizes.The development of the economy and increase of the people in the living standard, that prompts taxicar is more and more universal. Correspond to this, the people also put forward a more and more high request to the reasonable charge of the taxicar.Vehicle-use taximeter, Be an important tool of the charge standard, get people's recognition increasingly, have became of the gist of fair and reasonable charge between passenger and driver, there is the function of"fair steelyard" of both parties.Therefore taximeter as professional facilities of the taxicar has to be detected periodical compulsively by national measure organization.Not only taximeter must rule in the certain qualified scope, but odometer of automobiles have to satisfy corresponding provision. Because the automobile odometer recorded the mileage information of the car, recording mileage accurately, that can not only conveniently us understand the distance of road, more can provide a basis gist to maintain vehicle in time for us, so we can maintain the car condition better, expel hidden trouble, avoid traffic accident. In the meantime it also is an important reference index of vehicle discard and old cars trade.In addition, only both all satisfy corresponding error request, the mileage information that they show will not differ far away, will have credibility, and can be better guarantee the benefits of driver and passenger.《The People's Republic of China national calculation and examination rules JJG17-1998》discussed the related examination contents of taximeter in detail, the rules prescribed the qualified scope of the use error of the taximeter is +1.0%～-4.0%《;JJG750-90 the speedometer and odometer packed into the car》prescribed odometer use error is 6.0%～-3.0%. The detecting device of this text impoldered will actualize examination to both in the meantime. In addition, this device considered the influence of automobile technique condition towards use error when examination, and carry on an examination by the way of the whole car test.Because of decline of the start price in greatly parts cities of our country, its basic mileage also descends to 2km～4km from the original 10km or 7km, so we can reckon that the taximeter positive deviation is 0.02km～0.04km from the examination rules. Currently, the differentiation ratio that this index of the taximeter mileage is 0.1km, we can know by the test theories that the error is 0.05km for the differentiation ratio, the error exceeds currently the deviation request of the taximeter use error, so it will result in the phenomenon that can't examine taximeter use error. Be more dependable and accurate for assurance examination, we while examining have to find out the lose mileage datas because of the limit of taximeter accuracy, to make the accuracy value of taximeter attain 0.01km when examination, so we develop the detecting device based on the original speed examination equipments.The detecting equip adopts the system that to adjust speed by frequency conversion to supply dynamical power, to imitate road movement by the rollers drag wheels revolve. we can find out easily the lose mileage datas because of the limit of taximeter accuracy by controling transducer conveniently to start,stop,rise and decline speed, so it can raise examination accuracy. To guarantee the staff's safety and exclude the test error for the wheels horizontal swing, the equip adopt the system that defends the wheels horizontal swing, it can prevent the frontage wheels swing in the rollers by reliably clipping tightly to the tires, compel vehicle to move follow a straight line. The measure device adopts light and electric coder signal to carry out accurate measure to automobile mileage, firstly, the coder signal enters a singlechip to count, then enters computer directly by RS232 to commence to following processing. For examining mileage use error more accurately, the text analyses the error theories of wheels on roller detailedly, which will produce influence to the result. We actualize research on the influence of each factor and put forward correspond correction measure when we establish mathematics model, so as to avoid the tedious process of measuring the tire's correction coefficient in traditional method, raising the examination efficiency. In addition,we give the K value adjustment model of the taximeter based on the error analysis and revising, and provide the after_adjusting basis to taximeter unqualifiedly.The software part of the system takes Windows XP as terrace, adops VC++6.0 to realization. Through the numerical card I/O IPC5375 and transducer control_ports to control motor to run and collect various switch signals; by RS232 communication pots to receive the mileage and speed informations of sensor and deliver the leading information and test result toward the manifestation system. The system software carries out datas collecting,analysising and processing, at last assesses the taximeter use error and provids adjusting basis to unqualified taximeter.At last, the text gives an evaluation to the indetermination degree of measure results about the taximeter use error, expresses the detecting quality by the testing way of whole car. Through contrast experiment between the reality car rollers and road in the meantime, verified the function of the system and accuracy and credibility of taximeter mileage use error without disassembly, in addition, also verified "K" value adjusting model to taximeter unqualifiedly, the results expresse that the adjustment gist gived by the system is accurate and dependable .The detecting system work in security and credibility, the process reasonable,the datas repeat better.the system satisfies the design request, can apply directly in detecting line. Realising the whole car examination to taximeter and giving adjustment reference, that enhance the management of traffic manage departments to the taxies, guarantee the rights of consumers.