| The overload behavior of vehicles will not only damage the highway infrastructure,but also damage people’s lives and property,seriously affecting the safety of public transport.For a long time,the way to detect the overload behavior of highway vehicles in China is usually to set up an overload detection station at the entrance of the highway,and detect the overload behavior of vehicles through the dynamic weighing equipment.However,the traditional dynamic weighing equipment often has problems such as large measurement error and difficult axle identification.In view of the disadvantages of traditional dynamic weighing equipment,this paper puts forward a design scheme of dynamic weighing system based on axle group scale.The scheme mainly includes the selection and design of system hardware,the design of dynamic weighing signal processing algorithm and the design of system software.The main contents of this paper are as follows:Firstly,combined with the advantages of the traditional weighing equipment,the hardware structure of the axle group weighing system is designed.The weighing platform of the system is composed of a large and a small weighing platform.The axle load scale with small volume is selected as the auxiliary weighing platform,and the axle group scale with large volume is selected as the main weighing platform.Its length can accommodate the three axles of the measured vehicle to be weighed at the same time,which improves the measurement accuracy and anti cheating ability.At the same time,the selection of the hardware components of the system and the hardware design of the data acquisition device are completed,and the weighing signal acquisition,A/D conversion,data transmission and other functions are realized.Secondly,the common filtering algorithms of in motion weighing are compared and analyzed.EEMD algorithm is used to filter the symmetrical weight signal.The axle group in motion weighing system is simulated by ADAMS software,and the performance of EEMD filtering algorithm and the feasibility of its application in the in motion weighing system are verified by combining with MATLAB platform;The data distribution characteristics of vehicle axle load are analyzed.According to the results of feature analysis,a vehicle axle shape recognition algorithm based on expert algorithm is designed.The vehicle axle shape recognition is realized by combining and matching the measured vehicle axle number and axle weight feature information;Aiming at the problem that the weighing signal waveform of the axle group scale is chaotic,a waveform compensation method is designed,which makes the weighing signal waveform neat and easy to analyze,reduces the computational complexity,and improves the realtime performance of the system.Thirdly,the system software design is completed,including the data acquisition program design and the upper computer detection and control software design.Among them,the detection and control software is modularized on the VS platform using c++ language and MFC class library.The design and development of the monitoring and capturing,static calibration,data storage and other module functions of the detection and control software are completed,and the software algorithms such as filtering,axis recognition and waveform compensation are implemented in the software.Finally,the system function is tested.Firstly,the recognition rate of the system axis recognition algorithm is verified by establishing an independent test program;Then,three common freight cars were selected to carry out the actual weighing test at an overrun detection station,and the three models were tested on the double platform weighing equipment for the same number of weighing tests as a comparative test.The final test results show that the recognition rate of the axis recognition algorithm reaches 97%;When the vehicle passes through the weighing platform at low speed,the measurement error of the system is controlled within 2%,which is about 1% higher than that of the traditional double scale platform dynamic weighing equipment. |
