| Curbing the casualty accidents caused by commercial motor-vehicles has been thefocus of road traffic safety management in our country. The commercial motor-vehicle isone of the main factor causing road traffic accidents. The deterioration of the vehicle’stechnical performance and the failure of its key parts would cause the accident. Thecasualty accidents were mainly caused by large commercial motor-vehicles of passengertransport, which was taken as the research object in this paper. The monitoring methods forbraking system safety performance, steering system safety performance and running systemfatigue reliability were studied. The application of research results would have greatsignificance for curbing casualty accidents. The concrete research work and results are asfollows.(1)Construction of monitoring program and real vehicle test platform for safetyperformance of large commercial motor-vehicles of passenger transport. Considering thekey problems of safety performance monitoring for commercial motor-vehicles ofpassenger transport in current, the work principle of air braking system and hydraulicpower steering system was analyzed, and the main factors affecting the fatigue reliability ofrunning system were discussed, and then the monitoring programs for safety performanceof braking system and steering system and fatigue reliability of running system wereproposed. According to the monitoring program, the collected signals and installed sensorswere discussed, and the real vehicle test platforms for braking system and steering systemwere built based on VBOX(short for VBOX test platform), and the real vehicletest platform for running system fatigue reliability was built based on eDAQ(short foreDAQ test platform). The synchronous acquisition, real-time monitoring and dataprocessing of the monitoring scheme desired signal could be realized by VBOX testplatform and eDAQ test platform, which could meet the need of study work in this paper.(2) The large passenger vehicle dynamics model was established and verified with thereal vehicle test. Acoording to a lare passenger vehicle of FONTON, the large passengervehicle dynamics model was bulit using the dynamic simulation software Trucksim. Thesimulation test and real vehicle test of steady steering were carried out. Comparedsimulation test with real vehicle test in vehicle lateral acceleration, roll angle and yaw rate,the maximum error was less than10%. Therefore, the vehicle dynamics simulation model was validated.(3)A monitoring method for the braking system based on typical braking conditionswas proposed. The braking system was monitored comprehensively under smooth braking,downhill holding braking and straight slamming braking. Brake torque estimation undersmooth braking, braking efficiency monitoring under downhill holding braking, and meanfully developed deceleration(MFDD) estimation under straight slamming braking werediscussed in theory. The real vehicle tests of smooth braking were carried out with VBOXtest platform. The relationships between braking pedal force, braking pedal displacementand the brake torque were given. Real vehicle tests of straight slamming braking and faultsimulation tests of smooth braking and downhill holding braking were carried out, and thentheoretical analysis was verified.(4)A monitoring method for the steering system based on moving average value ofkalman filtering residual error was given. Three freedom model of large passenger vehiclewas built, and the state estimator with kalman filter was established. The vehicle yaw ratewas estimated in real time with steering wheel angle and vehicle speed as input and lateralacceleration for measuring signal. The residual error was calculated by comparingthe estimated value and the measured value, and the moving average value of the residualerror was calculated. A threshold was enacted by analyzing the residual error of the steeringsystem in good performance. A fault was detected when the residual error beyond theenacted threshold. The monitoring method was validated by the real vehicle test andsimulation test of steady steering.(5)A monitoring method for fatigue reliability of running system considering thedistribution of vehicle velocity was proposed. Based on pseudo damage fatigue assessmenttheory and Miner linear cumulative damage rule, the influence of vehicle velocity on thefatigue damage was mainly discussed, and the equivalent coefficients of different speedsections were proposed, and then the monitoring model for running system fatiguereliability was built. The large passenger vehicle axis load data was collected using eDAQtest platform, and the equivalent coefficients of different speed sections were calculated.According to the design target reliability, the vehicle speed distribution and equivalentcoefficient, the vehicle running system residual fatigue lies for four different operating lineswere calculated, and the effectiveness of the monitoring model was verified. |
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