Research On Decoupling And Optimization Of Structure Of Automobile Wheel Load Measuring Instrument

In design of the vehicle, the centroid position greatly influences vehicles’safety performance. The tilt method is one of the new methods which achievemulti-axis vehicles’ centroid measurement.During the measurement,Wheel loadmeasurement instrument is required with high accuracy in the inclined state. Asin tilt state, the tangential force together with normal force appiled on themeasuring instrument produce coupling effect on strain area of elasticbody.Therefore achieving decoupling of the wheel load measurement boardbecome the key of this subject.First of all, the wheel load measurement principle is described.According tothe actual working conditions of the measurement instrument when measuringwheel load, the mechanical model of the measurement elastomers at the level andoblique states are established. Through theoretical analysis and calculation,constraint forces and relationship between the strain output of the measurementstation and the load are derivated. By analyzing output of strain when the load isapplied on the elastomer in tilt state, coupling mechanism is researched. Resultsof analysis proves that decoupling of elastomer is able to achieved in structureand the amount of coupling due to the temperature is compensated automatically.Secondly,mechanical performance of three kinds of steel and hard alloy2A12is compared and researched. Simplified structure model of beam is firstly appliedand then theoretical calculation, finite element analysis(FEA) and experimentresearch are conducted respectively. Comparision of experimental results ofbeams verifies the validity of FEA and offers basis for choice of elastomer’smaterial. Reasonable choice of elastomeric material can improve the mechanicalproperties of elastomers, reduce the amount of coupling elastomer for thematerials aspect, while reducing hysteresis, creep caused by the mechanicalproperties the differences, therefore reduce the measurement error of the measurement instrument.Again, using batch processing of ANSYS software, writing programs byAPDL command stream, sensitivity and weight optimized design of elastomerstructure is done by using univariate and multivariate methods. At the same time,by optimization solution, the relation curve between the objective function andthe solution sequence is obtained. Further more, best dimention combanition ofelastomer is determined.This measuring instrument not only has large range, butalso has the characteristic of high sensitivity. In addition, it is portable.Finally, making measurement stations according to the optimization size ofthe elastomer body and formating the whole system of measurement instrument.Utilizing the datas collected at horizontal state and curve of measurementinstrument is calibrated in way of weight loading. After calibration measurementaccuracy in the horizontal state, decoupling precision of measurementinstruments in inclined state is verified.