Structure Optimization And Calibration Of The Vehicle Wheel Load Measuring Instrument

In the design of vehicles, the centroid position of the vehicles will directly affectthe vehicles’ safety, controllability and stability. At present, measurement methods ofcentroid position for vehicle mainly contain swaying method, weight feedbackmethod, suspension method, platform as well as supporting reaction method,etc.However, for multi-axial heavy vehicles, existing measurement methods of centroidposition all are of limitation and inapplicability. In view of multi-axial heavyvehicles’ center position measurement, this paper proposes a roll method whichmeasures the vehicle’s center position above a tipping table, calculating the centerposition by measuring wheel load value in different roll angles. In order to reduce theeccentric load error, the tilt error and increase the sensitivity of the measuringinstrument which has been developed, this paper will optimize the structure of themeasuring instrument, so as to improve the measurement precision of centroidposition of the vehicle.Firstly, the mechanical model is established basing on the actual forceconditions of the measuring instrument.Then this paper introduce the measuringprinciple of the wheel load, study on coupling mechanism, analyze the indicators ofwhich affect the measuring precision, so as to determine the optimal parameters.Secondly, in order to improve the anti-partial load and anti-tilt performance ofthe measuring instrument, the finite element model of the measuring instrument isestablished using the finite element simulation software ANSYS. The simulationboth in horizontal condition and in tilt condition are to be done to find the factors ofwhich affect the measuring accuracy of the measuring instrument. Throughcomparative analysis the influence of the strain guages be evenly spaced andunevenly spaced on the measurement precision of the measuring instrument, to getthe best scheme of pasting strain gauges,so as to improve the measurement precision of the measuring instrument.Thirdly, in order to improve the sensitivity of the measuring instrument, theparametric finite element model of the measuring instrument is established in theANSYS software. Based on ANSYS parametric design language(APDL), the groovedepth, the groove width, the groove spacing of the measuring instrument are taken asdesign variables, the strength and stiffness are taken as state variable, the sensitivityof the measuring instrument is taken as objective function, writing the structureanalysis file and optimization control file. Taking the zero-order optimization method,optimizing the sensitivity of the measuring instrument. Under the condition ofmeeting the requirements of the strength and stiffness, improving sensitivity of themeasuring instrument, so as to improve the measurement precision of the measuringinstrument.The measuring instrument specimen is processed and the practical measurementsystem is builded based on the optimized structure. The calibration scheme isdetermined according to data from the loading experiment, so as to get theinput/output curve of the measuring instrument. According to experimental data andthe input/output curve,getting the maximum eccentric load error, the maximum tilterror and the sensitivity of the optimized measuring instrument.