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Bayesian calibration of Vehicle-Terrain Interface algorithms for wheeled vehicles on loose sands

Ian Dettwiller, Masoud Rais-Rohani, Farshid Vahedifard, George L. Mason, Jody D. Priddy

Journal of Terramechanics, Volume 71, June 2017, Pages 45-56, ISSN 0022-4898,

Abstract:   The Vehicle-Terrain Interface (VTI) model is commonly used to predict off-road mobility to support virtual prototyping. The Database Records for Off-road Vehicle Environments (DROVE), a recently developed database of tests conducted with wheeled vehicles operating on loose, dry sand, is used to calibrate three equations used within the VTI model: drawbar pull, traction, and motion resistance. A two-stage Bayesian calibration process using the Metropolis algorithm is implemented to improve the performance of the three equations through updating of their coefficients. Convergence of the Bayesian calibration process to a calibrated model is established through evaluation of two indicators of convergence. Improvements in root-mean square error (RMSE) are shown for all three equations: 17.7% for drawbar pull, 5.5% for traction, and 23.1% for motion resistance. Improvements are also seen in the coefficient of determination (R2) performance of the equations for drawbar pull, 2.8%, and motion resistance, 2.5%. Improvements are also demonstrated in the coefficient of determination for drawbar pull, 2.8%, and motion resistance, 2.5%, equations, while the calibrated traction equation performs similar to the VTI equation. A randomly selected test dataset of about 10% of the relevant observations from DROVE is used to validate the performance of each calibrated equation.  
Keywords: Off-road mobility; Vehicle Terrain Interface (VTI) model; Bayesian calibration; Metropolis algorithm; Sand; Drawbar pull (DP); Traction; Motion resistance; Database Records for Off-road Vehicle Environments (DROVE)