Online Terrain Estimation for Autonomous Vehicles on Deformable Terrains (Preprint)
Journal Article - Embargoed Full-Text,01 Jan 2019,25 Sep 2019
Army Combat Capabilities Development Command Ground Vehicles Systems Center WARREN United States
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In this work, a terrain estimation framework is developed for autonomous vehicles operating on deformable terrains. Previous work in this area usually relies on steady state tire operation linearized classical terramechanics models, or on computationally expensive algorithms that are no suitable for rea-time estimation. To address these shortcomings, this work develops a reduced-order nonlinear terramechanics model as a surrogate of the Soil Contact Model SCM through extending a state-of-the art Bekker model to account for additional dynamic effects. It is shown that this reduced-order surrogate model is able to accurately replicate the forces predicted by the SCM while reducing the computation cost by an order of magnitude. This surrogate model is then utilized in a unscented Kalman filter to estimate the sinkage exponent. Simulations suggest this parameter can be estimated within 4 of its true value for clay and sandy loam terrains. It is also shown in simulation and experiments that utilizing this estimated parameter can reduce the prediction errors of the future vehicle states by orders of magnitude, which could assist with achieving more robust model-predictive autonomous navigation strategies.
- Navigation and Guidance
- Combat Vehicles