Traction control design for off-road mobility using an SPH-DAE cosimulation framework

We describe an analytical framework implemented in a general-purpose mobility simulation platform for enabling the design of control policies for improved rover mobility in granular terrain environments. We employ a homogenization of the granular material and use an elasto-plastic continuum model to capture the dynamics of the deformable terrain. The solution of the continuum problem is obtained using the smoothed particle hydrodynamics method. The Curiosity rover wheel geometry is defined through a mesh. The interaction between each wheel and the granular terrain is handled via cosimulation using so-called boundary conditions enforcing particles attached to the rover wheel. A traction control algorithm is implemented to reduce wheel slip and battery drain in hill-climbing scenario. Several parametric studies are carried out to assess rover simulation robustness for operation in uphill mobility scenario with different heights and friction coefficients. The analysis is carried out in an in-house developed simulation framework called Chrono. The implementation of the methods and models described herein is available on GitHub as open source for free use, modification, and redistribution, as well as reproducibility studies.