Optimal Path Planning using CAMIS: a Continuous Anisotropic Model for Inclined Surfaces

TL;DR

This paper introduces CAMIS, a continuous anisotropic cost model for inclined surfaces that improves path planning for ground robots by accounting for slope orientation, gravity, and terramechanic effects, enhancing energy efficiency and stability.

Contribution

The paper presents a novel anisotropic cost model compatible with existing path planners, allowing for better energy and stability optimization on inclined terrains.

Findings

The model improves path optimality on slopes compared to isotropic models.

Simulation results show advantages in energy efficiency and stability.

Field experiments validate the model's practical applicability.

Abstract

The optimal traverse of irregular terrains made by ground mobile robots heavily depends on the adequacy of the cost models used to plan the path they follow. The criteria to define optimality may be based on minimizing energy consumption and/or preserving the robot stability. This entails the proper assessment of anisotropy to account for the robot driving on top of slopes with different directions. To fulfill this demand, this paper presents the Continuous Anisotropic Model for Inclined Surfaces, a cost model compatible with anisotropic path planners like the bi-directional Ordered Upwind Method. This model acknowledges how the orientation of the robot with respect to any slope determines its energetic cost, considering the action of gravity and terramechanic effects such as the slippage. Moreover, the proposed model can be tuned to define a trade-off between energy minimization and Roll angle reduction. The results from two simulation tests demonstrate how, to find the optimal path in scenarios containing slopes, in certain situations the use of this model can be more advantageous than relying on isotropic cost functions. Finally, the outcome of a field experiment involving a skid-steering robot that drives on top of a real slope is also discussed.