Incorporating Stochastic Models of Controller Behavior into Kinodynamic Efficiently Adaptive State Lattices for Mobile Robot Motion Planning in Off-Road Environments

TL;DR

This paper introduces three methods to incorporate stochastic controller behavior into the KEASL motion planner, improving collision prediction and trajectory safety for off-road mobile robots in uncertain environments.

Contribution

It presents novel methods for integrating stochastic controller models into KEASL, enhancing motion planning robustness in real-world, unstructured terrains.

Findings

Stochastic sampling leads to more conservative, safer trajectories.

Incorporation reduces predicted collision likelihood compared to deterministic models.

Enhanced models improve planning safety but may affect success rates.

Abstract

Mobile robot motion planners rely on theoretical models to predict how the robot will move through the world. However, when deployed on a physical robot, these models are subject to errors due to real-world physics and uncertainty in how the lower-level controller follows the planned trajectory. In this work, we address this problem by presenting three methods of incorporating stochastic controller behavior into the recombinant search space of the Kinodynamic Efficiently Adaptive State Lattice (KEASL) planner. To demonstrate this work, we analyze the results of experiments performed on a Clearpath Robotics Warthog Unmanned Ground Vehicle (UGV) in an off-road, unstructured environment using two different perception algorithms, and performed an ablation study using a full spectrum of simulated environment map complexities. Analysis of the data found that incorporating stochastic controller sampling into KEASL leads to more conservative trajectories that decrease predicted collision likelihood when compared to KEASL without sampling. When compared to baseline planning with expanded obstacle footprints, the predicted likelihood of collisions becomes more comparable, but reduces the planning success rate for baseline search.