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Main Authors: Sang, Xinhuan, Abdelgawad, Abdelrahman, Tron, Roberto
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2602.12492
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author Sang, Xinhuan
Abdelgawad, Abdelrahman
Tron, Roberto
author_facet Sang, Xinhuan
Abdelgawad, Abdelrahman
Tron, Roberto
contents As autonomous robots move into complex, dynamic real-world environments, they must learn to navigate safely in real time, yet anticipating all possible behaviors is infeasible. We propose a composable, model-free reinforcement learning method that learns a value function and an optimal policy for each individual environment element (e.g., goal or obstacle) and composes them online to achieve goal reaching and collision avoidance. Assuming unknown nonlinear dynamics that evolve in continuous time and are input-affine, we derive a continuous-time Hamilton-Jacobi-Bellman (HJB) equation for the value function and show that the corresponding advantage function is quadratic in the action and optimal policy. Based on this structure, we introduce a model-free actor-critic algorithm that learns policies and value functions for static or moving obstacles using gradient descent. We then compose multiple reach/avoid models via a quadratically constrained quadratic program (QCQP), yielding formal obstacle-avoidance guarantees in terms of value-function level sets, providing a model-free alternative to CLF/CBF-based controllers. Simulations demonstrate improved performance over a PPO baseline applied to a discrete-time approximation.
format Preprint
id arxiv_https___arxiv_org_abs_2602_12492
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Composable Model-Free RL for Navigation with Input-Affine Systems
Sang, Xinhuan
Abdelgawad, Abdelrahman
Tron, Roberto
Robotics
Machine Learning
As autonomous robots move into complex, dynamic real-world environments, they must learn to navigate safely in real time, yet anticipating all possible behaviors is infeasible. We propose a composable, model-free reinforcement learning method that learns a value function and an optimal policy for each individual environment element (e.g., goal or obstacle) and composes them online to achieve goal reaching and collision avoidance. Assuming unknown nonlinear dynamics that evolve in continuous time and are input-affine, we derive a continuous-time Hamilton-Jacobi-Bellman (HJB) equation for the value function and show that the corresponding advantage function is quadratic in the action and optimal policy. Based on this structure, we introduce a model-free actor-critic algorithm that learns policies and value functions for static or moving obstacles using gradient descent. We then compose multiple reach/avoid models via a quadratically constrained quadratic program (QCQP), yielding formal obstacle-avoidance guarantees in terms of value-function level sets, providing a model-free alternative to CLF/CBF-based controllers. Simulations demonstrate improved performance over a PPO baseline applied to a discrete-time approximation.
title Composable Model-Free RL for Navigation with Input-Affine Systems
topic Robotics
Machine Learning
url https://arxiv.org/abs/2602.12492