Data-Driven Distributionally Robust Optimal Control with State-Dependent Noise
Rui Liu, Guangyao Shi, Pratap Tokekar
TL;DR
Data-Driven Distributionally Robust Optimal Control ($\mathrm{D}^3\mathrm{ROC}$) addresses the problem of unknown disturbance distributions by jointly learning the reference distribution $q$ and the KL divergence bound $d$ from data. It combines Gaussian Process-based noise modeling for state-dependent references with a $k$-NN KL-divergence estimator, integrated into a Differential Dynamic Programming (DDP) inner loop and a cross-entropy outer loop. The approach is validated on a car-like robot navigation task, where $\mathrm{D}^3\mathrm{ROC}$ demonstrates robust performance and risk-averse behavior, outperforming iLQG across multiple noise scenarios. The results indicate significant practical benefits for real-world systems with uncertain or non-stationary disturbances, enabling robust control without pre-specified ambiguity sets.
Abstract
Distributionally Robust Optimal Control (DROC) is a framework that enables robust control in a stochastic setting where the true disturbance distribution is unknown. Traditional DROC approaches require given ambiguity sets and KL divergence bounds to represent the distributional uncertainty; however, these quantities are often unavailable a priori or require manual specification. To overcome this limitation, we propose a data-driven approach that jointly estimates the uncertainty distribution and the corresponding KL divergence bound, which we refer to as $\mathrm{D}^3\mathrm{ROC}$. To evaluate the effectiveness of our approach, we consider a car-like robot navigation task with unknown noise distributions. The experimental results show that $\mathrm{D}^3\mathrm{ROC}$ yields robust and effective control policies, outperforming iterative Linear Quadratic Gaussian (iLQG) control and demonstrating strong adaptability to varying noise distributions.
