arXiv AI

Nonadaptive Learning in Robust Nonlinear Output Regulation

This paper presents a nonadaptive approach to robust nonlinear output regulation for general nonlinear systems with high relative degree in an output‑feedback setting. The design combines an input‑driven filter, a generic internal model, and a recursive backstepping law, transforming the regulation problem into robust input‑to‑state stabilization of an augmented error system. Under standard exosystem assumptions and a minimum‑phase input‑to‑state stability condition, the authors prove global asymptotic regulation and provide explicit inequalities for selecting design gains, demonstrating the method on a benchmark Duffing system.

arXiv Machine Learning
Aug 27

Non-Asymptotic Bounds for Closed-Loop Identification of Sub-Exponentially Growing Nonlinear Stochastic Systems

The paper studies least squares parameter estimation for discrete‑time, unstable, closed‑loop nonlinear stochastic systems with linearly parametrised uncertainty and additive i.i.d. process noise. By perturbing the control policy with exploratory input and assuming a sub‑exponential input‑to‑state growth property, the authors derive non‑asymptotic bounds on the estimation error whenever the state trajectory remains in an informative region of the state space. When the entire state space is informative, the bounds hold with high probability for all time steps, and the authors illustrate the applicability of their results with examples that extend beyond existing work.

By Seth Siriya, Jingge Zhu, Dragan Ne\v{s}i\'c, Ye Pu
arXiv Machine Learning
Sep 18

Demystifying Linear Operator Learning for Control Systems

The paper introduces a structured method for learning linear operators in control systems using data. It leverages the framework of (semi)groups for evolution equations to establish structural assumptions and applies inverse‑problems theory to analyze learning algorithms, revealing error decompositions, convergence guarantees, and optimal regularization. Focusing on bounded operators on Hilbert spaces, the authors derive a convergent estimator for time‑varying systems, illustrating the practical power of their approach.

By Max Beier, Nicolas Hoischen, Sandra Hirche, Petar Bevanda
arXiv Machine Learning
Aug 17

Consistent Model Chasing Is Minimax Optimal: The Exact Value of Scalar Adversarial Adaptive Control under Large Parametric Uncertainty

arXiv:2608. 13651v1 Announce Type: cross Abstract: We solve exactly a fundamental problem of adaptive control against adversarial disturbances: regulate the scalar system $x_{t+1} = ax_t + u_t + w_t$, $x_0=0$, $\|w\|_\infty \le 1$, where the constant pole $a \in [-\Delta, \Delta]$ is unknown in sign and magnitude and $\Delta$ is arbitrarily large.

By Dimitar Ho