2026· IEEE Control Systems Letters· Vol 10, pp. 1483-1488· 0 citations· 21 references
Computer Science
Abstract
This letter addresses the data-driven linear quadratic regulator (LQR) problem with input constraints under process noise and errors-in-variables measurement errors. Using noisy state and input measurements, we design controllers that ensure closed-loop stability, minimize a quadratic cost, and respect input bounds without identifying the system dynamics. The problem is formulated as a robust polynomial optimization over all models consistent with the data and noise bounds. By applying the theorem of alternatives and sum-of-squares techniques, we derive tractable certificates that eliminate the measurement-error variables, reducing the complexity of the resulting relaxations. Two formulations are proposed: a matrix-valued formulation based on Scherer’s Positivstellensatz and a scalarized alternative enabling Putinar-type certificates.
This paper studies learning-based model predictive control (MPC) for stabilizing unknown discrete-time linear systems with hard input constraints and additive unbounded sub-Gaussian disturbances. We adopt a certainty-equivalence (CE) design that combines a switching MPC control law with online regularized least-squares (RLS) parameter estimation. The resulting switching control law blends the MPC with a saturated deadbeat controller, ensuring global closed-loop stability. Building upon non-asymptotic error bound of least-squares, we derive non-asymptotic, high-probability stability bounds for the closed-loop system under the proposed switching controller. Numerical experiments illustrate and support the theoretical findings.
Changyi Lei, Seth Siriya, Dragan Nevsi'c et al.· 0 citations
This paper investigates the control of discrete-time linear time-invariant (LTI) systems subject to incomplete and corrupted measurements. Specifically, we focus on designing a Linear Quadratic Gaussian (LQG) controller without relying on explicit state estimation. By leveraging minimum variance duality, our approach allows the current control input to be represented as a linear function of available measurements and previously applied inputs, successfully reducing the task to a tractable deterministic optimization problem. We provide theoretical justification for this framework and demonstrate its practical effectiveness through numerical experiments.
We present a novel model predictive control framework for linear parameter varying (LPV) systems, leveraging a parameter-dependent Lyapunov function (PDLF) while eliminating the conventional double-sum formulation. Traditional PDLF-based approaches for LPV systems often rely on non-convex double summations, requiring approximation techniques such as sum-of-squares programming to derive tractable linear matrix inequality (LMI) conditions. These approximations introduce increased computational complexity and conservatism, limiting their practical applicability. In this paper, we show that for a class of LPV systems with a constant input matrix, it is possible to derive direct LMI conditions without any approximations by appropriately formulating the PDLF. This approach improves closed-loop performance while ensuring both recursive feasibility and asymptotic stability. Numerical comparisons with earlier solutions from the literature are given to illustrate effectiveness of the proposed method.
Jin Yan, Hoai-Nam Nguyen, N. Samama· International Journal of Con...· 0 citations
We present a robust safety-filtering framework for input-constrained underactuated linear systems subject to unknown disturbances. A baseline H-$\infty$ input is derived from a zero-sum differential game, while a disturbance observer supplies an estimate and a transient error bound. The baseline input is adjusted using the disturbance estimate, while the estimate and its error bound are used to define robust high-order control barrier function constraints; forward invariance holds as long as the admissible-input set remains nonempty. For scalar-input systems, pointwise feasibility is determined from an exact input interval, and the interval width defines the feasibility margin. A finite-horizon H-$\infty$ performance balance accounts for the accumulated deviation of the applied input from the baseline H-$\infty$ policy. Simulations on a linearized two-wheeled balancing robot show how position and body-pitch constraints compete for the same bounded wheel-torque input.