Optimal Adaptive Control of Linear Stochastic Systems with Quadratic Cost Function

Fuente: arXiv
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Main Authors: Liu, Nian, Zhao, Cheng, Tan, Shaolin, Lü, Jinhu
Format: Preprint
Published: 2024
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author Liu, Nian
Zhao, Cheng
Tan, Shaolin
Lü, Jinhu
author_facet Liu, Nian
Zhao, Cheng
Tan, Shaolin
Lü, Jinhu
contents In this paper, we consider the adaptive linear quadratic Gaussian control problem, where both the linear transformation matrix of the state $A$ and the control gain matrix $B$ are unknown. The proposed adaptive optimal control only assumes that $(A, B)$ is stabilizable and $(A, Q^{1/2})$ is detectable, where $Q$ is the weighting matrix of the state in the quadratic cost function. This condition significantly weakens the classic assumptions used in the literature. To tackle this problem, a weighted least squares algorithm is modified by using random regularization method, which can ensure uniform stabilizability and uniform detectability of the family of estimated models. At the same time, a diminishing excitation is incorporated into the design of the proposed adaptive control to guarantee strong consistency of the desired components of the estimates. Finally, by utilizing this family of estimates, even if not all components of them converge to the true values, it is demonstrated that a certainty equivalence control with such a diminishing excitation is optimal for an ergodic quadratic cost function.
format Preprint
id arxiv_https___arxiv_org_abs_2409_09250
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optimal Adaptive Control of Linear Stochastic Systems with Quadratic Cost Function
Liu, Nian
Zhao, Cheng
Tan, Shaolin
Lü, Jinhu
Optimization and Control
In this paper, we consider the adaptive linear quadratic Gaussian control problem, where both the linear transformation matrix of the state $A$ and the control gain matrix $B$ are unknown. The proposed adaptive optimal control only assumes that $(A, B)$ is stabilizable and $(A, Q^{1/2})$ is detectable, where $Q$ is the weighting matrix of the state in the quadratic cost function. This condition significantly weakens the classic assumptions used in the literature. To tackle this problem, a weighted least squares algorithm is modified by using random regularization method, which can ensure uniform stabilizability and uniform detectability of the family of estimated models. At the same time, a diminishing excitation is incorporated into the design of the proposed adaptive control to guarantee strong consistency of the desired components of the estimates. Finally, by utilizing this family of estimates, even if not all components of them converge to the true values, it is demonstrated that a certainty equivalence control with such a diminishing excitation is optimal for an ergodic quadratic cost function.
title Optimal Adaptive Control of Linear Stochastic Systems with Quadratic Cost Function
topic Optimization and Control
url https://arxiv.org/abs/2409.09250