On the Value of Linear Quadratic Zero-sum Difference Games with Multiplicative Randomness: Existence and Achievability

Fuente: arXiv
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Autores principales: Cai, Songfu, Cao, Xuanyu
Formato: Preprint
Publicado: 2023
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author Cai, Songfu
Cao, Xuanyu
author_facet Cai, Songfu
Cao, Xuanyu
contents We consider a wireless networked control system (WNCS) with multiple controllers and multiple attackers. The dynamic interaction between the controllers and the attackers is modeled as a linear quadratic (LQ) zero-sum difference game with multiplicative randomness induced by the the multiple-input and multiple-output (MIMO) wireless fading. The existence of the game value is of significant importance to the LQ zero-sum game. If it exists, the value characterizes the minimum loss that the controllers can secure against the attackers' best possible strategies. However, if the value does not exist, then there will be no Nash equilibrium policies for the controllers and attackers. Therefore, we focus on analyzing the existence and achievability of the value of the LQ zero-sum game. In stark contrast to existing literature, where the existence of the game value depends heavily on the controllability of the closed-loop systems, the multiplicative randomness induced by the MIMO wireless channel fading may destroy closed-loop controllability and introduce intermittent controllability or almost sure uncontrollability. We first establish a general sufficient and necessary condition for the existence of the game value. This condition relies on the solvability of a modified game algebraic Riccati equation (MGARE) under an implicit concavity constraint, which is generally difficult to verify due to the multiplicative randomness. We next introduce a novel positive semidefinite (PSD) kernel decomposition method induced by multiplicative randomness. A verifiable tight sufficient condition is then obtained by applying the proposed PSD kernel decomposition to the constrained MGARE. Under the existence condition, we finally construct a closed-form saddle-point policy based on the minimal solution to the constrained MGARE, which is able to achieve the game value in a certain class of admissible policies.
format Preprint
id arxiv_https___arxiv_org_abs_2310_05894
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle On the Value of Linear Quadratic Zero-sum Difference Games with Multiplicative Randomness: Existence and Achievability
Cai, Songfu
Cao, Xuanyu
Optimization and Control
49N10 (Primary), 93E20, 91A23 (Secondary)
We consider a wireless networked control system (WNCS) with multiple controllers and multiple attackers. The dynamic interaction between the controllers and the attackers is modeled as a linear quadratic (LQ) zero-sum difference game with multiplicative randomness induced by the the multiple-input and multiple-output (MIMO) wireless fading. The existence of the game value is of significant importance to the LQ zero-sum game. If it exists, the value characterizes the minimum loss that the controllers can secure against the attackers' best possible strategies. However, if the value does not exist, then there will be no Nash equilibrium policies for the controllers and attackers. Therefore, we focus on analyzing the existence and achievability of the value of the LQ zero-sum game. In stark contrast to existing literature, where the existence of the game value depends heavily on the controllability of the closed-loop systems, the multiplicative randomness induced by the MIMO wireless channel fading may destroy closed-loop controllability and introduce intermittent controllability or almost sure uncontrollability. We first establish a general sufficient and necessary condition for the existence of the game value. This condition relies on the solvability of a modified game algebraic Riccati equation (MGARE) under an implicit concavity constraint, which is generally difficult to verify due to the multiplicative randomness. We next introduce a novel positive semidefinite (PSD) kernel decomposition method induced by multiplicative randomness. A verifiable tight sufficient condition is then obtained by applying the proposed PSD kernel decomposition to the constrained MGARE. Under the existence condition, we finally construct a closed-form saddle-point policy based on the minimal solution to the constrained MGARE, which is able to achieve the game value in a certain class of admissible policies.
title On the Value of Linear Quadratic Zero-sum Difference Games with Multiplicative Randomness: Existence and Achievability
topic Optimization and Control
49N10 (Primary), 93E20, 91A23 (Secondary)
url https://arxiv.org/abs/2310.05894