Estimation of Continuous-time Stochastic System Parameters

Author(s):  
Erik K. Larsson ◽  
Magnus Mossberg ◽  
Torsten Söderström
2019 ◽  
Vol 17 (03) ◽  
pp. 1850140 ◽  
Author(s):  
Aadil Lahrouz ◽  
Adel Settati ◽  
Mohamed El Fatini ◽  
Roger Pettersson ◽  
Regragui Taki

This paper is devoted to a continuous-time stochastic differential system which is derived by incorporating white noise to a deterministic [Formula: see text] epidemic model with mass action incidence, cure and relapse. We focus on the impact of a relapse on the asymptotic properties of the stochastic system. We show that the relapse encourages the persistence of the disease in the population and we determine the threshold of the relapse rate, above the threshold the disease prevails in the population. Furthermore, we show that there exists a unique density function of solutions which converges in [Formula: see text], under certain conditions of the parameters to an invariant density.


Author(s):  
Jiang Wu ◽  
Fucheng Liao ◽  
Yuan Yan Tang

This paper discusses the optimal control problem for a class of linear continuous-time stochastic systems with time-delay based on the preview control method. In the design procedure, the time-delay terms are formally eliminated and the augmented error system method is used. The optimal controller of the time-delay stochastic system is obtained based on dynamic programming principle. In the previous approaches, the preview control method is applied to continuous-time deterministic system. Consequently, compared with the existing results, the main contributions of this paper are: (1) the conclusion of the non-singular transformation is improved and (2) the conclusion in deterministic system is extended by using the methods of designing an assistant system and introducing an integrator when building the stochastic augmented error system. The optimal tracking of the stochastic system with time-delay is realized by solving the optimal regulation problem of the stochastic augmented error system. The simulation shows the effectiveness of the controller designed in this paper.


Author(s):  
Jiang Wu ◽  
Fucheng Liao ◽  
Zhengguang Xu ◽  
Yuan Yan Tang ◽  
Yujie Xu

In this paper, the problem of preview control for continuous-time singular stochastic systems is studied by the augmented error system approach. First, a static output feedback is introduced to make the closed-loop system impulse-free. And through the second restricted equivalent transformation, the continuous-time singular stochastic system is transformed into a normal stochastic system and some algebra equations. Then, an assistant system is designed to overcome the difficulty of trying to make derivation to a stochastic system like in deterministic system condition. And the stochastic system after the transformation is translated to the assistant system. In order to make the output of the singular system track the reference signal as accurately as possible without static error, an integrator is introduced. Based on the system after the translation and the error equation, an augmented error system is constructed with the state vector, the error vector and the reference signal. Finally, the tracking problem for the singular stochastic system is transformed into the optimal regulating problem for the augmented error system. By the dynamic programming method, the optimal preview controller for the original singular stochastic system is obtained. The existence and uniqueness solution of the Riccati equation is discussed and the numerical analysis shows the effectiveness for the preview controller designed in this paper.


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