The Research Of State Estimation Problem On System With Delayed And Noisy Measurements

State estimation has always been an important topic in control science. When it is impossible to obtain a precise system state, designing a well-performing observer will be very helpful to realize the control over the system.In the context of network communication, problems like transmission delay or packet dropping will inevitably occur due to limited network bandwidth and unknown disturbances to transmission channels. These problems negatively influence the practical application of networked control systems and make it difficult to directly apply traditional control algorithms and filtering theory. Therefore, how to utilize the non-real-time information under disturbances to estimate a precise system state and give reasonable control quantity has become a huge challenge.Given that the sensor measurements transmitted via network in the context of network communication will influence state estimation, we firstly study the state estimation of single-sensor systems that feature random bounded output delay. The measurement transmission delay is modeled as Markov chain. By using the state augmentation technique, the system with delayed measurements is converted into a special multiple model system, then, the Interacting Multiple Model algorithm is applied to estimate the system states. Secondly, we study the problem of distributed consensus filtering in sensor networks with sensor noises. We design a PI observer based consensus filter and prove the convergence of the proposed filter theoretically. Then we design a modified consensus filter which has a better filtering result. Thirdly, we study distributed consensus filtering problem for system with delayed measurements. The measurement transmission delay is treated as unknown output disturbance, and two kinds of singular observer are proposed depending on the system is stable or not. These two kinds of filter improve the estimation result effectively. In addition, this paper also sets up mathematical models for the above three problems respectively, proposes and utilizes different algorithms, and finally conducts numerical simulation to verify the rationality of the theories in this paper.This paper attempts to provide a series of state estimation methods for systems with measurement noise and measurement transmission delay in the context of network communication, so as to offer theoretical support for the practical application of networked control systems.