scholarly journals Kalman observer design for marine craft models represented in frequency domain

2021 ◽  
pp. 109-115
Author(s):  
Я.Ю. Селезень ◽  
А.Н. Балабанов

В статье описывается предложенный авторами новый подход к построению стационарного оптимального наблюдателя Калмана по частотной характеристике линейного динамического объекта. Предложенный подход может иметь множество практических применений в задачах управления и анализа состояния морских судов так как различные частные виды движений судов описываются линейными динамическими стационарными моделями представленными изначально именно в частотной области. В частности в работе рассматривается задача оценки состояния системы курсового автопилота, использующего только измерения компаса. Для достижения цели работы – построения соотношений для определения наблюдателя Калмана по частотной характеристике объекта, использовался один из методов поиска решения стабилизирующего решения алгебраического уравнения Риккати – метод резольвенты. Модификация метода резольвенты позволила осуществить целевое построение с привлечением дополнительного условия на свойство линейного динамического объекта, сужающего область применения предложенного подхода до только полностью наблюдаемых объектов. A new approach which constructs a steady-state optimal Kalman observer by frequency response of a linear dynamic object is proposed in the paper. The proposed approach tend to have many practical applications in the area of control and state analysis of sea vessels problems, since various particular ship movements types described by linear dynamic stationary models presented initially in the frequency domain. In particular, the paper considers the problem of assessing the state of the system of the course autopilot using only compass measurements. To achieve the goal of the work - constructing relations for determining the Kalman observer by the object frequency characteristic, one of the algebraic Riccati equation solution method was improved. It was the resolvent method. The proposed resolvent method modification allows reaching the paper goal under one additional auxiliary condition to the linear dynamic object property. The condition narrows the scope of the proposed approach to only completely observable objects.

1995 ◽  
Author(s):  
Ilya V. Yaroslavsky ◽  
Anna N. Yaroslavsky ◽  
Hans-Joachim Schwarzmaier ◽  
Garif G. Akchurin ◽  
Valery V. Tuchin

Author(s):  
Yan Liu ◽  
Dirk So¨ffker

This paper introduces a robust nonlinear control method combining classical feedback linearization and a high-gain PI-Observer (Proportional-Integral Observer) approach that can be applied to control a nonlinear single-input system with uncertainties or unknown effects. It is known that the lack of robustness of the feedback linearization approach limits its practical applications. The presented approach improves the robustness properties and extends the application area of the feedback linearization control. The approach is developed analytically and fully illustrated. An example which uses input-state linearization and PI-Observer design is given to illustrate the idea and to demonstrate the advantages.


2021 ◽  
Vol 22 (12) ◽  
pp. 625-633
Author(s):  
A. V. Zuev ◽  
A. N. Zhirabok ◽  
V. F. Filaretov ◽  
A. A. Protsenko

The paper is devoted to the problem of fault identification in technical systems described by non-stationary nonlinear dynamic equations under unmatched disturbances. To solve the problem, sliding mode observers are used. The suggested ap- proach is based on the model of the original system of minimal dimension having different sensitivity to the faults and distur- bances in contrast to the traditional approaches to sliding observer design which are based on the original system. Additionally it is assumed that matrices describing such a model have the canonical form and are constant. The main purpose of using such a model is possibility to take into account the non-stationary feature of the systems. As a result, the model has stationary dynamic and non-stationary additional term that allows to promote sliding mode design. Besides, the new approach to design sliding mode observers is suggested. The peculiarity of this approach is that it does not require that original systems should be minimum phase and detectable. According to the traditional approaches stability of the observer is provided by minimum phase and detectability properties. In our approach, stability of the observer is achieved due to the canonical form of the matrices describing the model. In addition, the matching condition is not necessary. This allows to extend a class of systems for which sliding mode observers can be designed. Theoretical results are illustrated by practical example of electric servoactuator.


2020 ◽  
Author(s):  
Shine Win Naung ◽  
Mohammad Rahmati ◽  
Hamed Farokhi

Abstract The high-fidelity computational fluid dynamics (CFD) simulations of a complete wind turbine model usually require significant computational resources. It will require much more resources if the fluid-structure interactions between the blade and the flow are considered, and it has been the major challenge in the industry. The aeromechanical analysis of a complete wind turbine model using a high-fidelity CFD method is discussed in this paper. The distinctiveness of this paper is the application of the nonlinear frequency domain solution method to analyse the forced response and flutter instability of the blade as well as to investigate the unsteady flow field across the wind turbine rotor and the tower. This method also enables the aeromechanical simulations of wind turbines for various inter blade phase angles in a combination with a phase shift solution method. Extensive validations of the nonlinear frequency domain solution method against the conventional time domain solution method reveal that the proposed frequency domain solution method can reduce the computational cost by one to two orders of magnitude.


2011 ◽  
Vol 27 (6) ◽  
pp. 1080-1094 ◽  
Author(s):  
Lars Blackmore ◽  
Masahiro Ono ◽  
Brian C. Williams

Autonomous vehicles need to plan trajectories to a specified goal that avoid obstacles. For robust execution, we must take into account uncertainty, which arises due to uncertain localization, modeling errors, and disturbances. Prior work handled the case of set-bounded uncertainty. We present here a chance-constrained approach, which uses instead a probabilistic representation of uncertainty. The new approach plans the future probabilistic distribution of the vehicle state so that the probability of failure is below a specified threshold. Failure occurs when the vehicle collides with an obstacle or leaves an operator-specified region. The key idea behind the approach is to use bounds on the probability of collision to show that, for linear-Gaussian systems, we can approximate the nonconvex chance-constrained optimization problem as a disjunctive convex program. This can be solved to global optimality using branch-and-bound techniques. In order to improve computation time, we introduce a customized solution method that returns almost-optimal solutions along with a hard bound on the level of suboptimality. We present an empirical validation with an aircraft obstacle avoidance example.


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