Alpha beta filter

About: Alpha beta filter is a research topic. Over the lifetime, 5653 publications have been published within this topic receiving 128415 citations.

Robust Kalman filter for rank deficient observation models

Abstract: A robust Kalman filter is derived for rank deficient observation models. The datum for the Kalman filter is introduced at the zero epoch by the choice of a generalized inverse. The robust filter is obtained by Bayesian statistics and by applying a robust M-estimate. Outliers are not only looked for in the observations but also in the updated parameters. The ability of the robust Kalman filter to detect outliers is demonstrated by an example.

Backward-Smoothing Extended Kalman Filter

Abstract: The principle of the iterated extended Kalman filter has been generalized to create a new filter that has superior performance when the estimation problem contains severe nonlinearities. The new filter is useful when nonlinearities might significantly degrade the accuracy or convergence reliability of other filters. The new filter solves a nonlinear smoothing problem for the current and past sample intervals using iterative numerical techniques. This approach retains the nonlinearities of a fixed number of stages that precede the stage of interest, and it processes information from earlier stages in an approximate manner. The algorithm has been simulation tested on a difficult spacecraft attitude estimation problem that includes sensing of fewer than three axes and significant dynamic model uncertainty. The filter compensates for this uncertainty via simultaneous estimation of moment of inertia parameters. The new filter exhibits markedly better convergence reliability and accuracy than an extended Kalman filter and an unscented Kalman filter for estimation problems that start with large initial attitude or attitude rate errors.

A Contraction Theory-Based Analysis of the Stability of the Deterministic Extended Kalman Filter

Abstract: The contraction properties of the extended Kalman filter, viewed as a deterministic observer for nonlinear systems, are analyzed. The approach relies on the study of an auxiliary “virtual” dynamical system. Some conditions under which exponential convergence of the state error can be guaranteed are derived. Moreover, contraction provides a simple formalism to study some robustness properties of the filter, especially with respect to measurement errors, as illustrated by a simplified inertial navigation example. This technical note sheds another light on the theoretical properties of this popular observer.

Design of observer with integrators for linear systems with unknown input disturbances

Abstract: The problem of observer design for linear systems with unknown input disturbances is considered. By introducing an integral action into the Luenberger observer, a new kind of observer with integrators is presented. The existence condition for such an observer is given and an illustrative example is included.

Novel rotor-flux observer using observer characteristic function in complex vector space for field-oriented induction motor drives

Abstract: This paper proposes a new strategy to estimate the rotor flux of an induction machine. The electrical model of the induction machine presents the basic idea based on an observer structure, which is composed of a voltage model and a current model. However, the former has the defects of sensitivity to machine parameters in the low-speed range, and the latter also has defects that are sensitive to the machine parameters in wide-speed range. In spite of these shortcomings, the closed-loop flux observer based on two models has been a prevalent estimation method for direct field-oriented control. In this paper, a generalized analysis method called the "observer characteristic function method" is proposed to analyze all kinds of the linear flux observers in an unified form. By the observer characteristic function being utilized, the estimated rotor-flux error involved in the classical methods can be easily clarified. Moreover, the novel rotor-flux observer based on this analysis is also presented. The proposed flux observer is robust to the offset voltage and to parameter variation. The effectiveness of the novel flux observer has been verified by the numerical analysis and experimental results.