Improved estimation and fault detection scheme for a class of non‐linear hybrid systems using time delayed adaptive CD state estimator

Abstract

An improved fault detection scheme for a non-linear hybrid system with delayed measurement by using a modified non-linear adaptive state estimator is proposed. The proposed estimator performs acceptably even when the (i) covariance of the measurement noise is unknown and also (ii) when the measurements are delayed. The algorithm for the proposed estimator called time-delayed R-adaptive central difference Kalman filter (TD-RACDKF) uses a modified R-adaptive 2nd order Central Difference estimator, also called Central Difference Kalman Filter (CDKF) in some literature. Algorithm for the proposed TD-RACDKF has been presented and its performance evaluated as well as characterised with Monte Carlo simulation on two standard non-linear systems with delayed measurements. The characterisation includes comparison with existing estimators. Having demonstrated the improved performance of the proposed state estimator, its use for fault detection of non-linear hybrid systems was investigated. The performance of the fault detection scheme has been illustrated with the help of a benchmark non-linear hybrid system, namely 'three tank system' and by comparison with a previously available extended KF-based estimator.

Designing an Efficient Observer for the Non-Linear Lipschitz System to Troubleshoot and Detect Secondary Faults Considering Linearizing the Dynamic Error

“…With a density of ρ, the movable electrode is termed isotropic. Governing dynamic equation of movable electrode of capacitor is as: (15) where m=ρAh,c′, k=4K are mass, damping coefficient and resultant spring constant, respectively, t is time and ε0=8.854×10 -12 C 2 N -1 m -2 is permittivity of vacuum; z is deflection of movable electrode. Physical and geometrical properties of studied micro capacitor are presented in Table 1.…”

“…Detecting faults using adaptive observer are studied in refs. [15][16][17]. High gain observers [18][19][20][21] have been used frequently in non-linear systems, and a few cases where the Kalman Filter has been used are presented in refs.…”