Multibody-Based Input and State Observers Using Adaptive Extended Kalman Filter

The aim of this work is to explore the suitability of adaptive methods for state estimators based on multibody dynamics, which present severe non-linearities. The performance of a Kalman filter relies on the knowledge of the noise covariance matrices, which are difficult to obtain. This challenge can be overcome by the use of adaptive techniques. Based on an error-extended Kalman filter with force estimation (errorEKF-FE), the adaptive method known as maximum likelihood is adjusted to fulfill the multibody requirements. This new filter is called adaptive error-extended Kalman filter (AerrorEKF-FE). In order to present a general approach, the method is tested on two different mechanisms in a simulation environment. In addition, different sensor configurations are also studied. Results show that, in spite of the maneuver conditions and initial statistics, the AerrorEKF-FE provides estimations with accuracy and robustness. The AerrorEKF-FE proves that adaptive techniques can be applied to multibody-based state estimators, increasing, therefore, their fields of application.

State of Charge Estimation Algorithm Based on Fractional Order Adaptive Extended Kalman Filter and Unscented Kalman Filter

Accurate estimation of battery state of charge (SOC) is the basis of battery management system. the fractional order theory is introduced into the second-order resistance-capacitance (RC)model of lithium battery and adaptive genetic algorithm is used to identify the parameters of the second-order RC model based on fractional order. Considering the changes of internal resistance and battery aging during battery discharge, the battery health state (SOH) is estimated based on unscented Kalman filter (UKF), and the values of internal resistance and maximum capacity of the battery are obtained. Finally, a novel estimation algorithm of lithium battery SOC based on SOH and fractional order adaptive extended Kalman filter (FOAEKF) is proposed. In order to verify the effectiveness of the proposed algorithm, an experimental system is set up and the proposed method is compared with the existing SOC estimation algorithms. The experimental results show that the proposed method has higher estimation accuracy, with the average error lower than 1% and the maximum error lower than 2%.