Determining the State of a Nonlinear Flexible Multibody System Using an Unscented Kalman Filter

Abstract

This paper describes an estimator incorporating the Unscented Kalman Filter (UKF) technique and multibody system dynamics, to determine the state of the flexible multibody applications. The dynamic equation of the flexible mechanism is formed using a set of non-linear equations as functions of reference and modal coordinates. Since both reference and modal coordinates have no physical meaning, their information is not able to be obtained directly from sensors. Thus, a novel technique is proposed in this work that can successfully translate physical measurements collected by sensors into non-physical modal coordinates. To validate the performance of the proposed modeling technique to apply a UKF to determine the state of a nonlinear flexible multibody system, simulation were carried out for a four-bar mechanism case study to compare the simulation data and UKF data.

Keywords

• Deflection
• flexible simulation models
• nonlinear Kalman filter
• state observer
• unscented Kalman filter