Extended State Observer for Helicopter Mass and Center-of-Gravity Estimation
Abstract
In flight estimations of helicopter mass and center of gravity are critical for health and lifecycle maintenance, flight control system feedback, and mission planning. This paper explores the use of an extended state observer for online estimation of helicopter mass and center-of-gravity location. The core algorithm is a nonlinear observer that offers provable stability properties. After describing the methodology, it is applied to a simulation of a commercial radio-controlled microcoaxial helicopter. Monte Carlo trade studies employing a comprehensive rotorcraft flight dynamics model are used to assess the algorithm’s estimation accuracy in the presence of model and measurement errors. Results show the helicopter mass, longitudinal center-of-gravity location, and lateral center-of-gravity location are estimated accurately in the presence of expected errors. The vertical center-of-gravity position is more difficult to estimate due to its limited observability during typical maneuvers.
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