导航

Acta Aeronautica et Astronautica Sinica ›› 2025, Vol. 46 ›› Issue (7): 130920.doi: 10.7527/S1000-6893.2024.30920

• Fluid Mechanics and Flight Mechanics • Previous Articles    

Aerodynamic coefficient identification method based on noise statistics estimation

Qing WANG1,2, Fengqi ZHENG1,2(), Di DING1,2, Xi YUE2   

  1. 1.State Key Laboratory of Aerodynamics,Mianyang 621000,China
    2.Computational Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China
  • Received:2024-07-09 Revised:2024-07-29 Accepted:2024-09-24 Online:2024-10-24 Published:2024-10-23
  • Contact: Fengqi ZHENG E-mail:zhengfq_mail@163.com
  • Supported by:
    National Level Project

Abstract:

Using flight data to verify and update the wind-tunnel aerodynamic database is an important part of flight vehicle design and evaluation program. In response to the lack of angular acceleration measurement in flight tests, a novel aerodynamic coefficient identification method has been developed in this paper. Firstly, a mathematical model of aerodynamic coefficient identification was constructed by modeling the derivatives of aerodynamic coefficient respect to time as first-order Gauss-Markov process. Then, analytical expressions for the unknown statistics, such as the covariances of process and measurement noise, were derived theoretically by maximizing the likelihood function. The state estimation was conducted by using the Square Root Unscented Kalman Filter (SRUKF) associated with the Unscented Rauch-Tung-Striebel Smoother (URTSS). The unknown statistics were computed explicitly and updated iteratively, based on the state estimation results. Thereby, the time histories of aerodynamic coefficients, as the augmented state variables, were obtained. The effectiveness of the developed method was demonstrated by two examples of aircraft aerodynamic coefficient identification. The results showed that the unknown statistics and aerodynamic coefficients were estimated accurately. In addition, the method is of robust convergence with respect to the initial estimates of unknown statistics.

Key words: aerodynamic coefficient identification, noise covariance, square root unscented Kalman filter, unscented Rauch-Tung-Striebel smoother, likelihood function, flight test, aerodynamic parameter estimation

CLC Number: