Abstract: Aiming at the singularity problem of common full flight motion equation, a modeling method based on improved Euler angle formula is proposed. On the basis of the modified small perturbation modeling equation, this method increases the influence of aircraft maneuvering surface on the aircraft Euler angle and a variable step solution algorithm is used. The model can overcome the singularity problem of common Euler equation, and the accuracy of model calculation is higher than other flight simulation models which overcome the singularity of Euler equation. Compared with the flight simulation model using the conventional Euler angle formula, the proposed model can meet the requirements of simulation accuracy and real-time performance. The simulation of the aircraft's tumbling bucket motion is carried out to verify that the model can avoid the singularity of Euler equation.

Key words: improvement of Euler angle formula, aircraft particle model, flight simulation, variable step algorithm, model verification, fidelity of simulation