Аннотация:

This paper considers the features of motion mathematical models of elastic flight vehicle (FV) in flow (perturbation equations or elastic dynamic design of unmanned winged FV equations, FV FDS) used for the automatic control system (ACS) settings and FV motion statistical computer simulation. The details of perturbation equation generation are given for elastic FV in flow and application of FDS design models by design stages. The methods are also given to increase the presentation accuracy of elastic characteristics and aerodynamic influence on FV in order to improve the reliability of flight missions.

Ключевые слова:

elastic dynamic design, unmanned flying vehicles, automatic control system, equations and parameters of EDD

Основной текст труда

Various types of missile and aerospace systems can successfully operate only with automatic control and stabilization systems (ACS). The characteristics of FV either rigid or as elasticbody in the air flow are critical for ACS correct operation while choosing its structure and parameter settings. Discrepancies and counting errors in this regard can affect flight missions and even cause accidents that frequently occurred at the early stages of aircraft development.

FV complete dynamic model includes rigid FV and elastic FV. Flight motion dynamics of elastic FV is described by the corresponding mathematical models — perturbation equations [1, 2]. Such models developed with certain assumptions and used at NPOM for computer statistical simulation of elastic FV motion in flow are also called elastic dynamic design(EDD) of winged FV.

EDD equations are generated based on specific design models — elastic & mass models [3] and models of aerodynamic influence on FV [4]. Great efforts are taken at NPOM to define, confirm and amend FV mass, rigid, elastic, dynamic and aerodynamic characteristics by calculations and experiments at all design stages in order to avoid significant counting errors during FV designing.

Due to importance of tasks solved based on EDD, a great scope of calculations and trials are conducted in the process of design to confirm EDD and correct it if required. EDD equations and calculation models are added during sketch design. It is now possible to amend EDD calculation models according to design documentation at the stage of detailed design and to correct it according to stiffness and modal tests at the stage of stand testing. EDD calculation models can be used to analyze emergency situations at the stage of flight trials.

This paper presents the main details of winged FV EDD generation and amendment. All forces acting on elastic FV in flow are taken into account while generating EDD motion equation. These are the elastic and inertial forces acting both on FV as a system with the distributed parameters and its control systems; structural damping and friction in fin control circuit; aerodynamic forces acting on FV and its control systems as well as all types of the external factors acting on FV in flight. The typical form of EDD equations is also given.

Typical EDD equations are given. It is explained how to calculate parameters of FV as a rigid body motion tones, i. e. “zero” tones. Ratios bringing the initial equation system of elastic FV motion to its accepted form (main normal coordinates) are presented. Matrix structure of EDD equation system is presented. Coordinate transformation ratios of FV motion are presented as to coordinates determined by sensitive elements of ACS.

Methods to calculate and amend the parameters of elastic FV EDD in flow are given:

- calculation of summarized aerodynamic forces acting on elastic FV;
- replacement of design aerodynamic forces acting on fins for the experimental ones;
- determination of zero tones acting on elastic FV;
- conversion of aerodynamic rigidity matrix coefficients and damping while transferring to ACS physical coordinates;
- introduction of experimental pressure coefficients in the phases of nonlinear aerodynamics;
- recording of aerodynamic stiffness and damping matrixes which is valid for random points of FV motion lines including the area of non-linear aerodynamic characteristics;
- presentation of plays in fin control linkage.

These methods to define and amend parameters of elastic FV in flow are required for statistical computer simulation of FV motion and to improve the reliability of flight missions in the end.

Литература

- Kolesnikov K.S., Sukhov V.N. Uprugii letatel'nyi apparat kak ob"ekt avtomaticheskogo upravleniya [Elastic flying vehicle as the object of automatic control]. Moscow, Mashinostroenie Publ., 1974, 267 p. (In Russ.).
- Vatrukhin Yu.M., Nikitenko V.I., Popovskii V.N. Osobennosti uravnenii vozmushchennogo dvizheniya uprugogo izdeliya v potoke vozdukha. Proektirovanie i proizvodstvo sistem raketnogo i artilleriiskogo vooruzheniya [Features of equations for elastic object disturbance in flow. Designing and manufacturing of missile and artillery weapon systems]: Theses of All-Union seminar, BMSTU. Inv. no. 27498s. Moscow, 1986, pp. 156–157. (In Russ.).
- Vatrukhin Yu.M., Rybakov A.A., Nabiullin E.N. Postroenie matematicheskoi modeli uprugogo letatel'nogo apparata slozhnykh prostranstvennykh dinamicheskikh skhem v zadachakh aerouprugosti [Formulation of mathematical model for elastic flying vehicle of complex three-dimensional designs in aeroelastic problems]. MRS "TTE" [MRS TTE], 1983, ser. A, iss. 5. Moscow, p/ya 1420. (In Russ.).
- Vatrukhin Yu.M. Kompleksnyi analiz aerouprugikh kharakteristik letatel'nogo apparata slozhnoi silovoi skhemy [Complex analysis of FV aeroelastic characteristics with complex force diagram]: dissertation for Candidate Degree in Technical Sciences, by occupation 01.02.06. Moscow, 1988, 130 p. (In Russ.).