MEL’NICK V.M.

 

NATIONAL TECHNICAL UNIVERSITY OF UKRAINE "IGOR SIKORSKY KYIV POLYTECHNIC INSTITUTE"

 

ZERO DISPLACEMENT OF THE MOVING PART OF THE FLOAT GYROSCOPE IN THE ACOUSTIC ENVIRONMENT
 

Differential equations of a movable part of the device will be written  down as [1]:

,          (1)

where ; ;  - are moments of inertia of the float;  -  are polar and equatorial moments of inertia of the rotor; c,b - accordingly is the coefficient of inflexibility of the spring and the damping coefficient.

We will consider an individual case. Assume that, , and acoustic pressure  . It is easy to find out the connection between the stable value of the turning angle of the float , the angle rate of turn   of the aircraft about the sensitive  axis  and hard acoustic radiation. From equation (1) in this case we obtain -

                             (2)

Then expression will give:

  ;                (3)

                                   (4)

where  is pressure at a falling wave;  it is circular frequency of an acoustic wave.

Taking expression (4) into account, correlation (2) will be as following [2-3]:

.          (5)

Or so -

.                     (6)

From this we find the dependence between the stable value of the turning angle of the float and the angle rate about the sensitive axis:

.                                                                                  (7)

When acoustic vibration is missed (for this purpose it is necessary in formula (7) to accept  and  ),  for small angles  get the known formula which establishes a connection between the stable turning angle of the float and the input value   (by circulation of the fuselage) :

.                                                   (8)

Otherwise, to formula (8) another element is added, so:

                                         (9)

In this case the second element takes into account the influence of acoustic radiation on the instrumental errors at the stable value of the input value . In  formula (9) the value   is conformity  of the bending motion of the float end  under the action of hard acoustic radiation.

Thus, ignoring the constituents higher than the second order of infinitesimality, from expression (5.5) we obtain -

;

;

.                   (10)

Or in such form:

  ,                             (11)

where        - accordingly are the constituents of angle rate  of the first () and second () order of infinitesimality.

Before inserting expression (11), let’s expand the function  and trigonometric functions in rows in the neighbourhood value, which
satisfies (2) :

;

;

;

;

.                (12)

Equations, after the substitution of correlations (12), will look like -

,                                                                  (13)

where 

;  .       (14)

 

Literature:

1.    Êàðà÷óí, Â.Â. Íåñòàöèîíàðíîå âçàèìîäåéñòâèå àêóñòè÷åñêîãî èçëó÷åíèÿ ðàêåò-íîñèòåëåé ñ äâóõñòåïåííûì ãèðîñêîïîì [Text] / Â.Â. Êàðà÷óí, Â.Ã. Ëîçîâèê, Â.Í. Ìåëüíèê, Å.Ê. Êóíäåðåâè÷ // Space science and technology. - 2001. - Ò. 7, ¹5/6. - Ñ. 21-25.

2.    Korobiichuk, I.Karachun, V.

Mel’nick, V.
Kachniarz, M.  Modelling of influence of hypersonic conditions on gyroscopic inertial navigation sensor suspension// Metrology and Measurement Systems. ¹24 (2),