About optimal parameters of flexible gimbal elements

of dynamically tuned gyroscope

I.V.Balabanov, T.V.Balabanova

Ukrainian National Technical University "Kiev Polytechnic Institute"

G.M.Vinogradov, N.A.Temlyakov

Ramenskoye Instrument Design Bureau

Studies of a flexible gimbal of a dinamically tuned gyroscope of the type GVK-16 have been performed. There have been obtained optimal sizes of flexible gimbal elements and optimal flexibility magnitude of its frames which along with minimally probable angular rigidity in relation to mandrels provide linear equal gimbal rigidity as well as preset gyro overload capacity.

In developing past researches here the idealized flexible gimbal of a dinamically tuned gyroscope (TRG) of the type GVK-16 is considered. Though idealization of the flexible gimbal means total lack of its technological production errors.

The TRG of the type GVK-16 has a two-frame flexible gimbal assembled by a model. Moreover the axial direction of the TRG coincides with the axis Ox₀, and the radial direction - with the axes Oy₀ and Oz₀.

The constructively examined two-frame flexible gimbal consists of an internal and an external frame which are "parallel" between the rotor and the input drive. Moreover the internal gimbal frame attaches to the rotor and the input drive by two pairs working for flexure flexible elements which have longitudinal axes parallel to the input drive axis. In turn two pairs of flexible elements of the external gimbal frame have perpendicular arrangement of longitudinal axes in relation to the input drive axis.

Flexible elements are the principal elements of gimbal design that substantially determine its primary properties. In a TRG of the type GVK-16 the flexible elements are the plate of variable-cross section formed by two cylindrical holes. Two pairs of flexible elements belonging to the same frame (internal and external) are of equal nominal size. Moreover nominal geometric sizes of flexible elements of the internal frame may differ from similar flexible elements sizes of the internal frame.

The objective of our research is to identify optimal parameters of flexible TRG gimbal elements which could provide accomplishing of the principal requirements for the flexible gimbal. Moreover the principal requirements for a flexible TRG gimbal are the following conditions:

-              angular rigidity values in relation to the operational gimbal axes must be the minimal one;

-              linear rate of a flexible gimbal in the axial and radial direction must be and equal one;

-              the maximal stress values in a flexible gimbal material that may occur due to in-run external device loads must not exceed ultimate strength value;

-              geometric sizes of flexible elements must be no smaller than the minimal sizes conditioned by technological factors.

In the field of current task optimization we confine ourselves to consideration of geometric parameters of flexible gimbal elements as design variables.

The studies revealed fundamental chance to create a flexible gimbal that has acceptable dimension, overload capacity and rigid characteristics. Moreover it was defined that flexibility difference value of the internal and the external frame has an influence upon optimal parameters of flexible elements.

The obtained optimal sizes of flexible elements and the optimal flexibility difference value of the gimbal frames allow linear equal gimbal rigidity, preset TRG overload capacity and minimal-allowable angular rigidity in relation to gimbal mandrels.