JPS6042408B2 - Dynamic balance test method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating dynamic balance test method that is performed on the ground when determining the spin stable axis of a spin-stabilized artificial satellite or the like.

Generally, a dynamic balance tester is used when testing the balance of a rotating (rotating) object.

This dynamic balance tester rotates an object to be measured about a predetermined rotation axis and measures unbalance vector components in two axes orthogonal to the rotation axis. The structures of conventional satellites are often axially symmetrical, such as spherical or cylindrical, with respect to the rotation axis (spin axis). The apparent load/unbalance of the satellite was negligible. However, in recent years, there have been an increase in the number of satellites that have asymmetrical shapes or are equipped with deployable objects such as antenna deployment paddles, so when measuring dynamic balance, aerodynamic effects such as lift and drag that act on a rotating satellite are becoming more and more important. It has become impossible to ignore the apparent work-loss balance induced by force. To remove this aerodynamic influence, dynamic balance tests of the satellite in vacuum are required. However, testing in vacuum on the ground requires a combination of a large vacuum device and a dynamic balance test device, which has the disadvantage that the device becomes large-scale and the cost required is enormous. Ta. The purpose of the present invention is to eliminate these drawbacks and measure the amount of unbalanced work in gases with different gas densities using air and gases lighter than air. The object of the present invention is to provide a dynamic balance test method that removes the apparent work-loss balance and calculates the work-loss balance in a vacuum.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention during testing. In this case, helium gas (hereinafter referred to as H) is used as a gas lighter than air.
(referred to as e-gas). In the figure, 1 is a cylindrical He container (back) with a bottom that can be divided into upper and lower parts, and 2 is a He container.
3 is a gas inlet, 3 is a He gas exhaust port, 4 is an oxygen concentration measuring device, 5 is a dynamic balance tester drive unit, and 6 is an artificial satellite with four paddles. In this dynamic balance test, first, the He bag 1 is placed over the artificial satellite 6 mounted on the drive unit 5, and a dynamic balance measurement in the atmosphere is performed. Next, He gas is injected from the He gas inlet 2 and air is exhausted from the He gas exhaust port 3 to change the gas density in the bag 1. The density of the mixed gas inside the He bag is measured using the oxygen concentration measuring device 4, and by measuring the oxygen concentration of the mixed gas, the density of the mixed gas can be determined by back calculation. In addition, by rotating the artificial satellite 1 with the dynamic balance tester 5, H
E-gas and air can be easily mixed, resulting in a uniform distribution state, and the amount of dynamic unbalance can be measured in that state. In a similar way,
Furthermore, the density of the mixed gas in the He bag 1 is changed, and the amount of dynamic unbalance is measured. The amount of dynamic unbalance is measured in the atmosphere and in a mixture of He gas and air with different ratios of n types, and the measured value of the amount of dynamic unbalance is expressed as a vector (γ1, θ1).
Let (γ2, θ2)・ , (γ., θn) be the vector components (Xl, Yl), (X2, Y2), ・ , (X
n, Yn). Here, γ indicates the amount of dynamic unbalance of the lower correction surface on dynamic balance, and O is the angle from the x-axis. The changes in the dynamic unbalance vector component in these n types of mixed gases with different densities are plotted on the graph of gas density and dynamic unbalance amount shown in Figure 2, and the aerodynamic influence added to artificial hygiene is investigated, and its characteristic line is extended by 5 to obtain the dynamic unbalance vector components (X, Y) at zero gas density, that is, in vacuum. From this dynamic unbalance vector component (X, Y), the dynamic unbalance amount (γ
, 0) can be calculated using the following formula, and this (γ, θ) is the true dynamic unbalance of the satellite, and the aerodynamic influence is taken into account. This is the value that was removed. θ: When X≧0, Y≧0, X≦0, Y≧0, X≦0, Y≦0, X≧0, Y≦0 As explained above, the present invention The apparent amount of dynamic unbalance induced by aerodynamic forces during dynamic balance adjustment is calculated from measurement data in atmospheres with different gas densities.
The amount of dynamic unbalance in vacuum can be determined.

Therefore, it is effective for dynamic balance adjustment of objects to be measured such as asymmetrically shaped artificial satellites and artificial satellites to which deployable objects such as deployable paddles are attached. Although the above explanation describes the use of He gas, it is also possible to use light gases other than He gas, and another measurement method can be used to measure the density of a mixed gas with air using an oxygen concentration meter. Good too.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram during a test using an embodiment of the present invention;
The figure is a graph showing the characteristics during the test shown in FIG. In the figure, 1... He bag, 2...
・He gas inlet, 3... He gas exhaust port, 4
. . . Oxygen concentration measuring device, 5 . . . Dynamic balance tester drive unit, 6 . . . Artificial satellite.

Claims (1)

[Scope of Claims] 1. The object to be measured is rotated in a dynamic balance tester in gases with different gas densities, and the dynamic unbalance vector of the object to be measured is measured at each gas density. . A dynamic balance test method, characterized in that a dynamic unbalance vector in vacuum is determined by extending the dynamic unbalance vector component of each of the gas densities to a point where the gas density is zero. 2. The dynamic balance test method according to claim 1, wherein the different gas densities are comprised of air and a mixture of air and helium gas.