RU2593644C2 - Stand for determining mass and coordinates of centre of mass of article - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: invention relates to measurement equipment, particularly for measurement of weight characteristics of articles of aircraft and aerospace engineering areas. Test bench consists of table equipped with three mounting spherical supports. Position of spherical support on table can be changed depending on length of measured item. Rotary supports are fixed on table containing rotary device with electric drives. In coordination and installation of article on bench in seats of rotary supports spherical pins are installed. Spherical pins are intended for installation in sockets, when measuring their coordinates with laser coordinate measurement system. Fixation of rotary supports in extreme positions at turn through preset angle is performed by electric interlocking with disconnection of electric or mechanical stop at failure of previous one. Inclination angle value is determined by angle sensors built in struts with platform scales. Post with platform scales is supplied and is able to move along table with subsequent fixation at specified distance. Post with platform scales weighs article and determines reaction of forces acting on support. Post with platform scales has base with supports and rotary wheel for its movement along floor, and can be adjusted in height. Measurement test bench is controlled by computer.

EFFECT: technical result consists in improvement of accuracy of measurements, possibility of adjusting dimensions of bench table by permutation of supports for required size, possibility of storage of stand in disassembled form and short bench preparation for operation.

1 cl, 1 dwg

Description

The invention relates to the field of measuring the mass characteristics of aircraft and space engineering fields.

The prior art device (application RU No. 2009148994 A), on which the coordinates of the center of mass of the product are determined by the testimony of load cells mounted on a loading platform or directly on the body of the product. To measure the vertical coordinate on such a device, it is necessary to reinstall the product with a rotation of 90 ° around the longitudinal axis, which will increase the complexity of the measurement process.

Also known stand (patent RU No. 2313775 C1) for determining the position of the center of mass, the disadvantage of which is the need to rotate the product through an angle of 90 ° to obtain the value of the third coordinate, which leads to a narrowing of the scope of this design in case of inadmissibility of rotation of the product at such an angle.

Closest to the claimed technical solution for the technical nature and the technical result achieved is a stand for measuring mass, coordinates of the center of mass and the inertia tensor of the product (patent RU No. 2368880 C1). The device comprises a frame to which the product is attached, dynamometers, sensors, springs, a bed, a dynamometer platform with a frame rotation unit mounted on it, the axis of which is connected to an angle sensor, an oscillation setting device consisting of movable internal, external and lower frames. The dynamometer platform is connected through four vertical and two horizontal dynamometers to the inner frame of the oscillation setting device. The inner, outer and lower frames are interconnected with the frame by hinges mounted on brackets and a system of horizontal springs connected to the frames using consoles. The axes of the hinge pairs are connected to the axes of the angle sensors and are oriented along the orthogonal coordinate axes OX, OY, OZ, and the axes of the springs of the corresponding frame are rotated 90 ° relative to the axes of the hinges. Three independent oscillatory systems of the stand allow you to set the oscillation of the product along three mutually perpendicular axes, and the presence of a dynamometric platform - to measure the moments acting on the product relative to three axes. The natural frequencies of oscillations, the initial deviations of the oscillatory systems from the equilibrium position and the magnitudes of the moments are included in the form of simple dependences in the measurement equations and completely determine the inertia tensor of the product. The technical result consists in the possibility of measuring the parameters of the product on the stand, without resorting to turning it through an angle of 90 °, eliminating the mismatch of the coordinate axes, and increasing the accuracy and reliability of measurements.

The stand has two measurement modes: static and dynamic. Since the inertia tensor is not necessary to determine in our case, we consider the static mode in more detail.

In static mode, the mass and coordinates of the center of mass of the product are measured. Using a dynamometer platform, three components of the moment are measured along the corresponding axes and the total mass. When measuring the vertical coordinate, it is proposed to rotate the product by some allowable angle using the rotation unit and at the same time measure this angle by the angle sensor.

The described method is adopted as a prototype of the invention.

One of the disadvantages of this device is the lack of adjustment of the dimensions of the dynamometer table depending on the overall dimensions of the measured product.

In addition, the dynamometer platform is mounted on four vertical and two horizontal dynamometers, which introduces a greater share of the error in the measurement result compared to using fewer dynamometer devices.

Also, the above construction does not allow you to quickly deploy the stand for measurements and store it in a compact form due to the large overall dimensions in the case of using the stand for measuring large-sized large-sized products.

The problem to which the claimed invention is directed, is to achieve high accuracy of measuring the mass and position of the center of mass, the ability to adjust the bench table for the overall dimensions of the measured products and the ability to quickly deploy and store in a compact form.

The problem is solved due to the fact that in the stand for measuring mass and coordinates of the center of mass containing a table, mounting spherical bearings, rotary bearings with spherical fingers, angle sensors, racks with platform scales, rotary supports with spherical fingers, angle sensors, according to the invention the table rests on the supports of racks with platform scales, and it is possible to adjust the position of one support of racks with platform scales relative to the bench table, and the mounting spherical supports, depending on the length the measured product are installed with the possibility of changing the position on the long branch of the table and determining, based on their position, the coordinates of the center of mass of the product, while the table has the ability to quickly dismantle from supports with platform scales when installing the stand for storage.

The technical result achieved is the use of only three racks with platform scales, which leads to an increase in measurement accuracy, the possibility of adjusting the size of the bench table by rearranging the supports to the required size, the possibility of storing the stand unassembled and short-term preparation of the stand for work.

The invention is illustrated by the drawing, which does not cover and, moreover, does not limit the entire scope of the claims of this technical solution, but is only illustrative material of a particular case of execution.

The operation of the device is as follows.

The stand consists of a table 1, equipped with three mounting spherical supports 2. The position of the spherical support 2 on the long branch of table 1 can be changed depending on the length of the measured product. On the table 1, rotary supports 3 and 4 are fixed, containing rotary devices with electric drives.

When coordinating and installing the product on the stand, spherical fingers 5 are installed in the sockets of the pivot bearings 3, 4. Spherical fingers 5 are designed to be installed in the sockets when measuring their coordinates with a laser coordinate measuring system.

The rotation bearings 3, 4 are fixed in the extreme positions when turning through a predetermined angle by an electric lock with the drive switched off or by a mechanical stop in case of failure of the previous one. The value of the angle of inclination is determined by the angle sensor 7, built into the rotary support 3, 4.

The swivel bearing 4 is supplied and has the ability to move along the long branches of the table 1 with subsequent fixation at a given distance.

The coordinates of the spherical bearings 2 are determined by a laser coordinate measuring system.

The coordinates are determined with an error of 30 to 40 microns, entered into the computer database and are used to calculate the coordinates of the center of mass of the product.

Racks with platform scales 6 are designed to weigh the product and determine the reaction forces acting on the supports. The rack with platform scales 6 has a base with supports and swivel wheels to move it on the floor, has the ability to adjust in height.

To determine the three coordinates of the center of mass, the product is installed in a horizontal position and weighed on three high-precision scales mounted in racks with platform scales 6. The coordinates of the center of mass (x, y) are calculated relative to the origin based on the theorem on the addition of two parallel forces directed into one side. To determine the coordinate along the z axis, the product is rotated by an allowable angle by turning the supports 3, 4 in automatic mode and the weighing and calculation procedures are repeated.

On the rotary supports 3, 4, snap-in is installed and fixed to fix the measured product.

The stand for measuring mass and coordinates of the center of mass is controlled by a computer and works in the following modes:

- simultaneous lifting (lowering) of three weights installed in racks;

- calculation of the mass of the product;

- rotation of the product by an angle by an allowable angle;

- calculation of the three coordinates of the center of mass.

During storage, table 1 is removed from the racks with platform weights 6 and packaged in containers.

Thus, the claimed design of the stand allows you to measure the mass and position of the center of mass with high accuracy, the ability to adjust the bench table for the overall dimensions of the measured products and quick deployment and storage in a compact form.

Claims (1)

A stand for measuring mass and coordinates of the center of mass, containing a table, mounting spherical supports, racks with platform scales, rotary supports with spherical fingers, angle sensors, characterized in that the table rests on the supports of racks with platform scales, and it is possible to adjust the position of one support racks with platform scales relative to the bench table, and mounting spherical supports, depending on the length of the measured product, are installed with the possibility of changing position on the long branch of the table and determined based on their position of the coordinates of the center of mass of the product, while the table has the ability to quickly dismantle from supports with platform scales when installing the stand for storage.

Images