RU2660013C2 - Device for control of mutual orientation and mutual position of measurement devices - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: invention relates to the definition of technology and can be used in those systems where it is important to know the relative position and orientation of several devices, in particular, it can be used in transport, in space and laboratory equipment. Device is placed on a support and comprises a lower plate, side platforms, fastening means for securing the side platforms and the lower plate to the support, as well as displacement sensors and a data processing unit connected to the displacement sensors, the lower plate and the side platforms being configured to be mounted on the support to form a pyramidal structure. In this case, the lower plate and the side platforms are mutually disposed with gaps along the ribs of the pyramidal structure being formed, sufficient to accommodate biasing sensors therein, at least one bias sensor is located in each gap. Device is designed to accommodate measuring instruments on side platforms.

EFFECT: technical result is to improve the accuracy of joint instrument measurements.

5 cl, 1 dwg

Description

Technical field

The invention relates to the field of control and measuring equipment and technology and can be used in those systems where it is important to know the relative position and orientation of several devices. The invention can be applied in transport, space and laboratory technology, for example, as supporting platforms for telescopes, optical instruments, antenna devices, measuring systems, etc.

State of the art

From the prior art RU 2312771 C1 (published by B32B 33/00, G01B 9/06, B64G 1/22) a platform is known in the form of a flat annular or circular centrally symmetric panel used in high-precision space and ground technology, for example, as an optical support instruments, antenna devices, measuring systems. The platform contains casing made of layers of fibrous material impregnated with a polymeric binder, a honeycomb core between casing, and attachment points located with equal angular pitch. Each skin layer consists of sectors joined together with the same central angle. The number of sectors in each layer is equal to or a multiple of the number of attachment points. In each sector of one layer, the fibers are oriented at the same angle relative to the central axis of the sector. The sectors of each subsequent layer are offset relative to the sectors of the previous layer by an angle equal to half the central angle of the sector. In each sector of one layer, the fibers can be oriented at an angle of 90 ° to the central axis of the sector. Layers may also be present where the fibers are oriented at an angle of 0 ° to this axis. The platform provides the specified accuracy of positioning of the attachment points located on it when fulfilling the strength and stiffness requirements by controlling the thermal deformation of the structure through the use of new reinforcing structures of layers of composite material, consistent with the location of the attachment points.

The prior art US 6412346 B2 (published 02.07.2002, class G01C 21/16) known inertial measuring unit (IMU), mounted on a movable machine, adopted as the closest analogue. The measuring unit includes a housing on which three pairs of semiconductor sensors are placed, each pair contains a gyroscope and a corresponding acceleration meter. The casing is made in the shape of a triangular pyramid, and the base of the casing is fixed in a nominal position and fixed with appropriate fixtures for positioning and fixing the casing in a predetermined relation to the axis of the movable means. Each pair of semiconductor sensors is mounted on the corresponding front side of the housing. An advantage of the invention is a housing that is compact in size, weight and volume, and which can be easily mounted on a moving object (mobile vehicle).

A common disadvantage of the above devices is the inability to register their own deformations of the bases used in such devices.

To solve certain technical problems, it is necessary to control the mutual orientation and relative position of the measuring instruments, as well as the change in their orientation and position over time.

An example of a problem for which the proposed device can be applied is the construction of a high-precision stellar orientation system with several optical heads (sensors). Each optical head is a camera with a matrix photodetector, an electronics unit for image processing and special mathematical software. Each optical head photographs a fragment of the starry sky falling into its field of view. The electronic image of this frame is read from the matrix photodetector and transmitted to the electronics unit for processing. Images of stars are highlighted in the frame and the positions of their centers in the coordinate system associated with the optical head are determined. Part of the resulting list of images is identified with the stars from the on-board catalog stored in the memory of the electronics unit. Knowing the coordinates of the identified stars in the coordinate system of the optical head obtained as a result of image processing, and the coordinates of the same stars in the inertial coordinate system (for example, equatorial celestial coordinates of stars) stored in the catalog, one can determine the orientation (rotation) of the coordinate system associated with the optical head, relative to the inertial coordinate system, for example, two angular equatorial coordinates of the center of the field of view and the rotation of the sides of the frame relative directions to the pole of the world. The readings of all the optical heads of the orientation system are processed together and make it possible to determine the turn of the orientation system relative to the inertial coordinate system. For this, it is necessary to know the position of the optical heads within the coordinate system with an accuracy no worse than the internal error of the optical heads. It is also necessary that the position of the optical heads is maintained during operation of the orientation system with an accuracy no worse than the internal error of the optical heads.

Currently, the position of the optical heads in the orientation system is maintained due to the mechanical stability of the structures. Laboratory and flight tests have shown that the design of spacecraft orientation systems undergo thermoelastic deformation, leading to a change in the mutual orientation of the optical heads by 5-20 angular seconds, while the internal error of modern optical heads of stellar orientation sensors is 1-3 angular seconds. The solution to this problem by increasing the dimensional stability of the design of the orientation system is unpromising.

Thus, a technical problem is the creation of a device for controlling the mutual orientation and relative position of measuring instruments, which makes it possible to exclude the results of joint measurements of instruments with a large systematic error due to the effect of thermoelastic deformations on their mountings.

Disclosure of invention

The technical result of the invention is to improve the accuracy of joint measurements of devices.

The technical result is achieved by creating a device for controlling the mutual orientation and relative position of measuring instruments placed on a support, which contains a lower plate, side platforms, fasteners designed to fix the side platforms and the lower plate to the support, as well as displacement sensors and a processing unit data connected to the displacement sensors, while the lower plate and side platforms are made with the possibility of installation on a support with the formation of a pyramidal structure, while the lower plate and the side platforms are mutually arranged with gaps along the edges of the pyramidal structure formed, sufficient to accommodate displacement sensors, with at least one displacement sensor placed in each gap, and the device is arranged to place measuring instruments on the side platforms.

In this case, the pyramidal structure formed can be made in the form of a triangular, or quadrangular, or pentagonal, or hexagonal pyramid.

In each gap, two or three displacement sensors can be placed.

The displacement sensor may be a capacitive sensor. Brief Description of the Drawings

In FIG. 1 shows a device for monitoring the relative orientation and relative position of measuring instruments; an option in which one of the shear sensors is mounted on each of the edges of the triangular pyramid, while its axis is perpendicular to the edge of the formed pyramid on which it is mounted.

The positions in the drawings indicate:

1 - bottom plate of the device;

2 - side platforms of the device;

3 - displacement sensor;

4 - fastening means;

5 - data processing unit.

The implementation of the invention

The device consists of a bottom plate 1, side platforms 2, displacement sensors 3, fasteners 4, used to secure the side platforms 2 and the bottom plate 1 to the support as part of the apparatus in which the inventive device is used, as well as a data processing unit 5.

For the bottom plate 1, typical fastening means 4 may be ears intended for fastening to the support using screws / bolts and nuts. For the side platforms 2, the fastening means 4 can be brackets, one end of which is fixed on the side platform 2, and the other on the support with screws / bolts / nuts.

So, for example, the bottom plate 1 can be fixed on a support, which is part of a spacecraft or aircraft, or directly on the target equipment.

Each platform 2 has one measuring device (sensor) installed, the position and orientation of which relative to the bottom plate 1 of the device must be controlled. The bottom plate 1 and the side platforms 2 are fixed to the support in such a way that their planes form a pyramid (not necessarily correct), while the side platforms 2 are not in contact with each other and are not in contact with the bottom plate 1. That is, a small gap remains along the edges of the formed pyramid. At least one displacement sensor 3 (per edge) is installed in the gap along each edge of the pyramid. And in the gaps between the side platforms 2 and the bottom plate 1 is also installed at least one displacement sensor 3.

There are four possible embodiments of the inventive device:

the first option, when the device contains three side platforms 2, in which case a triangular pyramid is formed;

the second option - the device contains four side platforms 2, in which case a quadrangular pyramid is formed;

the third option - the device contains five side platforms 2, in which case a pentagonal pyramid is formed;

the fourth option - the device contains six side platforms 2, in which case a hexagonal pyramid is formed.

A device with three side platforms 2 can control the position of one, two or three measuring devices installed on the side platforms 2, which are the faces of a triangular pyramid. If there are less than three devices, one or two side faces will remain unoccupied. If it is necessary to control the position and orientation of more than three devices, then it is necessary to use a device with an appropriate number of side platforms 2, forming together with the bottom plate 1 a polygonal pyramid.

Displacement sensors 3 are uniaxial, i.e. register displacement in one direction - along the axis of the sensor - and do not respond to displacements across this axis. The readings of all displacement sensors are transmitted to the data processing unit 5 via connecting wires. Based on the sensor readings, the displacements and rotations of each side platform 2 relative to the bottom plate 1 are calculated.

One of the possible types of sensors 3 are capacitive displacement sensors (for example, sensors of the D100, D510 series from Physik Instrumente). These sensors 3 consist of a pair of contacts forming a capacitor. One of the contacts is fixed on one of the platforms 2, and the second on the opposite (or on the bottom plate 1). Changing the distance between the contacts leads to a change in the capacitance of the capacitor formed by them, which is recorded by the data processing unit 5. A configuration is possible when the sensor 3 contains only one measuring contact, and the second is a flat section of the opposite platform 2 (bottom plate 1).

As a data processing unit, a computer can be used that provides a solution to a system of linear algebraic equations, as a result of which the readings of the displacement sensors are translated into data on changes in the position and rotation of the faces of the pyramid that makes up the claimed device.

Each side platform 2 and, accordingly, the device installed on it have 6 degrees of freedom, for example, three coordinates of the position in space of the center of the platform and three angles of its rotation in space. For a device containing N side platforms, the number of degrees of freedom will be 6N.

When installing on each edge of the formed pyramid of the device three displacement sensors 3, the number of measured parameters is equal to the number of degrees of freedom. To determine the positions and turns of all platforms 2, it is necessary to solve a linear system of 6N equations for 6N unknowns (parameters of degrees of freedom). The system is non-degenerate if the axes of the sensors 3 are not parallel to each other.

If the number of sensors 3 installed on the edge of the pyramid is less than three, then the linear system of equations contains less than 6N equations for the same 6N variables and, accordingly, is underdetermined. As a result of solving this system, only a part of the parameters can be determined, or some linear combinations of these parameters can be determined.

The number of sensors 3 more than three on the edge of the formed pyramid allows you to save the device when the failure of one or more sensors.

The solution of the complete system of equations allows you to determine all the parameters (both position and turn) of the side platforms 2, but requires the installation of three displacement sensors 3 on the edge of the pyramid, which makes the device more complicated and more expensive.

With a smaller number of displacement sensors 3, not all parameters are determined, but they are not always needed. So when using stellar sensors as controlled instruments, the orientations of the centers of the platforms are unimportant, it is only necessary to determine the angles of rotation of the side platforms 2 of the device, and for narrow-field stellar sensors it is enough to determine only the changes in the direction of the normal to the side platform 2. In the first case, to determine these parameters, it is necessary to solve a system of 3N equations (2 displacement sensors per edge are sufficient), in the latter - 2N equations (1 displacement sensor per edge is sufficient).

As one of the embodiments of the invention: the claimed device can also be mounted on a single flat base plate, which in turn will be mounted on a support in the apparatus.

The device operates as follows.

Consider the operation of the device as an example of a configuration with three side platforms 2. The bottom plate 1 and three side platforms 2 are fixed by means of fasteners 4 on the support of the device (for example, a spaceship). Thus, the planes of the lower platform 1 and the three side platforms 2 form a triangular pyramid. Three displacement sensors 3 are installed in the gap along each edge of the pyramid, and three displacement sensors 3 are also installed in the gap between the side platforms 2 and the bottom plate 1 (i.e., a total of 18 displacement sensors). When one or more side platforms 2 are displaced with sensors 3 installed on them, the readings of all or part of the displacement sensors 3 will change. These readings of all 18 displacement sensors 3 are transmitted to the data processing unit 5 via connecting wires. In the data processing unit 5, based on the readings of all 18 displacement sensors 3, the orientation and displacements of the three side platforms 2 relative to the bottom plate 1 are calculated.

The proposed device allows simultaneously with high accuracy to control the position and orientation (rotation or turn) of several measuring instruments (sensors) relative to the support in the apparatus, i.e. eliminates the influence of systematic errors in the relative position and orientation of devices caused by thermoelastic deformations of fixtures. Each of the controlled devices can be displaced by a certain distance and rotated by a certain angle during operation. Typical displacement and rotation are small: the displacement does not exceed hundreds of microns, and the rotation is a few angular seconds.

Claims (5)

1. A device for monitoring the mutual orientation and relative position of the measuring devices, placed on a support, containing a lower plate, side platforms, fasteners designed to secure the side platforms and the lower plate to the support, as well as displacement sensors and a data processing unit connected to the sensors displacements, while the lower plate and side platforms are made with the possibility of installation on a support with the formation of a pyramidal structure, while the lower plate and side platforms are mutually located with gaps in the length l ribs formed by the pyramidal structure, sufficient to accommodate displacement sensors, while at least one displacement sensor is placed in each gap, and the device is arranged to place measuring instruments on the side platforms. 2. The device according to p. 1, characterized in that the formed pyramidal structure is made in the form of a triangular, or quadrangular, or pentagonal, or hexagonal pyramid. 3. The device according to p. 1, characterized in that in each gap there are two displacement sensors. 4. The device according to claim 1, characterized in that in each gap there are three displacement sensors. 5. The device according to claim 1, characterized in that the displacement sensor is a capacitive sensor.

Images