RU2759013C1 - Method for positioning elements of prefabricated structures in space - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to the field of mechanical engineering, in particular to aircraft construction, rocket engineering, shipbuilding, and concerns the development of methods for assembling objects of a complex shape in space that require high precision positioning of composite elements. A digital 3D model is formed. Adjustable racks are used on a coordinate table, the base of which contains a switchable magnet. A removable control bench mark is installed, having an identifying adapter equipped with labels, one of which is encoded. Coordinates are fixed for all adapters. Reference marks are placed on the surface of the coordinate table to digitize the base surface. An operator manually positions end bases by sequentially moving and rotating adjustable racks in space under control of a tracking device until bench marks are aligned with the required location on the 3D model. Positions of the bench mark are displayed on a screen. After setting the last rack, bench marks are removed and installed in landing sockets.

EFFECT: time is reduced, the accuracy of the assembly is increased, and the productivity of the assembly process is increased.

8 cl, 11 dwg

Description

The technical field to which the invention relates

The invention relates to the field of mechanical engineering, in particular to aircraft construction, rocketry, shipbuilding, and concerns the development of methods for assembling objects of complex shapes in space, can be used for assembling, monitoring and measuring complex spatial structures, for example, pipelines, trusses, rod structures and others composite products requiring high positioning accuracy of composite elements.

State of the art

There is a known assembly method used in the assembly of assembly equipment (RU 2226168, 2004), in which the features of the method, coinciding with the essential features of the claimed method of positioning the product, are positioning of the assembly component by installing it in the assembly position along the geometrically responsive carriers of the base points of the positioned assembly component and positioning devices to allow non-iterative installation.

The known method solves the problem of positioning and provides an increase in the productivity of the process of installing the product in a given spatial position, which consists in reducing the time for preparation, assembly and control of the spatial position of the product by eliminating sequential approximation operations when performing spatial movements of the product. However, the known method does not make it possible to match the bases of the assembly component at several working positions of various stages of the assembly, thereby increasing the time of assembly and control of spatial products.

There is a known method for assembling an aircraft fuselage (RU 2121452, 1998), according to which the process of positioning assembly elements is performed in three successive stages at separate workplaces. In this case, the features of the method that coincide with the essential features of the proposed method for positioning the product are the basing of the assembly component included in the product, while the basing elements of the assembly devices of the working positions at different stages of the assembly are mutually linked in an agreed coordinate system.

The known method also solves the problem of positioning and provides an increase in the productivity of the assembly process due to the implementation of the principle of constancy of bases throughout the entire process of assembling the product, however, this method does not allow increasing the productivity of the assembly process by reducing the time of basing the assembly unit due to the need to re-locate it on each from the following assembly steps after the first stages using duplicated locating elements to ensure interchangeability, as well as due to the appearance of additional errors in the manufacture and installation of duplicated locating elements of several assembly devices.

There is a known method for positioning objects in space (RU 2677121, 2019), considered as a prototype, which consists in the fact that adjustable racks are installed in the base holes of the coordinate table, holding the positioned object, while each of the racks is made with the possibility of angular and rectilinear movement and contains an element for holding an object, a mark is installed on the rack, which makes it possible to determine its position in space using means of contactless measurements, a digital prototype of the required location in space of the positioned object is created using the mentioned digital prototype, visual information about the required location of the positioned object is displayed on the screen, the position is determined each rack by means of contactless measurements and adjust the position of each rack, aligning the position of each mark installed on the rack with the corresponding point of the digital prototype displayed on the screen based on the information tions from the measuring system.

The signs of the method that coincide with the essential features of the proposed positioning method are the formation of a digital 3D model of the required location in space of the positioned elements of the prefabricated structure, the installation on the coordinate table of adjustable racks holding the positioned elements, each of which is made with the ability to move with six degrees of freedom and contains a base for fixing an element of a prefabricated structure, displaying a digital 3D model of positioned elements of a prefabricated structure on the display screen with information about their required location, determining the position of each adjustable post by means of non-contact measurements, setting a fixed position of the base in space to secure an element of the prefabricated structure of each post and aligning the position each base mounted on a rack with a corresponding point on the 3D model based on information from the measurement system.

The known method solves the problem of positioning when assembling an object according to a 3D model, while a stationary tooling is made for assembling each specific object. However, despite the fact that both domestic and Western manufacturers of aviation equipment have three-dimensional models of objects, it is necessary to spend significant time resources on the design and manufacture of tooling for assembling the object and in the future to store and regularly verify the created tooling, and when making changes to the structure of the object For example, after testing products or releasing a modification for another market, the cycle must be repeated. The design and manufacture of tooling takes from 1 to 3 months. This approach is justified in the case of large series, from 10 or more items per month. However, in the aviation industry, one-off or small-scale production is usually used. This leads to significant time expenditures throughout the positioning process during assembly, reduces the reliability and repeatability of assembly results, increases the time required to manufacture new products and make modifications to old ones, which causes a general rise in the cost of manufacturing products.

Also, the known method requires a significant amount of time to ensure positioning accuracy due to the need to use different bases when installing it at each stage in the corresponding support legs. In production practice, with this method of basing, the assembly error can exceed the permissible values, especially when using large, low-stiff, complex-shaped parts in an assembly unit.

The essence of the invention.

The problem to be solved by the present invention is to create a high-precision and highly efficient technology for assembling products that allows positioning complex-spatial products or their components with high accuracy. In particular, the invention involves the development of a cyber-physical method that allows a real technological process to be performed at a physical level (for example, a pipeline assembly) based on a digital twin. The invention combines elements such as a digital model of a product, a measurement system, feedback from a measurement system and complete control of the finished product.

The technical result of the claimed invention is to reduce the time of preparation, assembly, adjustment of slipways for assembly and control of spatial products (metal structures, pipelines, containers, etc.) with a simultaneous increase in assembly accuracy, which improves the productivity of the assembly process due to high reliability and repeatability assembly results when using digital prototypes and schemes for placing racks in space, as well as by eliminating duplicate base elements at the next assembly stages after the first one.

The technical result is achieved by the fact that in the method of positioning elements of prefabricated structures in space, which consists in the formation of a digital 3D model of the required location in space of the positioned elements of the prefabricated structure, installation on the coordinate table of adjustable racks holding the positioned elements, each of which is made with the possibility of moving with six degrees of freedom and contains a base for fixing an element, displaying a digital 3D model of positioned elements of a prefabricated structure on the display screen with information about their required location, determining the position of each adjustable rack by means of contactless measurements, setting a fixed position of the base in space to fix an element of each rack and aligning positions of each base, mounted on a rack, with the corresponding point of the 3D model based on information from the measuring system, use adjustable racks, the base of which contains a The removable magnet, on the end base of each post, is installed in a unified landing socket, or in a separate socket on the side surface of the end base of each post, a removable reference bench with a unique identifying adapter, equipped with labels, one of which is coded, is fixed for all identifying adapters. coordinates, angles of inclination and rotation relative to axes in space by means of a non-contact measurement follower, relative to the base surface, which is chosen as the surface of the coordinate table, while reference marks are placed on the surface of the coordinate table for digitizing the base surface, after which the operator manually positions the end bases by sequential movement and rotation of the adjustable racks in space under the control of the follower until the benchmarks are aligned with the required location on the 3D model, while the current position of the benchmark is displayed on the operator's control screen, e the required position and the correction necessary for alignment, after the last stand is set, the control benchmarks are removed and positioned elements of the assembled structure are installed in the unified landing nests on the end bases of the racks.

The tracking means can be installed above the assembly area and can be an optical tracking system, in particular a laser tracker.

Alternatively, the follower can be an end-probe coordinate measuring machine.

These tracking means provide a stable feedback between the movements of the adjustable elements in the assembly zone and their specified positions on the digital model and, thereby, providing a reduction in the time for preparation, assembly, adjustment of slipways for assembly and control of spatial products.

As a removable benchmark, a volumetric part can be used, on the surface of which a unique identifying adapter is placed.

For an optical tracking system, the adapter can be planes placed at angles to each other, preferably in the form of a polyhedral pyramid, on each of the planes of which reflective marks are placed, while one of the marks on each plane has a code, and the number and location of marks on each planes are unique.

For a coordinate measuring machine with an end stylus, the identification adapter is equipped with a matching end of the stylus with seating surfaces, one of which has a code.

The specified versions of the adapters ensure the uniqueness and unambiguous identification of each adapter in the group of removable benchmarks installed on the end bases of the posts, which eliminates the violation of feedback when moving the posts and carrying out repeated measurements, while reducing the time for preparation, assembly, adjustment of the slipways for the assembly and control of spatial products , which improves the productivity of the assembly process.

At the moment, the problem of pipeline assembly is being solved in the following way: according to the 3D model of the pipeline, stationary equipment is manufactured for the assembly of each specific pipeline. This method has been used without significant changes over the past 30 years.

However, despite the fact that both domestic and Western manufacturers of aviation equipment have three-dimensional models of prefabricated structures (in particular, pipelines), they still need to spend significant time and financial resources on the design and manufacture of equipment for assembling the structure and in the future to store and regularly check the created tooling. When design changes are made, for example, after product testing or a modification is released for another market, the cycle must be repeated. This significantly reduces the accuracy of assembly, as well as increases the time required to manufacture new products and make modifications to old ones.

The invention is intended to eliminate these limitations and will allow manufacturers to obtain a finished structure with the required assembly accuracy as soon as possible (pipeline in less than 2 hours), without the need to manufacture and store tooling, as well as without the use of machining centers and other machines.

Brief description of the drawings.

The invention is illustrated by drawings, in which:

FIG. 1 shows a general view of the assembly area.

FIG. 2 shows a general view of an adjustable stand for installing a positioned element.

FIG. 3 shows an example of a prefabricated structure - a pipeline. FIG. 3a - elements of the pipeline before assembly. FIG. 3b assembled pipeline.

FIG. 4 shows a general view of the end base for fixing the positioned element.

FIG. 5 shows the design of the rack with an end base and a removable reference bench installed on it. FIG. 5a shows a variant of installing the benchmark in a separate slot on the lateral surface of the end base (overhead benchmark). FIG. 5b shows a variant of installing a benchmark in a unified seat (axial benchmark).

FIG. 6 shows the setting of end bases with control benchmarks in space.

FIG. 7 shows the installation of pipeline elements on the basis of the installed end bases.

FIG. 8 shows the final assembly of the assembled pipeline with the control benchmarks removed.

FIG. 9 shows a block diagram of the positioning in space of the elements of the assembled structure according to the proposed method.

Implementation of the invention.

Positioning in space of prefabricated elements is carried out at the assembly site (Fig. 1). The worker sets up the adjustable racks of the system (Fig. 2) on the coordinate table for assembling the product (for example, a pipeline). FIG. 1 highlighted in color is the control zone of the tracking device for contactless measurements (optical measurement system), which is located in the upper part of the installation, above the table. The base for setting the racks is a coordinate table with holes that are located at a given distance from each other and are manufactured with high precision. The table is the base surface. Reference marks are placed on it, which allow the coordinate measuring system to transfer the physical base surface into digital space and already relative to this digital base surface to measure the positions of the end bases of the posts (Fig. 3) with benchmarks installed on them (Fig. 5a, b).

The base of the adjustable racks is magnetic, with a switchable magnet (Fig. 2). The position of the racks is set in accordance with the digital model of the product and the electronic assembly map. The collector fills items using feedback from the measurement system in real time.

The assembly area (slipway) also includes assemblies (clamps or cradles) for securing and orienting elements of the assembled structure, metal structures, pipelines, tanks, containers, etc.

Elements of pipelines can be straight or curved pipes (elbows), branching elements (tees, crosses, etc.), end fittings (fittings, tips, adapters, couplings) (Fig. 3a, b).

Assembly jig assemblies, for example, a pipeline, intended for fixing and orienting pipeline elements, make it possible to expose the pipeline route in space, i.e. pipes, as well as orientate in space and attach branch elements and end fittings to the pipe.

Connections of elements of assembled structures can be both one-piece, i.e. made by welding, soldering or gluing methods, on rivets or bullets, and detachable - using threaded, wedge or pin connections.

In this case, the pipes are placed in the lodgements or clamps of the pipe contour and remain stationary during assembly, and the connected elements are fixed in the end bases of the adjustable racks (Fig. 4, pos. 1) in the seats (pos. 2, 3) using the corresponding screws for tightening (pos. 4, 5). The sockets are axially movable to accommodate the axial dimension between the pipe end and the attached element.

End bases can be universal, for example, with a 3-jaw chuck or a clamp, for fixing a wide range of elements, specialized of the same type for similar typical parts, or individual for fixing non-standard elements that cannot be fixed using the first two types of clamps.

The bases (pos. 1, fig. 3) are the final elements of the movable racks (fig. 2) of the assembly system, while the rack mechanisms allow you to move and orient the bases in space along all available degrees of freedom (fig. 2), as well as to ensure the fixation of the required the positions of the bases and the invariability of these provisions under the influence of the design loads from the assembled structures.

For setting the position of the bases in space, i.e. when creating an assembly or control positioning, quick-detachable control benchmarks are placed on the end bases of the racks, by which the position of the end base in space is tracked in real time - its coordinates in the spatial axes, the angles of inclination and rotation relative to the axes.

The design of the reference includes an identification adapter, the design of which is determined by the tracking means used.

For an optical measuring system, which is used, for example, a laser tracker, the adapter is a set of planes placed at angles to each other, optimally in the form of a polyhedral pyramid (Fig. 6, 7). On each of its planes, reflective marks are placed in a certain configuration. The number of marks on each plane can be from 4 to 100, while one of the marks on each plane is encoded, i.e. has a unique identifier, others can be used without coding.

The set and location of marks on each plane of the adapter are unique, while the configuration of marks on the planes of the reference is programmatically linked and recorded in the memory of the control and measuring system.

This feature makes it possible to identify each benchmark at different angles of inclination and rotation of the end link of the rack, and therefore determine the position of each end link in space, since the control and measuring system only needs to see one plane of the benchmark.

In addition, the benchmark has a rigid shank, which ensures its quick mounting, which allows you to install the benchmark on the base in the shortest possible time, and after positioning the base and fixing it in this position, remove the benchmark in the shortest time without disturbing the position of the base in space.

The benchmark is made with precise landing surfaces, along which it is installed on the base to fix the elements of the assembled structures. The configuration of the reflective marks and their location on the surface of the benchmark allow to unambiguously determine its uniqueness, as well as the location and orientation relative to the landing surfaces in space.

The current position of the reference point is monitored by the measuring system with a frequency of at least 5 Hz, the delay in calculating the position of the reference point in space is less than 0.25 s.

When used as a coordinate measuring machine (CMM) as a tracking system, the end probe is attached to the end of the machine arm. The probe has, on one side, an attachment for the manipulator connector, while the CMM manipulator attachment has both axial fixation to determine the position of the measured object along the linear axes, and a rotation fixation to determine the angles of rotation of the object relative to the linear axes. On the opposite side, the stylus has a shank and precise seating surfaces, identical in design to the surfaces of the reference for optical tracking systems, which allows the end stylus to be installed on bases for fixing structural elements. When positioning the base in space, its position and orientation are monitored via the interface of the coordinate measuring machine.

Thus, the use of the above equipment during positioning provides multiple assembly / disassembly and adjustment, if necessary, is assembled according to a digital scheme coordinated with the digital prototype of the assembled / controlled product, while reducing the time for preparation, assembly, and adjustment of the positioning of elements of prefabricated structures. improves the productivity of the assembly process.

The proposed method for positioning an object is implemented as follows:

A digital 3D model of the required location in space of the positioned elements of the prefabricated structure is preliminarily formed. In this case, the parts positioning scheme is generated by the technologist in the CAD / CAM system and loaded into the memory of the system software package.

The assembly of the adjustable stands on the coordinate table is carried out manually according to the digital assembly diagram issued by the technologist. The racks are placed under the control of the system software complex due to feedback from the control and measuring system.

The operator sets each rack, which has six degrees of freedom, according to the coordinates and angles of inclination of the benchmark on the end base in space. In this case, the current position of the benchmark and its required position are displayed on the operator's control screen.

The measurement system allows you to display the change in the reference benchmark in space and calculates the necessary correction.

The algorithmic sequence for placing the racks is shown in Fig. 9. In this case, the first rack is selected in the software package. Preliminarily, the operator roughly sets the rotation of the end base with the installed control bench and the identifying adapter on it, fixed on the selected stand, in the plane of the XY table.

The proposed method allows you to install a control benchmark both in a separate socket on the side surface of the base (Fig.5a) and in the same unified seat in which the assembly (pipeline) element is installed to clamp it in the end base (Fig.5b).

Next, the angle of inclination of the benchmark relative to the XY plane is fine-tuned, while coding marks related to the first strut are recorded.

The next step is to adjust the rotation of the benchmark around the axis of the end base.

After setting all angles, the operator moves the column to the desired point in the XY plane, i.e. to the desired point on the table.

The next step is to adjust the precise rotation of the reference in the XY plane. This angle was pre-adjusted roughly, since when manually moving the entire rack, this angle gets lost.

The other angles do not need to be corrected, since their position does not change during a parallel translation in the specified plane.

The final adjustment of the rack is made in height (along the Z-axis).

Having placed the first rack in space, the operator fixes its position, marks the implementation of this step in the system software and proceeds to the next rack, the adapter of which has its own unique sets of labels and codes.

After placing the last rack, the control benchmarks are removed, and positioned elements of the assembled structure are installed in the unified landing nests on the end bases of the racks (Fig. 8).

The set of actions proposed in the method with the equipment standardized for it can significantly reduce the time for positioning and will allow manufacturers to obtain, for example, a finished pipeline in less than 2 hours, without the need to manufacture and store tooling, as well as without the use of machining centers and other machines.

Claims (8)

1. A method of positioning elements of prefabricated structures in space, which consists in forming a digital 3D model of the required location in space of positioned elements of a prefabricated structure, installing adjustable racks on a coordinate table, holding positioned elements, each of which is designed to move with six degrees of freedom and contains a base for fixing the element, displaying a digital 3D model of the positioned elements of the prefabricated structure on the display screen with information about their required location, determining the position of each adjustable post by means of contactless measurements, setting a fixed position of the base in space to fix the element of each post and aligning the position of each base installed on a stand, with the corresponding point of the 3D model based on information from the measuring system, characterized in that they use adjustable stands, the base of which contains a switchable magnet, on the end base of each post, installed in a unified landing socket, or in a separate socket on the side surface of the end base of each post, a removable reference bench with an identifying adapter provided with marks, one of which is coded, fixes for all identifying adapters their coordinates, angles of inclination and rotation relative to the axes in space by means of a tracking means of non-contact measurements, relative to the base surface, which is chosen as the surface of the coordinate table, while reference marks are placed on the surface of the coordinate table for digitizing the base surface, after which the operator manually positions the end bases by means of sequential movements and rotations adjustable racks in the space under the control of the follower until the benchmarks are aligned with the required location on the 3D model, while the operator's control screen displays the current benchmark position, its required position and the required Given an amendment for alignment, after the last stand has been set, the control benchmarks are removed and positioned elements of the assembled structure are installed in the unified landing nests on the end bases of the racks. 2. A method according to claim 1, characterized in that the tracking means is installed over the assembly area. 3. A method according to claim 1, wherein the tracking means is an optical tracking system. 4. The method according to claim. 3, characterized in that the optical tracking system is a laser tracker. 5. The method according to claim 1, characterized in that the tracking means is a coordinate measuring machine with an end probe. 6. A method according to any one of claims 3-5, characterized in that a volumetric piece is used as a removable reference bench, on the surface of which a unique identifying adapter is placed. 7. The method according to claim 6, characterized in that for the optical tracking system, the adapter is a plane placed at angles to each other, preferably in the form of a polyhedral pyramid, on each of the planes of which reflective marks are placed, with one of the marks on each plane has a code, and the number and location of marks on each plane are unique. 8. The method according to claim. 6, characterized in that for a coordinate measuring machine with an end probe, the identifying adapter is provided with a mating end of the probe with seating surfaces, one of which has a code.

Images