Method of aligning hardpoints in aeronautical structures

Abstract

The present disclosure relates to a method of assembling hardpoints in aeronautical structures, and more specifically, the disclosed method allows knowing the relative deviation of the hardpoints and of the positioning elements of the hardpoints with respect to a laser beam emitted by a laser collimator fixed to an adjustable support which can be adjusted in at least two directions in space, and by using a correction algorithm, it is possible to know the displacement necessary for locating the positioning elements such that they are aligned with respect to the hardpoints, the positioning elements in turn being moved as a result of the movement of the driven linear tables in one or in several iterative steps, at which time the position thereof is fixed and they are ready for the rest of the hardpoints to be assembled.

Claims

1. A method involving placement of an aeronautical structure which already has two hardpoints installed on an auxiliary structure, where said auxiliary structure in turn includes a set of positioning elements which allow varying their position according to at least one degree of freedom, the method comprising the steps of: a) installing on the auxiliary structure a laser collimator on an adjustable support which can be adjusted in at least two directions in space for orienting a laser beam from the laser collimator so that the laser beam passes through a number of through holes with which the two already installed hardpoints are equipped; b) coupling an opaque coaxiality sensor in a first of the through holes with which the first of the two already installed hardpoints is equipped; c) measuring a deviation of a point where the laser beam strikes the coaxiality sensor located in the first of the two already installed hardpoints with respect to a local reference system of said coaxiality sensor; d) coupling the coaxiality sensor in a second of the through holes with which the second of the two already installed hardpoints is equipped; e) measuring a deviation of the point where the laser beam strikes the coaxiality sensor located in the second of the two already installed hardpoints with respect to a local reference system of said coaxiality sensor; f) coupling the coaxiality sensor in one of the through holes with which one of the set of positioning elements is equipped; g) measuring a deviation of the point where the laser beam strikes a corresponding positioning element of the set of positioning elements by obtaining its deviation with respect to the local reference system of the coaxiality sensor; h) once the deviations with respect to the laser beam obtained in the preceding step are known, applying a correction algorithm to calculate necessary displacements to which the positioning element is to be subjected for proper alignment of the hardpoint associated with the corresponding positioning element; i) shifting the positioning element according to a displacement value obtained in the preceding step, resulting in the positioning element being aligned; j) taking a new reading of the position of the corresponding positioning element according to step g) above, and in the event of being considered unsuitable according to a previously established quality criterion, performing another calculation of the displacement of the set of positioning elements by repeating steps h) and i); k) once it has been found that the alignment between the two already installed hardpoints and the corresponding positioning element is sufficient according to the previously established quality criterion, locking the position of said corresponding positioning element; l) removing the coaxiality sensor from the already aligned positioning element and repeating steps f) to k) for the rest of the set of positioning elements; and m) assembling the rest of the hardpoints to which the preceding steps b) to l) of the method are then performed.

2. The method according to claim 1, and further comprising the additional step of: n) verifying a final alignment of all the already installed hardpoints by coupling the opaque coaxiality sensor in a sequential manner directly to the hardpoints and performing the calculation of the deviation in the same way as with the set of positioning elements.

3. The method according to claim 1, wherein the correction algorithm to calculate the necessary displacements to which the positioning elements are to be subjected for proper alignment of the hardpoints comprises: calculating a line R going through central points of the installed coaxiality sensor; calculating a line L going through points of incidence of the laser beam on the coaxiality sensor; using both lines R and L, calculating coordinates of a target point of the coaxiality sensor where the laser beam must strike when the positioning element of the hardpoint to be aligned is aligned with the two already installed hardpoints; and calculating a displacement vector that the positioning element must be moved so that the point of incidence is the target point.

4. The method according to claim 1, wherein the displacement of the set of positioning elements according to step e) is performed using driven linear tables comprising a horizontal driven portion and a vertical driven portion.

Description

DESCRIPTION OF THE DRAWINGS

(1) To complement the description that is being made and for the purpose of helping to better understand the features of the invention, a set of drawings is attached to the present specification as an integral part thereof, in which the following is depicted in an illustrative and non-limiting manner:

(2) FIG. 1 schematically shows a structure of the control surface type of the state of the art which could be an aileron, a rudder, or an elevator.

(3) FIG. 2 schematically shows an assembly tool for assembling a structure of the control surface type shown in FIG. 1.

(4) FIG. 3 shows a schematic perspective view of the main elements involved in the application of the method of assembly of the invention.

(5) FIG. 4 shows a detail view of the support for the laser collimator for carrying out the method of the invention.

(6) FIG. 5 shows several detail views of how the coaxiality sensor is coupled both to the hole of the hardpoints and to the hole of the positioning elements.

(7) FIG. 6 shows a perspective view of how the laser beam strikes the coaxiality sensor and the schematic depiction of the deviation of said beam on the plane defined by said sensor.

(8) FIG. 7 shows a perspective view of a horizontal driven table and a vertical driven table, and of the movement said tables impart on their positioning element.

(9) FIG. 8 shows a schematic perspective view of the measurement of the final position of the new hardpoints which have been assembled with the positioning elements (not depicted) so that they are aligned with the initial hardpoints.

(10) FIG. 9 shows various schematic perspective views of the steps to be taken according to the method of the invention for the case of using a single opaque coaxiality sensor in a sequential manner.

(11) FIG. 10 shows a schematic drawing of the mathematical demonstration of the calculation of displacements for the example in which there are already installed hardpoints A and B and a hardpoint C is to be aligned.

(12) FIG. 11 schematically shows a detail of the incidence of the laser on the sensor of hardpoint B for the case of FIG. 10 above.

(13) FIG. 12 schematically shows a detail of the incidence of the laser in the sensor located in positioning element “C” when the latter is aligned with hardpoints “A” and “B” of FIGS. 10 and 11 above.

(14) FIG. 13 shows several schematic views of the geometric calculation of the displacement vector.

(15) While the above-identified figures set forth one or more embodiments of the present invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features, steps and/or components not specifically shown in the drawings.

DESCRIPTION OF PREFERRED EMBODIMENT(S) OF THE INVENTION

(16) In view of the mentioned drawings, and according to the numbering used, the method of assembling hardpoints in mobile aeronautical structures of the invention can be seen therein.

(17) More specifically, a representative drawing of the aforementioned already known structures, which have a specific number of hardpoints (1) having their holes aligned with a very narrow tolerance as a requirement can be seen in FIG. 1. Specifically, said FIG. 1 shows a longeron (2), ribs (3), skins (4), and the mentioned fittings or hardpoints (1), among others.

(18) On the other hand, as can be seen in FIG. 2, the method of the invention needs a supporting structure which allows positioning the different parts or sub-assemblies making up the structure to be assembled for the correct assembly thereof, i.e., the assembly tool of the structure at hand which comprises: positioning devices or positioning elements (5) for the hardpoints, where said positioning elements (5) allow restricting one or several degrees of freedom of a part or sub-assembly of parts such that the proper positioning thereof with respect to the others is assured; an auxiliary structure (6) for supporting the assembly and the positioning elements (5) themselves in a sufficiently rigid manner.

(19) And additionally the following elements: laser collimator equipment (7) or a laser beam emitter, an adjustable support (8) for the laser collimator (7), at least one coaxiality sensor (9, 9′) capable of detecting the incidence of the laser beam (7′) on its surface and knowing its position with respect to a reference system in the device itself, i.e., a sensor which allows measuring the relative deviation of the laser beam emitted by the laser collimator (7) with respect to the coaxiality sensor (9, 9′) itself. These coaxiality sensors (9, 9′) could be of two types according to two possible alternative embodiments of the invention. Specifically, one of such alternative embodiments will be one in which the coaxiality sensors (9) are translucent, i.e., they allow the laser beam (7′) to pass through, in which case arranging sensors in all the holes of interest would be sufficient to obtain the measurements of each one of them simultaneously. The other alternative embodiment will be one in which the coaxiality sensors (9′) are opaque, and in this case it is necessary to perform several steps of the method in a sequential manner since not all the measurements can be taken at the same time. 2-axis adjustable driven linear tables (10) which consist of supports with one or more linear guides or tracks which allow displacing an element with respect to another, that is, they specifically allow displacement in two perpendicular directions, and therefore on one plane. mechanical actuators or devices (not depicted) the function of which is to provide force for moving the driven linear tables and which can be operated by hand or, for example, by an electric motor; and a computer system connected to both the coaxiality sensors and the actuators so as to interact with them and, through an interface, allow the user to perform the drive and direct the method and obtain information useful for the development of said method.

(20) More specifically, as can particularly be seen in FIG. 3, the laser collimator (7) is assembled on an adjustable support (8) such that the emitted beam (7′) goes through the holes of the hardpoints (1) previously installed in the structure. The actuators are connected to the driven linear tables (10) to provide said drive. These driven linear tables (10) are coupled to the positioning elements (5), thereby obtaining control over the movement thereof. Finally, the coaxiality sensors (9) are installed in the hardpoints (1) and in the positioning elements (5) such that the laser beam (7′) strikes them and the deviation of said laser beam (7′) with respect to the coaxiality sensors (9), and vice versa, can thereby be known.

(21) Therefore, as a result of the preceding configuration the relative deviation of the hardpoints (1) and of the positioning elements (5) with respect to the laser beam (7′) is known, and by using a correction algorithm, it is possible to know the displacement necessary for locating the positioning elements (5) such that they are aligned with respect to the hardpoints (1), said positioning elements (5) in turn being moved as a result of the movement of the driven linear tables (10), which comprise at least two driven portions, a horizontal driven portion (10′) and a vertical driven portion (10″). Specifically, by means of the movement of the driven linear tables (10), in one or in several iterative steps, the positioning elements (5) are located until being aligned with the hardpoints (1), at which time the position thereof is fixed and they are ready for the rest of the hardpoints (1) to be assembled.

(22) Therefore, according to a preferred embodiment, in order to carry out the assembly of a given product or structure once it is fixed on the auxiliary structure or support and is already equipped with two hardpoints assembled thereon, the steps comprised in the method of the invention according to the case in which translucent coaxiality sensors (9) are used are as follows: 1) INSTALLING AND ADJUSTING THE LASER COLLIMATOR (7). As can be seen in FIG. 4, in this step the laser collimator (7) is assembled in its adjustable support (8) and adjusted so that the laser beam (7′) goes through the through holes with which the already installed hardpoints (1) and positioning elements (5) are equipped. It must be pointed out that it is not necessary for the laser beam (7′) to go through the exact center of said holes, since it is sufficient for it to be within the reading range of the coaxiality sensor (9), which is usually several millimeters. As can be seen in said drawing, the adjustable support (8) is equipped with an adjustment such that it is possible to move it in at least two directions in space, for example horizontal and vertical, as well as to turn it horizontally and vertically for the purpose of orienting the laser beam (7′) towards the coaxiality sensors (9). 2) COUPLING THE COAXIALITY SENSORS (9). As can be seen in FIG. 5, the coaxiality sensors are coupled in the hole of the already installed hardpoints and of the positioning elements (5). More specifically, said drawing shows a detail of the coaxiality sensor (9) and how it is coupled by means of a built-in cylinder (12) and adapter sockets (11) to the hole of the hardpoints (1) and of the positioning elements (5). 3) MEASURING HARDPOINTS (1) AND POSITIONING ELEMENTS (5). As can be seen in FIG. 6, the laser beam (7′) strikes the coaxiality sensors (9) located in the hardpoints (1) and in the positioning elements (5), showing their deviation (13) with respect to the local reference system of said coaxiality sensors (9). 4) CALCULATING THE DISPLACEMENT OF THE POSITIONING ELEMENTS (5). Once the deviations with respect to the laser beam (7′) are known, the correction algorithm described in detail below is applied to calculate the necessary displacements to which the positioning elements (5) are to be subjected for proper alignment of the hardpoints (1). 5) MOVING THE POSITIONING ELEMENTS (5). As shown in FIG. 7, the driven linear tables (10), and more specifically their horizontal driven portion (10′) and their vertical driven portion (10″), perform displacements equivalent to those calculated in the preceding paragraph, resulting in the positioning element (5) being aligned. 6) CHECKING THE POSITIONING ELEMENTS (5). A new reading of the new position of the positioning elements (5) according to paragraph 3 above is taken, and in the event of being considered unsuitable, a new calculation of the displacement of the positioning elements (5) is performed by repeating steps 4 and 5. 7) FIXING THE POSITIONING ELEMENTS (5). Once it is checked that the alignment between hardpoints (1) and positioning elements (5) is good enough according to the established quality criterion, the position of the actuators and therefore of the positioning elements (5) is locked. 8) ASSEMBLING THE REST OF THE HARDPOINTS (1). After that time, the coaxiality sensors (9) are disassembled and the rest of the hardpoints (1) are assembled to then also apply to same steps 2 to 7 of the described method; and finally, in an optional manner, 9) VERIFYING HARDPOINTS (1). As can be seen in FIG. 8, the present invention also allows verifying the final alignment of the hardpoints (1) with accuracy, for which purpose the coaxiality sensors (9) must simply be coupled to the hardpoints (1) with different adapter sockets (11) and the calculation must be performed in the same way as with the positioning elements (5). In other words, said drawing shows a scheme for measuring the final position of the new hardpoints (1) which have been assembled with the positioning elements (5) (not depicted) so that they are aligned with the initial hardpoints (1).

(23) Finally, FIG. 9 shows an alternative embodiment of the method of the invention for the case in which a single opaque coaxiality sensor (9′) is used in a sequential manner. Therefore, as can be seen, first the position of a hardpoint (1) located, for example, at one of the ends, is measured, and then the position of another hardpoint (1′) located, for example, at the other end, is measured. After having established the position of both hardpoints (1, 1′) with respect to the laser beam (7′), each of the positioning elements (5) is adjusted in a sequential manner.

(24) Therefore, according to another possible embodiment, in order to carry out the assembly of a given product or structure once it is fixed on the auxiliary structure or support and is already equipped with two hardpoints assembled thereon, the steps comprised in the method of the invention according to the case in which opaque coaxiality sensors (9′) are used are as follows: a) Installing on the auxiliary structure (2) a laser collimator (7) on an adjustable support (8) which can be adjusted in at least two directions in space for the purpose of orienting the laser beam (7′) so that it passes through a number of through holes with which two already installed hardpoints (1) are equipped; b) Coupling a coaxiality sensor (9′) in the through hole with which the first of the two already installed hardpoints (1) is equipped; c) Measuring the deviation of the point where the laser beam (7′) strikes the coaxiality sensor (9′) located in the first hardpoint (1) with respect to a local reference system of said coaxiality sensor (9′); d) Coupling the coaxiality sensor (9′) in the through hole with which the second of the two already installed hardpoints (1) is equipped; e) Measuring the deviation of the point where the laser beam (7′) strikes the coaxiality sensor (9′) located in the second hardpoint (1) with respect to a local reference system of said coaxiality sensor (9′); f) Coupling the coaxiality sensor (9′) in the through hole with which one of the positioning elements (5) is equipped; g) Measuring the deviation of the point where the laser beam (7′) strikes the positioning element (5) by obtaining its deviation (13) with respect to the local reference system of the coaxiality sensor (9, 9′); h) Once the deviations with respect to the laser beam (7′) obtained in the preceding step are known, applying a correction algorithm to calculate the necessary displacements to which the positioning element (5) is to be subjected for proper alignment of the hardpoint (1) associated with it; i) Shifting the positioning element (5) according to the value obtained in the preceding step, resulting in the positioning element (5) being aligned; j) Taking a new reading of the position of the positioning element (5) according to paragraph g) above, and in the event of being considered unsuitable according to a previously established quality criterion, performing another calculation of the displacement of the positioning elements (5) by repeating steps h) and i); k) Once it has been found that the alignment between the already installed hardpoints (1) and the positioning element (5) is sufficient according to the established quality criterion, locking the position of said positioning element (5); l) Removing the coaxiality sensor (9′) from the already aligned positioning element and repeating steps f) to k) for the rest of the positioning elements (5); m) Assembling the rest of the hardpoints (1) to then also sequentially apply to same the preceding steps b) to l) of the described method; and in an optional manner, n) Verifying the final alignment of all the already installed hardpoints (1) by coupling the coaxiality sensor (9′) in a sequential manner directly to the hardpoints (1) and performing the calculation of the deviation in the same way as with the positioning elements (5).

(25) Below, as indicated in the steps of the methods described above, FIGS. 10 to 13 describe an example of a correction algorithm to calculate the necessary displacements to which the positioning elements (5) are to be subjected for proper alignment of the hardpoints (1).

(26) Therefore, FIG. 10 shows hardpoints A, B, and C, where A and B are previously installed and C is the hardpoint to be aligned. Points a.sub.R, b.sub.R, and c.sub.R, which are the centers of the sensors coupled to the mentioned hardpoints, and also points a.sub.L, b.sub.L, and c.sub.L, which are the points where the laser beam strikes each sensor, are likewise shown. Finally, the global reference system {A, X, Y, Z} that is used is shown.

(27) More specifically, there are two previously installed hardpoints (1) “A” and “B”, with respective installed sensors the central points of which are “a.sub.R” and “b.sub.R”; a positioning element (5) of the hardpoint C to be installed such that it is aligned with “A” and “B” with an installed sensor the central point of which is “c.sub.R”; a fictitious line “R” defined by points “a.sub.R” and “b.sub.R”; a laser beam “L” coming from the laser collimator (7) which strikes the sensors of the three hardpoints at points “a.sub.L”, “b.sub.L,” and “c.sub.L”; a global reference system S={A, X, Y, Z} the origin of which is “A”, the axis “Z” of which is parallel to the fictitious line “R” and the axes “X” and “Y” of which are parallel to the local axes of each sensor “x” and “y”, respectively.

(28) The distances in direction “Z” are very large compared to the deviations in “X” and “Y”, so the working hypothesis is that the angle between line “R” and line “L” is very small. This means that small variations in direction “Z” will not cause significant variations in “X” and in “Y”.

(29) On the other hand, FIG. 11 shows the detail of the incidence of the laser on the sensor of hardpoint B, which is valid for any other hardpoint. It is shown how the coordinates of the points of incidence of the laser “a.sub.L”, “b.sub.L,” and “c.sub.L” are obtained from the readings of the sensors and theoretical “Z”.

(30) More specifically, each of the sensors coupled to the hardpoints will provide a reading of the coordinates of the point of incidence of the laser in the local reference system of each sensor Δx.sub.l and Δy.sub.l which coincide, under the hypotheses considered, with coordinates “X” and “Y” in the global reference system. Coordinate “Z” is not precisely known such that under the hypotheses considered above, theoretical “Z” can take “z.sub.t” without causing significant variations in “x” or in “y”. The coordinates of the points of incidence of the laser on each of the sensors “a.sub.L”, “b.sub.L,” “c.sub.L”, in the reference system “S” are thereby known. They are known specifically from the expression:
a.sub.L=(Δx.sub.l.sup.a,Δy.sub.l.sup.a,z.sub.t.sup.a)
b.sub.L=(Δx.sub.l.sup.b,Δy.sub.l.sup.b,z.sub.b.sup.t)
c.sub.L=(Δx.sub.l.sup.c,Δy.sub.l.sup.c,z.sub.t.sup.c)
where Δx.sub.l.sup.a and Δy.sub.l.sup.a are the deviations measured by the sensor coupled to hardpoint A and z.sub.t.sup.a is the theoretical coordinate z of hardpoint A; where Δx.sub.l.sup.b and Δy.sub.l.sup.b are the deviations measured by the sensor coupled to hardpoint B and z.sub.t.sup.b is the theoretical coordinate z of hardpoint B; and where Δx.sub.l.sup.c and Δy.sub.l.sup.c are the deviations measured by the sensor coupled to hardpoint C and z.sub.t.sup.c is the theoretical coordinate z of hardpoint C.

(31) Therefore, by using the coordinates of the points of incidence of the laser “a.sub.L”, “b.sub.L,” line “L” is calculated using the so-called equations of a line, which are equations which mathematically represent all the points making up a line, in this case the points making up the laser beam. In that sense:

(32) $L=\left\{\begin{array}{c}X=mZ+n\\ Y=m^{\prime }Z+n\text{'}\end{array}\right\}$$m=\frac{\Delta x_l^a-\Delta x_l^b}{z_t^a-z_t^b};n=\Delta x_l^a-\frac{\Delta x_l^a-\Delta x_l^b}{z_t^a-z_t^b}{z}_t^a=\Delta x_l^b-\frac{\Delta x_l^a-\Delta x_l^b}{z_t^a-z_t^b}{z}_t^b$$m^{\prime }=\frac{\Delta y_l^a-\Delta y_l^b}{z_t^a-z_t^b};n^{\prime }=\Delta y_l^a-\frac{\Delta y_l^a-\Delta y_l^b}{z_t^a-z_t^b}{z}_t^a=\Delta y_l^b-\frac{\Delta y_l^a-\Delta y_l^b}{z_t^a-z_t^b}{z}_t^b$
where m and m′ are the slopes (inclination) of line L with respect to planes YZ and XZ, respectively;
where n and n′ are coordinates “x” and “y”, respectively, of the point of intersection of line L with plane XY; and
where X, Y, and Z are the coordinates of any one point belonging to line L.

(33) Therefore, as can be seen in FIG. 12, which shows a sketch of the laser beam striking the sensor of positioning element “C” when it is aligned with hardpoints “A” and “B”, with the equation of the line of the laser beam “L” being known, coordinates “X” and “Y” of point “c.sub.o” are calculated by substituting therein theoretical coordinate “Z” of hardpoint “C”. In that sense:
c.sub.o=(x.sub.o.sup.c,y.sub.o.sup.c,z.sub.o.sup.c)
x.sub.o.sup.c=m.Math.z.sub.t.sup.c+n
y.sub.o.sup.c=m′.Math.z.sub.t.sup.c+n′
z.sub.o.sup.c=z.sub.t.sup.c
where z.sub.t.sup.c is theoretical coordinate z of hardpoint C.

(34) And where point “c.sub.o” is the point of the sensor on which the laser must strike when the positioning element of hardpoint “C” is aligned with hardpoints “A” and “B”, so it is referred to as the target point. It should be observed that the laser beam does not have to be aimed at the center of the sensor of positioning element “C”; this only occurs when the laser beam has been positioned such that it also goes through the exact center of the sensors of hardpoints “A” and “B”.

(35) Finally, as can be seen, FIG. 13 shows a sketch of the displacement vector which gets the beam to successfully go from striking “c.sub.L” to “c.sub.o”. Specifically, FIG. 13.1 geometrically demonstrates how the displacement vector is calculated; FIG. 13.2 shows the sensor of positioning element “C” in the initial position which is displaced to the target position of FIG. 13.3, i.e., the position in which positioning element “C” is aligned with hardpoints “A” and “B”.

(36) In other words, once the initial point of incidence of laser “c.sub.L” is known, displacement vector “D.sub.C” which the positioning element must be moved for the point of incidence to be “c.sub.o” is calculated. In that sense:
D.sub.C=c.sub.L−c.sub.o=(x.sub.D.sup.c,y.sub.D.sup.c)
x.sub.D.sup.c=Δx.sub.L.sup.c−x.sub.o.sup.c
y.sub.D.sup.c=Δy.sub.L.sup.c−y.sub.o.sup.c

(37) where x.sub.D.sup.c is the theoretical displacement that must be applied to positioning element C to align it with A and B by means of the mentioned horizontal driven portion (10′) of the driven linear tables (10); and

(38) where y.sub.D.sup.c is the theoretical displacement that must be applied to positioning element C to align it with A and B by means of the mentioned vertical driven portion (10″) of the driven linear tables (10).

(39) Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.