Patent Application
20160137314
This invention relates to a construction method for constructing a lever kinematics with the features of the generic part of claim 1, and to uses of the method.
A correspondingly constructed lever kinematics is disclosed for example in EP 0 130 983 B1 or in U.S. Pat. No. 4,427,168.
For the structural deformation of flexible skin structures such as for gap-free high-lift configurations on wing leading edges of airplanes or similar aircrafts, accurately fixed paths have to be traced at distributed force application points. To reduce the complexity of the entire system, the actuating elements should be coupled in an effective manner. It is desired that individual kinematic subsystems (one force application point is included per kinematic system) be operated with only one central drive unit such as a rotary drive unit for example. The problem in the construction of such structures and their units is to define suitable kinematic nodes for an axis of rotation of the main lever and for connection points of the connecting struts which correspond to the rigidity specifications and mass specifications within a limited available space.
One possible approach for the construction could be setting up the kinematic problem numerically and solving it by an optimization process. However, as an influence on the solution finding, e.g. through additional boundary conditions, is possible to a limited extent only and as an unsuitable result does not allow to give information about the cause—such as wrong or unsolvable boundary conditions—the numerical approach cannot be used for challenging problems or can be used at best for high-precision optimization.
It is an object of the invention to provide a construction method for the construction of a lever kinematics with which even complicated lever mechanisms can be relatively easily constructed also under difficult boundary conditions.
For the solution of this object, there are provided the construction method according to claim 1, the use of the lever mechanism construction method according to claim 6, and uses of the construction method according to claim 7. A production method involving the use of such a construction method as well as a computer program product with computer program codes with which the construction method can be implemented on a computer, are the subject of additional claims.
Advantageous embodiments of the invention are the subject of the subclaims.
The invention provides a construction method for constructing a lever kinematics comprising a main lever and at least one connecting strut, wherein the main lever can be rotated about a main lever axis by a predetermined angle and the connecting strut connects a force application point to a hinge node on the main lever and wherein a first position of the force application point is predetermined at the beginning of the rotational angle and a second position of the force application point is predetermined at the end of the rotational angle, the method being characterized by the step:
The line, in the following also referred to as isogonic line, represents the loci of possible hinge points and thus can serve the design engineer to immediately find possible solutions based on a representation. Ideal hinge points are indicated on the line. For solutions, which are not ideal but still workable, hinge points may possibly be selected also in the proximity of the line.
For the ideal solution, the construction method preferably comprises the additional step:
A preferred construction method is characterized by geometrically representing the main lever at the beginning and at the end of the rotational angle and of the first and the second point of application.
Step a) preferably includes:
representing the line for the beginning of the rotational angle and representing the line for the end of the rotational angle.
Step a) preferably includes:
geometrically constructing the line in the form of a straight line on the basis of
Step b) preferably includes:
selecting the hinge node on the basis of boundary conditions and/or the available space for the lever kinematics.
It is preferred that the selection of the hinge node be made on the basis of boundary conditions at both endpoints of the rotational angle.
To keep the forces acting in the lever kinematics and in the supporting structure small and thus to achieve a lower weight of the entire lever kinematics, preferably large rotational angles of the main lever are chosen—which allows to obtain a high reduction ratio—if the available space permits.
The position of the axis of rotation is preferably chosen in dependence of the selection of the drive unit and/or the supporting structure. For example, at direct coupling with a rotary drive unit, the region of the axis of rotation of the main lever is predetermined by the dimensions of the drive unit, if the drive unit has to be located inside the available space.
The effective direction of the force on the connecting strut is preferably selected in dependence of the arrangement of the lever kinematics relative to the skin structure and the action of force on the skin structure.
In a preferred approach, a change of sign of the force vector along the connecting strut is avoided so that a possible bearing play will not lead to undesired impact loads. This can be influenced by the selection of the hinge point for the connecting strut.
When a lever kinematics is constructed for driving a deformation of a flexible skin structure, a selection is preferably made with view to a uniform movement of all points of force. For driving flexible skin structures, the uniform movement of all force application points is a criterion for the selection of node or hinge points which should be given priority. Should a single force application point be leading or trailing, this would instantly lead to bulging or to a change of flow in a flexible skin structure.
The procedure for designing a lever kinematics unit preferably takes place in the order of: 1) selecting the drive unit, 2) selecting the axis of rotation, 3) selecting the angle of rotation, 4) selecting the hinge point on the start or finish isogonic line. If a suitable hinge point cannot be found, it should be first examined whether a modified rotational angle will lead to success. Only then the axis of rotation or the drive unit should be changed. Reasons for unsuitable hinge points are for example: not constructible because no longer inside the available space; assembly not possible; lever lengths of the connecting strut or the main lever too short; unsuitable or acute angles (e.g. less than 40°) relative to the skin structure; excessively high forces.
In a further aspect, the invention provides a lever mechanism construction method for the construction of a lever mechanism arrangement with coupled lever kinematics each of which comprising: a main lever and at least one connecting strut such that the main lever can be rotated about a main lever axis by a predetermined angle and that the connecting strut connects a force application point to a hinge point on the main lever and that a first position of the force application point is predetermined at the beginning of the rotational angle and a second position of the force application point is predetermined at the end of the rotational angle, the method comprising: selecting the one of the lever kinematics that has to meet the majority of boundary conditions as the higher-ranking master kinematics, carrying out the construction method in compliance with one of the previously described configurations for the master kinematics and thereafter carrying out the construction method for a further coupled lever kinematics taking under consideration of the construction of the master kinematics as a boundary condition.
Preferably, the construction method is used for the construction of a drive mechanism for the structural deformation of flexible skin structures.
Preferably, the construction method is used for constructing a mechanical drive unit for a high-lift arrangement on a wing leading edge of an aircraft.
Preferably, the construction method is used for the construction of a control mechanism for controlling control surfaces in airplanes, helicopters or other aircrafts.
Preferably, the construction method is used for the construction of a control mechanism for controlling fluid-dynamically effective surfaces in fluid-dynamic bodies.
Preferably, the construction method is used for the construction of a control mechanism for controlling flaps in vehicles and aircrafts.
Preferably, the construction method is used for the construction of running gear kinematics of vehicles and aircrafts.
Preferably, the construction method is used for the construction of hinge systems or movement kinematics of doors, for example doors of vehicles and aircrafts.
A further preferred use is the construction of driving mechanisms with which the windmill blades can change their flow-effective form in order to adjust to the wind conditions. Especially, this can be done in the same manner as with aircraft wings having a flexible skin structure. A deformation can be enabled for example on the leading edge and/or trailing edge of the windmill blade. Such deformations can be easily controlled from central hub of the windmill using lever mechanisms of the kind constructible by the method.
In a further aspect, the invention relates to a production method for producing a lever kinematics comprising a main lever and at least one connecting strut, wherein said main lever can be rotated about a main lever axis by a predetermined angle and wherein said connecting strut connects a force application point to a hinge point on the main lever and wherein a first position of the force application point is predetermined at the beginning of the rotational angle and a second position of the force application point is predetermined at the end of the rotational angle, the production method comprising: performing the construction method in accordance with any one of the preceding configurations and production of the main lever and the connecting strut and coupling the same to each other at the hinge node determined by the construction method.
In a further aspect, the invention relates to a computer program product, characterized in that the same comprises a computer program with computer program code means, said computer program being configured for causing a computer or processor to perform the steps of the method in accordance with one of the above-described configurations.
To simplify the construction of even complicated lever kinematics, the invention proposes to initially represent for a given axis of rotation of the main lever and an associated rotational angle, those geometric curves on which the allowable kinematic points are located. In the following, these curves are also referred to as “isogonic lines”, namely lines corresponding to the same angle. Thereafter, a node is preferably selected on the isogonic line which best solves the kinematic problem. Possibly, even points near the isogonic line may be considered. The farther away from the isogonic line a point is, the less it is suited as a solution.
Geometrical processes offer themselves as a simple method for determining the isogonic line in order to avoid the ambiguous solutions obtained as a result in the analytical approach. Such isogonic lines can be determined not only for kinematic problems in the plane, but also for arbitrary paths or trajectories in the space.
By representing the curves for the possible hinge points—also referred to as isogonic lines—the described kinematic problem can be graphically solved step by step, especially in construction programs.
For example, it can be immediately seen in the representation whether the rotational angle or the axis of rotation common to the overall system have been correctly chosen and which additional boundary conditions are possible.
Possible additional boundary conditions could be for instance a strut orientation quasi-identical to the force direction, a uniform strut length, common kinematic nodes of coupled lever kinematics or the like.
Conclusions can be drawn as to which boundary conditions have to be changed in order to solve the kinematic problem.
A particularly preferred use is the construction of a load-introducing device and a structural component in a manner such as illustrated and described in European patent application 13 196 990.9-1754 (not previously published). Further details are described in this European patent application, the disclosure of which is fully incorporated herein by reference.
Additional conclusions may be drawn as to the position the curve of possible hinge points has to have in order to guarantee a robust kinematic solution with view to given manufacturing tolerances or installation tolerances.
Embodiments of the invention will be described in the following with reference to the drawings, wherein it is shown by:
In the following, novel construction methods for the construction of lever kinematics will be described which may be used in the construction of lever mechanisms, especially for driving control surfaces of aircrafts but also for other components, especially those of aircrafts.
One example of use in a lever kinematics to be constructed is shown in more detail in
In one embodiment, the flow body 14 is a wing 15, which forms part of a windmill of a wind power plant for electric current generation.
In a different configuration, the flow body 14 is for example a wing 15 or a fin of an aircraft such as an airplane. In this case, the wing 15 is provided with a droop nose flap that is implemented by said adaptive structure 10.
Especially in laminar profiles, it is of major importance that the flow on the wing has a particularly long laminar migration distance in every phase of the flight—different angles of attack and different flow rates. In a laminar profile, if one did without an adaptive front nose, a higher touch-down speed for landing the aircraft would be required for example in order to guarantee that the airplane is securely guided.
For this purpose, the embodiment illustrated in
Such droop noses are shown for example in the European patent application 13 196 990.9-1754 and in DE 29 07 912 A1.
For this purpose, the flexible skin 20 is fixed with its two terminal edges oriented in the span-wise direction to a supporting structure and is braced in the span-wise direction by bracing elements such as stringers, in particular omega stringers 25, but is deformable upwards and downwards. To this end, a deforming force is transmitted to the flexible skin 20 by a load-introducing device 16, with the force application points being preferably selected on the bracing elements.
To be able to implement such a leading edge on an aircraft, load-introducing devices 16 have to be constructed which correctly introduce the load for deforming the skin 20.
On the other hand, a particularly slim construction of the flow body 14 is desired. The space is therefore very limited.
Load-introducing devices 16 have to be effective along the whole length of the adaptive structure 10 that is to be deformed. A corresponding construction of the load-introducing device 16 creates problems for the design engineers.
Problem: “Morphing skin”
For the structural deformation of flexible skin structures 10 such as for gap-free high-lift configurations on wing leading edges, curved paths 28a, 28b, 28c, 28d have to be traced at distributed force application points 26a, 26b, 26c, 26d to lower the wing leading edge in order to obtain the desired target contour. The two profile contours for the flight conditions “cruise 22” and “high-lift” 24 essentially determine the design just as the smooth lowering action. The definition of the paths 28a, 28b, 28c, 28d can take place through time-discretized path points or through geometric approximation functions.
The introduction of the force into the skin structure 10 takes place at different span-wise positions (sections—one thereof being shown in
For each intersection, various connecting struts 38a, 38b, 38c, 38d, which are connected to the force application points 26a, 26b, 26c, 26d, are attached to a main lever 36.
In
Ideally, adjacent main levers 36—arranged for example on adjacent sections in the span-wise direction of the wing 15—should be connected (e.g. through a shaft or a rod assembly).
In
In the following, there will be described the construction methods the design engineer may use for the construction and production of such lever kinematics 34.
In the illustrated embodiment, several connecting struts, e.g. the second, third and fourth connecting strut 38b, 38c, 38d, engage on a common second hinge point 42b, whereas only one connecting strut engages on a first hinge point 42a. For example, the first connecting strut 38a engages on the first hinge point 42d. The hinge points 42 of the respective connecting struts 38 can also be chosen differently.
For constructing, it makes sense to divide the entire lever kinematics 18 into several sub-kinematics 34a-34d and to determine the parameters of the sub-kinematics 34a-34d as described in more detail below.
The overall lever kinematics 18 is defined through the parameters:
The common rotational angle α of the rotary drive unit 32 which is mostly freely selectable and essentially determines the position of the hinge node 42 of the connecting struts 38, plays a central role.
Specifications to be considered are:
Cause and effect are interchangeable for most kinematics. Accordingly, if the arrangement is identical, it is also possible to let the introduction of forces take place via path 28 (cause), which causes a rotary movement of a (main) lever 36 (effect).
For this purpose, there are composed in a span-wise section in the
The rotational angle α is a function dependent on the coordinates of the axis of rotation 44, the hinge node 42, the position 26S of the force application point 26 at the point of time tStart, and the position 26E of the force application point at the point of time tEnde of the path 28.
The path 28 of the force application point 26 can be straight, curved or any shape provided that the rotational movement of the main lever 36 is always in the same direction.
A classical approach for finding the kinematic points 26, 42, 46 would now be a numerical method which sets up a linear equation system for the determination of the kinematic points and for solving the equation by means of a target function, e.g. the deviation from the predetermined path. However, it turns out that the numerical approach cannot be used for challenging problems or can be used at best for fine optimization. The reason is that the influence on the solution finding is possible to a limited extent only, e.g. through additional boundary conditions, and that an unsuitable result does not allow to give information about the cause of that unsuitability—such as wrong or unsolvable boundary conditions for example.
In contrast, a geometrical approach to the solution of the problem is proposed in the following. The geometrical method allows the problem being described in a convenient and clear manner and permits selective influence on the solution finding.
To this end, the overall problem of constructing the overall lever kinematics 18 is divided into sub-problems of constructing lever kinematics 34 of the sub-kinematics 34a-34d. To this end, the position of the axis of rotation 44 of the main lever 36, the rotational angle α of the main lever 36, a first support point, e.g. the end point 26E, on the path 28 are predetermined. For these parameters, a line including the locus of all allowable hinge points 42 of the connecting strut 38 is obtained and graphically represented as an interim result.
This is shown in
Since the main lever 36 rotates about the angle α during the movement, the line 48 of all allowable hinge points is also rotated in a corresponding manner at the end of the path 28. The bold line 48S accordingly shows the line 48 of all possible hinge points at the beginning of the movement (tStart), and the line 48E, which is not plotted as a bold line, accordingly shows the line 48 of all allowable hinge points at the end of the movement (tEnde).
Geometrically, all possible hinge nodes that meet the predetermined conditions lie on a straight line. If the axis of rotation is fixed, the position of the straight line exclusively depends on the amount of the rotational angle α. Since a curve with same angle is also referred to as isogonic line, this term is also used in the following for the curve or line 48, 48S, 48E of the possible hinge nodes.
In principle, all points on the isogonic line 48, 48S, 48E represent practical solutions for fixing the hinge point 42 and accordingly for constructing the lever kinematics 34 with which the force application point 26 can be moved from its start position 26S to its end position 26E by rotating the main lever 36 about the angle α. Certain deviations are possible, especially in flexible structures. However, some possible regions on the isogonic line will be excluded or will appear less favorable due to the additional boundary conditions. After one or several isogonic lines 48 are determined, a particularly suitable hinge point 42 can be selected on an isogenic line 48, which hinge point accordingly defines the overall kinematic system.
With this method it can be readily seen whether practical hinge points for a desired rotational angle are possible within the desired installation space. If this is not the case, either the rotational angle needs to be changed or the axis of rotation shifted.
Accordingly, this provides a simple and very clear method for constructing the lever kinematics 34.
As already explained above,
The line 48, 48S, 48E then serves as a selection guide or model for the selection of possible hinge points.
In a preferred embodiment, the construction method further comprises the step:
If the hinge node 42 is selected on the line 48, the related main lever 36 can be geometrically represented at the beginning and at the end of the angle of rotation α, wherein the connecting strut 38 indicates the connection of the hinge point or hinge node 42 to the first position 26S and the second position 26E of the point of application 26 at the beginning and at the end of the angle of rotation α, as shown in
Accordingly, it can be immediately recognized graphically from
Therefore, for the construction method, the angle of rotation α and the support point 46 and a first position 26S and a second position 26E of the force application point 26 have to be fixed at first.
The selection of the position 26S, 26E of the force application point 26 is predetermined for example by a desired path 28 such as one of the paths 28a-28d for the respective sub-kinematics 34a-34a according to
In a lever kinematics 34 to be constructed, it may be desired that a third support point is approached by the movement of the force application point 26 in addition to said two specified support points 26S, 26E of the path 28. For example, as illustrated in
Concerning this, two examples are shown in
If the path 28 of a sub-kinematics 34 is defined over more than two support points 26S, 26Z, 26E, 26-1, 26-2, it is theoretically possible to use arbitrary combinations of support points 26S-26-Z, 26S-26-1, . . . as starting points and endpoints with associated angles of rotation, and to represent a respective isogonic line.
For the application example of a construction of a load-introducing structure for a control surface of an aircraft shown in
In coupled sub-systems such as in the sub-kinematics 34a-34d, the hinge point 42a, 42b of the connecting strut 38a-38d should coincide with the point of intersection of the isogonic line in order not to produce structural constraint forces. As a prerequisite, the support points of the individual paths 28a-28d should correlate with each other time-wise. Especially in the example of
If the connected structure 10 is elastically deformable and if constraint forces are largely insignificant, the kinematics can be designed alone by relevant support points (e.g. start 26S and end 26E and/or cruise 22 and high-lift 24). The result is a great variety of kinematic solutions that can be constrained by further criteria.
Further criteria are for example:
For example, the path 28 could be predetermined using eight points, but in an elastically connected structure it is not sufficient to identify merely relevant support points, namely the terminal points of the path 28 at the beginning 26S and at the end 26E.
Based on
In the
In the
The
On the other hand, a thrust rod solution is shown in
As shown in
A lever kinematics 34 can also be constructed in which the movement path 28 can extend parallel to the main lever 36 and to the connecting strut 38 at the starting time.
In the following, one possibility for the construction of a coupled overall kinematics 18 as illustrated in
One possible approach of designing a coupled kinematics system 18 is as follows.
The order in which the sub-kinematics 34a-34d are designed is from particularly critical sub-kinematics which are difficult to be solved also from the constructional aspect to those which can be solved more easily. The first sub-kinematics takes the “master” function for the additional “slave” kinematics. The “master” determines the angle of rotation of the individual time-correlated support points 26S, 26E of the path 28, 28a-28d. With these predetermined angles of rotation, the isogonic lines can be represented corresponding to selected support points of a single “slave” sub-kinematics. If more than two support points are considered, more than one isogonic line can be represented. The common intersection point thereof describes the ideal hinge point.
In
A further construction is shown in
On the basis of the representation of the isogonic lines 48, a corresponding hinge point for each sub-kinematics problem can be found step by step, and the solution is graphically displayed straight away so that the design engineer can immediately assess the suitability of the selected solution on the basis of various examples of differently selected hinge points.
With the aid of corresponding plot routines or mathematical routines, which can clearly represent simple geometric figures, the corresponding lever kinematics for differently selected hinge points can be quickly identified. Dynamic geometry software programs such as available for maths lessons can be used for this purpose. With the use of dynamic geometry software it is possible to set up geometric constructions interactively on the computer. Such programs can be downloaded as freeware from the Internet. Examples are programs like “Derive”, “Mathcad”, “Cinderella”, “Geonext” or “GeoGebra”. Auxiliary algorithms thereto can be easily written in order to develop a program for representing the isogonic lines on the basis of one of these programs with the aid of which the selected constructions can be promptly displayed.
The representation of the lines 48, which are herein referred to as isogonic lines, of any possible hinge points for the predetermined parameters: angle of rotation, axis of rotation, starting point and endpoint, is possible in different ways. In the following, a first possible embodiment will be described in more detail with reference to
To this end, the fulcrum 46 and the starting point 26S and the endpoint 26E in the xy plane are fixed at first using for example one of the above-mentioned software programs. In the following example, the angle of rotation in the clockwise direction is assumed to be 30°.
Thereafter, the vector w from the point 26S to the point 26E as well as the straight line f through the fulcrum 46 and the starting point 26S, the straight line g through the center M of the vector w and perpendicular to the vector w in the xy plane, and the straight line j through the fulcrum 46 and the endpoint 26E are plotted.
Then the straight line f is rotated about the fulcrum 46 in the direction of rotation by the angle α/2, which results in the straight line f. In a comparable manner, the straight line j is rotated in the opposite direction by half the angle of rotation α/2, which results in the straight line j′. The point of intersection between f and g is for example referred to as P1, the point of intersection between j′ and g is for example referred to as P2.
Thereafter the point P1 is rotated by −α, i.e. by a in the opposite direction, which results in point P1′. The point P2 is rotated by the angle of rotation α in the direction of rotation, which results in point P2′.
Point P2 is one of the possible hinge points if the system is at the starting of time. P1 is one of the possible hinge points if the system is at the ending time. The isogonic line 48S at the starting f time is thus given as a straight line through the point P2 and the rotated point P1′, whereas the isogonic line 48E is given as a straight line through the point P1 and the point P2′ rotated by α.
The above construction of the isogonic line is based on the consideration that the straight line g represents the sum of all points which have the same distance to 26S and 26E. If half the angle of rotation is completed and a point is reached which has the same distance to the starting point 26S as to the endpoint 26E, this is a possible point for a hinge node. In the same manner, half the angle of rotation is to be completed in point P2; on the other hand, point P2 is equally spaced from the starting point 26S and from the endpoint 26E. Thus the points P1 and P2 are possible hinge points for the initial state or the final state. Corresponding rotations by the angle α will then result in an additional possible hinge point for the final state or the initial state.
The present illustration of the isogonic line 48 according to
After the isogonic lines 48E, 48S are represented as shown in
To this end, it may be considered whether a thrust rod or a tension bar is desired.
The straight line f represents a case of an extended linkage—main lever 36 and connecting strut 38 on one line—at the starting point 26S. Accordingly, the point of intersection 48f of the straight line f with the isogonic line 48S is the locus for the hinge point 42 for this limit case of a tension strut solution.
The straight line j represents the limit case of an extended linkage—main lever 36 and connecting strut 38 on one line—for the endpoint 26E. Accordingly, the point of intersection 48j of the straight line j with the isogonic line 48E represents the limit case for this final state, for an allowable hinge point 42 for the thrust rod solution. Accordingly, the regions 48Zug and 48Schub indicated by the additional dashed lines are possible positions of hinge points 42 for a thrust rod solution or a tension strut solution. The region 48z in between should be avoided. This is indicated in
In
In the above description, solutions for the construction of lever kinematics have been discussed, wherein the lever and the connection strut and also the movement lie in one plane. However, the invention is not limited to this. The solution, which involves isogonic lines, can also be used for three-dimensional kinematic problems still to be described in more detail below.
The approach of deriving and representing the isogonic lines 48 chosen in the construction according to
Accordingly, a line perpendicular to the connection between both force application points 26S and 26E is plotted on the basis of the parameters, namely the two force application points and the locus of the main axis of rotation A.
The thought behind this construction is that when the axes are respectively reflected by α/2, i.e. half the angle of rotation, the same length of the connecting strut 38 must be given on the left and on the right. With this construction principle, the isogonic lines for the start 48S (the entire system is at the starting point) and for the end 48E (the entire system is at the endpoint) can be constructed.
Accordingly, the symmetry to the axes is utilized. There are defined axes where the points of equal length are given. The isogonic line is where the same intersect.
In the following, an alternative and far more simple and thus preferred approach of representing the isogonic line will be explained with reference to
In a first step, point C—starting point 26S—is rotated by the angle α (e.g. 29°) about the fulcrum 46. The resulting point is referred to as V in
The isogonic line 48S at the start can then be easily obtained by simply rotating the isogonic line 48E by the angle −α about the fulcrum 46.
However, it is also possible to rotate point C′—endpoint 26E—by the angle −α(29°) about the fulcrum 46. The resulting point is referred to as V′ in
The thought behind this construction is as follows: The midperpendicular to a connecting line between two reference points represents the quantity of all points which have the same distance to the reference points. Accordingly, the midperpendicular to C′-V represents the quantity of all points which have the same distance to the endpoint C′ and to the starting point V rotated by α. However, points with the same distance to the endpoint and the rotated starting point are the immediate possible hinge points 42. The isogonic lines 48 are thus obtained in a very simple and universal way.
In the following, the three-dimensional solution will be finally described. Corresponding to the above-described two-dimensional solution, the isogonic lines can be also obtained in different ways. A first case, which can be used universally, results from the solution involving the midperpendicular. The second solution process, which is based on the considerations of
In the universal solution process (case 1), the principle of the midperpendicular can be applied. In the other solution process (case 2), the same principle of line symmetry can be used for inferring the isogonic lines 48S and 48E. In this manner, intersection lines are obtained. The corresponding solutions are the points of intersection of the intersection line with the rotational plane i.
The easier way for constructing the isogonic lines in the 3D case, which can be applied to all 3D cases including the orthogonal case and also to the 2D case—as shown in
In the method for the determination of the isogonic lines for the general 3D case (also applicable to 2D) according to the
A precondition is a coordinate transformation in order to achieve that
At the given initial situation, the exemplary rotational angle alpha)(=40°, the rotational plane (xy plane), the axis of rotation (z axis), the fulcrum (A), and the path points at the start and at the end (B=26S and C=26E) are shown.
Step 1: Construction of the center K
The straight isogonic line 11 represents the isogonic line 48E at the ending time tEnde. The isogonic line 48E can be simply obtained by rotating line 48E by the angle −alpha about the rotational axis (=z axis).
Step 3 can also be performed: Construction of the center L
In
The construction takes place as previously described, but the planes o1 and j1 do not intersect the xy plane, but instead the rotational plane i, which runs parallel to the xy plane and through point H.
In the following, case 2 will be explained with reference to the illustration in the
The
In
First of all step 1 is performed: Construction of the symmetry plane a between B and C.
The next step is step 4: Construction of the second isogonic point (G) on the first isogonic line (Iso1):
The next step is step 5: Construction of the second isogonic point (F′) on the second isogonic line (Iso2)
The next step is step 6: Representation of the isogonic lines
These straight lines are represented in
In the following, further criteria for step b) “selection of suitable hinge points” will be explained. To this an approach exists according to which a third point N on the connecting line between the force points and an angle thereto are assumed. For example, the angle can be assumed through a ratio of the respective line segments. If N lies for example on 70% of the overall line segment, a rotational angle of 70% of the maximum angle can be assumed. Thereafter, the isogonic line problem is solved using this constellation. A suitable hinge point would for example be a point of intersection between the isogonic lines.
This is only one example. It could be provided for instance that not only the two force applications points 26S and 26E, but also a third force application point are to be approached; the problem could then be solved in this way, see
A further case of the selection is illustrated in
Such a transitional case could be possible in special solutions, for example for determining the overall kinematics by folding it down. In the application of the droop nose, this is not provided.
The
Also, a solution is conceivable (not illustrated) in which the initial position of the connecting strut 38 is aligned with the main lever 36 and the movement path 28 is aligned as well. In the kinematics of the crank mechanism, this represents the classical thrust rod problem.
Possible applications of lever kinematics 18, 34 to be constructed in this way are a deflection of the skin on the leading edges of wings, according to
Applications are for example the control of control surfaces in aircrafts. A control of other fluid-dynamically effective surfaces is also possible such as the control of a wing surface in order to influence a transition from a laminar flow to a turbulent flow using a corresponding lever kinematics. The lever kinematics 18, 34 can be constructed and used for any desired control of flaps in airplanes and aircrafts (flap elements) or also of hinge systems of doors (e.g. of aircrafts) or possibly also of running gear kinematics of vehicles and aircrafts.
Further fields of application are vehicles, for example aerodynamically effective surfaces of vehicles, ships, submarines, windmill plants etc.
A structure of the kind as shown in
The driving action for adjusting the position of the wing edges can take place analogously to that described and illustrated in European patent applications 13 196 990.9 and 13196994.1. Particularly the linear drive unit is of great interest for windmill blades because the actuation for the adjustment of the edges can be from the hub.
| Number | Date | Country | Kind |
|---|---|---|---|
| 14 193 280.6 | Nov 2014 | EP | regional |
