A design method for eliminating the sway of helicopter suspension

Abstract

The present invention discloses a design method for eliminating the sway of a helicopter suspension, which relates to the field of helicopter suspension design. The method comprises the following steps: firstly, performing a plane projection on a suspension system; then, assuming that the cargo swings at an angle at the lower end, and performing the projection again; and then, determining the equivalent sway center of the cargo based on the two projection results; then, adjusting the design parameters of the suspension system based on the relationship between the distance Δr between the equivalent sway center and the apex of the suspension system and the design parameters of the suspension system, so that Δr is equal to the distance from the apex of the suspension system to the center of gravity of the helicopter; and finally, adjusting the projection plane, repeating the above steps, and integrating the design parameters, thereby designing the suspension system and obtaining a suspension system product. According to the present invention, the negative impact of cargo sway on the helicopter can be minimized or even eliminated by adjusting the design parameters of the suspension system, thereby reducing the burden on observers or pilots and improving flight safety.

Description

Technical Field

[0001] The invention relates to the field of helicopter suspension design, and in particular to a design method for eliminating sway in a helicopter suspension. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] Helicopters have the ability to hover, circle, fly at low speed in the air and are independent of airport runways. Therefore, helicopters have great application prospects in areas such as material transportation, cargo delivery, and emergency rescue.

[0004] Currently, when helicopters carry out tasks such as material transportation and cargo delivery, they must add a rack to the bottom of the helicopter and use a hanging rope to hang the cargo. During the flight, the attitude of the helicopter directly determines the flight safety. Therefore, the swing of the cargo is coupled with the flight attitude and control, and there is a possibility of divergence, which endangers flight safety. Therefore, it is extremely important to avoid the impact of cargo swing on the helicopter attitude, which can also reduce the burden on observers and pilots. Summary of the Invention

[0005] The purpose of the present invention is to provide a design method for eliminating the swing of cargo when the helicopter is currently suspended, in order to address the problem that the swing of cargo is coupled with the flight attitude and control, which may diverge and endanger flight safety. The method can minimize or even eliminate the negative impact of cargo swing on the helicopter, reduce the burden on observers or pilots, improve flight safety, and thus solve the above-mentioned problem.

[0006] The technical solutions of the present invention are as follows:

[0007] A design method for eliminating sway in a helicopter suspension system comprises the following steps:

[0008] Step S1: Project the initial state of the hanging system onto the left and right symmetric plane of the helicopter; that is, project the initial state of the hanging system onto the front view plane, and the projection structure is as follows: Figure 3 As shown;

[0009] Step S2: Assume that the cargo swings at an angle at the lower end, and project the swinging hanging system onto the left-right symmetric plane of the helicopter; that is, assume that the cargo swings at a small angle at the lower end. Since point O is a universal joint, and point AD and the helicopter connection point are hinged, the entire hanging system will deflect with the cargo. The deflection result is as follows: Figure 3 shown by the dotted line;

[0010] Step S3: Determine the equivalent center of sway of the cargo based on the projections from steps S1 and S2. It should be noted that in this embodiment, the principle of sway elimination is to utilize the simultaneous translational motion of the swing mechanism to achieve an offset between the equivalent sway center and the actual attachment point position. When the equivalent sway center coincides with the helicopter's center of gravity, the cargo only exerts a force on the helicopter's center of gravity without generating any additional torque, thus achieving sway elimination. Therefore, in step S3, it is necessary to determine the equivalent center of sway of the cargo.

[0011] Step S4: determining the relationship between the distance Δr between the equivalent swing center and the vertex of the suspension system and the design parameters of the suspension system;

[0012] Step S5: By adjusting the design parameters of the suspension system, the distance Δr between the equivalent swing center and the apex of the suspension system is equal to the distance from the apex of the suspension system to the center of gravity of the helicopter, thereby eliminating the influence of the swing of the cargo on the left-right symmetry plane of the helicopter on the attitude of the helicopter. Specifically, based on the relationship between the distance Δr between the equivalent swing center and the apex of the suspension system and the design parameters of the suspension system, the design parameters of the suspension system are specifically designed to ensure that the distance Δr between the equivalent swing center and the apex of the suspension system is equal to the distance from the apex of the suspension system to the center of gravity of the helicopter. The center of gravity of the helicopter is automatically generated by the helicopter system after the suspension system is installed. However, those skilled in the art can also obtain the position of the center of gravity of the helicopter without creative work, so this will not be described in detail here.

[0013] Step S6: Project the suspension system with adjusted design parameters onto a plane passing through the suspension system vertex and perpendicular to the helicopter's bilateral symmetry plane. Repeat steps S2 to S5 to eliminate the effect of cargo swing on the helicopter's attitude due to the cargo swinging on the plane perpendicular to the helicopter's heading.

[0014] Step S7: Integrate the design parameters adjusted in steps S5 and S6, and use them to design the hanging system to obtain a hanging system product.

[0015] Further, if Figure 2 As shown, the hanging system includes: a tetrahedral hook and four steel ropes;

[0016] One end of the four steel cables is hinged to the helicopter fuselage, and the other end is hinged to the four points ABCD at the bottom of the tetrahedron hook;

[0017] At the top point O of the tetrahedron hook, there is a universal joint that can rotate around any position; below point O is connected a lifting rope for lifting cargo.

[0018] Further, if Figure 1 As shown, the projection result of step S1 is:

[0019] The projection of points AB is point A, the projection of points CD is point D, the projection of the tetrahedron hook is triangle OAD, K is the intersection of the extension lines of the two steel ropes, and points EF are the fuselage hanging points.

[0020] Further, if Figure 1 As shown, the projection result of step S2 is:

[0021] Point A moves to point A', point D moves to point D', point O moves to point O', and point K moves to point K'.

[0022] Furthermore, the step S3 includes:

[0023] The intersection of straight lines KO and K'O' at the far end is point S; according to the principle of the simple pendulum, point S is the equivalent center of swing of the cargo; since the lifting rope can only withstand tension, the force exerted by the cargo on the helicopter must pass through point S along the rope; when point S coincides with the center of gravity of the entire helicopter, the force exerted by the cargo on the helicopter passes through the center of gravity of the helicopter, thus generating no additional torque on the helicopter and thus not affecting the helicopter's flight attitude, thus fundamentally resolving the impact of cargo swing on the helicopter.

[0024] Furthermore, the relationship determined in step S4 is as follows:

[0025]

[0026] Where:

[0027] Δr is the distance from point S to point O;

[0028] M is the distance from point K to line AD;

[0029] H' is the distance from point O to line AD;

[0030] H is the distance from the fuselage suspension points E and F to the line AD;

[0031] θ is the angle between the steel rope and the vertical direction in the initial state;

[0032] Since M, H', H and θ are the design parameters of the suspension system, by adjusting the above four parameters, Δr can be made equal to the distance from the suspension system vertex to the center of gravity of the helicopter, thereby achieving the elimination of swing on the left and right symmetric plane of the helicopter.

[0033] Further, see Figure 1 , the steps determined in step S4 are as follows:

[0034] Let the distance from point S to point O be Δr;

[0035] The distance from point O to line AD is H';

[0036] The distance from point O to point O' is ΔS;

[0037] The distance from point K to point K' is ΔS';

[0038] The distance between the fuselage suspension points E and F and the line AD is H;

[0039] The distance from point K to line AD is M;

[0040] The length of the steel rope is l;

[0041] In the initial state, the angle between the steel rope and the vertical direction is θ;

[0042] The angle of the steel rope deflection is ;

[0043] Draw a line O'T through point O' that is parallel to line OK and intersects line KK' at T. The angle between line O'T and line O'K' is ΔΦ.

[0044]

[0045] in:

[0046]

[0047]

[0048] Substituting ΔS and ΔS' into Δr, we can finally get:

[0049]

[0050] Compared with the existing technology, the beneficial effects of the present invention are:

[0051] A design method for eliminating sway in a helicopter suspension system comprises: step S1: projecting a suspension system in an initial state onto the left-right symmetry plane of the helicopter; step S2: assuming that the cargo swings at an angle at the lower end, and projecting the swung suspension system onto the left-right symmetry plane of the helicopter; step S3: determining the equivalent sway center of the cargo based on the projections of step S1 and step S2; step S4: determining the relationship between the distance Δr between the equivalent sway center and the apex of the suspension system and the design parameters of the suspension system; step S5: adjusting the design parameters of the suspension system so that the distance Δr between the equivalent sway center and the apex of the suspension system is equal to the distance from the apex of the suspension system to the center of gravity of the helicopter, thereby eliminating sway. The impact of the swing of the cargo on the left and right symmetric plane of the helicopter on the helicopter's attitude; Step S6: Project the hanging system with adjusted design parameters onto a plane passing through the apex of the hanging system and perpendicular to the left and right symmetric plane of the helicopter, and repeat Steps S2 to S5 to eliminate the impact of the swing of the cargo on the plane perpendicular to the heading of the helicopter on the helicopter's attitude; Step S7: Integrate the design parameters adjusted in Steps S5 and S6, and use them to design the hanging system to obtain a hanging system product; By adjusting the design parameters of the hanging system, the negative impact of the cargo swing on the helicopter can be minimized or even eliminated, thereby reducing the burden on observers or pilots and improving flight safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a schematic diagram of a design method for helicopter suspension sway elimination;

[0053] Figure 2 This is a schematic diagram of the hanging system;

[0054] Figure 3 This is a projection diagram of a design method for helicopter suspension swing elimination. DETAILED DESCRIPTION

[0055] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0056] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0057] Example 1

[0058] Helicopters have the ability to hover, circle, fly at low speeds, and are independent of airport runways. Therefore, they have great application prospects in the fields of material transportation, cargo delivery, and emergency rescue. Currently, when helicopters perform tasks such as material transportation and cargo delivery, they must add a rack to the bottom of the helicopter and use a hanging rope to hang the cargo. During the flight, the attitude of the helicopter directly determines the flight safety. Therefore, the swing of the cargo is coupled with the flight attitude and control, and there is a possibility of divergence, which endangers flight safety. Therefore, it is extremely important to avoid the impact of cargo swing on the helicopter attitude. At the same time, it can reduce the burden on observers and pilots.

[0059] In response to the above-mentioned problem, this embodiment provides a design method for eliminating helicopter hanging swing, which can minimize or even eliminate the negative impact of cargo swing on the helicopter, reduce the burden on observers or pilots, and improve flight safety.

[0060] See also Figure 1-3 A design method for eliminating sway in a helicopter suspension system comprises the following steps:

[0061] Step S1: Project the initial state of the hanging system onto the left and right symmetric plane of the helicopter; that is, project the initial state of the hanging system onto the front view plane, and the projection structure is as follows: Figure 3 As shown;

[0062] Step S2: Assume that the cargo swings at an angle at the lower end, and project the swinging hanging system onto the left-right symmetric plane of the helicopter; that is, assume that the cargo swings at a small angle at the lower end. Since point O is a universal joint, and point AD and the helicopter connection point are hinged, the entire hanging system will deflect with the cargo. The deflection result is as follows: Figure 3 shown by the dotted line;

[0063] Step S3: Determine the equivalent center of sway of the cargo based on the projections from steps S1 and S2. It should be noted that in this embodiment, the principle of sway elimination is to utilize the simultaneous translational motion of the swing mechanism to achieve an offset between the equivalent sway center and the actual attachment point position. When the equivalent sway center coincides with the helicopter's center of gravity, the cargo only exerts a force on the helicopter's center of gravity without generating any additional torque, thus achieving sway elimination. Therefore, in step S3, it is necessary to determine the equivalent center of sway of the cargo.

[0064] Step S4: determining the relationship between the distance Δr between the equivalent swing center and the vertex of the suspension system and the design parameters of the suspension system;

[0065] Step S5: By adjusting the design parameters of the suspension system, the distance Δr between the equivalent swing center and the apex of the suspension system is equal to the distance from the apex of the suspension system to the center of gravity of the helicopter, thereby eliminating the influence of the swing of the cargo on the left-right symmetry plane of the helicopter on the attitude of the helicopter. Specifically, based on the relationship between the distance Δr between the equivalent swing center and the apex of the suspension system and the design parameters of the suspension system, the design parameters of the suspension system are specifically designed to ensure that the distance Δr between the equivalent swing center and the apex of the suspension system is equal to the distance from the apex of the suspension system to the center of gravity of the helicopter. The center of gravity of the helicopter is automatically generated by the helicopter system after the suspension system is installed. However, those skilled in the art can also obtain the position of the center of gravity of the helicopter without creative work, so this will not be described in detail here.

[0066] Step S6: Project the suspension system with adjusted design parameters onto a plane passing through the suspension system vertex and perpendicular to the helicopter's bilateral symmetry plane. Repeat steps S2 to S5 to eliminate the effect of cargo swing on the helicopter's attitude due to the cargo swinging on the plane perpendicular to the helicopter's heading.

[0067] Step S7: Integrate the design parameters adjusted in steps S5 and S6, and use them to design the hanging system to obtain a hanging system product.

[0068] In this embodiment, specifically, Figure 2 As shown, the hanging system includes: a tetrahedral hook and four steel ropes;

[0069] One end of the four steel cables is hinged to the helicopter fuselage, and the other end is hinged to the four points ABCD at the bottom of the tetrahedron hook;

[0070] At the top point O of the tetrahedron hook, there is a universal joint that can rotate around any position; below point O is connected a lifting rope for lifting cargo.

[0071] In this embodiment, specifically, Figure 1 As shown, the projection result of step S1 is:

[0072] The projection of points AB is point A, the projection of points CD is point D, the projection of the tetrahedron hook is triangle OAD, K is the intersection of the extension lines of the two steel ropes, and points EF are the fuselage hanging points.

[0073] In this embodiment, specifically, Figure 1 As shown, the projection result of step S2 is:

[0074] Point A moves to point A', point D moves to point D', point O moves to point O', and point K moves to point K'.

[0075] In this embodiment, specifically, step S3 includes:

[0076] The intersection of straight lines KO and K'O' at the far end is point S; according to the principle of the simple pendulum, point S is the equivalent center of swing of the cargo; since the lifting rope can only withstand tension, the force exerted by the cargo on the helicopter must pass through point S along the rope; when point S coincides with the center of gravity of the entire helicopter, the force exerted by the cargo on the helicopter passes through the center of gravity of the helicopter, thus generating no additional torque on the helicopter and thus not affecting the helicopter's flight attitude, thus fundamentally resolving the impact of cargo swing on the helicopter.

[0077] In this embodiment, specifically, the relationship determined in step S4 is as follows:

[0078]

[0079] Where:

[0080] Δr is the distance from point S to point O;

[0081] M is the distance from point K to line AD;

[0082] H' is the distance from point O to line AD;

[0083] H is the distance from the fuselage suspension points E and F to the line AD;

[0084] θ is the angle between the steel rope and the vertical direction in the initial state;

[0085] Since M, H', H and θ are the design parameters of the suspension system, by adjusting the above four parameters, Δr can be made equal to the distance from the suspension system vertex to the center of gravity of the helicopter, thereby achieving the elimination of swing on the left and right symmetric plane of the helicopter.

[0086] In this embodiment, please refer to Figure 1 , the steps determined in step S4 are as follows:

[0087] Let the distance from point S to point O be Δr;

[0088] The distance from point O to line AD is H';

[0089] The distance from point O to point O' is ΔS;

[0090] The distance from point K to point K' is ΔS';

[0091] The distance between the fuselage suspension points E and F and the line AD is H;

[0092] The distance from point K to line AD is M;

[0093] The length of the steel rope is l;

[0094] In the initial state, the angle between the steel rope and the vertical direction is θ;

[0095] The angle of the steel rope deflection is

[0096] Draw a line O'T through point O' that is parallel to line OK and intersects line KK' at T. The angle between line O'T and line O'K' is ΔΦ.

[0097]

[0098] in:

[0099]

[0100]

[0101] Substituting ΔS and ΔS' into Δr, we can finally get:

[0102]

[0103] The present embodiment provides a design method for eliminating helicopter hanging swing, which can minimize or even eliminate the negative impact of cargo swing on the helicopter, thereby reducing the burden on observers or pilots and improving flight safety.

[0104] The above-described embodiments merely represent specific implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of protection of the present application. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the technical concept of the present application, and all such variations and improvements fall within the scope of protection of the present application.

[0105] This background section is provided to generally present the context of the invention, and the work of the presently named inventors, the work to the extent described in this background section, and aspects of the description in this section that did not constitute prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art to the present invention.

Claims

1. A design method for eliminating sway in a helicopter suspension, characterized in that: include: Step S1: Projecting the initial state of the suspension system onto the left and right symmetric plane of the helicopter; Step S2: Assume that the cargo is swung at an angle at the lower end, and project the swung hanging system onto the left-right symmetric plane of the helicopter; Step S3: Determine the equivalent swing center of the cargo based on the projections of steps S1 and S2; Step S4: determining the relationship between the distance Δr between the equivalent swing center and the vertex of the suspension system and the design parameters of the suspension system; Step S5: By adjusting the design parameters of the suspension system, the distance Δr between the equivalent swing center and the suspension system vertex is equal to the distance from the suspension system vertex to the center of gravity of the helicopter, thereby eliminating the influence of the swing of the cargo on the left and right symmetric plane of the helicopter on the helicopter attitude; Step S6: Project the suspension system with adjusted design parameters onto a plane passing through the suspension system vertex and perpendicular to the helicopter's bilateral symmetry plane. Repeat steps S2 to S5 to eliminate the effect of cargo swing on the helicopter's attitude due to the cargo swinging on the plane perpendicular to the helicopter's heading. Step S7: Integrate the design parameters adjusted in steps S5 and S6, and use them to design the hanging system to obtain a hanging system product.

2. The design method for helicopter suspension sway elimination according to claim 1, characterized in that: The hanging system includes: a tetrahedral hook and four steel ropes; One end of the four steel cables is hinged to the helicopter fuselage, and the other end is hinged to the four points ABCD at the bottom of the tetrahedron hook; There is a universal joint at the top point O of the tetrahedron hook, and a lifting rope for lifting cargo is connected below point O.

3. The design method for helicopter suspension anti-sway according to claim 2 is characterized in that: The projection result of step S1 is: The projection of points AB is point A, the projection of points CD is point D, the projection of the tetrahedron hook is triangle OAD, K is the intersection of the extension lines of the two steel ropes, and points EF are the fuselage hanging points.

4. A design method for helicopter suspension sway elimination according to claim 3, characterized in that: The projection result of step S2 is: Point A moves to point A', point D moves to point D', point O moves to point O', and point K moves to point K'.

5. The design method for helicopter suspension anti-sway according to claim 4 is characterized in that: The step S3 comprises: The intersection of straight line KO and straight line K'O' at the far end is point S; according to the principle of simple pendulum, point S is the equivalent swing center of the cargo.

6. The design method for helicopter suspension sway elimination according to claim 4, characterized in that: The relationship determined in step S4 is as follows: Where: Δr is the distance from point S to point O; M is the distance from point K to line AD; H' is the distance from point O to line AD; H is the distance from the fuselage suspension points E and F to the line AD; θ is the angle between the steel rope and the vertical direction in the initial state.

7. The design method for helicopter suspension sway elimination according to claim 6, characterized in that: The steps determined in step S4 are as follows: Let the distance from point S to point O be Δr; The distance from point O to line AD is H'; The distance from point O to point O' is ΔS; The distance from point K to point K' is ΔS'; The distance between the fuselage suspension points E and F and the line AD is H; The distance from point K to line AD is M; The length of the steel rope is l; In the initial state, the angle between the steel rope and the vertical direction is θ; The angle of the steel rope deflection is Draw a line O'T through point O' that is parallel to line OK and intersects line KK' at T. The angle between line O'T and line O'K' is ΔΦ. in: Substituting ΔS and ΔS' into Δr, we can finally get:

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