An unmanned aerial vehicle adaptation method based on load constraint

Abstract

This invention discloses a UAV adaptation method based on load constraints, relating to the field of UAV structural design technology. The method includes adjusting the installation position of the current target mission load (or adjusting the mounting holes of the adapter structure and then re-checking) when the landing gear width is less than the lateral stability check value, or when the distance from any point on the outermost side of the target mission load to the inner safety boundary of the rotor disk on the same side is less than or equal to zero, based on the installation position of the current target mission load. By checking the lateral offset of the center of gravity and the rotor arrangement space after load installation, and re-checking when the check is not satisfied by adjusting the load installation position or the mounting holes of the adapter structure, the method provides clear parameter basis for the installation adaptation of different mission loads on the same UAV platform. This reduces the need to rely solely on trial installation, hole modification, or redesign of the adapter structure for adaptation, and establishes a corresponding relationship between the fixed position of the load, the bottom support structure, and the spatial arrangement constraints.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) structural design technology, and in particular to a UAV adaptation method based on load constraints. Background Technology

[0002] With the increasing application of drones in tasks such as logistics transportation, emergency delivery, inspection and mapping, meteorological detection, and artificial weather modification, the same drone platform often needs to change different payloads such as cargo holds, pods, detection equipment, or mounting devices according to the mission. Existing drone payload installation methods mostly use preset mounting points, special mounting brackets, or adapter plates for fixation. The design focus is usually on enabling the payload to be installed on the bottom of the fuselage, while insufficient consideration is given to the differences in size, weight, installation interface, lateral support points, installation pitch, and shape envelope of different payloads. For drone platforms that need to accommodate multiple mission payloads, it is difficult to achieve fast, reliable, and repeatable payload adaptation without redesigning the airframe structure by relying solely on fixed mounting points or experience-based adapter structures.

[0003] Existing UAV payload installation solutions often adjust the installation position based on experience during the assembly stage. They lack a unified adaptation method that links payload installation constraints, UAV platform structural parameters, longitudinal beam support range, matrix mounting hole positions, center of gravity offset verification, and rotor arrangement verification. This can easily lead to problems such as insufficient stability after installation even when the payload can be fixed, insufficient landing gear width margin, limited rotor clearance, or the need to repeatedly modify holes and redesign the adapter structure when changing to different payloads. This affects the UAV platform's general modification capability and mission adaptability efficiency. Summary of the Invention

[0004] In a first aspect, the present invention provides a UAV adaptation method based on load constraints, comprising,

[0005] Obtain the installation constraint information of the current target mission payload, including installation interface size, number of lateral support points, lateral distribution span, longitudinal installation pitch, external envelope size, mass, installation center position, and ground clearance requirements;

[0006] Read the preset parameters of the drone platform, including the ground clearance of the fuselage bottom, the critical rollover angle, the landing gear width, the fuselage width, the number of preset longitudinal beams at the bottom of the fuselage, and the thread hole spacing of the preset matrix mounting hole array;

[0007] Based on the number of lateral support points and the lateral span, determine the longitudinal beam selection scheme corresponding to the current target task load;

[0008] Based on the mass and installation center position of the current target mission payload, determine the lateral offset of the center of gravity of the current target mission payload after installation;

[0009] Based on the mass of the current target mission load and the vertical coordinates contained in its installation center position, calculate the vertical change in the center of gravity caused by the installation of the current target mission load.

[0010] Determine the current center of gravity height above the ground based on the vertical change in the center of gravity and the inherent center of gravity height of the UAV platform;

[0011] Calculate the lateral stability check value of the current installation scheme based on the current lateral offset of the center of gravity, the current height of the center of gravity above the ground, and the critical angle of rollover.

[0012] Based on the wingspan, vertical rotor radius, and minimum safe clearance between the vertical rotor and the fuselage, calculate the maximum allowable outer width of the rotor safety space for the current installation scheme;

[0013] When the landing gear width is greater than or equal to the lateral stability check value, and the distance from any point on the outermost side of the landing gear to the inner safety boundary of the rotor disk on the same side is greater than zero according to the installation position of the current target mission load, the corresponding mounting hole position is selected in the matrix mounting hole array based on the longitudinal installation pitch of the current target mission load and the thread hole spacing of the preset matrix mounting hole array, and the current target mission load is fixed to the bottom of the fuselage.

[0014] When the landing gear width is less than the lateral stability check value, or when the distance from any point on the outermost side of the landing gear to the inner safety boundary of the rotor disk on the same side is less than or equal to zero according to the installation position of the current target mission load, adjust the installation position of the current target mission load, or adjust the mounting hole position of the transition structure and then recheck.

[0015] The above adjustments include moving the current target mission payload installation center position, within the allowable lateral installation area of ​​the fuselage, in a preset step size towards the longitudinal symmetry center plane of the fuselage, and re-verifying based on the moved position;

[0016] If adjusting the installation center position still does not meet the requirements, the installation hole position of the current target mission payload is adjusted by changing the relative position between the first connecting hole group used to connect the matrix mounting hole array and the second connecting hole group used to connect the current target mission payload on the adapter structure, and then the verification is performed again.

[0017] As a preferred embodiment of the UAV adaptation method based on load constraints described in this invention, the step of determining the lateral offset of the center of gravity of the current target mission payload after installation based on the mass and installation center position of the current target mission payload includes:

[0018] When installing a single payload, let the total mass of the UAV platform without the payload be M0, the mass of the payload be M1, and the lateral offset distance of the payload installation center relative to the longitudinal symmetry center plane of the fuselage be y1. Then the lateral offset of the center of gravity Δy after installing the payload is determined by Δy=M1·y1 / (M0+M1).

[0019] When two or more mission loads are installed simultaneously, let the mass of the i-th mission load be Mi, and the lateral offset distance of the installation center of the i-th mission load relative to the longitudinal symmetry center plane of the fuselage be yi. Then, the lateral offset of the center of gravity Δy in the combined installation state is determined by Δy=Σ(Mi·yi) / (M0+ΣMi).

[0020] As a preferred embodiment of the load-constrained UAV adaptation method of the present invention, the step of determining the longitudinal beam selection scheme corresponding to the current target task load based on the number of lateral support points and the lateral distribution span includes:

[0021] If the current target task load is a single module concentrated load, then select two or more longitudinal beams as the installation support beams;

[0022] If the current target load is a cargo hold load or a combined load, then select the combination of longitudinal beams that makes the lateral connection areas of the current target load fall into the support range of the outermost longitudinal beam as the installation support beam.

[0023] When two or more mission loads are installed at the bottom of the fuselage at the same time, the smallest combination of longitudinal beams that can simultaneously meet the lateral installation support requirements of all mission loads shall be selected as the installation support beam.

[0024] As a preferred embodiment of the load-constrained UAV adaptation method of the present invention, the thread hole spacing of the preset matrix mounting hole array is obtained based on the longitudinal mounting pitch of the current target task load, the maximum allowable hole spacing of the local mounting area of ​​the longitudinal beam, the minimum net hole spacing corresponding to the fastener specification used, and the machining step distance.

[0025] As a preferred embodiment of the UAV adaptation method based on load constraints described in this invention, if the mounting interface of the current target mission payload corresponds to the matrix mounting hole array, then the current target mission payload is directly fixed on the matrix mounting hole array.

[0026] If the mounting interface of the current target mission payload does not correspond to the matrix mounting hole array, the adapter structure is first fixed at the selected mounting hole position, and then the current target mission payload is fixed on the adapter structure.

[0027] Secondly, the present invention provides a load-constrained unmanned aerial vehicle (UAV) adaptation platform, including landing gear, fuselage, wings, and a mission payload mounting structure disposed at the bottom of the fuselage;

[0028] The aforementioned mission load mounting structure includes a transverse frame arranged along the left-right direction of the fuselage and a longitudinal beam arranged along the front-back direction of the fuselage.

[0029] The aforementioned longitudinal beam has two or more threaded holes along its length.

[0030] The threaded holes on the aforementioned longitudinal beams together form a matrix-type mounting hole array;

[0031] The aforementioned landing gear is located on both sides of the bottom of the fuselage, with the bottom of the fuselage above the landing gear;

[0032] The mission payload is fixed to the bottom of the fuselage via a matrix of mounting holes or via an adapter structure.

[0033] As a preferred embodiment of the load-constrained UAV adaptation platform described in this invention, the fuselage is a flat fuselage;

[0034] The transverse frame and longitudinal beams together form the reinforcing structure at the bottom of the fuselage;

[0035] There are two or more longitudinal beams, which are arranged at intervals along the fuselage.

[0036] As a preferred embodiment of the payload-constrained UAV adaptation platform described in this invention, the mission payload is selected from one of the following: cargo hold, electro-optical pod, airdrop hook, survey equipment, atmospheric detection equipment, and weather modification equipment.

[0037] The mounting interface of the aforementioned mission payload corresponds to the matrix mounting hole array, or to the adapter structure fixed on the matrix mounting hole array.

[0038] The beneficial effects of this invention are:

[0039] Before installation, this invention obtains the interface dimensions, lateral support requirements, longitudinal installation pitch, mass, and installation center position of the target mission payload, and determines the longitudinal beam selection scheme and installation hole positions by combining the landing gear width of the UAV platform, the longitudinal beam at the bottom of the fuselage, and the matrix mounting hole array parameters.

[0040] At the same time, the lateral offset of the center of gravity and the rotor arrangement space after the load is installed are checked. If the check is not satisfied, the load installation position or the hole position of the transition structure is adjusted and then rechecked.

[0041] Therefore, this invention enables the installation and adaptation of different mission payloads on the same UAV platform to have clear parameter basis, reducing the need to rely solely on trial installation, hole modification, or redesign of adapter structure for adaptation, and establishing a corresponding relationship between the fixed position of the payload, the bottom support structure, and the spatial arrangement constraints. Attached Figure Description

[0042] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a flowchart of the UAV adaptation method based on load constraints in Example 1.

[0044] Figure 2 This is a schematic diagram of the mission load mounting structure at the bottom of the fuselage in Example 1. Detailed Implementation

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0046] Example 1, referring to Figure 1 This is the first embodiment of the present invention, which provides a UAV adaptation method based on load constraints, including:

[0047] Obtain the installation constraint information of the current target mission payload, including installation interface size, number of lateral support points, lateral distribution span, longitudinal installation pitch, external envelope size, mass, installation center position, and ground clearance requirements;

[0048] Read the preset parameters of the drone platform, including the ground clearance of the fuselage bottom, the critical rollover angle, the landing gear width, the fuselage width, the number of preset longitudinal beams at the bottom of the fuselage, and the thread hole spacing of the preset matrix mounting hole array;

[0049] Based on the number of lateral support points and the lateral span, determine the longitudinal beam selection scheme corresponding to the current target task load;

[0050] Based on the mass and installation center position of the current target mission payload, determine the lateral offset of the center of gravity of the current target mission payload after installation;

[0051] Based on the mass of the current target mission load and the vertical coordinates contained in its installation center position, calculate the vertical change in the center of gravity caused by the installation of the current target mission load.

[0052] Determine the current center of gravity height above the ground based on the vertical change in the center of gravity and the inherent center of gravity height of the UAV platform;

[0053] Calculate the lateral stability check value of the current installation scheme based on the current lateral offset of the center of gravity, the current height of the center of gravity above the ground, and the critical angle of rollover.

[0054] Based on the wingspan, vertical rotor radius, and minimum safe clearance between the vertical rotor and the fuselage, calculate the maximum allowable outer width of the rotor safety space for the current installation scheme;

[0055] When the landing gear width is greater than or equal to the lateral stability check value, and the distance from any point on the outermost side of the landing gear to the inner safety boundary of the rotor disk on the same side is greater than zero according to the installation position of the current target mission load, the corresponding mounting hole position is selected in the matrix mounting hole array based on the longitudinal installation pitch of the current target mission load and the thread hole spacing of the preset matrix mounting hole array, and the current target mission load is fixed to the bottom of the fuselage.

[0056] When the landing gear width is less than the lateral stability check value, or when the distance from any point on the outermost side of the landing gear to the inner safety boundary of the rotor disk on the same side is less than or equal to zero according to the installation position of the current target mission load, adjust the installation position of the current target mission load, or adjust the mounting hole position of the transition structure and then recheck.

[0057] The above adjustments include moving the current target mission payload installation center position, within the allowable lateral installation area of ​​the fuselage, in a preset step size towards the longitudinal symmetry center plane of the fuselage, and re-verifying based on the moved position;

[0058] If the installation center position is still not satisfactory after adjustment, the installation hole position of the current target mission payload is adjusted by changing the relative position between the first connecting hole group used to connect the matrix mounting hole array and the second connecting hole group used to connect the current target mission payload on the adapter structure, and then the verification is performed again.

[0059] Specifically, the above adaptation method is explained by taking the switching between material transportation and inspection tasks on the same drone platform as an example.

[0060] The aforementioned UAV platform has completed the pre-determination of the ground clearance of the fuselage bottom, the critical rollover angle, the landing gear width, the fuselage width, the number of longitudinal beams, and the spacing of the threaded holes in the matrix mounting hole array during the platform design phase;

[0061] The adaptation method in this embodiment performs installation verification and hole selection based on the above-mentioned preset parameters for the current target mission payload;

[0062] The unmanned aerial vehicle platform used includes landing gear, fuselage, wings, and a payload mounting structure located at the bottom of the fuselage;

[0063] The aforementioned mission load mounting structure includes a transverse frame arranged along the left-right direction of the fuselage and a longitudinal beam arranged along the front-back direction of the fuselage. The longitudinal beam has two or more threaded holes along its length, and the threaded holes on each longitudinal beam together form a matrix mounting hole array.

[0064] The bottom of the fuselage is located above the landing gear, and the space between the bottom of the fuselage and the ground forms a space for the installation of mission payloads.

[0065] First, select the target mission payload as the cargo compartment and read the installation constraint information of the cargo compartment;

[0066] The specific installation constraints are as follows: the bottom mounting interface of the cargo hold adopts a four-point connection method, the number of lateral support points is four, the lateral distribution span is 1400mm, the longitudinal installation pitch is 240mm, the outer envelope dimensions are 1500mm in length, 900mm in width, and 650mm in height, and the minimum ground clearance requirement after installation is 700mm.

[0067] The basic parameters of the drone platform are: fuselage length 6000mm, wingspan 8000mm, and fuselage width 400mm.

[0068] To explain the source of the preset value of the fuselage bottom ground clearance, this embodiment uses the rotor ground clearance safety boundary and the fuselage bottom ground clearance boundary under the maximum pitch attitude to jointly determine the fuselage bottom ground clearance S1;

[0069] First, the rotor ground clearance safety check value S11 is determined based on the propeller diameter R and the propeller ground clearance d. Then, the pitch attitude ground clearance check value S12 is determined based on the ground clearance boundary of the lowest point of the fuselage tail under the maximum allowable pitch angle. The larger value between S11 and S12 is taken as the ground clearance S1 of the fuselage bottom.

[0070] Wherein, S11 is determined according to S11=0.7R+1.1d;

[0071] In the formula, 0.7 and 1.1 are empirical correction coefficients set for the ground clearance safety margin of this type of UAV platform, which are used to comprehensively consider the influence of rotor profile, landing gear compression, ground unevenness and manufacturing and assembly errors on the ground clearance boundary;

[0072] S12 is determined using a geometric verification method, specifically as follows:

[0073] A two-dimensional geometric model of the UAV is established within the longitudinal symmetry plane. The spatial position of the lowest point of the tail relative to the reference point under neutral attitude is obtained with the platform pitch and rotation reference point as the benchmark.

[0074] Then rotate the aircraft around the pitch rotation reference point to the maximum allowable pitch angle, and read the lowest vertical position of the tail in this attitude;

[0075] By combining the vertical variation range of the center of gravity Δh and the reserved safety clearance, the pitch attitude ground clearance check value S12 is obtained;

[0076] In the process of obtaining the pitch attitude ground clearance value S12, the initial vertical coordinates of the lowest point of the tail relative to the pitch rotation reference point under the neutral attitude are first read, and then the attitude transformation is performed on the initial vertical coordinates according to the maximum allowable pitch angle θ to obtain the vertical lowest position of the lowest point of the tail under the maximum allowable pitch angle.

[0077] The reserved safety clearance is given comprehensively based on the ground unevenness compensation amount δg, the landing gear compression compensation amount δl, the fuselage tail structure elastic deformation compensation amount δe, and the manufacturing and assembly error compensation amount δm.

[0078] Among them, the reserved safety clearance δs is determined according to δs=δg+δl+δe+δm;

[0079] The above δg is determined based on the maximum allowable ground height difference of the predetermined take-off and landing site, δl is determined based on the static compression of the landing gear under the current load condition, δe is determined based on the vertical elastic deformation of the lowest point of the tail under the current load and maximum allowable pitch angle condition, and δm is determined based on the manufacturing and assembly allowable errors of the tail section, landing gear and mission load installation structure.

[0080] Where R is taken as 850mm and d is taken as 180mm, we can get S11 = 0.7×850 + 1.1×180 = 793mm;

[0081] Based on the 3D model of this UAV, the lowest point of the tail is at the maximum allowable pitch angle θ=15. ° The spatial position was geometrically checked, and combined with the vertical change range of the center of gravity Δh=50mm, the pitch attitude ground clearance check value S12 was found to be approximately 816mm.

[0082] Wherein, Δh=50mm is the maximum vertical change in center of gravity that may be caused by all mission payloads that the UAV platform is allowed to carry;

[0083] Take the larger value between S11 and S12, and determine that the bottom of the fuselage is 816mm above the ground;

[0084] The above pitch rotation reference points are the reference points used when the platform performs pitch attitude analysis in the longitudinal symmetry plane. The lowest point of the tail is the structural point closest to the ground in the tail section of the fuselage, the lower edge of the tail boom, or the rear section of the bottom of the fuselage under the maximum permissible pitch attitude.

[0085] The landing gear width S2 read is a fixed structural parameter predetermined during the platform design phase. During the mission adaptation phase, only its corresponding lateral stability boundary and rotor arrangement boundary are checked.

[0086] The platform's default landing gear width S2 is 1875mm;

[0087] After selecting the cargo hold as the current target mission load, first calculate the current lateral stability check value S23 based on the lateral offset Δy of the center of gravity after the current target mission load is installed, the current height h of the center of gravity above the ground, and the critical rollover angle φ. Then, determine the value according to S23=2(h·tanφ+|Δy|).

[0088] The aforementioned critical rollover angle is preset based on the anti-rollover design requirements of the UAV platform in a stopped or low-speed taxiing state. It is a preset constant value representing the maximum allowable lateral tilt angle of the platform during verification, used to define the safety boundary for lateral stability. It is usually determined according to the design specifications or airworthiness standards of similar UAVs, with a typical value range of 10. ° Up to 15 ° ;

[0089] To ensure that the drone does not tip over when encountering a disturbance with the maximum permissible roll angle φ in the lateral direction while parked or taxiing, the minimum lateral support width that the landing gear needs to cover;

[0090] The platform is considered as an object supported by the landing gear ground point, with its center of gravity at height h and lateral offset Δy;

[0091] In the critical state of rollover, the line of action of gravity points to the ground point on one side, and the lateral projection offset of the center of gravity is h·tanφ.

[0092] Considering the initial offset Δy, the total lateral lever arm is h·tanφ+|Δy|. Since it is necessary to ensure that neither the left nor the right sides will overturn, the minimum total support width is twice this lever arm, i.e., S23=2(h·tanφ+|Δy|).

[0093] Wherein, the current center of gravity height h above the ground is the vertical distance from the total center of gravity of the platform to the ground after the current target mission payload is installed, h=h0+Δz;

[0094] Δz≈Σ(Mi·zi) / (M0+ΣMi), where zi is the vertical distance between the center of mass of the load Mi and the inherent center of mass of the platform after installation;

[0095] The radius of a vertical propeller is denoted as R, which represents the radial dimension of a single vertical propeller from the center of rotation to the tip.

[0096] When the vertical rotors are respectively arranged at the left and right wingtips, the maximum allowable outer width S24 of the rotor safety space of the current installation scheme is determined according to S24=A-2(R+Δc) based on the wingspan A, the radius R of the vertical rotor, and the minimum safe clearance Δc between the vertical rotor and the fuselage.

[0097] When the given landing gear width S2 satisfies S2≥S23, and the actual maximum lateral outline dimension of the cargo hold after installation satisfies that it is less than or equal to S24, the current installation scheme is deemed to have passed the verification, and the subsequent hole selection and installation steps continue.

[0098] If any condition is not met, the installation center position of the current target mission load shall be adjusted first within the allowable installation area in the lateral direction of the fuselage. If the installation position is still not met after adjustment, the installation hole position of the adapter structure shall be adjusted until the verification condition is met.

[0099] The aforementioned maximum allowable outer width S24 for rotor safety space represents the permissible lateral space boundary on the inner side of the rotor under the wing;

[0100] By verifying that the actual maximum lateral profile of the load does not exceed S24, it is ensured that the mission load and its fixed structure always maintain a minimum safe clearance Δc with the outer edge of the rotor during flight.

[0101] The landing gear width S2 is checked for stability, and S2≥S23. At the same time, the actual maximum lateral profile dimension after load installation is checked to not exceed S24.

[0102] Finally, select the corresponding mounting holes according to the location of the cargo compartment mounting interface, fix the cargo compartment to the bottom of the fuselage, and complete the adaptation of the UAV platform from the basic flight state to the material transportation state.

[0103] By integrating the interface constraints, ground clearance constraints, and platform installation structure of the target mission payload into the same adaptation process, the installation of the mission payload no longer relies on temporary modifications. This ensures the ground clearance safety of the cargo hold after installation and also provides a unified installation foundation for subsequent replacement of other mission payloads, thereby improving the platform's versatility and mission switching efficiency.

[0104] It should be noted that the preset step size is set to be equal to the thread hole spacing of the matrix mounting hole array, i.e., 60mm. This ensures that after each movement, the new mounting center position can still be aligned with the available thread hole positions.

[0105] In this embodiment, the lateral offset of the center of gravity of the current target mission payload after installation is determined based on the mass and installation center position of the current target mission payload, including:

[0106] When installing a single payload, let the total mass of the UAV platform without the payload be M0, the mass of the payload be M1, and the lateral offset distance of the payload installation center relative to the longitudinal symmetry center plane of the fuselage be y1. Then the lateral offset of the center of gravity Δy after installing the payload is determined by Δy=M1·y1 / (M0+M1).

[0107] When two or more mission loads are installed at the same time, let the mass of the i-th mission load be Mi, and the lateral offset distance of the installation center of the i-th mission load relative to the longitudinal symmetry center plane of the fuselage be yi. Then the lateral offset of the center of gravity Δy in the combined installation state is determined by Δy=Σ(Mi·yi) / (M0+ΣMi).

[0108] Specifically, the lateral offset distance yi is zeroed out with the longitudinal symmetry center plane of the fuselage as the zero point. The offset distance on one side of the center plane is taken as a positive value, and the offset distance on the other side is taken as a negative value.

[0109] Wherein, the total mass M0 of the UAV platform without the mission payload is taken as 600kg, the mass of the cargo compartment M1 is taken as 40kg, and the lateral offset distance y1 of the cargo compartment installation center relative to the longitudinal symmetry center plane of the fuselage is taken as 160mm. Then, the lateral offset of the center of gravity after the cargo compartment is installed is Δy=M1·y1 / (M0+M1)=40×160 / (600+40)=10mm;

[0110] When the target mission changes from material transportation to inspection, the cargo hold is removed and replaced with an optoelectronic pod.

[0111] If the electro-optical pod is installed near the longitudinal center of symmetry of the fuselage, its lateral offset distance is close to zero, and the corresponding lateral offset of the center of gravity is also reduced.

[0112] If two or more mission loads are installed on the bottom of the fuselage at the same time, the mass and lateral offset distance of each mission load are read separately, and the lateral offset of the center of gravity in the combined installation state is determined according to the weighted relationship between the mass and lateral offset distance of each mission load.

[0113] By dynamically determining the lateral offset of the center of gravity according to the changes in load mass and installation position, the impact of different installation states on the lateral stability of the platform can be more realistically reflected. This can avoid mistaking the offset of the center of gravity under a specific working condition as a general constant, which is conducive to improving the pertinence and reliability of the landing gear width determination results.

[0114] In this embodiment, the longitudinal beam selection scheme corresponding to the current target task load is determined based on the number of lateral support points and the lateral distribution span, including:

[0115] If the current target task load is a single module concentrated load, then select two or more longitudinal beams as the installation support beams;

[0116] If the current target load is a cargo hold load or a combined load, then select the combination of longitudinal beams that makes the lateral connection areas of the current target load fall into the support range of the outermost longitudinal beam as the installation support beam.

[0117] When two or more mission loads are installed at the bottom of the fuselage at the same time, the smallest combination of longitudinal beams that can simultaneously meet the lateral installation support requirements of all mission loads shall be selected as the installation support beam.

[0118] Specifically, the platform has four longitudinal beams arranged laterally along the fuselage, with the first and fourth longitudinal beams located on the outer side and the second and third longitudinal beams located in the middle.

[0119] For the cargo hold in this embodiment, the first longitudinal beam and the fourth longitudinal beam are selected as the outer mounting support beams, and the second longitudinal beam and the third longitudinal beam are selected as the auxiliary mounting support beams, so that the connecting areas on both sides of the cargo hold fall within the support range of the outermost longitudinal beam.

[0120] If the current target mission load is changed to a single module concentrated load, such as a single optoelectronic pod, the two middle longitudinal beams can be selected as the installation support beams.

[0121] When two or more mission loads need to be installed at the bottom of the fuselage at the same time, the smallest combination of longitudinal beams that can simultaneously meet the lateral installation support requirements of all mission loads shall be selected as the installation support beam.

[0122] To explain the source of the thread hole spacing of the preset matrix mounting hole array, in this embodiment, the thread hole spacing of the preset matrix mounting hole array refers to the spacing obtained based on the longitudinal mounting pitch of the current target task load, the maximum allowable hole spacing of the structure in the local mounting area of ​​the longitudinal beam, the minimum net hole spacing corresponding to the fastener specification used, and the machining step distance.

[0123] Specifically, when determining the thread hole spacing, the core is to transform the longitudinal interface constraints of the task load into a standardized sequence of hole positions on the longitudinal beam.

[0124] The determination process does not depend on lateral parameters such as landing gear width, but only on longitudinal constraints and structural technology;

[0125] After determining the number of longitudinal beams, the spacing L of the threaded holes on each longitudinal beam is then determined.

[0126] First, a set of candidate hole spacings is formed based on the longitudinal installation pitch of the target mission load;

[0127] For the cargo hold in this embodiment, its longitudinal installation pitch is 240mm. Therefore, the candidate hole spacing should be able to form an integer multiple of 240mm. That is, the theoretical candidate values ​​of L are 240mm, 120mm, 80mm, 60mm, 48mm, 40mm, etc., to ensure that the center distance between the front and rear installation holes of the cargo hold can be composed of an integer number of adjacent hole spacings.

[0128] Secondly, based on the load-bearing requirements of the local installation area of ​​the longitudinal beam and the specifications of the fasteners used, the allowable structural boundaries are determined: the maximum hole spacing Lmax is obtained to ensure that the longitudinal span of adjacent installation points does not exceed the allowable stress range of the longitudinal beam, and the minimum hole spacing Lmin is obtained to ensure that there is sufficient material clearance and operating space for installation tools between adjacent threaded holes.

[0129] Then, from the set of candidate hole distances, candidate values ​​within the range of [Lmin, Lmax] are selected, and the selection results are rounded according to the preset processing step unit.

[0130] The above rounding process involves rounding the selected candidate values ​​down and up according to a preset processing step, respectively, to obtain the corresponding downward rounded value and upward rounded value.

[0131] Select one value from the obtained rounded values ​​that falls within the closed interval;

[0132] It should be noted that the preset machining step distance is determined in advance based on the minimum command increment of the linear axis of the CNC machine tool for machining longitudinal beams or the usual machining economic accuracy level.

[0133] When selecting this step distance, both the machining efficiency and hole position accuracy of the threaded hole should be taken into account. Its typical value range is one of 1mm, 2mm, 5mm or 10mm.

[0134] In this embodiment, to ensure that the hole position can be highly adaptable to various load interface pitches while maintaining good processing economy, 5mm is preferentially selected from the above typical range as the preset processing step distance for this purpose.

[0135] When the preset machining step distance is 1mm or 2mm, although the hole position approximation capability is strong, it will increase the machining program length and the complexity of hole position numbering.

[0136] When the preset machining step distance is 10mm, the machining complexity can be further reduced, but the compatibility with longitudinal installation pitches for various task loads is reduced.

[0137] Considering the overall processing economy, hole position accuracy, and load interface compatibility, this embodiment preferably uses 5mm as the preset processing step distance;

[0138] Lmax is 80mm and Lmin is 20mm. After screening and rounding, the largest candidate value of 60mm is selected as the final standardized thread hole spacing L, while taking into account the need to reduce the number of holes to obtain better single hole bearing strength and to ensure that the hole spacing is universal for more types of load pitches.

[0139] Therefore, the 240mm center distance between the front and rear mounting holes of the cargo hold can be formed by four adjacent hole distances (4×60mm), which not only meets the structural boundary requirements, but also makes the interface correspondence simple and stable.

[0140] In this embodiment, if the mounting interface of the current target mission payload corresponds to the matrix mounting hole array, then the current target mission payload is directly fixed on the matrix mounting hole array.

[0141] If the mounting interface of the current target mission payload does not correspond to the matrix mounting hole array, first fix the adapter structure at the selected mounting hole position, and then fix the current target mission payload on the adapter structure.

[0142] Specifically, the center distance between the front and rear mounting holes of the cargo hold is 240mm, while the threaded hole spacing determined in this embodiment is 60mm. Therefore, the cargo hold mounting interface can directly correspond to the matrix mounting hole array.

[0143] During installation, the two mounting ears on the front side of the cargo hold are fixed to the positions of the 6th threaded holes on the 1st and 4th longitudinal beams, respectively, and the two mounting ears on the rear side of the cargo hold are fixed to the positions of the 10th threaded holes on the 1st and 4th longitudinal beams, respectively.

[0144] Since the distance between hole No. 6 and hole No. 10 is 240mm, which is consistent with the longitudinal installation pitch of the cargo hold, the cargo hold can be directly fixed on the matrix mounting hole array.

[0145] When the target mission is switched to inspection mission, the cargo compartment can be removed and an electro-optical pod can be installed.

[0146] If the installation interface of the selected optoelectronic pod corresponds to the matrix mounting hole array, then directly select the corresponding hole position for fixing;

[0147] If the mounting interface does not correspond to the matrix mounting hole array, first fix the adapter structure at the selected mounting hole position, and then fix the optoelectronic pod on the adapter structure.

[0148] Therefore, the same UAV platform can be switched between the cargo compartment and the electro-optical pod without changing the main structure of the fuselage bottom.

[0149] Example 2, refer to Figure 2 This is a second embodiment of the present invention, which provides a payload-constrained unmanned aerial vehicle (UAV) adaptation platform, comprising:

[0150] In this embodiment, the landing gear, fuselage, wings, and mission payload mounting structure located at the bottom of the fuselage are included.

[0151] The aforementioned mission load mounting structure includes a transverse frame arranged along the left-right direction of the fuselage and a longitudinal beam arranged along the front-back direction of the fuselage.

[0152] The aforementioned longitudinal beam has two or more threaded holes along its length.

[0153] The threaded holes on the aforementioned longitudinal beams together form a matrix-type mounting hole array;

[0154] The aforementioned landing gear is located on both sides of the bottom of the fuselage, with the bottom of the fuselage above the landing gear;

[0155] The mission payload is fixed to the bottom of the fuselage via a matrix of mounting holes or via a connecting structure.

[0156] Specifically, the platform includes the fuselage, wings, landing gear, and a mission payload mounting structure located at the bottom of the fuselage;

[0157] The fuselage is located in the middle of the platform, the wings are set on both sides of the fuselage, and the landing gear is fixed to the left and right sides of the bottom of the fuselage.

[0158] The bottom of the fuselage is located above the landing gear, forming a space for the mission payload installation between it and the ground.

[0159] In this embodiment, the fuselage length is 6000mm, the wingspan is 8000mm, the fuselage width is 400mm, the bottom of the fuselage is 816mm above the ground, and the landing gear width is 1875mm. The mission payload mounting structure at the bottom of the fuselage is arranged in the upper area of ​​this mounting space to ensure sufficient ground clearance after the mission payload is installed.

[0160] The aforementioned task load mounting structure includes a transverse frame and longitudinal beams;

[0161] The transverse frames are arranged along the left and right sides of the fuselage, and the longitudinal beams are arranged along the front and rear sides of the fuselage. The transverse frames and longitudinal beams are fixedly connected to form the mounting frame at the bottom of the fuselage.

[0162] The transverse frame and longitudinal beam are located in the same mounting layer at the bottom of the fuselage;

[0163] The transverse frames are spaced along the front-to-back direction of the fuselage at the front, middle, and rear positions of the bottom of the fuselage, and the two ends of each transverse frame are fixedly connected to the main load-bearing frame at the bottom of the fuselage.

[0164] The longitudinal beams span between the transverse frames along the front-to-back direction of the fuselage and are rigidly fixed to each transverse frame, thereby forming a lattice-type installation frame at the bottom of the fuselage.

[0165] The lower surface of each longitudinal beam faces the installation space of the task load, and the threaded holes on the longitudinal beams are arranged along the front-to-back direction of the fuselage;

[0166] After the mission payload is installed, its own weight and the inertial load generated under flight conditions are first transferred from the installation interface to the area where the threaded hole is located, then transferred from the longitudinal beam to the transverse frame, and finally transferred from the transverse frame to the main load-bearing frame at the bottom of the fuselage.

[0167] In this embodiment, four longitudinal beams are used, arranged laterally along the fuselage, namely the first longitudinal beam, the second longitudinal beam, the third longitudinal beam, and the fourth longitudinal beam;

[0168] The first and fourth longitudinal beams are located on the outside, while the second and third longitudinal beams are located in the middle.

[0169] Multiple threaded holes are provided along the length of each longitudinal beam, and each threaded hole is numbered sequentially along the front and rear direction of the machine body;

[0170] The threaded holes on each longitudinal beam together form a matrix-type mounting hole array, wherein the spacing between adjacent threaded holes is 60mm;

[0171] With this setup, four parallel mounting tracks are formed on the bottom of the fuselage. Different mission loads can select the corresponding mounting hole positions from the matrix mounting hole array according to the lateral span and front-to-back pitch of their own mounting interfaces.

[0172] When installing the mission payload, its installation interface can directly correspond to the matrix mounting hole array, or it can indirectly correspond to the matrix mounting hole array through the adapter structure.

[0173] For loads that can be directly mounted on the mounting interface, they can be directly fixed to the corresponding holes; for loads that cannot be directly mounted on the mounting interface, they can be fixed to the bottom of the machine body through an adapter structure.

[0174] The above-mentioned adapter structure is a plate-type connector, and its upper surface is provided with a first connecting hole, which corresponds to the selected threaded hole in the matrix mounting hole array;

[0175] Its lower surface is provided with a second connection hole, which corresponds to the mounting interface of the target mission payload;

[0176] This structure allows for the installation of different mission payloads without altering the main structure at the bottom of the fuselage.

[0177] By unifying the landing gear, the fuselage bottom mounting space, and the matrix-style mounting hole array into the same platform structure, the relationship between the platform body and the mission payload mounting foundation is clear and complete.

[0178] By pre-forming a unified mounting frame and a matrix of mounting holes at the bottom of the fuselage, the platform does not need to re-drill holes or modify the main structure when missions change. It can directly install different mission payloads or adapt them through a transfer structure. Therefore, the platform's versatility and replacement efficiency can be improved.

[0179] In this embodiment, the fuselage is a flat fuselage;

[0180] The transverse frame and longitudinal beams together form the reinforcing structure at the bottom of the fuselage;

[0181] There are two or more longitudinal beams, which are arranged at intervals along the transverse side of the fuselage;

[0182] Specifically, the fuselage adopts a flat fuselage configuration;

[0183] The fuselage's height dimension is smaller than its length and width dimensions, forming a continuous, flat mounting area at the bottom of the fuselage;

[0184] Compared to structures that only have fixed suspension points in the fuselage, the flattened fuselage can form a larger continuous mounting surface at the bottom of the fuselage, which facilitates the overall arrangement of transverse frames and longitudinal beams, and also allows for different installation positions to be selected at the bottom of the fuselage for different mission loads;

[0185] The transverse frame and longitudinal beams together form the reinforcing structure at the bottom of the fuselage;

[0186] The function of the horizontal frame is to connect the longitudinal beams into a whole and to restrict the relative positions between the longitudinal beams;

[0187] The longitudinal beam serves as the direct mounting base for the mission load and bears the load transmitted along the front-to-back direction of the fuselage after the mission load is installed.

[0188] After the mission payload is installed, its weight and the inertial load generated under flight conditions are first transferred to the area where the threaded hole is located through the installation interface, then transferred to the transverse frame through the longitudinal beam, and finally distributed to the main fuselage structure through the transverse frame.

[0189] Through this force transmission path, the installation load of the mission load is not concentrated on a certain point at the bottom of the fuselage, but is distributed and transmitted along the reinforcing structure at the bottom of the fuselage;

[0190] There are four longitudinal beams, arranged at intervals along the transverse side of the fuselage. For mission loads with a large transverse span, the first and fourth longitudinal beams can be selected as the main mounting supports.

[0191] For mission loads with small lateral dimensions and installation positions that need to be close to the center of the fuselage, the second and third longitudinal beams can be used as installation supports;

[0192] When two loads need to be installed at the same time, different installation positions can be arranged on the outer longitudinal beam and the middle longitudinal beam respectively.

[0193] With this horizontal layered arrangement, the same bottom reinforcement structure can meet the installation requirements of both large-span and small-span loads, without the need to set up separate bases for different task loads.

[0194] With a flattened structure, the bottom of the fuselage can provide a larger continuous installation area;

[0195] The reinforced structure composed of transverse frames and longitudinal beams forms a clear force transmission path, allowing the load after the mission load is installed to be distributed more evenly along the bottom of the fuselage.

[0196] With longitudinal beams spaced laterally along the fuselage, the appropriate support positions can be selected for different lateral spans of the task load, thereby improving the platform's adaptability to different installation configurations.

[0197] In this embodiment, the mission payload is selected from one of the following: cargo hold, electro-optical pod, airdrop hook, survey equipment, atmospheric detection equipment, and weather modification equipment.

[0198] The mounting interface of the aforementioned mission payload corresponds to the matrix mounting hole array, or to the adapter structure fixed on the matrix mounting hole array;

[0199] Specifically, when the mission payload is a cargo hold, there are four mounting lugs at the bottom of the cargo hold, and the four mounting lugs are located at the four corners of the bottom of the cargo hold.

[0200] The center distance between the front and rear mounting holes in the cargo hold is 240mm;

[0201] During installation, the first longitudinal beam and the fourth longitudinal beam are selected as support beams, and two sets of holes with a front-to-back interval of 240mm are selected in their respective threaded holes.

[0202] For example, fix the two mounting ears on the front side of the cargo hold to the sixth threaded hole position of the first longitudinal beam and the fourth longitudinal beam, and fix the two mounting ears on the rear side of the cargo hold to the tenth threaded hole position of the first longitudinal beam and the fourth longitudinal beam.

[0203] Since the distance between hole No. 6 and hole No. 10 is 240mm, which is exactly the same as the pitch of the front and rear mounting holes of the cargo hold, the cargo hold mounting interface can directly correspond to the matrix mounting hole array, and the cargo hold can be directly fixed to the bottom of the fuselage.

[0204] After installation, the cargo hold is located in the installation space at the bottom of the fuselage, and its lowest point is still higher than the ground clearance requirement of 700mm.

[0205] When the mission payload is an optoelectronic pod, if the mounting holes on the mounting base plate of the optoelectronic pod directly match a certain set of holes in the matrix mounting hole array, then the optoelectronic pod can be directly fixed on the corresponding hole.

[0206] If the mounting hole pitch, hole orientation, or mounting base size of the selected optoelectronic pod does not match the matrix mounting hole array, then install the adapter structure first.

[0207] The aforementioned adapter structure is a flat connector with a first connecting hole on its upper surface corresponding to the matrix mounting hole array, and a second connecting hole on its lower surface corresponding to the mounting base plate of the optoelectronic pod.

[0208] During installation, first use fasteners to fix the adapter structure to the corresponding holes between the second and third longitudinal beams, and then fix the photoelectric pod to the second connection hole of the adapter structure.

[0209] In this way, even if the installation interface sizes of different models of optoelectronic pods are different, they can still be installed using the same matrix-type mounting hole array;

[0210] When the mission payload is an airdrop hook, survey equipment, atmospheric sounding equipment, or weather modification equipment, the installation path is the same as the two cases mentioned above:

[0211] For mounting interfaces that directly correspond to a matrix mounting hole array, a direct mounting method is adopted.

[0212] For installation interfaces that cannot be directly matched, an adapter structure should be used for installation.

[0213] Therefore, different types of mission payloads can be assembled on the same mounting base at the bottom of the fuselage, without the need for separate dedicated mounting bases;

[0214] Therefore, the same mounting base at the bottom of the fuselage can accommodate both direct mounting and adapter mounting, eliminating the need for separate mounting bases for different mission loads.

Claims

1. A payload-constrained based UAV adaptation method, characterized in that, include: Obtain the installation constraint information of the current target mission payload, including installation interface size, number of lateral support points, lateral distribution span, longitudinal installation pitch, external envelope size, mass, installation center position, and ground clearance requirements; Read the preset parameters of the drone platform, including the ground clearance of the fuselage bottom, the critical rollover angle, the landing gear width, the fuselage width, the number of preset longitudinal beams at the bottom of the fuselage, and the thread hole spacing of the preset matrix mounting hole array; Based on the number of lateral support points and the lateral span, determine the longitudinal beam selection scheme corresponding to the current target task load; Based on the mass and installation center position of the current target mission payload, determine the lateral offset of the center of gravity of the current target mission payload after installation; Based on the mass of the current target mission load and the vertical coordinates contained in its installation center position, calculate the vertical change in the center of gravity caused by the installation of the current target mission load. Determine the current center of gravity height above the ground based on the vertical change in the center of gravity and the inherent center of gravity height of the UAV platform; Calculate the lateral stability check value of the current installation scheme based on the current lateral offset of the center of gravity, the current height of the center of gravity above the ground, and the critical angle of rollover. Based on the wingspan, vertical rotor radius, and minimum safe clearance between the vertical rotor and the fuselage, calculate the maximum allowable outer width of the rotor safety space for the current installation scheme; When the landing gear width is greater than or equal to the lateral stability check value, and the distance from any point on the outermost side of the landing gear to the inner safety boundary of the rotor disk on the same side is greater than zero according to the installation position of the current target mission load, the corresponding mounting hole position is selected in the matrix mounting hole array based on the longitudinal installation pitch of the current target mission load and the thread hole spacing of the preset matrix mounting hole array, and the current target mission load is fixed to the bottom of the fuselage. When the landing gear width is less than the lateral stability check value, or when the distance from any point on the outermost side of the landing gear to the inner safety boundary of the rotor disk on the same side is less than or equal to zero according to the installation position of the current target mission load, adjust the installation position of the current target mission load, or adjust the mounting hole position of the transition structure and then recheck. The above adjustments include moving the current target mission payload installation center position, within the allowable lateral installation area of ​​the fuselage, in a preset step size towards the longitudinal symmetry center plane of the fuselage, and re-verifying based on the moved position; If adjusting the installation center position still does not meet the requirements, the installation hole position of the current target mission payload is adjusted by changing the relative position between the first connecting hole group used to connect the matrix mounting hole array and the second connecting hole group used to connect the current target mission payload on the adapter structure, and then the verification is performed again.

2. The payload-constrained based UAV adaptation method of claim 1, wherein: The step of determining the lateral offset of the center of gravity of the current target mission payload after installation, based on the mass and installation center position of the current target mission payload, includes: When installing a single payload, let the total mass of the UAV platform without the payload be M0, the mass of the payload be M1, and the lateral offset distance of the payload installation center relative to the longitudinal symmetry center plane of the fuselage be y1. Then the lateral offset of the center of gravity Δy after installing the payload is determined by Δy=M1·y1 / (M0+M1). When two or more mission loads are installed simultaneously, let the mass of the i-th mission load be Mi, and the lateral offset distance of the installation center of the i-th mission load relative to the longitudinal symmetry center plane of the fuselage be yi. Then, the lateral offset of the center of gravity Δy in the combined installation state is determined by Δy=Σ(Mi·yi) / (M0+ΣMi).

3. The UAV adaptation method based on load constraints as described in claim 1, characterized in that: The step of determining the longitudinal beam selection scheme corresponding to the current target task load based on the number of lateral support points and the lateral distribution span includes: If the current target task load is a single module concentrated load, then select two or more longitudinal beams as the installation support beams; If the current target load is a cargo hold load or a combined load, then select the combination of longitudinal beams that makes the lateral connection areas of the current target load fall into the support range of the outermost longitudinal beam as the installation support beam. When two or more mission loads are installed at the bottom of the fuselage at the same time, the smallest combination of longitudinal beams that can simultaneously meet the lateral installation support requirements of all mission loads shall be selected as the installation support beam.

4. The UAV adaptation method based on load constraints as described in claim 1, characterized in that: The thread hole spacing of the preset matrix mounting hole array is determined based on the longitudinal mounting pitch of the current target task load, the maximum allowable hole spacing of the local mounting area of ​​the longitudinal beam, the minimum net hole spacing corresponding to the fastener specifications used, and the machining step distance.

5. The UAV adaptation method based on load constraints as described in claim 1, characterized in that: If the mounting interface of the current target mission payload corresponds to the matrix mounting hole array, then the current target mission payload is directly fixed on the matrix mounting hole array. If the mounting interface of the current target mission payload does not correspond to the matrix mounting hole array, the adapter structure is first fixed at the selected mounting hole position, and then the current target mission payload is fixed on the adapter structure.

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