Control method for hoisting mechanisms used to lift near-space aircraft

Abstract

This disclosure provides a method for controlling a hoisting mechanism used to lift an aircraft in near space, comprising: setting the ultimate load that the aircraft must meet under target operating conditions based on risk factors that may cause abnormalities in the aircraft; establishing a finite element model to characterize the aircraft to be lifted and the hoisting mechanism used to lift the aircraft, and using the ultimate load as the excitation input of the finite element model to calculate the mechanical simulation under the target operating conditions to obtain displacement simulation data of the aircraft under the target operating conditions; manufacturing a solid scale-down model including the aircraft and the hoisting mechanism; adjusting the hoisting rope structure with the structural strength of the solid scale-down model of the aircraft as the limit, so that the solid scale-down model of the aircraft can switch between multiple target operating conditions, and constructing the allowable force envelope of each hoisting rope of the hoisting rope structure; controlling the hoisting mechanism carrying the aircraft based on the allowable force envelope of each hoisting rope, so that the aircraft can switch between multiple target operating conditions, from the lifting stage to the release stage.

Description

Technical Field

[0001] At least one embodiment of this disclosure relates to the field of near-space aircraft technology, and more specifically, to a method for controlling a hoisting mechanism for hoisting near-space aircraft. Background Technology

[0002] Near space refers to the region 20 to 100 kilometers above the ground. Aircraft used in near space include those that fly continuously for long periods or suborbital missions. These types of aircraft have advantages in communication relay, navigation, and information collection.

[0003] Currently, the general method for such aircraft to enter near space is to take off from a runway and autonomously climb to a preset cruising altitude. This method places high demands on the aircraft's propulsion system, and the climb phase must be considered during the aircraft's design. In light of this, existing technologies also explore using high-altitude balloons as the primary carrier to lift the aircraft onto a launch platform and release it upon reaching the preset cruising altitude.

[0004] However, the hoisting methods of the aforementioned deployment platforms mostly use single-rope hoisting. Since these aircraft are often large in size, light in weight, highly flexible, and have low longitudinal overload capacity, the single-rope hoisting method makes it difficult to adjust the stress on these aircraft. Therefore, it is easy for the aircraft to fail structurally. Furthermore, the hoisting method cannot adjust the attitude of the aircraft, thus affecting its release. Summary of the Invention

[0005] To address at least one technical problem in the prior art and other aspects, this disclosure provides a control method for a lifting mechanism used to lift an aircraft in near space. Based on multiple operating conditions divided from the lifting phase to the release phase of the aircraft to be lifted, the ultimate load that the aircraft must meet is set. A scaled-down solid model is established under the condition that the ultimate load requirement of the aircraft is met. The lifting process of the solid model is monitored to generate total envelope data that meets the stress level and operating condition requirements that the aircraft can withstand. Based on the total envelope data, the actuation structure in the lifting mechanism carrying the aircraft is controlled, so that during the lifting process, the attitude of the aircraft can be adjusted while meeting the stress level requirements of the aircraft.

[0006] This disclosure provides a method for controlling a lifting mechanism for hoisting an aircraft in near space, comprising: setting a limit load that the aircraft must meet under a target operating condition based on risk factors that could cause aircraft malfunctions, wherein the lifting phase to the release phase of the aircraft is divided into multiple operating conditions, and the target operating condition belongs to the multiple operating conditions; establishing a finite element model to characterize the aircraft to be hoisted and the lifting mechanism for hoisting the aircraft, and using the limit load as the excitation input of the finite element model to calculate a mechanical simulation under the target operating condition to obtain displacement simulation data of the aircraft under the target operating condition; and based on the above-mentioned... The constraints, installation relationships, and displacement simulation data between the aircraft and the aforementioned hoisting mechanism are used to create a scaled-down solid model of the aircraft and the aforementioned hoisting mechanism. Using the structural strength of the aircraft in the scaled-down solid model as the limit, the hoisting rope structure in the hoisting mechanism of the scaled-down solid model is adjusted to allow the aircraft in the scaled-down solid model to switch between multiple aforementioned target working conditions, and the allowable force envelope of each hoisting rope in the hoisting rope structure is constructed. Based on the allowable force envelope of each hoisting rope, the hoisting mechanism carrying the aircraft is controlled to allow the aircraft to switch between multiple aforementioned target working conditions, adjusting from the aforementioned lifting stage to the aforementioned release stage.

[0007] According to embodiments of this disclosure, the aforementioned risk factors leading to aircraft malfunctions include at least one of the following: causing structural failure of the aircraft, causing changes in the dynamic state of the aircraft, and environmental loads of the environment in which the aircraft is located.

[0008] According to embodiments of this disclosure, the above-mentioned establishment of a finite element model for characterizing the aircraft to be hoisted and the hoisting mechanism for hoisting the aircraft, and the calculation of mechanical simulation under the target working condition using the ultimate load as the excitation input of the finite element model to obtain displacement simulation data of the aircraft under the target working condition, includes: establishing a finite element model including the aircraft and the hoisting mechanism, and applying an ultimate load to the finite element model, wherein the hoisting mechanism includes a hoisting rope structure; adding multiple constraint points on the aircraft, and applying displacement constraints in three mutually orthogonal directions in space to each constraint point, so that the finite element model is in a fully constrained or over-constrained state; setting parameter values ​​and convergence criteria for each displacement constraint; calculating the stress corresponding to each displacement constraint based on the finite element model and the parameter values; and converging the finite element model until the stress corresponding to each displacement constraint satisfies the convergence criteria, and outputting the displacement simulation data.

[0009] According to embodiments of this disclosure, the above-mentioned method of manufacturing a scaled-down solid model including the aircraft and the hoisting mechanism based on the constraints, installation relationship, and displacement simulation data between the aircraft and the hoisting mechanism includes: setting the physical properties of the aircraft and the hoisting mechanism; and manufacturing the scaled-down solid model based on the constraints, installation relationship, and displacement simulation data between the aircraft and the hoisting mechanism.

[0010] According to embodiments of this disclosure, the target operating condition includes a lifting operating condition for lifting the aircraft, a release operating condition for releasing the aircraft, and a transition operating condition for adjusting from the lifting operating condition to the release operating condition.

[0011] According to embodiments of this disclosure, adjusting the sling structure in the hoisting mechanism of the scaled-down model of the aircraft, with the structural strength of the scaled-down model as the limit, to allow the scaled-down model to switch between multiple target operating conditions, includes: measuring the upper and lower limits of the tension applied to the scaled-down model of the aircraft by each sling in the sling structure under each target operating condition; and constructing the allowable force envelope of each sling based on the upper and lower limits of the tension of each sling and the attitude angle of the scaled-down model of the aircraft.

[0012] According to embodiments of this disclosure, the measurement of the upper and lower limits of the tension applied to the scaled-down aircraft by each suspension rope in the suspension rope structure under each target working condition includes: configuring a detection mechanism on the scaled-down aircraft to detect the stress at each measurement point of the scaled-down aircraft caused by the release and retraction of the suspension ropes, under the condition of applying the maximum allowable stress boundary of the material used in the scaled-down aircraft to the scaled-down aircraft.

[0013] According to embodiments of this disclosure, the aforementioned arrangement of a detection mechanism on the scaled-down model, to detect the stress at various measurement points of the scaled-down model of the aircraft caused by the raising and lowering of the suspension ropes, under conditions where the maximum allowable stress boundary of the material used in the scaled-down model of the aircraft is applied to the scaled-down model, includes:

[0014] Under the aforementioned lifting conditions, at least a portion of the aforementioned lifting ropes are retracted or released, and the upper and lower limits of the tension of each of the aforementioned lifting ropes are recorded; the pitch angle change of the aforementioned scaled-down model aircraft is preset, and under the aforementioned transition conditions, at least a portion of the aforementioned lifting ropes are retracted or released so that the pitch angle of the aforementioned scaled-down model aircraft is successively adjusted according to the aforementioned pitch angle change, and the upper and lower limits of the tension of each of the aforementioned lifting ropes are recorded; and at least a portion of the aforementioned lifting ropes are retracted or released so that the aforementioned scaled-down model aircraft is adjusted from the aforementioned transition conditions to the aforementioned release conditions, and the upper and lower limits of the tension of each of the aforementioned lifting ropes are recorded.

[0015] According to an embodiment of this disclosure, the above-mentioned construction of the allowable force envelope of each of the above-mentioned suspension ropes based on the upper limit and lower limit of the tension of each of the above-mentioned suspension ropes and the attitude angle of the aircraft in the above-mentioned scaled-down model includes: establishing the allowable force envelope of the suspension ropes with the attitude angle of the aircraft in the above-mentioned scaled-down model as the horizontal axis, the tension of the above-mentioned suspension ropes as the vertical axis, and the upper limit and lower limit of the tension as the coordinates on the vertical axis.

[0016] According to embodiments of this disclosure, the above-mentioned lifting mechanism for suspending the aircraft based on the allowable force envelope of each of the above-mentioned suspending ropes, so as to switch the aircraft between multiple target working conditions to adjust from the lifting stage to the release stage, includes: parameterizing the allowable force envelope of each of the above-mentioned suspending ropes to obtain the total force envelope data; and inputting the total force envelope data into the lifting mechanism for suspending the aircraft, and controlling the actuation structure of the lifting mechanism according to the total force envelope data, so as to stretch the suspending ropes of the suspending rope structure through the actuation structure, so as to adjust the aircraft from the lifting working condition to the release working condition.

[0017] According to the lifting mechanism control method for lifting near-space aircraft provided in this disclosure, based on multiple working conditions divided into the lifting and release phases of the aircraft to be lifted, the ultimate load that the aircraft needs to meet under each target working condition is set. Under the condition of meeting the ultimate load requirements of the aircraft, a solid scale model is established. By detecting the lifting process of the solid scale model, the total envelope data that meets the stress level and working condition requirements that the aircraft can withstand is generated. Based on the total envelope data, the actuation structure in the lifting mechanism that lifts the aircraft is controlled so that the attitude adjustment of the aircraft can be achieved while meeting the stress level of the aircraft during the lifting process. Attached Figure Description

[0018] Figure 1 This is a flowchart of a method for controlling a hoisting mechanism for hoisting an aircraft in near space, according to an illustrative embodiment of the present disclosure;

[0019] Figure 2 yes Figure 1 The flowchart shown is a schematic embodiment of establishing a finite element model to obtain displacement simulation data of the aircraft under target operating conditions.

[0020] Figure 3 yes Figure 1 The flowchart illustrating the manufacture of the illustrative embodiment includes a scaled-down model of the aircraft and the hoisting mechanism.

[0021] Figure 4 yes Figure 1 The flowchart shown in the illustrative embodiment illustrates the construction of the allowable force envelope of each suspension rope using a scaled-down physical model.

[0022] Figure 5 yes Figure 1 The schematic embodiment shown illustrates stress measurement of a scaled-down solid model.

[0023] Figure 6 yes Figure 1 The flowchart shown is a schematic embodiment of a hoisting mechanism for lifting an aircraft based on the allowable force envelope of each sling.

[0024] Figure 7 This is a graph showing the tension and pitch angle of a single-sided suspension cable adjusted based on a scaled-down model of an aircraft; and...

[0025] Figure 8 yes Figure 7 The diagram shows the upper and lower limits of the tension adjusted for the scaled-down model of the aircraft.

[0026] The meanings of the reference numerals in the attached figure are as follows:

[0027] 1. Suspension rope;

[0028] 2. A scaled-down model of an aircraft; and

[0029] 3. Measurement points. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0031] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0032] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0033] When using expressions such as "at least one of A, B, and C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C. Similarly, when using expressions such as "at least one of A, B, or C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C.

[0034] Near-space vehicles are configured with corresponding structures according to the mission they perform and their cruising altitude. For example, they include airframes, wings, tail fins, payload equipment, and other transitional structures or functional structures with other functional requirements located between the above structures.

[0035] To avoid the near-space vehicle having to climb from the ground to its cruising altitude, a launch platform is also provided to shorten the distance between the launch point and the cruising altitude of the near-space vehicle. Furthermore, a hoisting mechanism connects the near-space vehicle and the launch platform, allowing the near-space vehicle to be towed from the hoisting phase (lifting it from its position on the platform to its detached position) to the release phase (reaching near its cruising altitude and beginning cruising).

[0036] In one illustrative embodiment, the lifting mechanism includes a sling structure with a plurality of slings 1 to provide multiple connected lifting points (such as those configured on the fuselage, wings, tail, or other structures of the near-space vehicle) between the lifting mechanism and the near-space vehicle; the lifting mechanism also includes an actuation structure adapted to drive the extension and retraction of each sling 1 to adjust the near-space vehicle during the process from the lifting phase to the release phase.

[0037] Because near-space vehicles are characterized by large size, light weight, high flexibility, and low longitudinal allowable overload, and because they also have dynamic attitude requirements under certain operating conditions, the control of the hoisting mechanism must consider the ultimate load that the near-space vehicle can withstand and the adjustment of its attitude. Therefore, based on the overall inventive concept, the embodiments of this disclosure provide a method for controlling a hoisting mechanism for hoisting a near-space vehicle.

[0038] Figure 1 This is a flowchart of a lifting mechanism control method for lifting a near-space vehicle according to an illustrative embodiment of the present disclosure.

[0039] According to the lifting mechanism control method for near-space vehicles provided in this disclosure, such as Figure 1 As shown, it includes steps S110 to S150;

[0040] Step S110: Based on the risk factors that cause aircraft abnormalities, set the limit load that the aircraft must meet under the target working condition. The lifting phase to the release phase of the aircraft is divided into multiple working conditions, and the target working condition belongs to multiple working conditions.

[0041] Step S120: Establish a finite element model to characterize the aircraft to be hoisted and the hoisting mechanism for hoisting the aircraft, and use the ultimate load as the excitation input of the finite element model to calculate the mechanical simulation under the target working condition in order to obtain the displacement simulation data of the aircraft under the target working condition.

[0042] Step S130: Based on the constraints, installation relationship and displacement simulation data between the aircraft and the hoisting mechanism, create a scaled-down solid model including the aircraft and the hoisting mechanism;

[0043] Step S140: Using the structural strength of the scaled-down model of the aircraft 2 as the limit, adjust the hoisting rope structure in the hoisting mechanism of the scaled-down model so that the scaled-down model of the aircraft can switch under multiple target working conditions, and construct the allowable force envelope of each hoisting rope in the hoisting rope structure.

[0044] Step S150: Control the hoisting mechanism carrying the aircraft based on the allowable force envelope of each hoisting rope, so that the aircraft can switch between multiple target working conditions to adjust from the hoisting stage to the release stage.

[0045] According to embodiments of this disclosure, risk factors leading to aircraft anomalies include at least one of the following: causing structural failure of the aircraft, causing changes in the dynamic state of the aircraft, and environmental loads of the environment in which the aircraft is located.

[0046] In one illustrative embodiment, factors leading to structural failure of the aircraft include the stress level that the aircraft can withstand. Specifically, this includes all structures of the aircraft (e.g., fuselage, wings, tail, mounting equipment, and other transitional structures or functional structures with other functional requirements located between these structures) being at the maximum stress value among those stress values ​​that would prevent structural failure in the respective structure.

[0047] In one illustrative embodiment, the factors that cause changes in the dynamic state of the aircraft include at least one of the aircraft's attitude angle, angular rate, acceleration, and position.

[0048] In one illustrative embodiment, environmental loads include, but are not limited to, wind conditions in the environment in which the aircraft is located (e.g., level 2, level 3, or any other wind level).

[0049] In this implementation, based on multiple working conditions divided from the lifting stage to the release stage of the aircraft to be lifted, the ultimate load that the aircraft needs to meet is set. Under the condition of meeting the ultimate load requirements of the aircraft, a solid scale model is established. By detecting the lifting process of the solid model, the total envelope data that meets the stress level and working condition requirements that the aircraft can withstand is generated. Based on the total envelope data, the actuation structure in the lifting mechanism that lifts the aircraft is controlled so that the attitude adjustment of the aircraft can be achieved while meeting the stress level of the aircraft during the lifting process.

[0050] Figure 2 yes Figure 1 The flowchart shown is for establishing a finite element model to obtain displacement simulation data of the aircraft under target operating conditions, representing an illustrative embodiment.

[0051] According to embodiments of this disclosure, such as Figure 2 As shown, step S120: Establish a finite element model to characterize the aircraft to be hoisted and the hoisting mechanism for hoisting the aircraft, and use the ultimate load as the excitation input of the finite element model to calculate the mechanical simulation under the target working condition, so as to obtain the displacement simulation data of the aircraft under the target working condition, including steps S121 to S125:

[0052] Step S121: Establish a finite element model including the aircraft and the hoisting mechanism, and apply the ultimate load to the finite element model, wherein the hoisting mechanism includes a hoisting rope structure;

[0053] Step S122: Add multiple constraint points on the aircraft and apply displacement constraints in three mutually orthogonal directions in space to each constraint point, so that the finite element model is in a fully constrained or over-constrained state.

[0054] Step S123: Set the parameter values ​​and convergence criteria for each displacement constraint;

[0055] Step S124: Calculate the stress corresponding to each displacement constraint based on the finite element model and parameter values;

[0056] Step S125: Converge the finite element model until the stress corresponding to each displacement constraint meets the convergence criterion, and output the displacement simulation data.

[0057] In one illustrative embodiment, the finite element model established in step S121 includes beam elements (beam element B31) and truss elements (beam element T3D2). The beam elements are two-node linear beam elements, and the truss elements are two-node three-dimensional truss elements. Specifically, one end of the truss element is mounted on the beam element, and the other end of the truss element is mounted on an actuation structure (such as a motor) suitable for applying traction force to the suspension rope structure.

[0058] In one illustrative embodiment, beam elements include, but are not limited to, tubular structures of two sizes (76×2 and 60×2.5, length×diameter) spaced around each other. Furthermore, truss elements include, but are not limited to, having a circular cross-section of 12 mm. Furthermore, in the simulation based on Abaqus software, the "mm-Ts" unit system is used.

[0059] In this implementation, by establishing finite element models of the aircraft to be lifted and the lifting mechanism for lifting the aircraft, the geometric relationship between the connection positions (such as lifting point interfaces) between the lifting mechanism and the aircraft can be obtained. This facilitates the rational selection of the lifting point positions of the aircraft, preventing structural failure (such as structural damage) of the aircraft due to unreasonable connection positions between the lifting mechanism and the aircraft. Furthermore, based on the aforementioned finite element model and mechanical simulation calculations, the selection of lifting ropes that meet the requirements of the lifting process can be obtained, and the stress-strain levels of the ultimate load can be checked based on the lifting ropes.

[0060] Figure 3 yes Figure 1 The flowchart illustrating the manufacture of the illustrative embodiment includes a scaled-down model of the aircraft and the hoisting mechanism.

[0061] According to embodiments of this disclosure, such as Figure 3 As shown, step S130: Based on the constraints, installation relationship and displacement simulation data between the aircraft and the hoisting mechanism, a scaled-down solid model including the aircraft and the hoisting mechanism is manufactured, including steps S131 to S132.

[0062] Step S131: Set the physical properties of the aircraft and hoisting mechanism;

[0063] Step S132: Create a scaled-down solid model based on the constraints, installation relationship, and displacement simulation data between the aircraft and the hoisting mechanism.

[0064] In one illustrative embodiment, the physical properties of the aircraft and the hoisting mechanism in step S131 include the materials of the aircraft and the hoisting mechanism.

[0065] In one illustrative embodiment, the aircraft to be simulated is configured as follows: 30 meters in length, 70 meters in width, with a landing deformation of approximately 10% under its own weight, and a structural weight of 2 tons. Furthermore, the pitch angle of the aircraft during the release phase is configured as 60°±3°, and the roll attitude angle as 0°±3°. A scaled-down solid model is constructed based on the above parameters of the aircraft to be simulated and the displacement simulation data obtained through step S125.

[0066] According to embodiments of this disclosure, such as Figure 1 As shown, in steps S110 to S150, the target working conditions include a lifting working condition for lifting the aircraft, a releasing working condition for releasing the aircraft, and a transition working condition for adjusting from the lifting working condition to the releasing working condition.

[0067] Figure 4 yes Figure 1 The flowchart shown in the illustrative embodiment illustrates the construction of the allowable force envelope of each suspension rope using a scaled-down physical model.

[0068] According to embodiments of this disclosure, such as Figure 4 As shown, step S140: Using the structural strength of the scaled-down model of the aircraft 2 as the limit, adjust the hoisting rope structure in the hoisting mechanism of the scaled-down model to allow the scaled-down model to switch under multiple target working conditions, and construct the allowable force envelope of each hoisting rope in the hoisting rope structure, including steps S141 and S142:

[0069] Step S141: Measure the upper and lower limits of the tension applied to the scaled-down model of the aircraft 2 by each rope in the rope structure under each target working condition.

[0070] Step S142: Construct the allowable force envelope of each suspension rope based on the upper and lower limits of the tension of each rope and the attitude angle of the aircraft 2 in the scaled-down model.

[0071] According to an embodiment of this disclosure, step S141: Measuring the upper and lower limits of the tension applied to the aircraft 2 of the scaled-down model by each suspension rope in the suspension rope structure under each target working condition includes:

[0072] Step S1411: Configure a detection mechanism on the scaled-down model to detect the stress at each measurement point of the scaled-down model of the aircraft 2 caused by the raising and lowering of the suspending rope, under the condition of applying the maximum allowable stress boundary of the material used in the scaled-down model of the aircraft 2 to the scaled-down model.

[0073] In one illustrative embodiment, the scaled-down solid model employs a similar rigid body model that will produce a certain deformation under stress.

[0074] In this implementation, representative working conditions from the lifting phase to the release phase of the aircraft are selected as target working conditions (such as lifting, release, and transition working conditions). Under the target working conditions, the allowable limit values ​​of strain during the lifting and dynamic state change process are obtained by measuring the scaled-down model of the solid object. Thus, the allowable force envelope is plotted to provide a safe and reasonable method for controlling the tension of the lifting rope. Figure 5 yes Figure 1 The schematic embodiment shown illustrates stress measurement of a scaled-down solid model.

[0075] In one illustrative embodiment, such as Figure 5 As shown, the detection mechanism includes multiple strain gauges. Specifically, step S1411 involves configuring the detection mechanism on the scaled-down model to detect the stress at various measurement points 3 of the aircraft 2 in the scaled-down model due to the release and retraction of the suspension rope 1. This includes setting up multiple detection point arrays (including but not limited to arrays arranged in rows and / or columns) on the aircraft 2 of the scaled-down model. Further, strain gauges are attached to each detection point, and the output terminals of the strain gauges are wired to acquire the stress signals detected by the strain gauges.

[0076] In one illustrative embodiment, the maximum allowable stress boundary of the material used in the solid scale model is applied to the solid scale model, including but not limited to being set to 80% of the maximum allowable stress of the material used.

[0077] In one illustrative embodiment, for testing agencies that have passed horizontal and / or symmetrical measurements, the measurement of the test point can be performed using a single-sided test, followed by mirroring of the other side (e.g., testing the measurement point 3 on the left side, and then obtaining the test result of the measurement point 3 on the other side through mirroring), and the measurement result is extracted. Further, based on the extracted measurement results, the allowable force range during the adjustment process is calculated through simulation.

[0078] According to an embodiment of this disclosure, step S1411: configuring a detection mechanism on the scaled-down model to detect the stress at each measurement point of the scaled-down model of the aircraft 2 due to the release and retraction of the suspending rope under the condition of applying the maximum allowable stress boundary of the material used in the scaled-down model of the aircraft 2 to the scaled-down model. This includes steps S14111 to S14113.

[0079] Step S14111: Under lifting conditions, retract or extend at least a portion of the lifting ropes and record the upper and lower limits of the tension of each rope.

[0080] Step S14112: Preset the pitch angle change of the scaled-down model aircraft 2. Under the transition condition, at least a portion of the suspension ropes are released or retracted so that the pitch angle of the scaled-down model aircraft 2 is adjusted successively according to the preset pitch angle change. Record the upper and lower limits of the tension of each suspension rope.

[0081] Step S14113: Loosen or release at least a portion of the suspension ropes to adjust the scaled-down model of the aircraft 2 from the transition condition to the release condition, and record the upper and lower limits of the tension of each suspension rope.

[0082] In one illustrative embodiment, the lifting operation in step S14111 includes bringing the scaled-down model of the aircraft 2 to a pitch angle of 0°. Specifically, the aircraft is lifted upwards by adjusting each hoisting rope 1 to maintain a pitch angle of 0° until the bottom surface of the aircraft is separated from the working surface (including but not limited to the ground).

[0083] In one illustrative embodiment, the transition condition in step S14112 includes placing the scaled-down model of the aircraft 2 in a state where the pitch angle is not 0°. Specifically, the preset pitch angle of the aircraft includes, but is not limited to, 10° (i.e., each adjustment makes the angle between the pitch angle of the scaled-down model and the horizontal plane 10°). Furthermore, during each adjustment (i.e., each 10° pitch angle adjustment), the upper and lower limits of the tension on each suspension rope 1 are recorded.

[0084] In one illustrative embodiment, during the transitional phase of step S14112, when adjusting the pitch angle of the scaled-down model aircraft 2, the pitch angle adjustment process should be controlled to be as uniform as possible (e.g., maintaining a constant speed, with the specific angle adjustment configured to be less than or equal to 10° / min). Furthermore, if the pitch angle adjustment process is affected by external factors (such as wind), the stability of the adjustment process needs to be maintained by adjusting the suspension rope 1. Even further, for each successive adjustment of the scaled-down model, the pitch angle adjustment accuracy should be maintained; for example, the pitch angle control accuracy should be maintained within ±1°, the velocity in each direction of the scaled-down model should be maintained at 5 cm / s, and the angular rate of the scaled-down model should be less than or equal to 1° / s.

[0085] In one illustrative embodiment, the release condition of step S14113 includes placing the scaled-down model of the aircraft 2 in a releaseable pitch angle (e.g., 60°±3°) state so that the scaled-down model has lift that meets cruise requirements.

[0086] In one illustrative embodiment, in step S1411, the condition under which the maximum allowable stress applied to the scaled-down model of the non-aircraft occurs is limited to the stress range of each measurement point 3 being within 50% of the simulation result and less than or equal to the allowable stress value of the material properties of the material used in the scaled-down model. Under this condition, the upper and lower limits of the tension of each suspension rope 1 are recorded.

[0087] According to embodiments of this disclosure, such as Figure 1 As shown, step S142: Constructing the allowable force envelope of each suspension rope based on the upper and lower limits of the tension of each rope and the attitude angle of the aircraft 2 in the scaled-down model includes: step S1421: Using the attitude angle of the aircraft 2 in the scaled-down model as the horizontal axis, the tension of the suspension rope as the vertical axis, and the upper and lower limits of the tension as coordinates on the vertical axis, establish the allowable force envelope of the suspension rope.

[0088] In one illustrative embodiment, the allowable force envelope of each suspension rope 1 is obtained by processing the allowable force envelope of each rope 1 (i.e., the tension of the rope 1 - attitude angle of the scaled-down model).

[0089] Figure 6 yes Figure 1 The flowchart shown is a schematic embodiment of a hoisting mechanism for lifting an aircraft based on the allowable force envelope of each sling.

[0090] According to embodiments of this disclosure, such as Figure 6As shown, step S150: Controlling the hoisting mechanism carrying the aircraft based on the allowable force envelope of each hoisting rope 1, so that the aircraft switches between multiple target working conditions to adjust from the hoisting stage to the release stage, includes steps S151 and S152:

[0091] Step S151: Parametrically process the allowable force envelope of each suspension rope 1 to obtain the total force envelope data;

[0092] Step S152: Input the total package data into the hoisting mechanism that is carrying the aircraft, and control the actuation structure of the hoisting mechanism according to the total package data, so as to stretch the hoisting rope 1 of the hoisting rope structure through the actuation structure, so as to adjust the aircraft from the hoisting condition to the release condition.

[0093] In one illustrative embodiment, step S151: parameterizing the allowable force envelope of each suspension rope 1 includes steps S1511 to S151.

[0094] Step S1511: Take the allowable force envelope collected for each suspension rope 1 under each target working condition in the scaled-down model as a data set;

[0095] Step S1512: Interpolate each point in each data group and output the allowable force envelope corresponding to the minimum value as the target allowable force envelope;

[0096] Step S1513: Output the target allowable force envelope of each suspension rope 1 as the total envelope data.

[0097] In one illustrative embodiment, step S152 includes: using a PID (i.e., proportional, integral, and derivative control) algorithm to control and correct the actuation structure in order to adjust the pitch angle of the aircraft hoisted by the hoisting mechanism so that the aircraft meets the structural and / or dynamic requirements under various target operating conditions.

[0098] Figure 7 This is a graph showing the tension and pitch angle of a single-sided suspension cable adjusted based on a scaled-down model of an aircraft. Figure 8 yes Figure 7 The diagram shows the upper and lower limits of the tension adjusted for the scaled-down model of the aircraft.

[0099] In one illustrative embodiment, such as Figure 7 and Figure 8As shown, a scaled-down model of the aircraft 2, with a ratio of 1:8, is configured and hoisted using six slings. Specifically, the six slings are connected to the left, left front, left rear, right, right front, and right rear ends of the scaled-down model of the aircraft 2. Further, a series of points on one side are selected for extraction (e.g., the left side), while the other side (right side) is assumed to have symmetrical results, to obtain the allowable force envelope.

[0100] Step S14111: Lift the scale model aircraft, adjust the tension of each hoisting rope to make it at a 0° angle with the horizontal plane, and ensure that the scale model aircraft reaches the maximum allowable stress boundary (including but not limited to 80% of the maximum allowable stress of the materials used to make each position of the scale model aircraft), and record the upper and lower limits of the tension of each hoisting rope.

[0101] Step S14112: The angle between the scaled-down model of the aircraft and the horizontal plane is preset to -66° as the release condition, and the state between 0° and -60° is used as the transition condition. The pitch angle change is preset (including but not limited to 10°) so that the scaled-down model of the aircraft is adjusted successively. When the scaled-down model of the aircraft reaches the maximum allowable stress boundary, the upper limit and lower limit of the tension of each suspension rope are recorded.

[0102] Specifically, the pitch angle adjustment should be kept as uniform as possible, and the adjustment speed should be maintained at less than or equal to 10° / min; the control accuracy range of the pitch angle is ±1°; the stable velocity range of the scaled-down model aircraft in all directions is 5cm / s, and the angular rate is maintained at less than or equal to 1° / s.

[0103] Step S14113: Loosen or retract at least a portion of the suspension ropes to adjust the scaled-down model aircraft 2 from the transition condition to the release condition of -60°, and adjust the scaled-down model aircraft step by step to record the upper and lower limits of the tension of each suspension rope when the scaled-down model aircraft reaches the maximum allowable stress boundary.

[0104] Step S1511: With each suspension rope (i.e. Figure 7 and Figure 8 The allowable force envelopes collected by the left rope, left front rope, and left rear rope shown (the right rope, right front rope, and right rear rope are omitted and are symmetrical to it, with consistent results) under each target working condition in the scaled-down solid model are used as a data set.

[0105] Step S1512: Interpolate each point in each data group and output the allowable force envelope corresponding to the minimum value as the target allowable force envelope.

[0106] Step S1513: Output the target allowable force envelope of each suspension rope 1 as the total force envelope data, resulting in Table 1 below:

[0107] Table 1 Target values ​​of UAV sling-mounted tilting tension

[0108]

[0109] Step S152: Input the total package data in Table 1 above into the hoisting mechanism that is hoisting the aircraft, and control the actuation structure of the hoisting mechanism according to the total package data, so as to stretch the hoisting rope 1 of the hoisting rope structure through the actuation structure, so as to adjust the aircraft from the hoisting condition to the release condition.

[0110] The adjustment of the aircraft's operating conditions includes a continuous operation mode that makes the actuating structure (such as the hoisting equipment) run continuously, and a point operation mode that makes the actuating structure (such as the hoisting equipment) run intermittently. During the testing process, the point operation mode is preferred for fine-tuning with high precision requirements, while during stable operation, the continuous operation mode is preferred to improve the efficiency of hoisting.

[0111] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional mechanisms or structures will be omitted where they may cause confusion in understanding this disclosure.

[0112] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A method for controlling a hoisting mechanism used for hoisting an aircraft in near space, comprising: Based on the risk factors that may cause aircraft malfunctions, the ultimate load that the aircraft must meet under the target operating condition is set. The lifting phase to the release phase of the aircraft is divided into multiple operating conditions, and the target operating condition belongs to the multiple operating conditions. A finite element model is established to characterize the aircraft to be hoisted and the hoisting mechanism for hoisting the aircraft. Using the ultimate load as the excitation input to the finite element model, a mechanical simulation is performed under the target working condition to obtain displacement simulation data of the aircraft under the target working condition, including: A finite element model including the aircraft and the hoisting mechanism is established, and an ultimate load is applied to the finite element model, wherein the hoisting mechanism includes a hoisting rope structure; Multiple constraint points are added to the aircraft, and displacement constraints in three mutually orthogonal directions in space are applied to each constraint point, so that the finite element model is in a fully constrained or over-constrained state. Set the parameter values ​​and convergence criteria for each of the displacement constraints; Calculate the stress corresponding to each displacement constraint based on the finite element model and the parameter values; and The finite element model is converged until the stress corresponding to each displacement constraint satisfies the convergence criterion, and the displacement simulation data is output. Based on the constraints and installation relationship between the aircraft and the hoisting mechanism, as well as the displacement simulation data, a scaled-down solid model including the aircraft and the hoisting mechanism is manufactured. Using the structural strength of the scaled-down aircraft model as the limit, the hoisting rope structure in the hoisting mechanism of the scaled-down model is adjusted to allow the aircraft model to switch between multiple target operating conditions, and the allowable force envelope of each hoisting rope in the hoisting rope structure is constructed; and The hoisting mechanism carrying the aircraft is controlled based on the allowable force envelope of each of the hoisting ropes, so that the aircraft can switch between multiple target working conditions to adjust from the lifting phase to the release phase, including: The allowable force envelope of each of the aforementioned suspension ropes is parameterized to obtain the total force envelope data; and The total envelope data is entered into the hoisting mechanism that hoists the aircraft, and the actuation structure of the hoisting mechanism is controlled according to the total envelope data, so as to stretch the hoisting rope of the hoisting rope structure through the actuation structure, so as to adjust the aircraft from the hoisting condition to the release condition.

2. The method according to claim 1, wherein, The risk factors that cause aircraft malfunctions include at least one of the following: causing structural failure of the aircraft, causing changes in the dynamic state of the aircraft, and environmental loads of the environment in which the aircraft is located.

3. The method according to claim 1, wherein, The process of creating a scaled-down solid model of the aircraft and the hoisting mechanism based on the constraints, installation relationship, and displacement simulation data between the aircraft and the hoisting mechanism includes: Set the physical properties of the aircraft and the hoisting mechanism; and The scaled-down model of the solid object is manufactured based on the constraints between the aircraft and the hoisting mechanism, the installation relationship, and the displacement simulation data.

4. The method according to claim 1, wherein, The target operating conditions include a lifting condition for hoisting the aircraft, a release condition for releasing the aircraft, and a transition condition for adjusting from the lifting condition to the release condition.

5. The method according to claim 4, wherein, The step of adjusting the hoisting rope structure in the hoisting mechanism of the scaled-down aircraft model, using the structural strength of the scaled-down model as the limit, to allow the scaled-down model to switch between multiple target working conditions, includes: Measure the upper and lower limits of the tension applied to the scaled-down aircraft by each suspension rope in the suspension rope structure under each target operating condition; and The allowable force envelope of each suspension rope is constructed based on the upper and lower limits of the tension of each rope and the attitude angle of the aircraft in the scaled-down model of the solid object.

6. The method according to claim 5, wherein, The measurement of the upper and lower limits of the tension applied to the scaled-down aircraft model by each suspension rope in the suspension rope structure under each target working condition includes: A detection mechanism is configured on the scaled-down model to detect the stress at various measurement points of the scaled-down model of the aircraft caused by the raising and lowering of the suspending rope, under the condition that the maximum allowable stress boundary of the material used in the scaled-down model of the aircraft is applied to the scaled-down model.

7. The method according to claim 6, wherein, The provision of a detection mechanism on the scaled-down model, to detect the stress at various measurement points of the scaled-down model of the aircraft due to the raising and lowering of the suspending rope, under the condition of applying the maximum allowable stress boundary of the material used in the scaled-down model of the aircraft to the scaled-down model, includes: Under the lifting conditions, at least a portion of the lifting ropes are retracted or released, and the upper and lower limits of the tension of each lifting rope are recorded. The pitch angle variation of the scaled-down aircraft model is preset. Under the transition condition, at least a portion of the suspension ropes are retracted or released so that the pitch angle of the scaled-down aircraft model is successively adjusted according to the pitch angle variation. The upper and lower limits of the tension of each suspension rope are recorded. At least a portion of the suspension ropes are retracted or released to adjust the scaled-down model of the aircraft from the transition condition to the release condition, and the upper and lower limits of the tension of each suspension rope are recorded.

8. The method according to claim 7, wherein, The construction of the allowable force envelope for each suspension rope based on the upper and lower limits of the tension of each rope and the attitude angle of the aircraft in the scaled-down model includes: The allowable force envelope of the suspension rope is established by taking the attitude angle of the aircraft in the scaled-down model as the horizontal axis, the tension of the suspension rope as the vertical axis, and the upper and lower limits of the tension as coordinates on the vertical axis.

Images