Identification and Repair Method for Design Defects in the Motion Function Reliability of Aircraft Door Mechanisms

Abstract

The present invention discloses a method for identifying and repairing design defects in the motion function reliability of an aircraft cabin door mechanism, including: establishing a mathematical mapping model between the design parameters of the cabin door mechanism and the cam curve groove, conducting a fault tree analysis (FTA) on the motion function reliability failure of the cam curve groove to find the main indicators affecting the motion function reliability of the cam curve groove; establishing a mapping model between the main parameters and the motion function reliability of the aircraft cabin door mechanism, and deriving the limit state equation; calculating the allowable values of kinematic parameters based on the motion function reliability of the cabin door mechanism through the motion function reliability analysis of the limit state position; identifying and repairing the design defects in the motion function reliability in the design of the cam curve groove mechanism; the present invention improves the motion function reliability of the cabin door cam four-bar mechanism.

Description

Technical Field

[0001] The present invention relates to the technical fields of mechanical design and computer software, and particularly to a method for identifying and repairing design defects in the motion function reliability of an aircraft cabin door mechanism. Background Art

[0002] When the semi-blocking aircraft cabin door is closed, it can maintain the airtightness of the cabin through internal pressurization of the cabin body, and after opening, it can be moved outside the fuselage without occupying the internal space of the fuselage, so it is widely used in civil aviation aircraft. The action of this type of aircraft cabin door is mainly completed by a cam four-bar mechanism.

[0003] The planar hinge four-bar mechanism is the basic form of the planar four-bar mechanism, and other types and structural forms of four-bar mechanisms can be considered as evolved forms of the hinge four-bar mechanism. Based on different selections of the fixed link, there will be different trajectory syntheses in the design of the planar hinge four-bar mechanism. In the working condition of the cabin door with the hinge point as the fixed link, the planar hinge four-bar mechanism will generate two degrees of freedom. Based on this, a cam mechanism is introduced to limit the degrees of freedom of the cabin door mechanism, so that the designed product has a definite motion to meet the design requirements. The introduction of the cam mechanism also makes the structure of the entire cabin door mechanism more compact, and the cam curve groove only needs a very small space to guide the four-bar mechanism to complete the specified action.

[0004] The semi-blocking aircraft cabin door needs to go through three stages of "translation", "tilting", and "rotation" to achieve the door opening action, so the cam curve groove of the cam four-bar mechanism is also divided into three sections. If the kinematic analysis and design accuracy of the cam curve groove are not considered enough in the design of the cam four-bar mechanism, it will lead to design defects in the cam curve groove, especially the curve transition between two adjacent stages. These defects will seriously affect the kinematic and dynamic characteristics of the cabin door mechanism during the subsequent operation process, greatly reducing the motion function reliability of the cabin door. In the lightest case, it will cause irregular motion or jamming of the aircraft cabin door during use, and in the most serious case, it will damage the entire cabin door mechanism, and even cause serious safety accidents and economic losses. Summary of the Invention

[0005] To solve the problems existing in the prior art, the purpose of the present invention is to provide a method for identifying and repairing design defects in the motion function reliability of an aircraft cabin door mechanism. The present invention can identify the design defects in the design process of the cam curve groove of the cam four-bar mechanism and propose repair methods to improve the motion function reliability of the cabin door cam four-bar mechanism.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: a method for identifying and repairing design defects in the motion function reliability of an aircraft cabin door mechanism, including the following steps:

[0007] Step 1: Establish a mapping model between the design parameters of the hatch mechanism and the cam curve groove. According to the motion states of the hatch at each stage, establish the mapping relationship between the main parameters among the relevant design parameters of the hatch mechanism, and complete the initial design of the cam curve groove;

[0008] Step 2: Conduct a fault tree analysis on the failure of the motion function reliability of the cam curve groove, find the main indicators affecting the motion function reliability of the cam curve groove, establish a function model between the design parameters and the main indicators of the motion function reliability of the aircraft hatch mechanism, deduce the limit state equation, and complete the deterministic analysis;

[0009] Step 3: Through the analysis of the motion function reliability at the limit state position, obtain the deviation values of the main indicators required to meet the motion function reliability requirements when the cam curve groove mechanism is at the limit position, and calculate the allowable values of the kinematic parameters based on the motion function reliability of the hatch mechanism;

[0010] Step 4: Based on the mapping model of the motion function reliability of the aircraft hatch mechanism, taking whether the kinematic parameter indicators are met as the judgment condition, identify the points where the motion function reliability fails in the model within the global range, select the defective segments for repair, and after the defect repair is completed, substitute the optimized function model into the mapping model between the hatch mechanism design parameters and the cam curve groove, and output the repaired cam curve groove model.

[0011] As a further improvement of the present invention, in Step 1, the parameters that can still be adjusted after the hatch mechanism is put into operation are identified as secondary parameters, and the indicator parameters for realizing the expected motion of the hatch are identified as main parameters.

[0012] As a further improvement of the present invention, in Step 3, the numerical simulation analysis method is adopted for the analysis of the motion function reliability at the limit state position; the numerical simulation analysis method is the Monte carlo numerical simulation method.

[0013] As a further improvement of the present invention, in Step 4, the repair of the cam curve groove model specifically includes:

[0014] Taking the functional relationship between the main parameters and the output angle of the expected motion of the hatch as the independent variable, and taking meeting the kinematic parameter indicators of the motion function reliability as the objective function, optimize the mapping model between the main parameters and the cam curve groove, and further repair the design defects of the cam curve groove of the cam four-bar mechanism.

[0015] As a further improvement of the present invention, the aircraft door mechanism includes a cam curve groove mechanism, a first active rod, a door body, a third driven rod, a fourth driven rod and a cam roller. One end of the first active rod is hinged as a frame and is fixedly connected to the aircraft door shaft where the cam curve groove mechanism is located. The other end of the first active rod is hinged to the door body, one end of the third rod driven rod is connected to the door body, and the cam roller is installed at the other end of the third rod driven rod. The cam roller contacts the cam curve groove. The third rod driven rod has a hinge in the middle connected to one end of the fourth rod driven rod, and the other end of the fourth rod driven rod is hinged to the frame. The first active rod, the third rod driven rod, the fourth rod driven rod and the door body constitute a cam four-bar mechanism.

[0016] As a further improvement of the present invention, the step 1 is specifically as follows:

[0017] Based on the design parameter diagram of the door cam four-bar mechanism, the mapping model between the theoretical contour line of the cam curve groove and the design parameters is obtained by using the complex vector method:

[0018] E(x e ,y e )=(l1,l2,l3,l4,l5,θ1,θ2,θ3,θ x ,θ i )

[0019] Among them, x e ,y e is the coordinate value of the point E where the cam roller is located, l1 is the rod length of the first active rod, l2 is the distance between the connection points of the first active rod and the third rod follower rod on the door body, l3 is the distance between the hinge point of the third rod follower rod and the fourth rod follower rod and the connection point of the third rod follower rod on the door body, l4 is the rod length of the fourth rod follower rod, l5 is the distance between the hinge point of the third rod follower rod and the fourth rod follower rod and the cam roller; θ1, θ2, θ3, θ x is the angle between the rods, where θ1 corresponds to the angle between l1 and l4, θ2 corresponds to the angle between l3 and l1, θ3 corresponds to the supplementary angle between l1 and l2, and θ x is the angle between l1 and the horizontal line of the rack, θ i Indicated angles to achieve the desired door movement;

[0020] Through the analysis of the mapping model, it can be seen that the angle between each rod is an important parameter affecting the coordinates of the theoretical contour line. If the angle θ between the first active rod and the horizontal line of the frame is x As the main design parameters, θ1, θ2, θ3 can be calculated through the four-bar relationship and the door's expected motion indication angle θ i At this time, the motion input and output of the cam curve slot mechanism can be described by the motion equation:

[0021] C eq =(θ x ,θ i )

[0022] According to the envelope theory of surface clusters, the mapping model between the actual contour line of the cam curve groove and the design parameters is obtained:

[0023]

[0024] Among them, X and Y are the coordinate values of the inner and outer envelope lines of the cam roller at point E, is the derivative of the coordinate value of point E with respect to θ x , and r is the roller radius. In the formula:

[0025]

[0026] Among them, can be obtained by taking the derivative of the motion input and output motion equation C eq of the cam curve groove mechanism;

[0027] Thus, both the theoretical contour line and the actual contour line of the hatch curve groove mechanism are determined by the motion equation C eq =(θ x ,θ i ).

[0028] As a further improvement of the present invention, in step 2, according to the mapping model between the hatch mechanism design parameters and the cam curve groove, a function function of the main parameters and the motion function reliability of the aircraft hatch mechanism is established:

[0029] Z = [Δα Δρ Δa] T

[0030] Among them, Δα, Δρ, and Δa are three kinematic parameters affecting the motion function reliability of the hatch, namely the output error vectors of the pressure angle, curvature, and acceleration. In the formula:

[0031] Δα = α * -α

[0032] Δρ = ρ * -ρ

[0033] Δa = a * -a

[0034] Among them, α * , ρ * , a * are the allowable pressure angle, allowable curvature, and allowable acceleration respectively, and α, ρ, and a are the actual pressure angle, actual curvature, and actual acceleration of the hatch cam four-bar mechanism respectively. In the formula:

[0035]

[0036]

[0037]

[0038] As a further improvement of the present invention, in step 2, according to the functional function of the aircraft door mechanism's motion function reliability and the design parameter mapping model of the cam curve groove mechanism, the limit value of the reliability index and the state and position of the mechanism in the limit state can be obtained; in step 3, reliability analysis is respectively carried out on the main reliability indexes of the aircraft door mechanism under the limit state. Assuming that there is a deviation value ε when the design parameters of the aircraft door meet the motion function reliability indexes, the reliability work function can be rewritten as:

[0039] Z = [Z α Z ρ Z a T

[0040] Wherein:

[0041] Z α = α * - α - ε α

[0042] Z ρ = ρ * - ρ - ε ρ

[0043] Z a = a * - a - ε a

[0044] The distribution of the functional function is related to the design parameters, that is, it satisfies:

[0045] z = g(x) = g(l1, l2, l3, l4, l5, θ1, θ2, θ3, θ x , θ i , ε)

[0046] Then the limit state equation g(l1, l2, l3, l4, l5, θ1, θ2, θ3, θ x , θ i , ε) = 0 divides the design parameter variables of the mechanism into two parts: the failure region and the reliable region; then the failure domain of the aircraft door's motion function reliability is:

[0047] F = {x: g(x) ≤ 0}

[0048] The indication function I of the motion function reliability failure domain F ​(x) can be expressed as:

[0049]

[0050] According to the distribution form and numerical values of the design parameters, and based on the Monte Carlo reliability analysis method, N groups of random vector samples are substituted into the limit state equation of the performance function, and finally the estimated value of the failure probability can be obtained:

[0051]

[0052] As a further improvement of the present invention, in step 4, the output parameters of the cam groove mapping models in the three stages of translation, tilting, and rotation of the hatch body are substituted into the mapping model between the main parameters and the kinematic function reliability of the aircraft hatch mechanism. Taking whether the kinematic parameter indexes are satisfied as the judgment condition, the points where the kinematic function reliability fails are searched and identified within the global range, and are marked as the failure points of the kinematic function reliability.

[0053] As a further improvement of the present invention, in step 4, the repair of the design defect of the kinematic function reliability in the design of the cam curve groove mechanism is specifically as follows:

[0054] Select the curve segment where the defect points densely occur in the design of the cam curve groove mechanism as the segment to be repaired, and extract the main design parameters at the beginning and end of the repaired segment as part of the constraint conditions to achieve the original expected motion conditions;

[0055] Taking the functional relationship between the main parameters and the output angle of the expected action of the hatch as the independent variable, and taking the kinematic parameter indexes that meet the kinematic function reliability as the objective function, considering various constraint conditions, an intelligent algorithm is used to obtain a function model that meets the design requirements under the expected motion conditions, thereby repairing the design defects existing in the design of the cam curve groove mechanism;

[0056] The kinematic parameter indexes as the objective function can be expressed by the current pressure angle, curvature, and the vector norm of the acceleration ‖α‖ ∞ , ‖ρ‖ ∞ , ‖a‖ ∞ ,;

[0057] Among them, the objective function is:

[0058]

[0059] The beneficial effects of the present invention are:

[0060] The present invention can identify the design defects of the curve groove during the design process of the cam curve groove, comprehensively consider the kinematic function reliability of the hatch mechanism and the completion of the expected action, and repair the defects by optimizing the design parameters to meet the requirements of the kinematic function reliability of the aircraft hatch. Brief Description of the Drawings

[0061] Figure 1 This is the specific flowchart of the defect identification and repair method for the embodiment of the present invention;

[0062] Figure 2 This is the three-dimensional solid model diagram of the hatch cam four-bar mechanism in the embodiment of the present invention;

[0063] Figure 3 This is the schematic diagram of the design parameters of the hatch cam four-bar mechanism in the embodiment of the present invention;

[0064] Figure 4 This is the schematic diagram of the three motion stages of the cam curve groove mechanism in the embodiment of the present invention;

[0065] Figure 5 This is the fault tree (FTA) analysis diagram in the embodiment of the present invention;

[0066] Figure 6 This is the initial design curve diagram of the cam groove of the aircraft hatch mechanism in the embodiment of the present invention;

[0067] Figure 7 This is the initial design defect identification diagram of the cam groove of the aircraft hatch mechanism in the embodiment of the present invention;

[0068] Figure 8 This is the optimized design curve diagram of the cam groove of the aircraft hatch mechanism in the embodiment of the present invention;

[0069] Figure 9 This is the comparison diagram of the pressure angle of the design curve of the cam groove of the aircraft hatch mechanism in the embodiment of the present invention;

[0070] Figure 10 This is the comparison diagram of the curvature radius of the design curve of the cam groove of the aircraft hatch mechanism in the embodiment of the present invention;

[0071] Figure 11 This is the comparison diagram of the acceleration of the design curve of the cam groove of the aircraft hatch mechanism in the embodiment of the present invention.

[0072] Reference Signs:

[0073] 1. Cam curve groove mechanism, 2. First driving rod, 3. Hatch body, 4. Third driven rod, 5. Fourth driven rod, 6. Cam roller. Detailed Description of the Embodiment

[0074] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0075] Embodiment

[0076] As Figure 1 shown, a method for identifying and repairing design defects in the motion function reliability of an aircraft hatch mechanism specifically includes:

[0077] First, establish a mathematical mapping model between the design parameters of the hatch mechanism and the cam curve groove, and complete the initial design model of the cam curve groove according to the expected output motion of the aircraft hatch. Then, based on the analysis of the relevant accident reports and literature of the hatch, taking the failure of the cam groove curve motion function as the top event, conduct a top-down fault tree analysis (FTA) to find the main indicators affecting the motion function reliability of the cam curve groove, so as to establish a mapping model between the main design parameters and the motion function reliability of the aircraft hatch mechanism. Among the relevant design parameters of the hatch mechanism, the parameters that can still be adjusted after the hatch mechanism is put into operation are identified as secondary parameters (such as the length condition of the hatch rod), and the indicating parameters (the included angles between the rods) that realize the expected motion of the hatch are identified as main parameters. Through the analysis of the motion function reliability at the limit state position, obtain the allowable values of the kinematic parameters based on the motion function reliability of the hatch mechanism, and identify the points where the motion function reliability fails within the global range of the initial design based on these allowable values. If points where the cam curve groove mechanism has motion function reliability failures are identified, select the motion segment where the defect points are located for repair. Taking the functional relationship between the main parameters and the expected action output angle of the hatch as the independent variable, taking the kinematic parameter indicators that meet the motion function reliability as the objective function, considering various constraint conditions, use an intelligent algorithm to calculate the parameter combination that makes the expected output action meet the design index requirements and the motion function is reliable, and then repair the design defects existing in the design of the cam curve groove mechanism.

[0078] The intelligent algorithm for repairing design defects can be a genetic algorithm, a particle swarm optimization algorithm, or other intelligent optimization algorithms.

[0079] The following uses Figure 2 the cam curve groove mechanism of the aircraft hatch cam four-bar mechanism shown in

[0080] Figure 2 to further illustrate this embodiment:

[0081] For Figure 2 the identification and repair of the design defects in the motion function reliability of the aircraft hatch mechanism include:

[0082] 1. Establish a mathematical mapping model between the door mechanism design parameters and the cam curve groove:

[0083] like Figure 3 As shown in the figure, based on the design parameter diagram of the door cam four-bar mechanism, the mapping model between the theoretical contour line of the cam curve groove and the design parameters is obtained by using the complex vector method:

[0084] E(x e ,y e )=(l1,l2,l3,l4,l5,θ1,θ2,θ3,θ x ,θ i )

[0085] Among them, x e ,y e is the coordinate value of point E, l1, l2, l3, l4, l5 are the lengths of the bars of the cam four-bar mechanism, θ1, θ2, θ3, θ x is the angle between the rods, θ i Indicates the angle of movement to achieve the desired door movement.

[0086] Through the analysis of the mapping model, it can be seen that the angle between the rods is an important parameter affecting the coordinates of the theoretical contour line. If the angle θ between the first rod and the horizontal line of the rack is x As the main design parameters, θ1, θ2, θ3 can be calculated through the four-bar relationship and the door's expected motion indication angle θ i At this time, the motion input and output of the cam curve slot mechanism can be described by the motion equation:

[0087] C eq =(θ x ,θ i )

[0088] According to the surface cluster envelope theory, the mapping model between the actual contour line of the cam curve groove and the design parameters is obtained:

[0089]

[0090] Among them, X, Y are the coordinate values ​​of the inner and outer envelopes of the cam at point E. is the coordinate value of point E with respect to θ x The derivative of , r is the roller radius, where:

[0091]

[0092] in, The motion input and output motion equations C of the cam curve slot mechanism can be eq Derivation to obtain.

[0093] In summary, both the theoretical contour line and the actual contour line of the cabin door curve groove mechanism are determined by the motion equation C eq =(θ x , θ i ).

[0094] The semi-blocking aircraft cabin door needs to go through three stages of "translation", "tilting", and "rotation" to achieve the door opening action. As Figure 4 shown, the cam curve groove of the cam four-bar mechanism is also divided into three sections. According to the expected output actions of the cabin door in each stage, the initial design of the aircraft cabin door mechanism can be completed.

[0095] 2. Establish the mapping model between the main parameters and the motion function reliability of the aircraft cabin door mechanism:

[0096] According to the analysis of the cabin door-related accident reports and literature, as Figure 5 shown, taking the failure of the cam groove curve motion function as the top event, perform a top-down fault tree analysis to find the main indicators affecting the motion function reliability of the cam curve groove.

[0097] According to the mapping model between the cabin door mechanism design parameters and the cam curve groove, establish the mapping model between the main parameters and the motion function reliability of the aircraft cabin door mechanism:

[0098] Z = [Δα Δρ Δa] T

[0099] where Δα, Δρ, and Δa are three kinematic parameters affecting the motion function reliability of the cabin door, namely the output error vectors of the pressure angle, curvature, and acceleration. In the formula:

[0100] Δα = α * - α

[0101] Δρ = ρ * - ρ

[0102] Δa = a * - a

[0103] where α * , ρ * , a * are the allowable pressure angle, allowable curvature, and allowable acceleration respectively, and α, ρ, and a are the actual pressure angle, actual curvature, and actual acceleration of the cabin door cam four-bar mechanism. In the formula:

[0104]

[0105]

[0106]

[0107] Next, according to the functional function of the aircraft cabin door mechanism's motion function reliability and the design parameter mapping model of the cam curve groove mechanism, the limit value of the reliability index and the state and position of the mechanism at the limit state are obtained.

[0108] 3. Through the analysis of the motion function reliability at the limit state position, calculate the allowable values of the kinematic parameters based on the motion function reliability of the cabin door mechanism.

[0109] Conduct a reliability analysis of the main reliability indicators of the aircraft cabin door mechanism under the limit state. Assuming that there is a deviation value ε in the design parameters of the aircraft cabin door on the premise of meeting the motion function reliability indicators, the reliability function can be rewritten as:

[0110] Z = [Z α Z ρ Z a T

[0111] Where:

[0112] Z α = α * -α - ε α

[0113] Z ρ = ρ * -ρ - ε ρ

[0114] Z a = a * -a - ε a

[0115] The distribution of the functional function is related to the design parameters, that is, it satisfies:

[0116] z = g(x) = g(l1, l2, l3, l4, l5, θ1, θ2, θ3, θ x , θ i , ε)

[0117] Then the limit state equation g(l1, l2, l3, l4, l5, θ1, θ2, θ3, θ x , θ i , ε) = 0 divides the design parameter variables of the mechanism into two parts: the failure region and the reliable region. Then the failure domain of the motion function reliability of the aircraft cabin door is:

[0118] F = {x: g(x) ≤ 0}

[0119] The failure domain indicator function I F (x) can be expressed as:

[0120] ​

[0121] According to the distribution form and numerical values of the design parameters, based on the Monte Carlo reliability analysis method, N groups of random vector samples are substituted into the limit state equation of the performance function, and finally the estimated value of the failure probability can be obtained:

[0122]

[0123] Next, substituting the reliability index required by the cam groove mechanism at the limit position into the reliability analysis method, the deviation value ε between the allowable index and the actually satisfied reliability index can be obtained. Then, the optimized allowable value based on the kinematic function reliability is:

[0124] α o = α * + ε α

[0125] ρ o = ρ * + ε ρ

[0126] a o = a * + ε a

[0127] 4. Identify and repair the design defects in the kinematic function reliability of the cam curve groove mechanism:

[0128] Substitute the output parameters of the cam groove mapping models in the three stages of "translation", "tilting", and "rotation" into the mapping model between the main parameters and the kinematic function reliability of the aircraft door mechanism, and search and identify the points where the kinematic function reliability fails within the global range. By comparing the optimized allowable values of each kinematic parameter with the actual kinematic parameters, search for the defect points in the design of the cam groove mechanism and mark them as the failure points of the kinematic function reliability.

[0129] To improve the repair efficiency and considering the continuity of the defect points at the same time, select the curve segment where the defect points densely occur in the design of the cam groove mechanism as the segment to be repaired, and extract the main design parameters at the beginning and end of the repaired segment as part of the constraint conditions to achieve the original expected motion conditions.

[0130] Taking the functional relationship between the main parameters and the output angle of the expected motion of the door as the independent variable, taking the kinematic parameter index that satisfies the kinematic function reliability as the objective function, considering various constraint conditions, and using an intelligent algorithm to obtain the function model that meets the design requirements under the expected motion conditions, and then repair the design defects existing in the design of the cam curve groove mechanism.

[0131] The kinematic parameter index as the objective function can use the current pressure angle, curvature, and the vector norm of acceleration ‖α‖∞ , ‖ρ‖ ∞ , ‖a‖ ∞ , to express.

[0132] In summary, the objective function is:

[0133]

[0134] Next, this embodiment is verified:

[0135] According to Figure 1 the design defect identification and repair process, the design parameters of a certain aircraft cabin mechanism are shown in Table 1 below. When the cabin door is opened, the angle between the first active rod and the aircraft body in the translation section has an activity range of 0 - 20 degrees; in the tilting section, the maximum tilting angle of the first active rod with the aircraft body can reach 35 degrees; at the end of the door opening section, the aircraft cabin door can finally open outward so that the cabin door is parallel to the aircraft body.

[0136]

[0137] Table 1

[0138] According to the mathematical mapping model between the design parameters of the cabin door mechanism and the mapping model of the cam curve groove, the initial design model of the cam curve groove is obtained as Figure 6 shown.

[0139] Based on the fault tree analysis of the failure of the cam curve groove's motion function reliability, the main indicators affecting the motion function reliability of the cam curve groove are found to be the pressure angle, curvature, and acceleration. Establish a functional function between the design parameters and the main indicators of the motion function reliability of the aircraft cabin door mechanism, deduce the limit state equation, and complete the deterministic analysis.

[0140] Through the motion function reliability analysis of the limit state position, the deviation values of the main indicators required to meet the motion function reliability requirements when the cam curve groove mechanism is at the limit position are obtained, and the allowable values of the kinematic parameters based on the motion function reliability of the cabin door mechanism are calculated.

[0141] Then, based on the mapping model of the aircraft cabin door's motion function reliability, taking whether the kinematic parameter indicators meet the motion function reliability as the judgment condition, the points where the motion function reliability fails are identified within the global range of the initial design. The identification results are as Figure 7 shown.

[0142] According to the identification results, the points where the reliability of the motion function fails are mainly concentrated near the maximum tilting angle in the tilting section. Therefore, in the tilting section, taking the functional relationship between the main parameters and the output angle of the expected movement of the hatch as the independent variable, and the kinematic parameter index that meets the reliability of the motion function as the objective function, considering various constraints, an intelligent algorithm is used to obtain a function model that meets the design requirements under the expected motion conditions, and then the defects of the points where the reliability of the motion function fails in the tilting section are repaired. The final repair results are as Figure 8 shown.

[0143] Based on the final repair results, the comparison diagrams of the pressure angle, curvature, and acceleration of the tilting section before and after repair are as Figure 9 , Figure 10 and Figure 11 shown.

[0144] The above-described embodiments only represent the specific implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A method for identifying and repairing design defects in the motion function reliability of an aircraft cabin door mechanism, characterized in that It includes the following steps: Step 1: Establish a mapping model between the design parameters of the hatch mechanism and the cam curve groove. According to the motion states of each stage of the hatch, establish the mapping relationship between the main parameters among the relevant design parameters of the hatch mechanism, and complete the initial design of the cam curve groove; The specific content of Step 1 is as follows: Based on the schematic diagram of the design parameters of the hatch cam four-bar mechanism, use the complex vector method to obtain the mapping model between the theoretical contour line of the cam curve groove and the design parameters: E(x e ,y e ) = (l1, l2, l3, l4, l5, θ1, θ2, θ3, θ x , θ i ) where x e , y e are the coordinate values of the point E where the cam roller is located, l1 is the rod length of the first driving rod, l2 is the distance between the connection points of the first driving rod and the third driven rod on the hatch body, l3 is the distance between the hinge point of the third driven rod and the fourth driven rod and the connection point of the third driven rod on the hatch body, l4 is the rod length of the fourth driven rod, and l5 is the distance between the hinge point of the third driven rod and the fourth driven rod and the cam roller; θ1, θ2, θ3, θ x are the included angles between the rods, where θ1 corresponds to the included angle between l1 and l4, θ2 corresponds to the included angle between l3 and l1, θ3 corresponds to the supplementary angle of the included angle between l1 and l2, and θ x is the included angle between l1 and the horizontal line of the frame, and θ i is the indicated angle for achieving the expected movement of the hatch; Through the analysis of the mapping model, it can be seen that the angle between each rod is an important parameter affecting the coordinates of the theoretical contour line. If the angle θ between the first active rod and the horizontal line of the frame is x As the main design parameters, θ1, θ2, θ3 can be calculated through the four-bar relationship and the door's expected motion indication angle θ i At this time, the motion input and output of the cam curve slot mechanism can be described by the motion equation: C eq = (θ x , θ i ) According to the envelope theory of surface clusters, obtain the mapping model between the actual contour line of the cam curve groove and the design parameters: where X and Y are the coordinate values of the inner and outer envelopes of the cam roller at point E, is the derivative of the coordinate value of point E with respect to θ x and r is the roller radius. In the formula: Among them, The motion input and output motion equation C of the cam curve groove mechanism eq can be obtained by derivation. Therefore, both the theoretical contour line and the actual contour line of the hatch curve groove mechanism are determined by the motion equation C eq =(θ x ,θ i ); Step 2: Conduct a fault tree analysis on the failure of the motion function reliability of the cam curve groove, find the main indicators affecting the motion function reliability of the cam curve groove, establish a function between the design parameters and the main indicators of the motion function reliability of the aircraft hatch mechanism, derive the limit state equation, and complete the deterministic analysis; Step 3: Through the analysis of the motion function reliability at the limit state position, obtain the deviation values of the main indicators required to meet the motion function reliability requirements when the cam curve groove mechanism is at the limit position, and calculate the allowable values of the kinematic parameters based on the motion function reliability of the hatch mechanism; Step 4: Based on the mapping model of the motion function reliability of the aircraft hatch mechanism, taking whether the kinematic parameter indicators are met as the judgment condition, identify the points where the motion function reliability fails in the model globally, select the defective segments for repair, and after the defect repair is completed, substitute the optimized function model into the mapping model between the hatch mechanism design parameters and the cam curve groove, and output the repaired cam curve groove model.

2. The method for identifying and repairing the design defect of the motion function reliability of the aircraft cabin door mechanism according to claim 1, characterized in that, In Step 1, the parameters that can still be adjusted after the hatch mechanism is put into operation are identified as secondary parameters, and the indicator parameters for realizing the expected motion of the hatch are identified as main parameters.

3. The method for identifying and repairing the design defect of the motion function reliability of the aircraft cabin door mechanism according to claim 1 or 2, characterized in that, In Step 3, the numerical simulation analysis method is used for the analysis of the motion function reliability at the limit state position; the numerical simulation analysis method is the Monte Carlo numerical simulation method.

4. The method for identifying and repairing the design defect of the motion function reliability of the aircraft cabin door mechanism according to claim 3, characterized in that, In Step 4, the repair of the cam curve groove model specifically includes: Taking the functional relationship between the main parameters and the output angle of the expected hatch action as the independent variable, and the kinematic parameter indicators that meet the motion function reliability as the objective function, optimize the mapping model between the main parameters and the cam curve groove, and then repair the design defects of the cam curve groove of the cam four-bar mechanism.

5. The method for identifying and repairing the design defect of the motion function reliability of the aircraft cabin door mechanism according to claim 1 or 4, characterized in that The aircraft hatch mechanism includes a cam curve groove mechanism, a first driving rod, a hatch body, a third driven rod, a fourth driven rod, and a cam roller. One end of the first driving rod is hinged as a frame and is fixedly connected to the aircraft door shaft where the cam curve groove mechanism is located. The other end of the first driving rod is hinged to the hatch body. One end of the third driven rod is connected to the hatch body. The other end of the third driven rod is provided with the cam roller at the end. The cam roller is in contact with the cam curve groove. There is a hinge in the middle of the third driven rod to connect one end of the fourth driven rod. The other end of the fourth driven rod is hinged to the frame. The first driving rod, the third driven rod, the fourth driven rod, and the hatch body form a cam four-bar mechanism.

6. The method for identifying and repairing the design defect of the motion function reliability of the aircraft cabin door mechanism according to claim 1, characterized in that In step 2, according to the mapping model between the design parameters of the hatch mechanism and the cam curve groove, a function function of the main parameters and the motion function reliability of the aircraft hatch mechanism is established: Z = [Δα Δρ Δa] T Among them, Δα, Δρ, and Δa are three kinematic parameters affecting the motion function reliability of the hatch, that is, the output error vectors of the pressure angle, curvature, and acceleration. In the formula: Δα = α * -α Δρ = ρ * -ρ Δa = a * -a where α * , ρ * , a * are the allowable pressure angle, allowable curvature and allowable acceleration respectively, and α, ρ, a are the actual pressure angle, actual curvature and actual acceleration of the four-bar mechanism of the hatch cam respectively. In the formula:

7. The method for identifying and repairing the design defect of the motion function reliability of the aircraft cabin door mechanism according to claim 6, characterized in that, In step 2, according to the function function of the motion function reliability of the aircraft hatch mechanism and the design parameter mapping model of the cam curve groove mechanism, the limit value of the reliability index and the state and position of the mechanism in the limit state can be obtained; in step 3, the main reliability indexes of the aircraft hatch mechanism are respectively analyzed for reliability under the limit state. Assuming that there is a deviation value ε in the design parameters of the aircraft hatch under the premise of meeting the motion function reliability index, the reliability work function can be rewritten as: Z = [Z α Z ρ Z a T ​ Among them: Z α = α * -α - ε α Z ρ = ρ * -ρ - ε ρ Z a = a * -a - ε a The distribution of the function function is related to the design parameters, that is, it satisfies: z = g(x) = g(l1, l2, l3, l4, l5, θ1, θ2, θ3, θ x , θ i , ε) Then the limit state equation \(g(l_1, l_2, l_3, l_4, l_5, \theta_1, \theta_2, \theta_3, \theta\) x , \theta i , \varepsilon)=0 divides the design parameter variables of the mechanism into two parts: the failure region and the reliable region; then the failure domain of the motion functional reliability of the aircraft cabin door is: F = {x: g(x) ≤ 0} Motion function reliability failure domain indication function I F (x) can be expressed as: According to the distribution form and numerical value of the design parameters, and based on the Monte Carlo reliability analysis method, N groups of random vector samples are substituted into the limit state equation of the function function, and finally the estimated value of the failure probability can be obtained:

8. The method for identifying and repairing the design defect of the motion function reliability of the aircraft cabin door mechanism according to claim 7, characterized in that In step 4, the output parameters of the cam groove mapping model in the three stages of translation, tilting, and rotation of the hatch body are substituted into the mapping model between the main parameters and the motion function reliability of the aircraft hatch mechanism. Taking whether the kinematic parameter indexes are met as the judgment condition, the points where the motion function reliability fails are searched and identified globally, and are marked as the failure points of the motion function reliability.

9. The method for identifying and repairing the design defect of the motion function reliability of the aircraft cabin door mechanism according to claim 8, characterized in that, In step 4, the repair of the design defects in the motion function reliability design of the cam curve groove mechanism is as follows: Select the curve segment where the defect points are densely located in the design of the cam curve groove mechanism as the segment to be repaired, and extract the main design parameters at the beginning and end of the repair segment as part of the constraint conditions to achieve the original expected motion conditions; Taking the functional relationship between the main parameters and the expected action output angle of the hatch as the independent variable, and the kinematic parameter indexes that meet the motion function reliability as the objective function, considering various constraint conditions, an intelligent algorithm is used to obtain a function model that meets the design requirements under the expected motion conditions, and then the design defects existing in the design of the cam curve groove mechanism are repaired; The kinematic parameter index as the objective function can be expressed by the vector norms of the current pressure angle, curvature, and acceleration, ‖α‖ ∞ , ‖ρ‖ ∞ , ‖a‖ ∞ . Among them, the objective function is:

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