An aircraft cabin section docking method based on a six-degree-of-freedom parallel mechanism

Abstract

The application discloses a kind of based on six degrees of freedom parallel mechanism's aircraft cabin section butt joint method, comprising: S1: construct global assembly coordinate system, ground reference point is laid to specified position;S2: numerical control positioner is hoisted to specified work station;S3: fuselage shape frame is hoisted to specified work station;S4: middle and rear fuselage is connected with fuselage shape frame;S5: middle and rear fuselage pose is adjusted;S6: rear fuselage is connected with fuselage shape frame;S7: rear fuselage pose is adjusted;S8: by numerical control positioner, middle and rear fuselage is connected with rear fuselage;The application compact structure is stable, with good rigidity and carrying capacity, suitable for large, heavy fuselage cabin body butt joint work, process planning efficiency is high, reliable high strength.

Description

Technical Field

[0001] This invention relates to the field of aircraft fuselage docking methods, and in particular to an aircraft section docking method based on a six-degree-of-self parallel mechanism. Background Technology

[0002] The docking of aircraft fuselage sections (between the mid- and aft fuselage sections) is a crucial step in aircraft manufacturing and a key aspect of the overall aircraft assembly process. Stable and precise assembly ensures good connection and alignment between sections, reducing structural weaknesses and cracks, and improving aircraft structural safety. Traditional fuselage docking methods rely on worker experience, typically involving repeated adjustments to component positions via hoisting or other methods. This results in low assembly precision, poor coordination between workstations, and low work efficiency. Automated assembly docking allows for more accurate positioning, alignment, and docking of the fuselage, achieving standardization, accuracy, and efficiency in aircraft fuselage section docking.

[0003] Chinese patent application number 201510928666.8, entitled "A Six-Degree-of-Freedom Non-Redundant Driven Automatic Attitude Adjustment Mechanism for Airframes," discloses a non-redundant attitude adjustment device suitable for cylindrical airframes, capable of achieving six-degree-of-freedom adjustment within the airframe space. The patent employs a "3-2-1-0" drive method, resulting in only three supports in the direction of gravity during airframe docking, leading to relatively moderate stability.

[0004] Chinese patent application number 201911142948.X, entitled "A Variable Constraint Aircraft Component Attitude Adjustment and Docking Positioning Method," discloses a method to ensure the attitude continuity of aircraft components by changing the allocation of positioning constraints. However, under heavy load conditions, this method faces different attitude adjustment targets, resulting in an uneven distribution of driving force in the direction of gravity, thus limiting the load-bearing capacity of the docking mechanism.

[0005] It is evident that fuselage docking mechanisms based on discrete numerical control (CNC) positioners suffer from insufficient load-bearing capacity and uneven distribution of driving force in the direction of gravity when performing large fuselage docking operations. Therefore, providing a method for large fuselage docking that can solve these technical problems is a pressing technical issue that needs to be addressed by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide an aircraft segment docking method based on a six-degree-of-freedom parallel mechanism to solve the problems existing in the prior art and to achieve stable docking of large, heavy-load aircraft segments.

[0007] To achieve the above objectives, the present invention provides the following solution: The present invention provides a method for docking aircraft sections based on a six-degree-of-freedom parallel mechanism, comprising:

[0008] S1: Construct a global assembly coordinate system and place ground reference points at the specified locations;

[0009] S2: The CNC positioners that dock with the middle and rear fuselage and the rear fuselage are respectively hoisted to the designated work positions in the global assembly coordinate system, and installed, fastened and leveled.

[0010] S3: Hoist the fuselage conformal frame that is docked with the middle and rear fuselage and the rear fuselage to the designated work position in step S2, and connect and lock it with the CNC positioner through a ball joint connector;

[0011] S4: Connect the mid-rear fuselage to the fuselage conformal frame;

[0012] S5: Construct a mid-rear fuselage attitude adjustment measurement network, attach and lay multiple backlight target balls on the outer surface of the mid-rear fuselage, and adjust the attitude of the mid-rear fuselage through a laser tracker and the backlight target balls on the mid-rear fuselage.

[0013] S6: Connect the rear fuselage to the fuselage conformal frame;

[0014] S7: Construct a rear fuselage attitude adjustment measurement network, attach and lay multiple backlight target balls on the outer surface of the rear fuselage, and adjust the attitude of the rear fuselage through a laser tracker and the backlight target balls on the rear fuselage.

[0015] S8: Connect the middle and rear bodies to the rear body using a CNC positioner.

[0016] Furthermore, in step S1, the ground reference point is calibrated using the mean iteration method.

[0017] Furthermore, step S5 includes:

[0018] S501: Initial pose measurement stage, the position of each of the backlight target balls on the middle and rear fuselage is measured by a laser tracker to determine the initial pose of the middle and rear fuselage in the global assembly coordinate system;

[0019] S502: Target pose determination stage;

[0020] S503: Trajectory planning stage;

[0021] S504: Pose verification stage.

[0022] Furthermore, step S502 specifically includes the following steps: establishing a digital model in the global assembly coordinate system and confirming the target pose of the mid-rear fuselage in the global assembly coordinate system.

[0023] Furthermore, step S503 specifically includes the following steps: determining the motion trajectory of the mid-rear fuselage from the initial pose to the target pose based on the initial pose and the target pose, confirming the joint drive amount of the CNC positioner through inverse kinematics of the mechanism, calculating the driving force input amount corresponding to the joint drive amount of the CNC positioner through inverse dynamics, and outputting power to the fuselage conformal frame and the rear fuselage according to the motion trajectory and the driving force input amount to adjust the mid-rear fuselage from the initial pose to the target pose.

[0024] Furthermore, step S504 specifically includes the following steps: after step S503 is completed, the position of each of the backlight target balls on the middle and rear fuselage is measured by a laser tracker to determine the post-movement pose of the middle and rear fuselage in the global assembly coordinate system, and the post-movement pose is compared with the target pose to confirm whether the post-movement pose has reached the target pose.

[0025] Furthermore, step S7 includes:

[0026] S701: Initial pose measurement stage. In the initial pose measurement stage, the position of each of the backlight target balls on the rear fuselage is measured by a laser tracker to determine the initial pose of the rear fuselage in the global assembly coordinate system.

[0027] S702: Target pose measurement stage. In the target pose measurement stage, a digital model is established in the global assembly coordinate system to confirm the target pose of the rear fuselage in the global assembly coordinate system.

[0028] S703: In the trajectory planning stage, the motion trajectory of the rear fuselage from the initial pose to the target pose is determined based on the initial pose and the target pose. The joint drive amount of the CNC positioner is confirmed through inverse kinematics of the mechanism. The driving force input corresponding to the joint drive amount of the CNC positioner is calculated through inverse dynamics. The CNC positioner outputs power to the fuselage conformal frame and the rear fuselage according to the motion trajectory and the driving force input, so as to adjust the rear fuselage from the initial pose to the target pose.

[0029] S704: Pose verification stage. After step S703, the position of each of the backlight target balls on the rear fuselage is measured by the laser tracker to determine the post-movement pose of the rear fuselage in the global assembly coordinate system. The post-movement pose is compared with the target pose to confirm whether the post-movement pose has reached the target pose.

[0030] Furthermore, step S8 also includes step S801: pre-alignment stage of fuselage assembly. Using the middle and rear fuselage as the alignment reference, the rear fuselage is moved to a position 10mm away from the middle and rear fuselage in the X-axis direction by the CNC positioner. Check whether there is any interference between the skin of the middle and rear fuselage and the skin of the rear fuselage. If there is no interference, continue the alignment until the seam of the skin is 2±1mm, and complete the pre-alignment of fuselage assembly.

[0031] Furthermore, step S8 also includes step S802: fuselage hole making and deburring stage. After step S801 is completed, the CNC positioner corresponding to the rear fuselage is locked, and hole making is performed on the middle and rear fuselage and the cabin components of the rear fuselage. After the hole making is completed, the CNC positioner corresponding to the middle and rear fuselage is locked. The rear fuselage is moved 600-800mm away from the middle and rear fuselage along the X-axis by the CNC positioner and then locked. The burrs on the surface of the docking compartment of the middle and rear fuselage and the rear fuselage are removed and / or other uneven areas are leveled.

[0032] Furthermore, step S8 also includes step S803: assembly alignment and evaluation stage. The rear body is moved along the X-axis to a distance of 10mm from the middle and rear body by the CNC positioner. After confirming that there is no interference between the middle and rear body and the rear body, the rear body is reset to the position of the pre-alignment of the body assembly in step S801 and then the middle and rear body are docked. After docking, the position of each of the backlight target balls on the middle and rear body and the rear body is measured by the laser tracker to measure the assembly alignment accuracy.

[0033] The present invention discloses the following technical effects:

[0034] 1. The present invention has a compact and stable structure with good rigidity and load-bearing capacity, and is suitable for docking work of large and heavy-duty fuselage compartments. The process planning is efficient and highly reliable.

[0035] 2. This invention can solve the defects of mechanism singularity and limited load-bearing capacity caused by the lack of redundant drive; based on the initial pose and target pose combined with the mechanism's inverse kinematics and inverse dynamics, it can accurately control the driving force and movement trajectory required for the rear fuselage and rear fuselage adjustment process, ensuring the continuous and stable movement trajectory while realizing the coordinated distribution of the mechanism's driving force, thus improving the dynamic performance and load-bearing capacity of the docking mechanism.

[0036] 3. This invention is compatible with the assembly process requirements of fuselage sections of various aircraft models. The modular and standardized design allows the CNC positioner to be flexibly combined and configured according to the specific needs of the fuselage section, and it is easier to integrate with other equipment and systems. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the docking of the rear fuselage and the rear fuselage in this invention;

[0039] Among them, 1. CNC positioner; 2. Machine body conformal frame; 3. Ground reference point; 4. Middle and rear machine body; 5. Rear machine body. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] This invention provides a method for docking aircraft modules based on a six-degree-of-freedom parallel mechanism, comprising:

[0043] S1: Construct a global assembly coordinate system and place ground reference point 3 at the designated location. The global assembly coordinate system includes an X-axis, a Y-axis, and a Z-axis. The X-axis and Y-axis are located on the ground, the Z-axis is the vertical axis perpendicular to the ground, and the X-axis is the axis in which the middle and rear fuselage 4 and the rear fuselage 5 are docked. There is an error between the theoretical position of the reference point and the actual installation position. When using it for the first time, the reference point needs to be calibrated using the mean iteration method to improve the matching accuracy between the measurement coordinate system of the subsequent laser tracker measuring equipment and the global assembly coordinate system.

[0044] S2: The CNC positioners 1, which are connected to the middle and rear fuselage 4 and the rear fuselage 5, are hoisted to their designated positions in the global assembly coordinate system and installed, tightened, and leveled. The CNC positioners 1 are common fuselage support drive components (generally composed of a ball joint mounting base, force sensor, angle encoder, planar screw clamp, motor gear reducer, and other machined parts for installation). They are the power mechanism for fuselage posture adjustment. The CNC positioners 1 can output power along the X, Y, and Z axes and can be locked. In this embodiment, four CNC positioners 1 are installed below each of the middle and rear fuselage 4 and the rear fuselage 5. After the CNC positioners 1 are hoisted to their designated positions, frequent movement should be avoided. After installation, the CNC positioners 1 should be reset to adjust each joint within them to its initial position. Simultaneously, to prevent the subsequent installation of the fuselage conformer 2 from affecting the joint state of the CNC positioners 1, each CNC positioner 1 needs to be locked.

[0045] S3: The fuselage retainer 2, which docks with the mid-rear fuselage 4 and aft fuselage 5, is hoisted to the designated position in step S2 and connected and locked to the CNC positioner 1 via a ball joint connector. During the installation of the fuselage retainer 2, the ball joint connector is in a free-rotation mode. The pressure on the ball joint connector is guided by a linear bearing and transmitted to a force sensor. By detecting the sensor reading, it can be determined whether the fuselage retainer 2 and the ball joint connector are correctly connected. After connection, the ball joint connector is adjusted to the locking mode to fix the fuselage tooling retainer. The fuselage retainer consists of a retainer unit and a fuselage connecting pin manual adjustment unit. The retainer unit is mainly used to support the fuselage section and has reinforced panels designed in weak areas. Protective pads are used in the contact area with the fuselage to reduce the occurrence of cabin deformation. The fuselage connecting pin manual adjustment unit is located on the retainer platform and is mainly used to compensate for the positional error of the fuselage fixing pin holes during aircraft assembly.

[0046] S4: Connect the mid-rear fuselage 4 to the fuselage conformal frame 2;

[0047] S5: Construct a mid-rear fuselage 4 attitude adjustment measurement network, attach and lay multiple backlight target balls on the outer surface of the mid-rear fuselage 4, and adjust the attitude of the mid-rear fuselage 4 through a laser tracker and the backlight target balls on the mid-rear fuselage 4.

[0048] S501: In the initial pose measurement stage, the position of each reflective target ball on the mid-rear fuselage 4 is measured by the laser tracker to determine the initial pose of the mid-rear fuselage 4 in the global assembly coordinate system.

[0049] S502: Target pose determination stage; Establish a digital model in the global assembly coordinate system and confirm the target pose of the mid- and rear fuselage 4 in the global assembly coordinate system;

[0050] S503: Trajectory planning stage; Based on the initial and target poses, determine the motion trajectory of the mid-rear fuselage 4 from the initial pose to the target pose, and confirm the joint drive amount of the CNC positioner 1 through inverse kinematics. Calculate the driving force input corresponding to the joint drive amount of the CNC positioner 1 through inverse dynamics. The CNC positioner 1 outputs power to the fuselage conformal frame 2 and the rear fuselage 5 according to the motion trajectory and driving force input amount, adjusting the mid-rear fuselage 4 from the initial pose to the target pose. During the pose adjustment process, the ball joint connector needs to be locked and adjusted to an anti-escape rotation mode.

[0051] S504: Pose Verification Stage: After step S503, the position of each reflective target ball on the mid-rear fuselage 4 is measured by the laser tracker to determine the pose of the mid-rear fuselage 4 after movement in the global assembly coordinate system. The pose after movement is compared with the target pose to confirm whether the pose after movement has reached the target pose.

[0052] S6: Connect the rear fuselage 5 to the fuselage conformal frame 2;

[0053] S7: Construct an attitude adjustment measurement network for the rear fuselage 5, attach and lay multiple backlight target balls on the outer surface of the rear fuselage 5, and adjust the attitude of the rear fuselage 5 using a laser tracker and the backlight target balls on the rear fuselage 5.

[0054] S701: Initial pose measurement stage. The initial pose measurement stage uses a laser tracker to measure the position of each reflector target ball on the rear fuselage 5, thereby determining the initial pose of the rear fuselage 5 in the global assembly coordinate system.

[0055] S702: Target pose measurement stage. In the target pose measurement stage, a digital model is established in the global assembly coordinate system, and the target pose of the fuselage 5 in the global assembly coordinate system is confirmed.

[0056] S703: In the trajectory planning stage, the motion trajectory of the rear fuselage 5 from the initial pose to the target pose is determined based on the initial pose and the target pose. The joint drive quantity of the CNC positioner 1 is confirmed through inverse kinematics, and the driving force input corresponding to the joint drive quantity of the CNC positioner 1 is calculated through inverse dynamics. The CNC positioner 1 outputs power to the fuselage conformal frame 2 and the rear fuselage 5 according to the motion trajectory and driving force input, adjusting the rear fuselage 5 from the initial pose to the target pose. For the attitude adjustment process of the rear fuselage 5, in the redundant drive (partial CNC positioner 1...) In cases where the drive joints have no power output (these joints are called position-driven joints), the position-driven joints are selected from the four CNC positioners 1 corresponding to the rear fuselage 5 according to the "3-2-1-0" allocation method adopted in the background art application number 201510928666.8. The joints of the remaining CNC positioners 1 are force-driven joints. The control law of the position-driven joints is based on position error feedback. The driving force of the corresponding joint is affected by the force state of the entire docking mechanism, while the force-driven joints can actively adjust their own driving force input. The force-position hybrid drive method can ensure that the fuselage component docking system can continuously and stably complete the predetermined trajectory task while realizing the coordinated distribution of joint driving forces in the mechanism and optimizing the force state of the system.

[0057] S704: Pose verification stage. After step S703, the position of each reflective target ball on the rear fuselage 5 is measured by the laser tracker to determine the post-movement pose of the rear fuselage 5 in the global assembly coordinate system. The post-movement pose is compared with the target pose to confirm whether the post-movement pose has reached the target pose.

[0058] S8: Connect the middle and rear body 4 to the rear body 5 using the CNC positioner 1.

[0059] Step S801: Pre-alignment stage of fuselage assembly. Using the middle and rear fuselage 4 as the alignment reference, the rear fuselage 5 is moved to a position 10mm away from the middle and rear fuselage 4 in the X-axis direction by the CNC locator 1. Check whether there is any interference between the skin of the middle and rear fuselage 4 and the skin of the rear fuselage 5. If there is no interference, continue the alignment until the skin seam is 2±1mm, and the pre-alignment of fuselage assembly is completed.

[0060] Step S802: Hole making and deburring stage. After step S801, lock the CNC positioner 1 corresponding to the rear fuselage 5 and perform hole making on the cabin components of the middle and rear fuselage 4 and the rear fuselage 5. After the hole making is completed, lock the CNC positioner 1 corresponding to the middle and rear fuselage 4. Move the rear fuselage 5 600-800mm away from the middle and rear fuselage 4 along the X-axis using the CNC positioner 1 and lock it. Remove the burrs on the surface of the docking compartment of the middle and rear fuselage 4 and the rear fuselage 5 and / or level other uneven areas.

[0061] Step S803: Assembly alignment and evaluation stage. The rear body 5 is moved along the X-axis to a distance of 410mm from the middle rear body 4 using the CNC positioner 1. After confirming that there is no interference between the middle rear body 4 and the rear body 5, the rear body 5 is reset to the position of the pre-alignment of the body assembly in step S801. Then, the middle rear body 4 and the rear body 5 are docked. After docking, the position of each reflector target ball on the middle rear body 4 and the rear body 5 is measured by the laser tracker to measure the assembly alignment accuracy.

[0062] In this embodiment, the dynamic model for calculating the driving force of each mechanism is as follows:

[0063] 1. Dynamic model of CNC positioner

[0064] There are four CNC positioners 1 corresponding to the middle and rear fuselage 4, which are distinguished by the i-th (i=1,2,3,4) positioner 1. The four CNC positioners 1 can translate along the X-axis, Y-axis and Z-axis in the global assembly coordinate system. The mass of the bottom tray and its internal components is m1, the mass of the upper tray and its internal components is m2, and the mass of the telescopic column is m3.

[0065] In the redundant drive scenario, the four CNC positioners 1 have identical constructions, and the mass information of each part of the CNC positioner 1 is consistent with that in the non-redundant drive scenario. Based on the working principle and structural characteristics of the CNC positioner 1, and ignoring friction and external interference, the dynamic equation of a single positioner is:

[0066]

[0067] In the formula, M = diag[m1 + m2 + m3, m2 + m3, m3], and the driving force vector composed of the driving forces in the three joint directions of the CNC positioner 1 is F. i =[F ix ,F iy ,F iz ] T F i Let F1 be the driving force in the three joint directions of the i-th CNC positioner 1. Since the first CNC positioner 1 has driving forces in all three directions, the second CNC positioner 1 has driving forces in the xy direction, the third CNC positioner 1 only experiences driving forces in the z direction, and the fourth CNC positioner 1 has zero driving forces in all three directions as each joint is a follower, we have F1 = [F 1x ,F 1y ,F 1z ] T F2 = [F 2x ,0,F 2z ] T F3 = [0,0,F 3z ] T F4 = [0,0,0] T Fi q Let be the force exerted by the i-th CNC positioner 1 on the machine body conformal frame 2 under the global system, and It is the acceleration of the i-th CNC positioner 1 at the origin of the coordinate system.

[0068] 2. Dynamic model of the fuselage conformal frame

[0069] Let F i q Let m be the force exerted by the i-th CNC positioner 1 on the aft fuselage 5 under the global system, considering only the weight of the fuselage section itself during its movement. c The acceleration, angular velocity, and angular acceleration vectors are respectively

[0070] According to Euler's equations and Newton's second law, the dynamic equations of the fuselage and fuselage conformal in the global frame can be expressed as follows:

[0071]

[0072] In the formula, g is the gravitational acceleration vector, and I c It is the inertia matrix of the fuselage and fuselage conformal 2 relative to the global frame. Let I be the rotation transformation matrix of the cabin system relative to the global system. b It is the inertia matrix of the fuselage and fuselage conformal frame 2 relative to the cabin system.

[0073] 3. Dynamic model of the docking system

[0074] The fuselage docking system consists of four CNC positioners 1, a fuselage conformal frame 2, and a rear fuselage 5. The attitude adjustment and docking process of the fuselage sections is completed by coordinating and controlling the joint movements of the CNC positioners 1. Combining (1) and (2), the dynamic model of the system can be obtained:

[0075] JF = H 3)

[0076] In the formula,

[0077]

[0078]

[0079]

[0080] In the formula, H is a non-square matrix, the vector F consists of 12 force components, and the number of dynamic equations established is 6. Therefore, the positioner has countless combinations of driving forces, and the forces can be optimized according to a certain goal to obtain a unique driving force solution.

[0081] 4. Drive force optimization

[0082] Because the rear fuselage attitude adjustment mechanism is a redundant 4-PPPS parallel mechanism under redundant drive conditions, the number of drives exceeds its number of degrees of freedom. This means that the attitude adjustment mechanism has countless combinations of driving forces in each motion state. Therefore, it is necessary to optimize the driving forces, and the method of minimizing the L2 norm of the forces is used to optimize the driving forces.

[0083] The force optimization control problem is to solve for the force F under the premise of satisfying the equality constraint JF=H, so that the objective function Z=F T WF is minimized. This can be expressed by the following equation:

[0084]

[0085] Where W is the locator weight, construct the Lagrange function.

[0086] L(F,λ)=F T WF+λ T (JF-H) 5)

[0087] The optimization problem is transformed into a problem of finding conditional extrema using the Lagrange multiplier method, where λ = {λ1, λ2, ..., λ6}. T ∈R 6×1 Given the Lagrange multipliers, take the partial derivatives of equation (5) with respect to F and λ respectively.

[0088]

[0089]

[0090] In the formula, I is the identity matrix. For the function L(F,λ) to have a local minimum, it must satisfy the above two necessary conditions. By simplifying equation (5), we can obtain

[0091]

[0092] Substituting the above equation into equation (6), we can obtain

[0093] λ=-2(JW -1 J T ) -1 H (9)

[0094] Substituting the above equation into equation (8), we get:

[0095] F = W -1 J T (JW -1 J T ) -1 H 10)

[0096] If W is taken as the identity matrix, then the objective function becomes Z = F.T F, that is, the optimization objective is to minimize the L2 norm of the driving force of each joint of the CNC positioner 1, and the driving force is obtained as follows:

[0097] F = J T (JJ T ) -1 H 11)

[0098] This invention provides an aircraft compartment docking method based on a six-degree-of-freedom parallel mechanism. The method features a compact and stable structure with good rigidity and load-bearing capacity, making it suitable for docking large, heavy-duty fuselage compartments. It offers high efficiency and reliability in process planning. It addresses the shortcomings of mechanisms lacking redundant drive, such as singularity and limited load-bearing capacity. By combining initial and target poses with inverse kinematics and inverse dynamics, it precisely controls the driving force and trajectory required for the adjustment process of the aft fuselage 4 and 5, ensuring continuous and stable motion trajectories while achieving coordinated distribution of driving forces, thus improving the dynamic performance and load-bearing capacity of the docking mechanism. It is compatible with the assembly process requirements of various aircraft types. The modular and standardized design allows the CNC positioner 1 to be flexibly combined and configured according to specific fuselage compartment needs, and facilitates integration with other equipment and systems.

[0099] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0100] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for docking of aircraft cabin sections based on a six-degree-of-freedom parallel mechanism, characterized in that, include: S1: Construct a global assembly coordinate system and place the ground reference point (3) at the specified location; S2: The CNC positioners (1) that are docked with the middle and rear fuselage (4) and the rear fuselage (5) are respectively hoisted to the designated work positions in the global assembly coordinate system and installed, tightened and leveled. S3: The body conformal frame (2) that docks with the middle and rear fuselage (4) and the rear fuselage (5) is hoisted to the designated work position in step S2 and connected and locked with the CNC positioner (1) through a ball joint connector; S4: Connect the mid-rear fuselage (4) to the fuselage conformal frame (2); S5: Construct a mid-rear fuselage (4) attitude measurement network, attach and lay multiple backlight target balls on the outer surface of the mid-rear fuselage (4), and adjust the attitude of the mid-rear fuselage (4) through a laser tracker and the backlight target balls on the mid-rear fuselage (4); S6: Connect the rear fuselage (5) to the fuselage conformal frame (2); S7: Construct a rear fuselage (5) attitude measurement network, attach and lay multiple backlight target balls on the outer surface of the rear fuselage (5), and adjust the attitude of the rear fuselage (5) through a laser tracker and the backlight target balls on the rear fuselage (5); S8: Connect the middle and rear body (4) to the rear body (5) using the CNC positioner (1); Step S7 includes: S701: Initial pose measurement stage. The initial pose measurement stage uses a laser tracker to measure the position of each of the backlight target balls on the rear fuselage (5) and thus determine the initial pose of the rear fuselage (5) in the global assembly coordinate system. S702: Target pose measurement stage. During the target pose measurement stage, a digital model is established in the global assembly coordinate system to confirm the target pose of the rear fuselage (5) in the global assembly coordinate system. S703: In the trajectory planning stage, the motion trajectory of the rear fuselage (5) from the initial pose to the target pose is determined according to the initial pose and the target pose. The joint drive amount of the CNC positioner (1) is confirmed by the inverse kinematics of the mechanism. The driving force input corresponding to the joint drive amount of the CNC positioner (1) is calculated by inverse dynamics. The CNC positioner (1) outputs power to the fuselage conformal frame (2) and the rear fuselage (5) according to the motion trajectory and the driving force input amount, and adjusts the rear fuselage (5) from the initial pose to the target pose. S704: Pose verification stage. After step S703, the position of each of the backlight target balls on the rear fuselage (5) is measured by the laser tracker to determine the post-movement pose of the rear fuselage (5) in the global assembly coordinate system. The post-movement pose is compared with the target pose to confirm whether the post-movement pose has reached the target pose. Step S8 further includes: S801: In the pre-alignment stage of fuselage assembly, the middle and rear fuselage (4) is used as the alignment reference. The rear fuselage (5) is moved to a position 10mm away from the middle and rear fuselage (4) in the X-axis direction by the CNC positioner (1). Check whether the skin of the middle and rear fuselage (4) and the skin of the rear fuselage (5) interfere. If there is no interference, continue the alignment until the skin seam is 2±1mm, and the pre-alignment of fuselage assembly is completed. S802: The stage of drilling and deburring the fuselage. After step S801, the CNC positioner (1) corresponding to the rear fuselage (5) is locked, and the cabin components of the middle and rear fuselage (4) and the rear fuselage (5) are drilled. After the drilling is completed, the CNC positioner (1) corresponding to the middle and rear fuselage (4) is locked. The rear fuselage (5) is moved 600-800mm away from the middle and rear fuselage (4) along the X-axis by the CNC positioner (1) and then locked. The burrs on the docking section surface of the middle and rear fuselage (4) and the rear fuselage (5) are removed and / or other uneven areas are leveled. S803: Assembly alignment and evaluation stage. The rear body (5) is moved along the X-axis to a distance of 10mm from the middle and rear body (4) by the CNC locator (1). After confirming that there is no interference between the middle and rear body (4) and the rear body (5), the rear body (5) is reset to the position of the pre-alignment of the body assembly in step S801 and then the middle and rear body (4) and the rear body (5) are docked. After docking, the position of each of the backlight target balls on the middle and rear body (4) and the rear body (5) is measured by the laser tracker to measure the assembly alignment accuracy.

2. The aircraft bay docking method based on a six-degree-of-freedom parallel mechanism according to claim 1, characterized in that, In step S1, the ground reference point (3) is calibrated using the mean iteration method.

3. The aircraft bay docking method based on a six-degree-of-freedom parallel mechanism according to claim 1, characterized in that, Step S5 includes: S501: In the initial pose measurement stage, the position of each of the backlight target balls on the middle and rear fuselage (4) is measured by the laser tracker to determine the initial pose of the middle and rear fuselage (4) in the global assembly coordinate system; S502: Target pose determination stage; S503: Trajectory planning stage; S504: Pose verification stage.

4. The aircraft bay docking method based on a six-degree-of-freedom parallel mechanism according to claim 3, characterized in that, Step S502 specifically includes the following steps: A digital model is established in the global assembly coordinate system to confirm the target pose of the mid-rear fuselage (4) in the global assembly coordinate system.

5. The aircraft bay docking method based on a six-degree-of-freedom parallel mechanism according to claim 4, characterized in that, The specific steps of step S503 include the following steps: determining the motion trajectory of the middle and rear fuselage (4) from the initial pose to the target pose based on the initial pose and the target pose, confirming the joint drive amount of the CNC positioner (1) through inverse kinematics, calculating the driving force input amount corresponding to the joint drive amount of the CNC positioner (1) through inverse dynamics, and outputting power to the fuselage conformal frame (2) and the rear fuselage (5) according to the motion trajectory and the driving force input amount, thereby adjusting the middle and rear fuselage (4) from the initial pose to the target pose.

6. The aircraft bay docking method based on a six-degree-of-freedom parallel mechanism according to claim 5, characterized in that, The step S504 specifically includes the following steps: After step S503 is completed, the position of each of the backlight target balls on the middle and rear fuselage (4) is measured by the laser tracker to determine the post-movement pose of the middle and rear fuselage (4) in the global assembly coordinate system. The post-movement pose is compared with the target pose to confirm whether the post-movement pose has reached the target pose.

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