Posture adjusting mechanism position control axis optimization method based on target point error sensitivity index

Abstract

The invention provides a target point error sensitivity index-based attitude adjustment mechanism position control axis optimization method, which specifically comprises the following steps of: firstly, deducing an attitude deviation equation of an aircraft large component according to a coordinate system conversion principle; thirdly, constructing a mapping relation between the motion error of the positioner and the pose deviation of the large component, so as to determine Jacobian vectors corresponding to all axes of the positioner, and obtaining a transfer matrix between the motion error of the positioner and the positioning error of the large component of the aircraft in combination with the spatial position deviation of the target point; and finally, optimizing the combination of the position control shafts according to the maximum singular value of the positioning error transfer matrix of the large part of the aircraft. According to the method, the weighted deviation of the target point is taken as an optimization target, and the position control axis combination is optimized in real time based on the positioning error transfer matrix of the large aircraft component, so that the positioning precision of the large aircraft component is improved.

Description

Technical Field

[0001] This invention relates to the field of attitude control for large aircraft components, and more particularly to a method for optimizing the position control axis of an attitude adjustment mechanism based on a target point error sensitivity index. Background Technology

[0002] In digital docking systems for large aircraft components, redundant drive parallel mechanisms composed of multiple CNC positioners are typically used as actuators to adjust the spatial attitude of these components. However, the number of drive axes in a redundant drive attitude adjustment mechanism exceeds the number of degrees of freedom. If each axis of the positioner is controlled by position control, interference between positioners may occur, easily leading to deformation of the large aircraft component or damage to the positioners. Therefore, only some axes of the attitude adjustment mechanism can be controlled by position control, while other axes require force servo control. However, the motion performance of the attitude adjustment mechanism varies under different combinations of position control axes. An unreasonable combination of position control axes may not only increase the positioning error of the large aircraft component but may even cause the attitude adjustment mechanism to be in a singular configuration, resulting in loss of control. Traditional control methods for redundant drive attitude adjustment mechanisms describe the motion performance of the mechanism based on the condition number of the mechanism's Jacobian matrix; the smaller the Jacobian condition number, the higher the motion accuracy of the mechanism. However, the positioning error of large aircraft components is usually characterized by the deviation of the target point, and the positioning error of the attitude adjustment mechanism itself cannot accurately represent the positioning accuracy of the large aircraft component. Therefore, this invention proposes a method for optimizing the position control axis of the attitude adjustment mechanism based on the target point error sensitivity index, thereby improving the positioning accuracy of large aircraft components. Summary of the Invention

[0003] To address the problems mentioned in the background section, this invention provides a method for optimizing the position control axis of an attitude adjustment mechanism based on a target point error sensitivity index. The specific steps of this technical solution are as follows: Step 1: Derive the attitude deviation equations for major aircraft components based on the coordinate system transformation principle; Step 2: Establish the transfer matrix between the motion error of the attitude adjustment mechanism's position control axis and the positioning error of the aircraft's major components; Step 3: Optimize the combination of position control axes based on the transfer matrix of the positioning error of the major aircraft components.

[0004] As an improvement, in step one, the aircraft large component attitude adjustment system mainly includes a CNC positioner, a ball joint, and the aircraft large component; the CNC positioner is used to support and adjust the attitude of the aircraft large component and has three degrees of freedom (X / Y / Z); the ball joint consists of a ball head and a ball socket, and the CNC positioner is connected to the aircraft large component through the ball joint, forming a redundant drive parallel mechanism; the aircraft large component is equipped with... n Target points and By measuring the positional deviation of these target points in the global coordinate system, the positioning error of large aircraft components can be characterized.

[0005] As an improvement, three CNC positioners are provided, with one CNC positioner corresponding to one ball joint.

[0006] As an improvement, in step one, the coordinate system constructed includes a global coordinate system and local coordinate systems for major aircraft components. Specifically, the global coordinate system... It is the reference coordinate system within the entire assembly space; the Z-axis of the global coordinate system is perpendicular to the horizontal plane; the local coordinate system of large aircraft components. It is a coordinate system fixed to the aircraft's main components, which adjusts as the main components move, representing the spatial position and attitude of the main components.

[0007] As an improvement, the derivation process of the attitude deviation equations for major aircraft components in step one includes: (1.1) Let P be any point on the large aircraft component, and let the coordinates of this point in the local coordinate system of the large aircraft component be... The coordinates in the global coordinate system are Based on the principle of coordinate system transformation, the following equation is obtained. (1) in, This represents the attitude matrix of a large aircraft component relative to the global coordinate system. Let be the position vector of a large aircraft component relative to the global coordinate system, and its expressions are as follows: (2) (3) In formula (1) Let be the attitude angle of the large aircraft component relative to the global coordinate system, in equation (3) These are the position coordinates of major aircraft components relative to the global coordinate system.

[0008] (1.2) According to formula (1), the error of point P in the global coordinate system is expressed as: (4) in, , It is the attitude error matrix of the large component. It is the position error vector of the large component.

[0009] (1.3) Let the attitude angle error of the major components of the aircraft be... The actual attitude matrix of the large component is The attitude angle deviation matrix of the large component relative to the theoretical attitude is: Then there is (5) According to formula (2), when Approaching infinity, there is (6) Therefore, the attitude error matrix of the large component is expressed as: (7) (1.4) Substituting the above formula into formula (4), we obtain the position error of point P on the large component with respect to the pose deviation. The equation is (8) in, This refers to the pose deviation of large components. is the unit direction vector of the base coordinate system.

[0010] As an improvement, step two involves establishing the transfer matrix between the motion error of the attitude adjustment mechanism's position control axis and the positioning error of major aircraft components, including: (2.1) Ball hinge j The center is the common point of the aircraft's major components and the locator, and a ball joint is provided. j The coordinates of the center in the local coordinate system of the large component are The coordinates in the global coordinate system are According to the principle of rigid body rotation, and Satisfy equation (9).

[0011] (9) (2.2) Setting positioner j The motion errors of the X-axis, Y-axis, and Z-axis are respectively According to formula (8) the locator j Motion error and pose deviation of large components The mapping relationship between them is expressed as (10) in, (11) They represent the positioners respectively j The Jacobian vectors corresponding to the X / Y / Z axes.

[0012] (2.3) To achieve six degrees of freedom attitude control for the large aircraft components and prevent interference between the drive axes of the attitude adjustment mechanism, six axes from the nine axes of the attitude adjustment mechanism are selected as position control axes, and the remaining axes use force servo control to release the attitude adjustment internal force. Since the Z-axis of the positioner needs to bear the weight of the large component, to maintain the stability of the control system, the Z-axis of three positioners are determined as position control axes. Let... This is a vector consisting of the motion errors of the position control axes of the attitude adjustment mechanism. The Jacobian matrix corresponding to the six position control axes of the attitude adjustment mechanism is given by formula (10). (12) when When reversible, ;when When it is irreversible, There is no solution; in this case, the attitude adjustment mechanism will be in a singular configuration. When always selecting a position control axis, the Jacobian matrix of the position control axis should be guaranteed. Reversible.

[0013] (2.4) Let the coordinates of the target point on the large component of the aircraft in the local coordinate system be... The error in the global coordinate system is According to formula (8), the mapping equation between the spatial position error of the target point and the attitude deviation of the large components of the aircraft is obtained. (13) in, (14) (2.5) Assume that large components of the aircraft are equipped with n Target points, target points i The error weights are Then the positioning error of the large components of the aircraft can be expressed as: (15) in, , Let be the Jacobian matrix for the measurement point.

[0014] (2.6) Combining formulas (12) and (15), we can obtain the motion error of the position control axis of the attitude adjustment mechanism. Positioning error of major aircraft components transfer matrix E .

[0015] (16) in, .

[0016] As an improvement, in step three, the transfer matrix of the positioning error of the large aircraft components is used. E The process of optimizing the position control axis combination includes: (3.1) From formulas (11) and (16), we can find the aircraft major component positioning error transfer matrix corresponding to different position control axis combinations. E They are different, let the first... k The positioning error transfer matrix of the major aircraft components corresponding to the various position control axis combinations is as follows: The motion error of the position control axis of the attitude adjustment mechanism is , can obtain the first k The equation for the propagation of positioning error of large aircraft components under a combination of position control axes.

[0017] (17) (3.2) Taking the 2-norm on both sides of the equation, according to the properties of the norm, we have (18) in The larger the value, the larger the upper bound of the positioning error of large aircraft components. This is to reduce the random error of the positioner. Positioning error of large aircraft components The influence of this on the positioning error transfer matrix of large aircraft components The L2 norm is chosen to be a small value. Considering that the positioning error of large aircraft components is characterized by the weighted error of target points, this invention uses a matrix... The L2 norm is considered to be the sensitivity index of target point error to position control axis motion error.

[0018] (3.3) The 2-norm of a matrix is ​​equal to the largest singular value of the matrix. Singular value decomposition has (19) in, It is a 9th order orthogonal matrix. It is a 9th order orthogonal matrix. for (20) Arranged in descending order, according to the properties of matrix condition numbers, we have .

[0019] (3.4) The error transfer matrix is ​​obtained from equation (16) when the attitude of the large components of the aircraft is adjusted. It is constantly changing. In this invention, when performing attitude control, the Z-axis of the three positioners is first selected as the position control axis, and then the Jacobian matrix that causes the position control axis is eliminated. Irreversible position control axis combination, based on the positioning error transfer matrix The L2 norm is used to correct the position control axis assembly in a timely manner, thereby improving the positioning accuracy of large aircraft components.

[0020] Beneficial effects: The present invention provides a method for optimizing the position control axis of the attitude adjustment mechanism based on the target point error sensitivity index, including: First, deriving the attitude deviation equation of the large aircraft component according to the coordinate system transformation principle; then, constructing the mapping relationship between the motion error of the locator and the attitude deviation of the large component, thereby determining the Jacobian vector corresponding to each axis of the locator, and combining the spatial position deviation of the target point to obtain the transfer matrix between the motion error of the locator and the positioning error of the large aircraft component; finally, obtaining the optimal combination of position control axes based on the maximum singular value of the transfer matrix of the positioning error of the large aircraft component. Compared with the prior art, the optimization method of the present invention has the following advantages: (6) (1) The present invention abandons the traditional position control axis optimization idea based on the condition number of the mechanism Jacobian matrix, and directly uses the weighted deviation of the target point on the large aircraft component as the optimization target, effectively improving the final assembly positioning accuracy of the large aircraft component; (2) The present invention optimizes the combination of position control axes based on the positioning error transmission matrix of large aircraft components. According to the transmission law and change trend of error during attitude adjustment, the combination of position control axes is dynamically adjusted so that the large aircraft components maintain the best positioning accuracy throughout the attitude adjustment process, rather than achieving optimal performance only in a single state. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the preferred method for position control axis according to the present invention.

[0022] Figure 2 This is a schematic diagram of the composition of the aircraft large component attitude adjustment system in this invention.

[0023] Figure 3 This is a schematic diagram of the CNC positioner in this invention.

[0024] Figure 4 This is a schematic diagram of the experimental apparatus of the present invention. Figure 5 This is a schematic diagram of the average deviation of target points 1 to 6 in this invention. In the diagram: Target point 1, Aircraft major component 2, First ball joint 3, First CNC positioner 4, Second ball joint 5, Second CNC positioner 6, Third ball joint 7, Third CNC positioner 8, First ball head 9, First ball socket 10. Detailed Implementation

[0025] 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.

[0026] The aircraft large component attitude adjustment system involved in this invention includes a CNC positioner, a ball joint, measurement target points, and the aircraft large component. The CNC positioner is used to support and adjust the attitude of the aircraft large component and has three degrees of freedom: X, Y, and Z. The ball joint consists of a ball head and a ball socket, and the CNC positioner is connected to the aircraft large component through the ball joint. The target points are arranged on the aircraft large component, and are generally designed to be no less than four. By measuring the positional deviation of these target points in the global coordinate system, the positioning error of the aircraft large component can be characterized.

[0027] See Figure 1 The following is an example of the implementation process of the present invention.

[0028] See Figure 2 As shown in the figure, as a specific embodiment of the present invention, the aircraft large component attitude adjustment system involved in the present invention includes three CNC positioners, three ball joints and an aircraft large component, specifically a target point 1, an aircraft large component 2, a first ball joint 3, a first CNC positioner 4, a second ball joint 5, a second CNC positioner 6, a third ball joint 7, a third CNC positioner 8, a first ball head 9, and a first ball socket 10, wherein each CNC positioner corresponds to a ball joint.

[0029] See Figure 3 As shown, the first ball joint 1 includes a first ball head 11 and a first ball socket 12.

[0030] Please see Figure 1 The preferred method for position control axis of the attitude adjustment mechanism based on the target point error sensitivity index of the present invention includes: Step 1: Derive the attitude deviation equations for major aircraft components based on the coordinate system transformation principle.

[0031] (1.1) Let P be any point on the large aircraft component, and let the coordinates of this point in the local coordinate system of the large aircraft component be... The coordinates in the global coordinate system are Based on the principle of coordinate system transformation, the following formula can be obtained. (1) in, This represents the attitude matrix of a large aircraft component relative to the global coordinate system. Let be the position vector of a large aircraft component relative to the global coordinate system, and its expressions are as follows.

[0032] (2) (3) In formula (1) Let be the attitude angle of the large aircraft component relative to the global coordinate system, in equation (3) These are the position coordinates of major aircraft components relative to the global coordinate system.

[0033] (1.2) According to formula (1), the error of point P in the global coordinate system can be expressed as: (4) in, , It is the attitude error matrix of the large component. It is the position error vector of the large component.

[0034] (1.3) Let the attitude angle error of the major components of the aircraft be... The actual attitude matrix of the large component is The attitude angle deviation matrix of the large component relative to the theoretical attitude is: Then there is (5) According to formula (2), when Approaching infinity, there is (6) Therefore, the attitude error matrix of the large component can be expressed as: (7) (1.4) Substituting the above formula into formula (4), we obtain the position error of point P on the large component with respect to the pose deviation. The equation is (8) in, This refers to the pose deviation of large components. is the unit direction vector of the base coordinate system.

[0035] Step 2: Establish the transfer matrix between the motion error of the attitude adjustment mechanism's position control axis and the positioning error of the aircraft's major components.

[0036] (2.1) Ball hinge j The center is the common point of the aircraft's major components and the locator, and a ball joint is provided. j The coordinates of the center in the local coordinate system of the large component are The coordinates in the global coordinate system are According to the principle of rigid body rotation, and Satisfy equation (9).

[0037] (9) (2.2) Setting positioner j The motion errors of the X-axis, Y-axis, and Z-axis are respectively According to formula (8) the locator j Motion error and pose deviation of large components The mapping relationship between them can be represented as (10) in, (11) , and They represent the positioners respectively j The Jacobian vectors corresponding to the X / Y / Z axes.

[0038] (2.3) To achieve six degrees of freedom attitude control for the large aircraft components and prevent interference between the drive axes of the attitude adjustment mechanism, six axes need to be selected from the nine axes of the attitude adjustment mechanism as position control axes, and the remaining axes use force servo control to release the attitude adjustment internal force. Since the Z-axis of the positioner needs to bear the weight of the large component, to maintain the stability of the control system, the Z-axis of three positioners can be determined as position control axes. Let... This is a vector consisting of the motion errors of the position control axes of the attitude adjustment mechanism. The Jacobian matrix corresponding to the six position control axes of the attitude adjustment mechanism is given by formula (10). (12) when When reversible, ;when When it is irreversible, There is no solution; the attitude adjustment mechanism will be in a singular configuration at this point. Therefore, when selecting the position control axis, the Jacobian matrix of the position control axis should be ensured. Reversible.

[0039] (2.4) Let the coordinates of the target point on the large component of the aircraft in the local coordinate system be... The error in the global coordinate system is According to formula (8), the mapping equation between the spatial position deviation of the target point and the attitude deviation of the large components of the aircraft can be obtained. (13) in, (14) (2.5) Assume that large components of the aircraft are equipped with n Target points, target points i The error weights are Then the positioning error of the large components of the aircraft can be expressed as: (15) in, , .

[0040] (2.6) Combining formulas (12) and (15), we can obtain the motion error of the position control axis of the attitude adjustment mechanism. Positioning error of major aircraft components transfer matrix E (16) in, .

[0041] Step 3: Based on the transfer matrix of the positioning error of major aircraft components E Optimize the position control axis combination.

[0042] (3.1) From formulas (11) and (16), we can find the aircraft major component positioning error transfer matrix corresponding to different position control axis combinations. E They are different, let the first... k The positioning error transfer matrix of the major aircraft components corresponding to the various position control axis combinations is as follows: The motion error of the position control axis of the attitude adjustment mechanism is , can obtain the first k The equation for the propagation of positioning error of large aircraft components under a combination of position control axes.

[0043] (17) (3.2) Taking the 2-norm on both sides of the equation, according to the properties of the norm, we have (18) The conclusion is The larger the value, the larger the upper bound of the positioning error of large aircraft components. This is to reduce the random error of the positioner. Positioning error of large aircraft components Due to the influence of this, the present invention selects the aircraft large component positioning error transfer matrix. The L2 norm is a relatively small value. Considering that the positioning error of large aircraft components is characterized by the weighted error of target points, this invention uses a matrix... Let the L2 norm be the sensitivity index of the target point error to the position control axis motion error.

[0044] (3.3) The 2-norm of a matrix is ​​equal to the largest singular value of the matrix. Singular value decomposition has (19) in, It is a 9th order orthogonal matrix. It is a 9th order orthogonal matrix. for (20) Arranged in descending order, according to the properties of matrix condition numbers, we have .

[0045] (3.4) From equation (16), it can be found that when the attitude of large components of the aircraft is adjusted, the error transfer matrix It is constantly changing.

[0046] In the attitude control process of this invention, the Z-axis of the three positioners is first selected as the position control axis, and then the Jacobian matrix that causes the position control axis is eliminated. Irreversible position control axis combination, based on the positioning error transfer matrix The L2 norm is used to correct the position control axis assembly in a timely manner, thereby improving the positioning accuracy of large aircraft components. Example 1

[0047] Given that the coordinates of the ball joint center in the local coordinate system of the aircraft's major components are as follows: , , Six target points are set on the major aircraft component (wing). The coordinates of the six target points in the local coordinate system of the major aircraft component are shown in Table 1. The experimental setup is as follows: Figure 4 As shown, two sets of comparative experiments were designed. The control group determined the combination of position control axes based on the initial Jacobian matrix condition number of the position control axes. The experimental group used the position control axis optimization method based on the target point error sensitivity index proposed in this invention to optimize and adjust the combination of position control axes in real time. Each experiment was repeated 8 times. The initial pose and target pose of the major components of the aircraft in each experiment are shown in Table 2. To facilitate the representation of the combination of position control axes, the X / Y / Z axes of locators one to three are numbered as axes X1, Y1, Z1, X2, Y2, Z2, X3, Y3, and Z3, respectively. The combination of position control axes during the attitude adjustment process is shown in Table 3.

[0048] Table 1. Coordinates of the target point in the local coordinate system of the large component.

[0049] Table 2 Initial pose and target pose of the component

[0050] Table 3. Combinations of position control axes during attitude adjustment of major aircraft components

[0051] After the experiment, a laser tracker was used to measure the target points on the aircraft components, and the spatial coordinate error of the target points was calculated by comparing the measurements with the theoretical coordinates of the target points. The average deviation from target point 1 to target point 6 is as follows: Figure 5As shown, it can be observed that determining the combination of position control axes based on the initial Jacobian matrix condition number of the position control axes results in an average coordinate error of 0.39 mm for the target point after attitude adjustment of the aircraft's large components. Furthermore, using the position control axis optimization method based on the target point error sensitivity index proposed in this invention to optimize and adjust the combination of position control axes in real time, the average coordinate error of the target point after attitude adjustment of the aircraft's large components is 0.28 mm. Moreover, the positioning errors of the experimental groups in all eight experiments were shorter than those of the control group, demonstrating that the position control axis optimization method based on the target point error sensitivity index proposed in this invention can effectively improve the positioning accuracy of aircraft's large components.

[0052] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for optimizing the position control axis of an attitude adjustment mechanism based on a target point error sensitivity index, characterized in that, Includes the following steps: S1: Derive the attitude deviation equations of major aircraft components based on the coordinate system transformation principle; S2: Establish the transfer matrix between the positioner motion error and the positioning error of large aircraft components; S3: Optimize the combination of position control axes based on the positioning error transfer matrix of major aircraft components.

2. The preferred method for position control axis of attitude adjustment mechanism based on target point error sensitivity index according to claim 1, characterized in that: the preferred method is based on an aircraft large component attitude adjustment system, the system including a CNC positioner, a ball joint and an aircraft large component; the CNC positioner is used to support and adjust the attitude of the aircraft large component and has three degrees of freedom (X / Y / Z); the ball joint consists of a ball head and a ball socket, and the CNC positioner is connected to the aircraft large component through the ball joint to form a redundant drive parallel mechanism; a number of target points are arranged on the aircraft large component, and the position deviation of the target points in the global coordinate system is measured to characterize the positioning error of the aircraft large component.

3. The preferred method for position control axis of attitude adjustment mechanism based on target point error sensitivity index according to claim 1, characterized in that: three CNC positioners are provided, one of which corresponds to one ball joint.

4. The method for optimizing the position control axis of an attitude adjustment mechanism based on the target point error sensitivity index according to claim 1, characterized in that: in step one, the constructed coordinate system includes a global coordinate system and a local coordinate system for large aircraft components, wherein the global coordinate system... It is the reference coordinate system within the entire assembly space; the Z-axis of the global coordinate system is perpendicular to the horizontal plane; the local coordinate system of large aircraft components. It is a coordinate system fixed to the aircraft's main components, which adjusts as the main components move, representing the spatial position and attitude of the main components.

5. The method for optimizing the position control axis of the attitude adjustment mechanism based on the target point error sensitivity index according to claim 1, characterized in that: in S1, the specific derivation steps of the attitude deviation equation of the large aircraft components are as follows: (1.1) Let P be any point on the large aircraft component, and let the coordinates of this point in the local coordinate system of the large aircraft component be... The coordinates in the global coordinate system are Based on the principle of coordinate system transformation, the following equation is obtained. (1) in, This represents the attitude matrix of a large aircraft component relative to the global coordinate system. Let be the position vector of a large aircraft component relative to the global coordinate system, and the expressions are as follows: (2) (3) In formula (1) Let be the attitude angle of the large aircraft component relative to the global coordinate system, in equation (3) These are the position coordinates of major aircraft components relative to the global coordinate system. (1.2) According to formula (1), the error of point P in the global coordinate system is expressed as: (4) in, , It is the attitude error matrix of the large component. It is the position error vector of the large component; (1.3) Let the attitude angle error of the major components of the aircraft be... The actual attitude matrix of the major components of the aircraft is The attitude angle deviation matrix of the large component relative to the theoretical attitude is: Then there is (5) According to formula (2), when Approaching infinity, there is (6) Therefore, the attitude error matrix of the large component is expressed as: (7) (1.4) Substituting the above formula into formula (4), we obtain the position error of point P on the large component with respect to the pose deviation. The equation is (8) in, This refers to the pose deviation of large components. is the unit direction vector of the base coordinate system.

6. The method for optimizing the position control axis of the attitude adjustment mechanism based on the target point error sensitivity index according to claim 1, characterized in that: in S2, the specific steps for establishing the transfer matrix between the motion error of the position control axis of the attitude adjustment mechanism and the positioning error of the large aircraft components include: (2.1) Ball hinge j The center is the common point of the aircraft's major components and the locator, and a ball joint is provided. j The coordinates of the center in the local coordinate system of the large component are The coordinates in the global coordinate system are According to the principle of rigid body rotation, and Satisfying equation (9) (9) (2.2) Setting positioner j The motion errors of the X-axis, Y-axis, and Z-axis are respectively According to formula (8) the locator j Motion error and pose deviation of large components The mapping relationship between them is expressed as (10) in, (11) , and They represent the positioners respectively j The Jacobian vectors corresponding to the X / Y / Z axes; (2.3) Select 6 axes from the 9 axes of the attitude adjustment mechanism as position control axes, and use force servo control to release the attitude adjustment internal force for the remaining axes. Since the Z-axis of the positioner needs to bear the weight of the large component, the Z-axis of the three positioners are determined as position control axes; then set... This is a vector consisting of the motion errors of the position control axes of the attitude adjustment mechanism. The Jacobian matrix corresponding to the six position control axes of the attitude adjustment mechanism is given by formula (10). (12) when When reversible, ;when When it is irreversible, There is no solution. At this point, the attitude adjustment mechanism is in a singular configuration. When selecting the position control axis, the Jacobian matrix of the position control axis should be ensured. reversible; (2.4) Let the coordinates of the target point on the large component of the aircraft in the local coordinate system be... The error in the global coordinate system is According to formula (8), the mapping equation between the spatial position error of the target point and the attitude deviation of the large components of the aircraft is obtained. (13) in, (14) (2.5) Assume that large components of the aircraft are equipped with n Target points, target points i The error weights are The positioning error of a large aircraft component is then expressed as: (15) in, , ; (2.6) Combining formulas (12) and (15), we can obtain the motion error of the position control axis of the attitude adjustment mechanism. Positioning error of major aircraft components transfer matrix E (16) in, .

7. The method for optimizing the position control axis of the attitude adjustment mechanism based on the target point error sensitivity index according to claim 6, characterized in that: in S3, according to the transfer matrix of the positioning error of the large aircraft components... E The specific steps for optimizing the position control axis combination are as follows: (3.1) The positioning error transfer matrix of the major aircraft components corresponding to different combinations of control axes is obtained from formulas (11) and (16). E They are different, let the first... k The positioning error transfer matrix of the major aircraft components corresponding to the various position control axis combinations is as follows: The motion error of the position control axis of the attitude adjustment mechanism is , obtained the k The error transfer equation for the positioning of large aircraft components under various position control axis combinations (17) (3.2) Taking the 2-norm of both sides of the equation, according to the properties of the norm, we have (18) (3.3) The 2-norm of a matrix is ​​equal to the largest singular value of the matrix. Singular value decomposition has (19) in, It is a 9th order orthogonal matrix. It is a 9th order orthogonal matrix. for (20) Arranged in descending order, according to the properties of matrix condition numbers, we have ; (3.4) When performing attitude control, the Z-axis of the three positioners should be selected first as the position control axis, and then the Jacobian matrix of the position control axis should be eliminated. Irreversible position control axis combination, based on the positioning error transfer matrix The L2 norm is used to correct the position control axis assembly in a timely manner to improve the positioning accuracy of large aircraft components.

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