Precise motion platform based on three-axis spherical head flexible hinge and use method

Abstract

This application provides a precision motion platform based on a three-axis ball joint flexible hinge and its usage method, belonging to the field of precision instruments. It includes: a cabinet; two motion platforms; a vertex ball joint hinge, a left ball joint hinge, and a right ball joint hinge mounted on each motion platform; a first connector connected to the vertex ball joint hinge; a second connector connected to the left ball joint hinge; and a third connector connected to the right ball joint hinge. The first, second, and third connecting seats are all slidably connected to the inner wall of the cabinet along a first direction. Multiple driving devices are mounted on the inner wall of the cabinet. These driving devices drive the first, second, or third connecting seats to move along the first direction. The precision motion platform and usage method based on a three-axis ball joint flexible hinge provided by this application can effectively solve the over-constraint problem during micro-angle adjustment and improve motion compliance.

Description

Technical Field

[0001] This application relates to the field of precision instruments, and more specifically, to a precision motion platform based on a three-axis ball joint flexible hinge and a method of using it. Background Technology

[0002] In precision manufacturing, optical alignment, and micro / nano manipulation, triaxial ball-joint flexible hinges are widely used in precision motion platforms due to their frictionless, backlash-free, and high-resolution characteristics. However, because the elastic deformation of flexible hinges has nonlinear characteristics and the three-axis motion is strongly coupled, traditional geometric models are insufficient to accurately describe the pose of the moving platform (i.e., Z-axis movement and rotation angles around the X and Y axes). Existing technologies mostly rely on finite element simulation or empirical formulas, which cannot achieve high-precision real-time attitude feedback, thus limiting the application of the platform in closed-loop control. Summary of the Invention

[0003] This application provides a precision motion platform and its usage method based on a three-axis ball joint flexible hinge, aiming to effectively solve the over-constraint problem during micro-angle adjustment and improve motion compliance.

[0004] The first aspect of this application provides a precision motion platform based on a three-axis ball joint flexible hinge, comprising: Server rack; Two motion platforms are installed inside the cabinet, and the two motion platforms are stacked in a first direction; The motion platform is provided with a vertex ball joint hinge, a left ball joint hinge, and a right ball joint hinge. The vertex ball joint hinge is located on the first side of the motion platform, and the left ball joint hinge and the right ball joint hinge are located on the second side of the motion platform. The first side and the second side are opposite to each other. A first connector is connected to the vertex ball joint hinge. The first connector includes a first connecting seat and a first connecting plate disposed on the first connecting seat. The ball of the vertex ball joint is in contact with the first connecting plate. The second connector is connected to the left ball joint hinge. The second connector includes a second connecting seat and a second connecting plate disposed on the second connecting seat. A groove is formed on the second connecting plate, and the groove extends along a second direction. The ball of the left ball joint hinge is located in the groove. The third connector is connected to the right ball joint hinge. The third connector includes a third connecting seat and a third connecting plate disposed on the third connecting seat. A recess is provided on the third connecting plate, and the ball of the right ball joint hinge is located in the recess. The first connecting seat, the second connecting seat, and the third connecting seat are all slidably connected to the inner side wall of the cabinet along the first direction; Multiple drive devices are disposed on the inner side wall of the cabinet. The multiple drive devices are respectively connected to the first connecting seat, the second connecting seat and the third connecting seat. The drive devices are used to drive the first connecting seat, the second connecting seat or the third connecting seat to move along the first direction, so as to drive the various positions of the motion platform to move respectively.

[0005] Optionally, the cross-section of the tank in a third direction includes a bottom wall, a first side wall, and a second side wall. The bottom wall is located between the first side wall and the second side wall, and both sides of the bottom wall are connected to the first side wall and the second side wall, respectively. The angle between the first side wall and the second side wall and the bottom wall is greater than 90°.

[0006] Optionally, the cross-sectional shape of the socket is conical or arc-shaped.

[0007] Optionally, the drive device includes a motor and a lead screw, the motor is mounted on the cabinet, and the output end of the motor is fixedly connected to the lead screw, the lead screw being rotatably connected to the cabinet in a first direction; The first connecting seat, the second connecting seat, and the third connecting seat are respectively mounted on the corresponding threaded screw, and the first connecting seat, the second connecting seat, and the third connecting seat are threadedly connected to the corresponding threaded screw. The inner wall of the cabinet is provided with multiple slide rails extending along a first direction, and the first connecting seat, the second connecting seat and the third connecting seat are slidably connected to the corresponding slide rails.

[0008] Optionally, the two motion platforms include a first motion platform and a second motion platform, with the apex of the first motion platform and the apex of the second motion platform located on opposite sides of the cabinet, respectively.

[0009] A second aspect of this application provides a method for using a precision motion platform based on a three-axis ball joint flexible hinge, the method comprising: The sample to be tested is placed on the motion platform, and the initial positions of the vertex ball joint, left ball joint, and right ball joint of the motion platform are recorded. The initial height, initial pitch angle, and initial yaw angle of each point on the motion platform are obtained by using the inverse motion formula. Input the preset height, preset pitch angle and preset yaw angle, and obtain the preset positions of the vertex ball joint, left ball joint and right ball joint of the motion platform through the positive motion formula, and start the drive device to drive each point of the motion platform to move to the preset position; Substituting the difference between the preset position and the initial position into the inverse motion formula, the actual height, actual pitch angle, and actual yaw angle of each point on the motion platform are obtained, and compared with the preset height, preset pitch angle, and preset yaw angle to obtain the analysis results; The motion platform includes a first connector connected to the vertex ball joint hinge. The first connector includes a first connecting seat and a first connecting plate disposed on the first connecting seat. The ball of the vertex ball joint hinge contacts the first connecting plate. The second connector is connected to the left ball joint hinge. The second connector includes a second connecting seat and a second connecting plate disposed on the second connecting seat. A groove is formed on the second connecting plate, and the groove extends along a second direction. The ball of the left ball joint hinge is located in the groove. The third connector is connected to the right ball joint hinge. The third connector includes a third connecting seat and a third connecting plate disposed on the third connecting seat. A recess is provided on the third connecting plate, and the ball of the right ball joint hinge is located in the recess.

[0010] Optionally, the inverse motion formula is:

[0011]

[0012]

[0013] Where H represents the real-time position of the motion platform, H 顶 H represents the height of the vertex ball joint of the motion platform. 右 H represents the height of the right ball joint hinge of the motion platform. 左 The position height of the right ball joint hinge of the motion platform is represented by α, the actual pitch angle of the motion is represented by β, the actual yaw angle of the motion platform is represented by L1, the distance between the left and right ball joint hinges of the motion platform is represented by L2, and the distance between the midpoint of the line connecting the left and right ball joint hinges of the motion platform and the vertex ball joint hinge is represented by L2.

[0014] Optionally, the forward motion formula is:

[0015]

[0016]

[0017] Where H0 represents the preset height of the motion platform, H 顶H represents the height of the vertex ball joint of the motion platform. 右 H represents the height of the right ball joint hinge of the motion platform. 左 The position height of the right ball joint of the motion platform is represented by α0, the preset pitch angle of the motion is represented by β0, and the preset yaw angle of the motion platform is represented by β0.

[0018] Beneficial effects: This application provides a precision motion platform based on a three-axis ball joint flexible hinge and its usage method. The precision motion platform includes a cabinet, two motion platforms, a first connector, a second connector, a third connector, and multiple drive devices. A vertex ball joint hinge, a left ball joint hinge, and a right ball joint hinge are provided on the motion platforms. The ball of the vertex ball joint hinge contacts the first connecting plate of the first connector; the ball of the left ball joint hinge is located in a groove on the second connecting plate of the second connector; and the ball of the right ball joint hinge is located in a recess on the third connecting plate of the third connector. The drive devices are used to drive the first, second, or third connector to move along a first direction. Thus, by having the ball joint hinge contact different connecting surfaces, the over-constraint problem during micro-angle adjustment is effectively solved, improving motion compliance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a precision motion platform based on a three-axis ball joint flexible hinge, according to an embodiment of this application. Figure 2 This is a schematic diagram of the motion platform structure in a precision motion platform based on a three-axis ball joint flexible hinge, according to an embodiment of this application. Figure 3 This is a schematic diagram of a motion platform and spatial orientation in a precision motion platform based on a three-axis ball joint flexible hinge, as proposed in an embodiment of this application. Figure 4 This is a schematic diagram of the structure of the first connecting member in a precision motion platform based on a three-axis ball joint flexible hinge, according to an embodiment of this application. Figure 5 This is a schematic diagram of the structure of the second connecting member in a precision motion platform based on a three-axis ball joint flexible hinge, according to an embodiment of this application. Figure 6This is a schematic diagram of the structure of the third connecting member in a precision motion platform based on a three-axis ball joint flexible hinge, according to an embodiment of this application. Figure 7 This is a schematic diagram of a kinematic model of a precision motion platform based on a three-axis ball joint flexible hinge, as proposed in one embodiment of this application. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In related technologies, triaxial ball-joint flexible hinges exhibit strong nonlinear coupling between Z-axis translation and the two rotational degrees of freedom (pitch and yaw) during motion. Traditional geometric models (such as simple trigonometric relationships) cannot accurately describe this complex spatial deformation relationship, leading to significant errors in attitude calculation results.

[0023] In view of this, this application proposes a precision motion platform and its usage method based on a three-axis ball joint flexible hinge, aiming to effectively solve the over-constraint problem during micro-angle adjustment and improve motion compliance.

[0024] Reference Figure 1 As shown, this application discloses a precision motion platform 2 based on a three-axis ball joint flexible hinge. The precision motion platform 2 includes a cabinet 1 and two motion platforms 2.

[0025] Specifically, both motion platforms 2 are installed inside the cabinet 1. The two motion platforms 2 include a first motion platform 21 and a second motion platform 22. In this embodiment, the first motion platform 21 and the second motion platform 22 are stacked in the first direction Z, and the second motion platform 22 is located below the first motion platform 21.

[0026] It should be noted that, as Figure 1 and Figure 3 As shown in the embodiment of this application, the cabinet 1 is generally rectangular, and its whole includes a first direction Z, a second direction Y, and a third direction X. Among them, the first direction Z is the height direction of the cabinet 1, the second direction Y is the length direction of the cabinet 1, and the third direction X is the width direction of the cabinet 1, that is, the first direction Z, the second direction Y, and the third direction X are all perpendicular to each other.

[0027] Reference Figure 2As shown, the motion platform 2 is equipped with a vertex ball joint hinge 41, a left ball joint hinge 42, and a right ball joint hinge 43. The vertex ball joint hinge 41 is located on the first side of the motion platform 2, while the left ball joint hinge 42 and the right ball joint hinge 43 are located on the second side of the motion platform 2. The first side and the second side are opposite each other; that is, the vertex ball joint hinge 41, the left ball joint hinge 42, and the right ball joint hinge 43 are located on opposite sides of the motion platform 2, while the left ball joint hinge 42 and the right ball joint hinge 43 are located on the same side of the motion platform 2. In this embodiment, the vertex ball joint hinge 41 on the first motion platform 21 is the first ball joint hinge, the left ball joint hinge 42 is the third ball joint hinge, and the right ball joint hinge 43 is the fifth ball joint hinge; the vertex ball joint hinge 41 on the second motion platform 22 is the second ball joint hinge, the left ball joint hinge 42 is the fourth ball joint hinge, and the right ball joint hinge 43 is the sixth ball joint hinge. It should be noted that the vertex ball joint hinge 41, the left ball joint hinge 42, and the right ball joint hinge 43 are independent of each other and can achieve rotation and translation in multiple directions.

[0028] Reference Figure 1 and Figure 2 As shown, the precision motion platform 2 also includes a first connector 31, a second connector 32, a third connector 33, and multiple drive devices.

[0029] Specifically, refer to Figure 2 and Figure 4 As shown, the first connecting member 31 is connected to the vertex ball joint hinge 41 of the motion platform 2. The first connecting member 31 includes a first connecting seat 311 and a first connecting plate 312 fixedly connected to the first connecting seat 311. The first connecting seat 311 is slidably connected to the inner wall of the cabinet 1 along the first direction Z. The ball of the vertex ball joint hinge 41 contacts and connects with the first connecting plate 312. Thus, the connection point between the ball of the vertex ball joint hinge 41 and the first connecting plate 312 is planar, making the contact point a single point, possessing a relatively high degree of freedom. That is, the vertex ball joint hinge 41 connected to the first connecting plate 312 can achieve rotation in multiple directions (including the first direction Z, the second direction Y, and the third direction X) and translational movement in the second direction Y and the third direction X.

[0030] Reference Figure 2 and Figure 5 As shown, the second connector 32 is connected to the left ball joint hinge 42 of the motion platform 2. The second connector 32 includes a second connecting seat 321 and a second connecting plate 322 fixedly connected to the second connecting seat 321. The second connecting seat 321 is slidably connected to the inner wall of the cabinet 1 along the first direction Z. At the same time, a groove 323 is formed on the second connecting plate 322, which extends along the second direction Y. The ball of the left ball joint hinge 42 is located in the groove 323.

[0031] In this embodiment of the application, the cross section of the tank 323 in the third direction X includes a bottom wall 3233, a first side wall 3231 and a second side wall 3232. The bottom wall 3233 is located between the first side wall 3231 and the second side wall 3232, and the two sides of the bottom wall 3233 are connected to the first side wall 3231 and the second side wall 3232 respectively. The angle between the first side wall 3231 and the second side wall 3232 and the bottom wall 3233 is greater than 90°. That is, the cross section shape of the tank 323 in the third direction X is approximately "V" shaped.

[0032] Thus, the ball of the left ball joint hinge 42 will contact at least the first sidewall 3231 and the second sidewall 3232 within the groove 323. That is, the contact position between the left ball joint hinge 42 and the second connecting plate 322 is two points, which can be connected into a line. This can reduce the tensile stress in the third direction X caused by the movement of the second connecting seat 321 along the first direction Z. The left ball joint hinge 42 with the second connecting member 32 can realize rotation in multiple directions (including the first direction Z, the second direction Y and the third direction X) and movement in the second direction Y.

[0033] Reference Figure 2 and Figure 6 As shown, the third connector 33 is connected to the right ball joint hinge 43 of the motion platform 2. The third connector 33 includes a third connecting seat 331 and a third connecting plate 332 fixedly connected to the third connecting seat 331. The third connecting seat 331 is slidably connected to the inner wall of the cabinet 1 along the first direction Z. Simultaneously, a recess 333 is formed on the third connecting plate 332, and the ball of the right ball joint hinge 43 is located within this recess 333. In this embodiment, the cross-sectional shape of the recess 333 may include a conical shape or an arc shape. Thus, the ball of the right ball joint hinge 43 will at least contact the inner wall of the socket 333 within the socket 333. That is, the contact position between the right ball joint hinge 43 and the third connecting plate 332 is a circle. A circle can form a surface, thereby allowing the right ball joint hinge 43 to retain its own spherical rotational freedom within the socket 333. The movement distance of the third connecting seat 331 in the first direction Z can be calculated with the center of the ball of the right ball joint hinge 43 as the origin of the coordinate system and converted into the displacement difference in the first direction Z according to the angle change. The left ball joint hinge 42 with the second connecting member 32 can realize rotation in multiple directions (including the first direction Z, the second direction Y, and the third direction X).

[0034] Multiple drive devices are mounted on the inner wall of the cabinet 1, and are respectively connected to the first connecting seat 311, the second connecting seat 321, and the third connecting seat 331. In this embodiment, the drive device includes a motor and a lead screw. The motor is mounted on the cabinet 1, and its output end is fixedly connected to the lead screw. The lead screw is rotatably connected to the cabinet 1 along the first direction Z. Meanwhile, the first connecting seat 311, the second connecting seat 321, and the third connecting seat 331 are respectively mounted on the corresponding lead screw, and are threadedly connected to the corresponding lead screw. In addition, multiple slide rails extending along the first direction Z are provided on the inner wall of the cabinet 1, and the first connecting seat 311, the second connecting seat 321, and the third connecting seat 331 are slidably connected to the corresponding slide rails.

[0035] Taking the first connecting seat 311 as an example, when the motor drives the threaded screw to rotate, since the first connecting seat 311 is slidably connected to the slide rail, the first connecting seat 311 cannot rotate with the threaded screw. Moreover, the first connecting seat 311 is threadedly connected to the threaded screw. Therefore, the first connecting seat 311 will move along the length direction of the threaded screw (i.e., the first direction Z) on the threaded screw. The rotation direction of the threaded screw will determine the movement direction of the first connecting seat 311. For example, when the threaded screw rotates forward, the first connecting seat 311 will move upward; when the threaded screw rotates in reverse, the first connecting seat 311 will move downward.

[0036] Reference Figure 1 As shown in this embodiment, since the precision motion platform 2 includes a first motion platform 21 and a second motion platform 22, to avoid interference between the connectors connected to the first motion platform 21 and the connectors connected to the second motion platform 22 during movement, the apexes of the first motion platform 21 and the second motion platform 22 are located on opposite sides of the cabinet 1. The apex of the first motion platform 21 is also the location of the first ball joint hinge, and the apex of the second motion platform 22 is also the location of the second ball joint hinge.

[0037] The precision motion platform 2 provided in this application embodiment can drive the movement of different connecting seats using a driving device, thereby driving the independent movement of each position of the first motion platform 21 and the second motion platform 22. In this application embodiment, the vertex ball joint hinge 41, the left ball joint hinge 42, and the right ball joint hinge 43 of the motion platform 2 are connected by the first connecting member 31, the second connecting member 32, and the third connecting member 33, respectively. The vertex ball joint hinge 41 forms point contact with the first connecting plate 312 of the first connecting member 31, the left ball joint hinge 42 forms line contact with the second connecting plate 322 of the second connecting member 32, and the right ball joint hinge 43 forms surface contact with the third connecting plate 332 of the third connecting member 33. This allows each ball joint hinge to adapt to position changes caused by small angular displacement within a certain range, effectively reducing the situation of adjustment jamming, thereby effectively solving the over-constraint problem during micro-angle adjustment and improving motion compliance.

[0038] This application embodiment also provides a method for using a precision motion platform 2 based on a three-axis ball joint flexible hinge, the method including: Step 101: Place the sample to be tested on the motion platform 2 and record the initial positions of the vertex ball joint 41, the left ball joint 42 and the right ball joint 43 of the motion platform 2.

[0039] Specifically, the precision motion platform 2 also includes a first connector 31, a second connector 32, and a third connector 33.

[0040] The first connecting member 31 is connected to the vertex ball joint hinge 41 of the motion platform 2. The first connecting member 31 includes a first connecting seat 311 and a first connecting plate 312 fixedly connected to the first connecting seat 311. The first connecting seat 311 is slidably connected to the inner wall of the cabinet 1 along the first direction Z. The ball of the vertex ball joint hinge 41 contacts and connects with the first connecting plate 312. Thus, the connection point between the ball of the vertex ball joint hinge 41 and the first connecting plate 312 is planar, making the contact point a single point, possessing a relatively high degree of freedom. That is, the vertex ball joint hinge 41 connected to the first connecting plate 312 can achieve rotation in multiple directions (including the first direction Z, the second direction Y, and the third direction X) and translational movement in the second direction Y and the third direction X.

[0041] The second connector 32 is connected to the left ball joint hinge 42 of the motion platform 2. The second connector 32 includes a second connecting seat 321 and a second connecting plate 322 fixedly connected to the second connecting seat 321. The second connecting seat 321 is slidably connected to the inner wall of the cabinet 1 along the first direction Z. At the same time, the second connecting plate 322 has a groove 323 extending along the second direction Y, and the ball of the left ball joint hinge 42 is located in the groove 323.

[0042] Thus, the ball of the left ball joint hinge 42 is in the groove 323, and the contact position with the second connecting plate 322 is two points. The two points can be connected into a line, thereby reducing the tensile stress in the third direction X caused by the movement of the second connecting seat 321 along the first direction Z. The left ball joint hinge 42 with the second connecting member 32 can realize rotation in multiple directions (including the first direction Z, the second direction Y and the third direction X) and movement in the second direction Y.

[0043] The third connector 33 is connected to the right ball joint hinge 43 of the motion platform 2. The third connector 33 includes a third connector 331 and a third connector plate 332 fixedly connected to the third connector 331. The third connector 331 is slidably connected to the inner wall of the cabinet 1 along the first direction Z. At the same time, a recess 333 is provided on the third connector plate 332, and the ball of the right ball joint hinge 43 is located in the recess 333. The ball of the right ball joint hinge 43 is in contact with the inner wall of the socket 333 within the socket 333. That is, the contact position between the right ball joint hinge 43 and the third connecting plate 332 is a circle. A circle can form a surface, so that the right ball joint hinge 43 can retain its own spherical rotational freedom within the socket 333. The movement distance of the third connecting seat 331 in the first direction Z can be calculated with the center of the ball of the right ball joint hinge 43 as the origin of the coordinate system and converted into the displacement difference in the first direction Z according to the angle change. The left ball joint hinge 42 with the second connecting member 32 can realize rotation in multiple directions (including the first direction Z, the second direction Y and the third direction X).

[0044] Step 102: Obtain the initial height, initial pitch angle, and initial yaw angle of each point on the motion platform 2 using the inverse motion formula.

[0045] Step 103: Input the preset height, preset pitch angle and preset yaw angle, and obtain the preset positions of the vertex ball joint 41, left ball joint 42 and right ball joint 43 of the motion platform 2 through the forward motion formula, and start the drive device to drive each point of the motion platform 2 to move to the preset position.

[0046] Specifically, the forward and inverse motion formulas are based on the second motion platform 22 in the initial state (the second motion platform 22 is at its lower limit position and is in a horizontal state), with the center of the right ball joint hinge 43 (i.e., the sixth ball joint hinge) of the second motion platform 22 as the origin of the coordinate system, and the third direction X as the X0 axis, the second direction Y as the Y0 axis, and the first direction Z as the Z0 axis. A kinematic model is then established (a simplified model diagram is shown below). Figure 7The calculation formula obtained after (as shown) is as follows. It should be noted that the distance between the center of the fourth ball joint (left ball joint 42) and the center of the sixth ball joint of the second motion platform 22 is a fixed value L1, and the distance between the midpoint of the line connecting the centers of the fourth and sixth ball joints and the center of the second ball joint (apex ball joint 41) is a fixed value L2. In this embodiment, L1 = 700mm, L2 = 920mm.

[0047] Depend on Figure 7 The relationship between the pitch angle α, the yaw angle β and the displacement values ​​of each ball joint can be obtained as shown in formulas (1) and (2).

[0048] …………………..(1) ……………………..(2) Among them, H 顶 H represents the height of the vertex ball joint 41 of the motion platform 2. 右 H represents the height of the right ball joint hinge 43 of the motion platform 2. 左 H represents the position height of the right ball joint hinge 43 of the motion platform 2, and H represents the preset position height of the motion platform 2.

[0049] The forward kinematics analysis of motion platform 2 involves inputting (α, β, H) to obtain the displacement values ​​at the positions of each ball joint hinge. The forward kinematics formulas can be derived from formulas (1) and (2) as follows:

[0050]

[0051]

[0052] Where H0 represents the preset height of motion platform 2, H 顶 H represents the height of the vertex ball joint 41 of motion platform 2. 右 H represents the height of the right ball joint hinge 43 of motion platform 2. 左 The position height of the right ball joint hinge 43 of the motion platform 2 is represented by α0, the preset pitch angle of the motion is represented by β0, and the preset yaw angle of the motion platform 2 is represented by β0.

[0053] Meanwhile, during or after the motion platform 2 has reached its position, the H value of each ball joint hinge position will be displayed in real time. The inverse motion formula is to calculate the height of each ball joint hinge position and the pitch angle α and yaw angle β of the motion platform 2 by using the real-time H value of the motion platform 2.

[0054] From formulas (1) and (2), the formula for the inverse motion can be obtained as follows:

[0055]

[0056]

[0057] Where H represents the real-time position of motion platform 2, H 顶 H represents the height of the vertex ball joint 41 of motion platform 2. 右 H represents the height of the right ball joint hinge 43 of motion platform 2. 左 The position height of the right ball joint hinge 43 of the motion platform 2 is represented by α, the actual pitch angle of the motion is represented by β, the actual yaw angle of the motion platform 2 is represented by L1, the distance between the left ball joint hinge 42 and the right ball joint hinge 43 of the motion platform 2 is represented by L2, and the distance between the midpoint of the line connecting the left ball joint hinge 42 and the right ball joint hinge 43 of the motion platform 2 and the vertex ball joint hinge 41 is represented by L2.

[0058] It should be noted that the absolute position, absolute zero position, and relative zero position of the motion platform 2 are all feedback values ​​obtained from the absolute grating ruler. Therefore, the position of the motion platform 2 is calculated using the feedback value from the absolute grating ruler. However, the accuracy of laser interferometry is higher than that of grating measurement. Therefore, the pitch angle α and yaw angle β of the motion platform 2 are calculated using the motion displacement value measured by laser interferometry.

[0059] Step 104: Substitute the difference between the preset position and the initial position into the inverse motion formula to obtain the actual height, actual pitch angle and actual yaw angle of each point on the motion platform 2, and compare them with the preset height, preset pitch angle and preset yaw angle to obtain the analysis results.

[0060] Specifically, in this embodiment, the motion platform 2 includes a first motion platform 21 and a second motion platform 22. Therefore, the position calculation of the motion platform 2 includes the position calculation of the first motion platform 21 and the position calculation of the second motion platform 22. The first motion platform 21 utilizes a first ball joint, a third ball joint, and a fifth ball joint for load-bearing and coordinated movement, and the displacement values ​​of the first, third, and fifth ball joints are fed back from the real-time position of an absolute grating ruler. Similarly, the second motion platform 22 utilizes a second, fourth, and sixth ball joint for load-bearing and coordinated movement, and the displacement values ​​of the second, fourth, and sixth ball joints are fed back from the real-time position of an absolute grating ruler.

[0061] The connecting plates in the first motion platform 21 that are connected to the first ball joint hinge, the third ball joint hinge, and the fifth ball joint hinge are respectively a "point connection" planar connecting plate (first connecting plate 312), a "line connection" V-groove connecting plate (second connecting plate 322), and a "surface connection" conical socket connecting plate (third connecting plate 332). According to the kinematic model and the establishment of the base coordinate system, the base coordinate system and motion coordinate system of the motion platform 2 are both located on the ball joint hinges corresponding to the "surface connection" conical socket connecting plates. Therefore, the set platform position is also determined by the position feedback from the absolute grating ruler of the corresponding motion axis of the ball joint hinge, i.e., the position of the first motion platform 21. The calculated position is the height value of the fifth ball joint hinge. Similarly, the connecting plates connected to the second, fourth, and sixth ball joint hinges in the second motion platform 22 are respectively a "point connection" planar connecting plate (first connecting plate 312), a "line connection" V-groove connecting plate (second connecting plate 322), and a "surface connection" conical socket connecting plate (third connecting plate 332). Therefore, the set platform position is also determined by the position feedback of the absolute grating ruler of the motion axis corresponding to the ball joint hinge connected by the "surface connection" conical socket connecting plate. That is, the calculated position of the second motion platform 22 is the height value of the sixth ball joint hinge.

[0062] The attitude calculation for motion platform 2 includes the calculation of pitch angle α and yaw angle β. Both angles are calculated using inverse kinematics. The real-time values ​​of pitch angle α and yaw angle β are obtained by substituting the displacement values ​​of the corresponding motion axes of each platform measured in real time by laser interferometry into the inverse kinematics formula. The pitch angle α1 and yaw angle β1 of the first motion platform 21 are obtained by substituting the height values ​​of the positions of the first, third, and fifth ball joints measured by the laser interferometer. Similarly, the pitch angle α2 and yaw angle β2 of the second motion platform 22 are obtained by substituting the height values ​​of the positions of the second, fourth, and sixth ball joints measured by the laser interferometer.

[0063] Understandably, after obtaining the analysis results, it is necessary to choose whether to maintain or continue to adjust the height of each point on the first motion platform 21 and / or the second motion platform 22, depending on the situation.

[0064] The above-described method provided in this application incorporates the elastic deformation and force-displacement coupling effect of the ball-head hinge into the calculation model by introducing a flexibility matrix or a pseudo-rigid body model. This makes the solution results closer to physical reality, significantly improving the accuracy of attitude angle (such as pitch angle and yaw angle) calculations and providing a reliable data foundation for high-precision closed-loop control.

[0065] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0066] It should also be noted that, in this document, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "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 application and simplifying the description, and do not 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 application. Furthermore, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. In the absence of further restrictions, an element defined by the phrase "includes a..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes the element.

[0067] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand this application, and the content of this specification should not be construed as a limitation of this application. Furthermore, for those skilled in the art, there will be different forms of changes in the specific implementation methods and application scope based on this application. It is neither necessary nor possible to exhaustively list all implementation methods here, and obvious changes or modifications derived therefrom are still within the protection scope of this application.

Claims

1. A precision motion platform based on a three-axis ball-joint flexible hinge, characterized in that, include: Server rack; Two motion platforms are installed inside the cabinet, and the two motion platforms are stacked in a first direction; The motion platform is provided with a vertex ball joint hinge, a left ball joint hinge, and a right ball joint hinge. The vertex ball joint hinge is located on the first side of the motion platform, and the left ball joint hinge and the right ball joint hinge are located on the second side of the motion platform. The first side and the second side are opposite to each other. A first connector is connected to the vertex ball joint hinge. The first connector includes a first connecting seat and a first connecting plate disposed on the first connecting seat. The ball of the vertex ball joint is in contact with the first connecting plate. The second connector is connected to the left ball joint hinge. The second connector includes a second connecting seat and a second connecting plate disposed on the second connecting seat. A groove is formed on the second connecting plate, and the groove extends along a second direction. The ball of the left ball joint hinge is located in the groove. The third connector is connected to the right ball joint hinge. The third connector includes a third connecting seat and a third connecting plate disposed on the third connecting seat. A recess is provided on the third connecting plate, and the ball of the right ball joint hinge is located in the recess. The first connecting seat, the second connecting seat, and the third connecting seat are all slidably connected to the inner side wall of the cabinet along the first direction; Multiple drive devices are disposed on the inner side wall of the cabinet. The multiple drive devices are respectively connected to the first connecting seat, the second connecting seat and the third connecting seat. The drive devices are used to drive the first connecting seat, the second connecting seat or the third connecting seat to move along the first direction, so as to drive the various positions of the motion platform to move respectively.

2. The precision motion platform based on a three-axis ball joint flexible hinge according to claim 1, characterized in that: The cross-section of the tank in a third direction includes a bottom wall, a first side wall, and a second side wall. The bottom wall is located between the first side wall and the second side wall, and both sides of the bottom wall are connected to the first side wall and the second side wall, respectively. The angle between the first side wall and the second side wall and the bottom wall is greater than 90°.

3. The precision motion platform based on a three-axis ball joint flexible hinge according to claim 1, characterized in that: The cross-sectional shape of the socket is conical or arc-shaped.

4. The precision motion platform based on a three-axis ball joint flexible hinge according to claim 1, characterized in that: The drive device includes a motor and a lead screw. The motor is mounted on the cabinet, and the output end of the motor is fixedly connected to the lead screw. The lead screw is rotatably connected to the cabinet in a first direction. The first connecting seat, the second connecting seat, and the third connecting seat are respectively mounted on the corresponding threaded screw, and the first connecting seat, the second connecting seat, and the third connecting seat are threadedly connected to the corresponding threaded screw. The inner wall of the cabinet is provided with multiple slide rails extending along a first direction, and the first connecting seat, the second connecting seat and the third connecting seat are slidably connected to the corresponding slide rails.

5. The precision motion platform based on a three-axis ball joint flexible hinge according to claim 1, characterized in that: The two motion platforms include a first motion platform and a second motion platform, with the apex of the first motion platform and the apex of the second motion platform located on opposite sides of the cabinet, respectively.

6. A method for using a precision motion platform based on a three-axis ball joint flexible hinge, characterized in that, The method of use includes: The sample to be tested is placed on the motion platform, and the initial positions of the vertex ball joint, left ball joint, and right ball joint of the motion platform are recorded. The initial height, initial pitch angle, and initial yaw angle of each point on the motion platform are obtained by using the inverse motion formula. Input the preset height, preset pitch angle and preset yaw angle, and obtain the preset positions of the vertex ball joint, left ball joint and right ball joint of the motion platform through the positive motion formula, and start the drive device to drive each point of the motion platform to move to the preset position; Substituting the difference between the preset position and the initial position into the inverse motion formula, the actual height, actual pitch angle, and actual yaw angle of each point on the motion platform are obtained, and compared with the preset height, preset pitch angle, and preset yaw angle to obtain the analysis results; The motion platform includes a first connector connected to the vertex ball joint hinge. The first connector includes a first connecting seat and a first connecting plate disposed on the first connecting seat. The ball of the vertex ball joint hinge contacts the first connecting plate. The second connector is connected to the left ball joint hinge. The second connector includes a second connecting seat and a second connecting plate disposed on the second connecting seat. A groove is formed on the second connecting plate, and the groove extends along a second direction. The ball of the left ball joint hinge is located in the groove. The third connector is connected to the right ball joint hinge. The third connector includes a third connecting seat and a third connecting plate disposed on the third connecting seat. A recess is provided on the third connecting plate, and the ball of the right ball joint hinge is located in the recess.

7. The method of using the precision motion platform based on the three-axis ball joint flexible hinge according to claim 6, characterized in that: The formula for the inverse motion is: Where H represents the real-time position of the motion platform, H 顶 H represents the height of the vertex ball joint of the motion platform. 右 H represents the height of the right ball joint hinge of the motion platform. 左 The position height of the right ball joint hinge of the motion platform is represented by α, the actual pitch angle of the motion is represented by β, the actual yaw angle of the motion platform is represented by L1, the distance between the left and right ball joint hinges of the motion platform is represented by L2, and the distance between the midpoint of the line connecting the left and right ball joint hinges of the motion platform and the vertex ball joint hinge is represented by L2.

8. The method of using the precision motion platform based on the three-axis ball joint flexible hinge according to claim 6, characterized in that: The formula for the forward motion is: Where H0 represents the preset height of the motion platform, H 顶 H represents the height of the vertex ball joint of the motion platform. 右 H represents the height of the right ball joint hinge of the motion platform. 左 The position height of the right ball joint of the motion platform is represented by α0, the preset pitch angle of the motion is represented by β0, and the preset yaw angle of the motion platform is represented by β0.

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