A multi-degree-of-freedom coupling loading test method and device for intervertebral discs and intervertebral disc prostheses based on a Stewart platform

Abstract

The application belongs to the technical field of intervertebral disc simulation test, and particularly relates to a multi-degree-of-freedom coupling loading test method and device for intervertebral disc and intervertebral disc prosthesis based on a Stewart platform. The device comprises an upper seat and a lower seat, a plurality of actuating arms are arranged between the upper seat and the lower seat, each actuating arm is connected with a driving unit, the driving unit is connected with a control unit, a sensor and an upper clamp are mounted on the lower surface of the upper seat, the upper clamp is used for clamping the upper cone of the intervertebral disc prosthesis, the sensor is electrically connected with the control unit, and the sensor is used for detecting load data, an extension adjusting shaft is mounted on the upper surface of the lower seat, the other end of the extension adjusting shaft is provided with a lower clamp, and the lower clamp is used for clamping the lower cone of the sample. The multi-degree-of-freedom coupling loading test device for intervertebral disc and intervertebral disc prosthesis based on the Stewart platform can perform six-degree-of-freedom coupling loading test and characterization on the intervertebral disc and the replacement prosthesis, the result is accurate, the device is simple, and the cost is low.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of intervertebral disc simulation testing, and particularly relates to a multi-degree-of-freedom coupling loading test method and device for intervertebral discs and intervertebral disc prostheses based on a Stewart platform. BACKGROUND

[0002] An intervertebral disc in the human body plays a function of axial bearing and providing flexion, extension, torsion, and lateral bending activity. Under the influence of multiple factors such as genetics, age, physical labor, and improper lifestyle, the intervertebral disc is prone to degeneration. Intervertebral disc degeneration is often accompanied by problems such as a decrease in intervertebral disc height and a change in shape, which can cause a loss of corresponding functions of the intervertebral disc. An intervertebral disc herniation can cause the patient's nerve to be compressed, resulting in severe pain. Intervertebral disc prosthesis replacement is a frequently used and most promising way for clinical treatment of intervertebral disc degeneration.

[0003] In order to obtain an intervertebral disc prosthesis that meets the application requirements, the intervertebral disc prosthesis needs to be tested during research and development. An intervertebral disc daily bears complex three-dimensional coupling load conditions, and the characterization of the movement function of the intervertebral disc and its replacement prosthesis needs to be tested under axial compression, flexion, extension, lateral bending, torsion, and shear in multiple directions to quantitatively analyze the influence of the intervertebral disc on the spine bearing and activity after being implanted into the human body. At present, most methods for measuring the activity of the intervertebral disc generally use a spine biomechanics testing machine and a six-degree-of-freedom loading scheme based on a mechanical arm, but the former can only perform two-degree-of-freedom testing of compression or compression plus torsion, and the latter has problems such as a large platform size, high cost, low load upper limit, and inaccurate and inconvenient displacement control. Patent CN114903660A proposes an artificial intervertebral disc in vitro test method based on a mechanical arm, which connects a sensor and a connecting shaft through a mechanical arm, applies equivalent load to an artificial intervertebral disc with vertebrae, and assists an angle sensor and an infrared camera to obtain three-dimensional movement data. However, a longer connecting shaft can cause greater measurement errors of the load, especially the bending moment; the use of an additional angle sensor and a high-speed camera to indirectly obtain displacement can also cause errors to increase, and displacement control is not accurate and convenient; commercial mechanical arms generally have high cost, large size, and low load upper limit; and multi-directional force coupling loading under load and displacement control is difficult to achieve.

[0004] Therefore, how to simply, accurately, and low-costly perform multi-degree-of-freedom coupling loading testing and characterization of intervertebral discs and replacement prostheses is a technical problem to be solved. SUMMARY

[0005] In order to solve the above technical problems, the application provides a kind of intervertebral disc and intervertebral disc prosthesis multi-degree-of-freedom coupling loading test method and device based on Stewart platform, the three-dimensional physiological movement of human spine is simulated by customizing improved Stewart platform, and equivalent physiological load is applied to intervertebral disc and its prosthesis, three-dimensional motion data of intervertebral disc and its prosthesis are obtained by using three axial displacement and three rotational angle of platform itself, six-direction load data of intervertebral disc and its prosthesis are synchronously collected by using sensor connected with intervertebral disc and its prosthesis, so as to output corresponding test structure (specifically six-direction force-displacement and torque-rotation angle curve).The application can be used for intervertebral disc and its prosthesis compression bending torsion shear coupling loading and fatigue test under displacement control and load control, and can test and quantitatively characterize the complex three-dimensional in-vitro movement of intervertebral disc and its prosthesis similar to human spine, which is simple in device, low in cost, accurate in test result and suitable for popularization and application.

[0006] The application is implemented by the following technical solutions.

[0007] The application provides a kind of intervertebral disc and intervertebral disc prosthesis multi-degree-of-freedom coupling loading test device based on Stewart platform, including upper seat and lower seat, and a plurality of actuating arms are distributed between the upper seat and the lower seat, the two ends of each actuating arm are movably connected with the upper seat and the lower seat respectively, each actuating arm can axially stretch and retract, and can rotate relatively around the surface of the upper seat and the lower seat, each actuating arm is connected with a driving unit, and the driving unit is electrically connected with a control unit; the control unit is used to control the driving unit to drive the plurality of actuating arms to move cooperatively, so that the upper seat moves in three directions and rotates around three axes; the control unit collects displacement data in the movement process.

[0008] The lower surface of the upper seat is sequentially provided with a sensor and an upper clamp, the upper clamp is used to clamp the upper cone of the intervertebral disc prosthesis test sample; the sensor is electrically connected with the control unit, and the sensor is used to detect load data and transmit the load data to the control unit; one end of a telescopic adjusting shaft is installed on the upper surface of the lower seat, and the other end of the telescopic adjusting shaft is provided with a lower clamp, and the lower clamp is used to clamp the lower cone of the intervertebral disc prosthesis test sample.

[0009] Preferably, the upper clamp comprises a fixed block and a stop block, a guide piece is fixedly connected to one side of the fixed block, the stop block is installed on the guide piece and can move towards or away from the fixed block along the guide piece, a locking piece is arranged between the fixed block and the stop block, and is used to fix the relative position between the stop block and the fixed block.More preferably, the locking piece is a kinematic pair composed of a first bolt and a lead screw, which is used to drive the stop block to move along the guide piece and lock.

[0010] Preferably, the actuating arms comprise a telescopic body, a plurality of hinge seats are respectively fixed on the upper seat and the lower seat, and the two ends of the telescopic body are movably connected to the hinge seats through connecting members, and the lower end of the telescopic body is electrically connected to the driving unit.

[0011] Preferably, the sensor and the upper clamp are fixedly connected through a first flange.

[0012] Preferably, the upper end of the telescopic adjusting shaft is fixedly connected to the lower clamp through a second flange, and the lower end of the telescopic adjusting shaft is fixed to the upper surface of the lower seat through a third flange.

[0013] Preferably, the driving unit is a driving motor, and the control unit is a computer.

[0014] The application provides a multi-degree-of-freedom coupled loading test method for intervertebral discs and intervertebral disc prostheses based on a Stewart platform.

[0015] The telescopic adjusting shaft is adjusted to a proper length, then the intervertebral disc prosthesis test sample connected with the upper vertebral body and the lower vertebral body is placed on the lower clamp, the lower vertebral body is clamped by the lower clamp, the upper seat is controlled to move to the position where the upper clamp contacts the upper vertebral body, and the upper vertebral body is clamped by the upper clamp.

[0016] The test method is selected on the control unit, the test is started, the control unit controls the driving unit to drive the plurality of actuating arms to move cooperatively, the movement of the upper seat is controlled to simulate the three-dimensional movement of a natural spine, and the movement of the upper vertebral body is changed, so that the intervertebral disc prosthesis test sample completes the required movement.

[0017] During the movement, the control unit and the sensor synchronously collect the corresponding displacement data and load data in real time at a certain sampling frequency, and the test result is output on the control unit.

[0018] Preferably, when the displacement loading is performed on the intervertebral disc prosthesis test sample, the control unit directly controls the driving unit to drive the plurality of actuating arms to move cooperatively, and the control unit collects the displacement data in the movement.

[0019] Preferably, when the load loading is performed on the intervertebral disc prosthesis test sample, the control unit controls the driving unit to drive the plurality of actuating arms to move cooperatively according to the load data feedback value returned by the sensor.

[0020] Preferably, during the movement, the control unit outputs a six-way force-displacement or torque-rotation angle curve according to the collected data.

[0021] Preferably, the movement comprises axial compression, flexion and extension, lateral bending, torsion and shearing.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] The application provides a multi-degree-of-freedom coupling loading test device for intervertebral discs and intervertebral disc prostheses based on a Stewart platform, which can perform six-degree-of-freedom coupling loading test and characterization on intervertebral discs and their replacement prostheses, and has accurate results, simple device and low cost.

[0024] The device comprises an upper seat and a lower seat, a plurality of actuating arms are distributed between the upper seat and the lower seat, two ends of each actuating arm are movably connected with the upper seat and the lower seat respectively, each actuating arm can axially stretch and retract and relatively rotate around the surface of the upper seat and the lower seat, each actuating arm is connected with a driving unit, and the driving unit is electrically connected with a control unit; the control unit is used to control the driving unit to drive the plurality of actuating arms to move coordinately, so that the upper seat performs three-direction translational movement and three-direction rotation around an axis; the control unit collects displacement data in the movement process; the lower surface of the upper seat is sequentially provided with a sensor and an upper clamp, the upper clamp is used to clamp the upper cone of an intervertebral disc prosthesis test sample; the sensor is electrically connected with the control unit, the sensor is used to detect load data and transmit the load data to the control unit; one end of an extension adjusting shaft is installed on the upper surface of the lower seat, and the other end of the extension adjusting shaft is provided with a lower clamp, the lower clamp is used to clamp the lower cone of the intervertebral disc prosthesis test sample. The device can perform displacement loading or load loading on the intervertebral disc prosthesis test sample. When displacement loading is performed, the control unit directly controls the driving unit to drive the plurality of actuating arms to move coordinately, and the control unit collects displacement data in the movement process. When load loading is performed, the control unit controls the driving unit to drive the plurality of actuating arms to move coordinately according to the load data feedback value returned by the sensor. In the movement process, the control unit outputs a six-way force-displacement or torque-rotation angle curve according to the collected data.

[0025] The application customizes an improved commercial Stewart platform, has low cost, high replicability, relatively small size, and a very large load application range, does not need to rely on additional displacement sensors and cameras to measure displacement, and can conveniently and accurately acquire displacement and load, can simultaneously apply six-way coupling load to intervertebral discs and their prostheses, is not limited to one-way or two-way loading, has universal test method, can be applied to the test of intervertebral discs and multiple intervertebral disc prostheses of multiple sizes by customizing specific artificial cones, and is suitable for popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The application provides a multi-degree-of-freedom coupling loading test device for intervertebral discs and intervertebral disc prostheses based on a Stewart platform.

[0027] Figure 2 In the figure, (a) is a front view of the structure, (b) is a side view of the structure, and (c) is a perspective view of the structure. Figure 1 In the figure, (a) is a front view of the structure, (b) is a side view of the structure, and (c) is a perspective view of the structure. Figure 1 In the figure, (a) is a front view of the structure, (b) is a side view of the structure, and (c) is a perspective view of the structure.Figure 1 Structure top view.

[0028] Figure 3 Specific structure diagram of the upper seat.

[0029] Figure 4 Specific structure diagram of the sensor.

[0030] Figure 5 Specific structure diagram of the first flange.

[0031] Figure 6 Specific structure diagram of the upper clamp or the lower clamp.

[0032] Figure 7 Specific structure diagram of the second flange or the third flange.

[0033] Figure 8 Specific structure diagram of the movable outer rod in the telescopic adjusting shaft.

[0034] Figure 9 Specific structure diagram of the fixed inner rod in the telescopic adjusting shaft.

[0035] Figure 10 Specific structure diagram of the lower seat.

[0036] Figure 11 Specific structure diagram of the hinge seat.

[0037] Figure 12 Specific structure diagram of the actuating arm.

[0038] Figure 13 In the figure, (a) is a three-way force-displacement curve, and (b) is a three-way force-rotation angle curve.

[0039] Figure 14 The figure is a real photo of the intervertebral disc and intervertebral disc prosthesis multi-degree-of-freedom coupling loading test device based on the Stewart platform, wherein the arrow in the figure a indicates a driving unit, specifically a driving motor, the figure b is a photo of an experimental platform, the arrow in the figure c indicates a control unit, specifically a computer, the figure d is an enlarged photo of the specific structure in the box in the figure b, and the arrow at e indicates a sensor. DETAILED DESCRIPTION

[0040] In order to enable a person skilled in the art to better understand the technical solutions of the present application and implement the same, the present application will be further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present application.

[0041] The spinal column biomechanical testing machine can only perform one-way compression or two-degree-of-freedom compression and torsion tests, and is difficult to meet the multi-way loading test working conditions similar to the human spine; and is only suitable for natural spines, and is not good for general prosthesis testing.

[0042] The mechanical arm-based test scheme has the following problems: the long connecting shaft will cause measurement errors of loads, especially bending moments; indirect acquisition of displacement by using additional angle sensors and high-speed cameras will also cause errors to increase, and displacement control is not accurate and convenient; commercial mechanical arms are generally high in cost, large in size, and low in upper load limit; and multi-directional force coupling loading under load and displacement control is difficult to achieve.

[0043] Therefore, the application provides a multi-degree-of-freedom coupling loading test device for intervertebral discs and intervertebral disc prostheses based on a Stewart platform, as shown in Figure 1 and Figure 2 The device comprises an upper seat 1 and a lower seat 9, a plurality of actuating arms 10 are distributed between the upper seat 1 and the lower seat 9, both ends of each actuating arm 10 are movably connected to the upper seat 1 and the lower seat 9, each actuating arm 10 can axially stretch and retract, and can relatively rotate around the surfaces of the upper seat 1 and the lower seat 9, each actuating arm 10 is connected to a driving unit 12, and the driving unit 12 is electrically connected to a control unit 11; the control unit 11 is used to control the driving unit 12 to drive the plurality of actuating arms 10 to move cooperatively, so that the upper seat 1 performs three-directional translational motion and three-directional rotation around an axis; the control unit 11 collects displacement data in the motion process; the lower surface of the upper seat 1 is sequentially provided with a sensor 2 and an upper clamp 4, the upper clamp 4 is used to clamp an upper cone of an intervertebral disc prosthesis test sample 5; the sensor 2 is electrically connected to the control unit 11, the sensor 2 is used to detect load data and transmit the load data to the control unit 11; the upper surface of the lower seat 9 is provided with one end of an extension adjusting shaft 8, the other end of the extension adjusting shaft 8 is provided with a lower clamp 6, and the lower clamp 6 is used to clamp a lower cone of the intervertebral disc prosthesis test sample 5.

[0044] The control unit 11 controls the driving unit 12 to drive the plurality of actuating arms 10 to move cooperatively, so that the upper seat 1 performs three-directional translational motion and three-directional rotation around an axis, thereby realizing six-degree-of-freedom coupling motion; during the six-degree-of-freedom coupling motion of the upper seat 1, the upper clamp 4 applies a force to the intervertebral disc prosthesis test sample 5, and the sensor 2 detects load data; the sensor 2 is connected to the control unit 11 and transmits the load data to the control unit 11, the three-directional translation and the rotation angle can directly refer to the translation and rotation of the upper seat 1, the positions of the six directions of motion are calibrated and recorded in the lower computer of the control unit 11 part, and the control unit 11 outputs corresponding six-directional force-displacement or torque-rotation angle curves.

[0045] The application provides a physical photo of the multi-degree-of-freedom coupling loading test device for intervertebral discs and intervertebral disc prostheses based on a Stewart platform, as shown in Figure 14As shown in the figure, the arrow in a figure refers to the driving unit, specifically the driving motor, b figure is the experimental platform photo, the arrow in c figure refers to the control unit, specifically the computer, d figure is the specific structure in the box in b figure, the arrow in e refers to the sensor.

[0046] The improved custom commercial Stewart platform of the application uses the three-axis displacement and three-rotation angle of the platform itself to obtain three-dimensional motion data of the intervertebral disc and its prosthesis, and uses the sensor connected with the intervertebral disc and its prosthesis to synchronously collect six-direction load data of the intervertebral disc and its prosthesis, thereby outputting corresponding six-direction force-displacement and torque-angle curves. The improved custom commercial Stewart platform of the application has low cost, high replicability, relatively small size, and a very large range of applied load, does not need to rely on additional displacement sensors and cameras to measure displacement, and is convenient and accurate in displacement and load acquisition. The six-direction coupled load can be applied to the intervertebral disc and its prosthesis at the same time, and the test method has universality. The test method can be applied to the test of intervertebral discs and intervertebral disc prostheses of various sizes by customizing specific artificial cones, and is suitable for popularization and application.

[0047] It should be noted that the control loading mode of the above test device is divided into displacement control loading and load control loading. In displacement control loading, the control unit 11 directly controls the driving unit 12, thereby controlling the coordinated movement of the plurality of actuating arms 10 connected thereto to a specified six-direction position. In load control loading, the control unit 11 controls the driving unit 12 according to the feedback value of the load data returned by the sensor 2, thereby further controlling the movement of the actuating arms 10. The displacement data of the test device is obtained by three-direction translation and three-direction rotation of the platform itself (specifically, the three-direction translation and rotation can directly refer to the translation and rotation of the upper seat 1, and the six-direction position of the movement is marked and recorded in the lower computer of the control unit 11 part), and the load data is synchronously collected by the sensor 2 connected with the intervertebral disc prosthesis test sample 5, thereby outputting the corresponding six-direction force-displacement / torque-angle curves. In the preferred embodiment of the application, the driving unit 12 is a driving motor, and the control unit 11 is a computer.

[0048] The connection modes of the application will be described in detail below.

[0049] The lower surface of the upper seat 1 is sequentially provided with the sensor 2 and the upper clamp 4, and the sensor 2 and the upper clamp 4 are fixedly connected through the first flange 3. Specifically, Figure 3 The specific structure diagram of the upper seat 1 is shown in the figure, Figure 4 The specific structure diagram of the sensor is shown in the figure, Figure 3 The sensor 2 is connected to the lower surface of the upper seat 1 through the first through hole 3-1 in Figure 4 and the first threaded hole 4-1 in Figure 5The diagram shows the specific structure of the first flange 3, which is connected to the bottom of the sensor 2 through the other side of the second through hole 5-1 and the first threaded hole 4-1; Figure 6 This is a schematic diagram of the upper or lower clamp. It should be noted that the upper and lower clamps have the same structure. In use, the openings of the two clamps face each other, and they are used to clamp the upper and lower vertebrae of the intervertebral disc prosthesis test sample 5, respectively. (The diagram is repeated in the original text.) Figure 6 The third threaded hole 6-1 and Figure 5 The third through hole 5-2 connects to fix the upper clamp below the first flange 3, with the clamp opening facing downwards, used to clamp the upper cone of the intervertebral disc prosthesis test sample 5; through Figure 6 The rotation of the first bolt 6-6 controls the movement of the lead screw 6-5 and the stop block 6-2 to control the clamping and loosening of the fixture.

[0050] The function of the upper or lower clamp is to clamp and fix the intervertebral disc prosthesis test sample 5. Any structure in the prior art that can perform this function can be used. Preferably, the upper or lower clamp has the same structure, including a fixing block 6-3 and a stop block 6-2. A guide member 6-4 is fixedly connected to one side of the fixing block 6-3. The stop block 6-2 is mounted on the guide member 6-4 and can move closer to or away from the fixing block 6-3 along the guide member 6-4, thereby clamping or releasing the upper or lower cone. A locking member is provided between the fixing block 6-3 and the stop block 6-2 to fix the relative position between the stop block 6-2 and the fixing block 6-3. More preferably, the locking member is a kinematic pair composed of a first bolt 6-6 and a lead screw 6-5. A groove is provided on the guide member 6-4, and the kinematic pair is disposed in the groove, with one end passing through the stop block 6-2 and the other end mounted on the fixing block 6-3, for driving the stop block 6-2 to move along the guide member 6-4 and lock it. Specifically, by Figure 6 The rotation of the first bolt 6-6 controls the movement of the lead screw 6-5 and the stop block 6-2 to control the clamping and loosening of the fixture. The structure of the lower fixture 6 is the same as that of the upper fixture 4, and they are used in a symmetrical configuration.

[0051] The upper end of the telescopic adjustment shaft 8 is fixedly connected to the lower clamp 6 via the second flange 7, and the lower end of the telescopic adjustment shaft 8 is fixed to the upper surface of the lower seat 9 via the third flange. The telescopic adjustment shaft 8 adjusts its axial length to accommodate intervertebral disc prosthesis test samples 5 of different sizes and even long-segment vertebral bone tests, and can be steplessly adjusted. The specific connection method is as follows:

[0052] Figure 7 This is a schematic diagram of the second flange 7. It should be noted that when the third flange is used, the structure of the second flange is inverted; both have the same structure. Figure 7 The fourth through hole 7-1 in the middle is connected to the third threaded hole 6-1 in the lower clamp, and the second flange 7 is installed below the lower clamp 6; the telescopic adjustment shaft 8 is composed of a movable outer rod (structure as follows)Figure 8 As shown), fixed inner rod (structure as shown) Figure 9 As shown), it is composed of a movable outer rod at one end ( Figure 8 The middle left end is connected to the second flange 7, and one end of the fixed inner rod is connected to the third flange. The structure of the third flange is the same as that of the second flange 7, except that the structure shown in the second flange 7 is inverted when in use. Figure 9 The fifth through hole 9-1, when fitted with the second bolt, allows the movable outer rod to be relatively fixed while the inner rod's rotation direction is fixed. Figure 8 The guide rail 8-1, in conjunction with the third bolt, enables the movable outer rod to move axially relative to the fixed inner rod, thereby achieving stepless adjustment of the length of the telescopic adjustment shaft. Figure 10 This is a schematic diagram of the structure of the lower seat 9, which is achieved through... Figure 10 The sixth through hole 10-1 and Figure 7 The fourth through hole 7-1 is fixed to the third flange (which is a second flange used in reverse); Figure 11 This is a schematic diagram of the hinge seat structure, used to connect each actuator arm 10 to the upper seat 1 and the lower seat 9. Figure 11 The seventh through hole 11-1 and Figure 3 The first bolt hole 3-2 or Figure 10 The second bolt hole 10-2 is connected to connect and fix 6 fixed hinge seats to the upper seat 1 and the lower seat 9; Figure 12 This is a schematic diagram of the specific structure of the actuating boom, through Figure 12 Connector 12-1 and Figure 11 The eighth through hole 11-4 in the middle is connected to the hinge seat. Each actuator arm is connected to a hinge seat at both ends to connect with the upper seat and the lower seat hinge.

[0053] This invention also provides a multi-degree-of-freedom coupling loading test method for intervertebral discs and intervertebral disc prostheses based on the Stewart platform. The test is performed using the aforementioned device and includes the following steps:

[0054] Adjust the telescopic adjustment shaft 8 to a suitable length, then place the intervertebral disc prosthesis test sample 5, which is connected to the upper and lower vertebral bodies, on the lower clamp 6 and clamp the lower vertebral body with the lower clamp 6; control the upper seat 1 to move to the position where the upper clamp 4 contacts the upper vertebral body, and clamp the upper vertebral body with the upper clamp 4.

[0055] The test method is selected on the control unit 11 and the test is started. The control unit 11 controls the drive unit 12 to drive multiple actuator arms 10 to move in coordination, control the upper seat 1 to move to simulate three-dimensional movement similar to the natural spine, thereby changing the movement of the upper vertebral body, so that the intervertebral disc prosthesis test sample 5 completes the required movement.

[0056] During the motion, the control unit 11 and the sensor 2 synchronously collect the corresponding displacement data and load data in real time at a certain sampling frequency, and output corresponding six-way force-displacement or torque-rotation curves at the control unit 11 end.

[0057] The motion includes axial compression, flexion and extension, lateral bending, torsion and shear.

[0058] It can be known from the above that the application provides a test method and device based on a Stewart platform, which is lower in cost, more accurate in measurement and characterization, and can couple complex human equivalent six-way physiological loads to an in-vitro intervertebral disc (prosthesis) to evaluate whether the prosthesis can match the three-dimensional motion of human vertebrae after being implanted into the human body, thereby avoiding the occurrence of clinical adverse events. In order to further illustrate the content of the application, the following will be specifically described by way of example 1.

[0059] Example 1

[0060] Adjust the telescopic adjusting shaft 8 to a suitable length, then place the intervertebral disc prosthesis test sample 5 on the lower clamp 6, rotate the clamp screw to clamp the lower vertebral body of the intervertebral disc prosthesis test sample 5, move the upper seat 1 to the upper clamp 4 in contact with the upper cone of the intervertebral disc prosthesis test sample 5, and rotate the clamp screw to clamp the upper cone.

[0061] The computer selects a test method, such as a selected displacement test, and sequentially performs the following tests: ① compression 1.5 mm, return to zero position ② shear motion 2 mm along the X direction, return to zero position ③ shear motion 2 mm along the Y direction, return to zero position ④ flexion and extension ± 7° along the X axis, return to zero position ⑤ lateral bending ± 7° along the Y axis, return to zero position ⑥ torsion ± 7° along the Z axis, return to zero position. After starting the test, the driving motor controls the coordinated motion of the six actuating arms 10, controls the motion of the upper seat 1 to simulate the three-dimensional motion of the human spine, and changes the motion of the upper vertebral body of the intervertebral disc prosthesis test sample 5, so that the intervertebral disc prosthesis test sample 5 completes the axial compression Fz, flexion and extension Mx, lateral bending My, torsion Tz, shear Fx / Fy and other motion characteristics.

[0062] During the motion, the computer built-in displacement and the sensor 2 synchronously collect the corresponding six-way displacement and load data in real time at a certain sampling frequency, and output corresponding six-way force-displacement / torque-rotation curves at the computer 11 end, as shown in Figure 13 (a) is a three-way force-displacement curve, and (b) is a three-way force-rotation curve.

[0063] Obviously, those skilled in the art can make various modifications and variations to the application without departing from the spirit and scope of the application. Thus, if these modifications and variations of the application fall within the scope of the claims of the application and their equivalent technologies, these modifications and variations are also intended to be included.

Claims

1. A multi-degree-of-freedom coupling loading test device for intervertebral disc and intervertebral disc prosthesis based on a Stewart platform, characterized in that, The device comprises an upper seat (1) and a lower seat (9), a plurality of actuating arms (10) are distributed between the upper seat (1) and the lower seat (9), both ends of each actuating arm (10) are movably connected with the upper seat (1) and the lower seat (9) respectively, each actuating arm (10) can axially stretch and retract, and can rotate relative to the surface of the upper seat (1) and the lower seat (9), each actuating arm (10) is electrically connected with a driving unit (12), the driving unit (12) is electrically connected with a control unit (11), the control unit (11) is used for controlling the driving unit (12) to drive the plurality of actuating arms (10) to move coordinately, so that the upper seat (1) performs three-direction translational movement and three-direction rotation around the axis, and the control unit (11) collects displacement data in the movement process. A sensor (2) and an upper clamp (4) are sequentially mounted on the lower surface of the upper seat (1), the upper clamp (4) is used for clamping the upper cone of an intervertebral disc prosthesis test sample (5), the sensor (2) is electrically connected with the control unit (11), the sensor (2) is used for detecting load data and transmitting the load data to the control unit (11), one end of an extension adjusting shaft (8) is mounted on the upper surface of the lower seat (9), the other end of the extension adjusting shaft (8) is provided with a lower clamp (6), the extension adjusting shaft (8) is used for adjusting the distance between the upper clamp (4) and the lower clamp (6), and the lower clamp (6) is used for clamping the lower cone of the intervertebral disc prosthesis test sample (5). In the movement process, the control unit (11) outputs a test result according to the collected displacement data and load data.

2. The multi-DOF coupled loading testing device for intervertebral disc and intervertebral disc prosthesis based on Stewart platform according to claim 1, characterized in that, The test result is a six-way force-displacement or torque-rotation curve.

3. The multi-DOF coupled loading testing device for intervertebral disc and intervertebral disc prosthesis based on Stewart platform according to claim 1, characterized in that, The sensor (2) and the upper clamp (4) are fixedly connected through a first flange (3).

4. The multi-DOF coupled loading testing device for intervertebral disc and intervertebral disc prosthesis based on Stewart platform according to claim 1, characterized in that, The upper end of the extension adjusting shaft (8) is fixedly connected with the lower clamp (6) through a second flange (7), and the lower end of the extension adjusting shaft (8) is fixed on the upper surface of the lower seat (9) through a third flange.

5. The multi-DOF coupled loading testing device for intervertebral disc and intervertebral disc prosthesis based on Stewart platform according to claim 1, characterized in that, The driving unit (12) is a driving motor, and the control unit (11) is a computer.

6. A method for multi-degree-of-freedom coupling loading test of intervertebral disc and intervertebral disc prosthesis based on a Stewart platform, characterized in that, The device is used for testing, and the testing comprises the following steps: Adjusting the extension adjusting shaft (8) to a proper length, placing the intervertebral disc prosthesis test sample (5) connected with the upper vertebral body and the lower vertebral body on the lower clamp (6), clamping the lower vertebral body by the lower clamp (6), moving the upper seat (1) to the position where the upper clamp (4) contacts the upper vertebral body, and clamping the upper vertebral body by the upper clamp (4); Selecting a test method on the control unit (11), starting the test, controlling the driving unit (12) to drive the plurality of actuating arms (10) to move coordinately, controlling the movement of the upper seat (1) to simulate the three-dimensional movement of a natural spine, and changing the movement of the upper vertebral body so that the intervertebral disc prosthesis test sample (5) completes the required movement; In the movement process, the control unit (11) and the sensor (2) respectively collect corresponding displacement data and load data in real time and synchronously at a certain sampling frequency, and output the test result at the control unit (11) end.

7. The multi-DOF coupled loading test method for intervertebral disc and intervertebral disc prosthesis based on the Stewart platform according to claim 6, characterized in that, When displacement loading is performed on the intervertebral disc prosthesis test sample (5), the control unit (11) directly controls the driving unit (12) to drive the plurality of actuating arms (10) to move in coordination, and the control unit (11) collects displacement data in the movement process.

8. The multi-DOF coupled loading test method for intervertebral disc and intervertebral disc prosthesis based on the Stewart platform according to claim 6, characterized in that, When load loading is performed on the intervertebral disc prosthesis test sample (5), the control unit (11) controls the driving unit (12) to drive the plurality of actuating arms (10) to move in coordination according to the load data feedback value returned by the sensor (2).

9. The multi-DOF coupled loading test method for intervertebral disc and intervertebral disc prosthesis based on the Stewart platform according to claim 6, characterized in that, In the movement process, the control unit (11) outputs a six-way force-displacement or torque-rotation curve according to the collected data.

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