An artificial joint friction and wear test system swing angle measurement and calibration device

Abstract

The application relates to a swing angle measuring and calibrating device of an artificial joint friction and wear test system, which is characterized by comprising a first connecting shaft, a second connecting shaft, a locking sleeve, a special-shaped flange, an incremental encoder and a laser instrument, the head of the first connecting shaft is used for fixedly connecting a first swing arm of the artificial joint friction and wear test system, the tail of the first connecting shaft is vertically provided with the second connecting shaft, the second connecting shaft is installed at the upper end of the special-shaped flange, the installation position of the second connecting shaft can be adjusted along a radial direction of the upper end of the special-shaped flange, and the lower end of the special-shaped flange is coaxially provided with the incremental encoder; and the laser instrument is coaxially installed at the center of the upper end of the special-shaped flange. The device can convert the swing of the swing arm of the artificial joint friction and wear test system into the self-rotation of the incremental encoder, so that the swing angle of the swing arm of the artificial joint friction and wear test system can be accurately calibrated.

Description

Technical Field

[0001] This invention belongs to the field of test instrument calibration, specifically a device for measuring and calibrating the swing angle of an artificial joint friction and wear test system. Background Technology

[0002] The advent and development of artificial joint replacement surgery has greatly improved the health and quality of life for many patients with joint diseases. However, implanted artificial joints experience friction and wear in daily life, which can lead to a series of diseases such as joint subsidence, tissue adhesion, and osteolysis, seriously affecting patients' well-being. Therefore, friction and wear testing before artificial joints leave the factory is a crucial step in ensuring their performance during service.

[0003] The latest artificial joint friction and wear testing system uses a swing arm to swing the artificial joint prosthesis relative to the artificial joint socket. The swing angle of the swing arm is a crucial measurement and control parameter for this system. However, a precise calibration device and method for the swing arm angle is currently lacking; the rotation angle of the axis connected to the swing arm is simply used as the swing arm angle. Since mechanical connections inevitably have some clearance, and the swing arm vibrates significantly during high-frequency motion, an error will occur between the swing arm angle and the rotation angle of the axis. Therefore, to improve the accuracy and stability of the artificial joint friction and wear testing system, it is necessary to calibrate the measurement and control precision of the swing arm angle. Summary of the Invention

[0004] To address the problem of low accuracy in measuring and controlling the swing angle of the artificial joint friction and wear testing system, this invention provides a swing angle calibration device for an artificial joint friction and wear testing system. This device can effectively calibrate the swing angle of the artificial joint friction and wear testing system. Furthermore, the calibration device is highly adaptable, easy to operate, and has a reliable structure.

[0005] The technical problem solved by this invention is achieved through the following technical solution:

[0006] A device for measuring and calibrating the swing angle of an artificial joint friction and wear testing system is characterized by comprising a first connecting shaft, a second connecting shaft, a locking sleeve, a special-shaped flange, an incremental encoder, and a laser. The head of the first connecting shaft is used to fix and connect the first swing arm of the artificial joint friction and wear testing system. The tail of the first connecting shaft is vertically mounted with the second connecting shaft, which is installed on the upper end of the special-shaped flange. The installation position of the second connecting shaft can be adjusted along a radius of the upper end of the special-shaped flange. The incremental encoder is coaxially mounted on the lower end of the special-shaped flange. The laser is coaxially mounted at the center of the upper end of the special-shaped flange.

[0007] Furthermore, the head of the first connecting shaft is provided with a keyway, which is used to connect the free end of the first swing arm.

[0008] Furthermore, the tail of the first connecting shaft is coaxially provided with a mounting shaft with a diameter smaller than that of the middle part of the first connecting shaft. The mounting shaft is fitted onto the mounting groove of the second connecting shaft. The tail of the mounting shaft is provided with an external thread and is coaxially engaged with a locking sleeve. The locking sleeve can clamp and fix the second connecting shaft.

[0009] Moreover, the mounting groove is an arc groove structure, and the second mounting shaft can be rotated and fixed about the first mounting shaft.

[0010] Furthermore, two symmetrically arranged L-shaped support plates are radially arranged on one side of the upper end of the special-shaped flange. Each L-shaped support plate is provided with an installation groove, and bolts that can be connected to the second connecting shaft are installed in the installation groove.

[0011] Furthermore, a radially arranged square groove is left between the two symmetrically arranged L-shaped support plates, and the square groove is sized to match the square key at the lower center of the second connecting shaft.

[0012] Furthermore, this device is used to test an artificial joint friction and wear test system. The artificial joint friction and wear test system includes a second swing arm driven by a second swing arm drive motor. A first swing arm is mounted on the cantilever end of the second swing arm. The first swing arm is connected to a first swing arm drive motor. The rotation axes of the first swing arm drive motor and the second swing arm drive motor are perpendicular to each other.

[0013] Furthermore, this device is used to detect the swing angle calibration of the first swing arm, and the steps are as follows:

[0014] Step 1: Connect the cantilever end of the first swing arm to the head of the first connecting shaft, rotate and adjust the position of the second connecting shaft so that the second connecting shaft is parallel to the first swing arm, and at the same time, the laser beam is parallel to the first swing arm.

[0015] Step 2: Adjust the radial position of the second connecting shaft on the irregular flange so that the beam axis of the laser instrument coincides with the rotation axis of the first swing arm drive motor;

[0016] Step 3: Start the first swing arm drive motor to drive the first swing arm to swing, and keep the laser beam coaxial with the rotation axis of the first swing arm drive motor.

[0017] Step 4: According to the preset swing angle, control the first swing arm drive motor to rotate at an arbitrary angle by setting parameters through the control software, control the first swing arm to swing to the corresponding angle, and the incremental encoder converts the swing angle of the first swing arm into the spin angle to measure the actual swing angle of the first swing arm.

[0018] Step 5: Repeat step 4 five times or more. Based on the difference between the measured actual swing angle and the preset swing angle, adjust the preset swing angle and the parameters of the control software so that the swing angle displayed by the control software is the same as the actual swing angle, and complete the calibration.

[0019] Furthermore, this device is used to detect the swing angle calibration of the second swing arm, and the steps are as follows:

[0020] Step 1: Connect the cantilever end of the first swing arm to the head of the first connecting shaft, control the first swing arm drive motor to rotate the first swing arm to a position perpendicular to the second swing arm, adjust the second connecting shaft to make it parallel to the second swing arm, and make the laser beam parallel to the second swing arm.

[0021] Step 2: Adjust the relative position of the irregular flange and the second connecting shaft so that the beam axis of the laser instrument coincides with the rotation axis of the second swing arm drive motor, and then fix the irregular flange.

[0022] Step 3: Start the second swing arm drive motor to drive the second swing arm to swing, and keep the laser beam coaxial with the rotation axis of the second swing arm drive motor;

[0023] Step 4: According to the preset swing angle, control the rotation of the second swing arm drive motor to an arbitrary angle by setting parameters through the control software, control the second swing arm to swing to the corresponding angle, and the incremental encoder converts the swing angle of the second swing arm into the spin angle to measure the actual swing angle of the first swing arm.

[0024] Step 5: Repeat step 4 five times or more. Based on the difference between the measured actual swing angle and the preset swing angle, adjust the preset swing angle and the parameters of the control software so that the swing angle displayed by the control software is the same as the actual swing angle, and complete the calibration.

[0025] The advantages and positive effects of this invention are:

[0026] 1. Through its unique structural design, this device can convert the swing of the swing arm of the artificial joint friction and wear testing system into the spin motion of the incremental encoder, thereby achieving precise calibration of the swing angle of the swing arm of the artificial joint friction and wear testing system.

[0027] 2. This device can complete the calibration of multiple swing angles of the artificial joint friction and wear test system in one installation by adjusting the relative position of the second connecting shaft and the first connecting shaft. It is characterized by simple operation and high efficiency.

[0028] 3. This device can calibrate the swing angle of swing arms of different sizes in the artificial joint friction and wear test system by adjusting the relative position of the special flange and the second connecting shaft, and has the characteristics of strong universality. Attached Figure Description

[0029] Figure 1 Artificial joint friction and wear testing system pendulum angle calibration device.

[0030] Figure 2 : Schematic diagram for first swing arm swing angle calibration.

[0031] Figure 3 : Schematic diagram for second swing arm swing angle calibration.

[0032] Figure 4 : Schematic diagram of the first connecting shaft structure.

[0033] Figure 5 : Schematic diagram of the second connecting shaft structure.

[0034] Figure 6 : Schematic diagram of locking sleeve structure.

[0035] Figure 7 Schematic diagram of irregular flange structure.

[0036] Reference numerals: 1. First connecting shaft; 2. Second connecting shaft; 3. Locking sleeve; 4. Special-shaped flange; 5. Incremental encoder; 6. Laser device; 7. First swing arm; 8. Second swing arm; 9. First swing arm connecting flange; 10. First swing arm drive motor; 11. Second swing arm drive motor; 101. Keyway; 102. Mounting shaft; 103. External thread section; 201. Mounting groove; 202. Fixed threaded hole; 203. Square key; 301. Internal thread section; 401. Mounting countersunk hole; 402. L-shaped support plate; 403. Mounting long groove; 404. Mounting threaded hole. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0038] The terms "horizontal" and "vertical" mentioned in this embodiment are used to describe the relative position of the structure and do not limit the installation direction of the structure.

[0039] A pendulum angle measurement and calibration device for an artificial joint friction and wear testing system, see attached document. Figure 1 - Appendix Figure 7 It includes a first connecting shaft 1, a second connecting shaft 2, a locking sleeve 3, a special-shaped flange 4, an incremental encoder 5, and a laser instrument 6.

[0040] The first connecting shaft 1 is used to connect with the first swing arm of the artificial joint prosthesis encapsulation fixture in the artificial joint friction and wear testing system. Its head is provided with a keyway 101 that mates with the end of a typical artificial joint prosthesis encapsulation fixture for fixing to the first swing arm. Its tail is provided with a mounting shaft 102 of relatively small diameter for mounting the second connecting shaft 2. The rear end of the mounting shaft 102 is also provided with an external thread section 103 for mates with the internal thread section 301 at the end of the locking sleeve 3.

[0041] The second connecting shaft 2 can be installed at any angle at the tail of the first connecting shaft 1. It has a mounting groove 201 on its upper part, which can cooperate with the mounting shaft 102 at the tail of the first connecting shaft 1, and is fixed to the tail of the first connecting shaft 1 by a locking sleeve 3. The bottom of the second connecting shaft 2 has a fixing threaded hole 202 for fixing to the irregular flange 3. A square key 203 is also provided at its bottom to further determine the fixed position of the second connecting shaft 2 on the irregular flange 3.

[0042] The locking sleeve 3 has an internal thread section 301 at its end, which is used to cooperate with the external thread section 103 at the tail of the first connecting shaft 1 to press and fix the second connecting shaft 2 to the first connecting shaft 1.

[0043] The irregular flange 4 connects the second connecting shaft 2 and the incremental encoder 5. Two symmetrically arranged L-shaped support plates 402 are mounted on top. Each L-shaped support plate has a mounting slot 403, which can be bolted to any position on the second connecting shaft 2 using the threaded holes 202 at the bottom of the second connecting shaft 2. Simultaneously, a square keyway formed in the middle of the symmetrically arranged L-shaped support plates 402 can mate with the square key 203 at the bottom of the second connecting shaft 2, further defining the fixed position of the second connecting shaft 2 on the irregular flange 3. The irregular flange 4 has six countersunk holes 401 around its circumference for mounting the incremental encoder 5. A threaded hole 404 is located in the center for mounting the laser device 6.

[0044] The incremental encoder 5 is coaxially mounted below the irregular flange 4 to accurately measure the swing angle of the swing arm in order to complete the calibration work.

[0045] The laser instrument 6 is coaxially mounted above the center of the irregular flange 4 to assist in adjusting the detection position of the irregular flange 4 relative to the second connecting shaft 2.

[0046] The latest artificial joint friction and wear testing system has two completely independent swing arms, such as Figure 2As shown, the second swing arm 8 is connected to the second swing arm drive motor 11, and the first swing arm drive motor 10 is mounted on the second swing arm 8 via the first swing arm connecting flange 9. The first swing arm 7 passes through the second swing arm 8 and is fixed to the rotating shaft of the first swing arm drive motor 10. The first swing arm 7 can convert the rotational motion of the first swing arm drive motor 10 into swing motion, and the second swing arm 8 can convert the rotational motion of the second swing arm drive motor 11 into swing motion. The swing angle calibration device of the artificial joint friction and wear testing system of the present invention can be used to calibrate the swing angle of the first swing arm 7 as well as the swing angle of the second swing arm 8.

[0047] The schematic diagram of the pendulum angle calibration device of the artificial joint friction and wear testing system described in this invention applied to the pendulum angle calibration of the first pendulum arm 7 is shown below. Figure 2 As shown, firstly, the swing angle calibration device of the artificial joint friction and wear testing system of the present invention is installed on the first swing arm 7 via the first mounting shaft 1. The relative position of the second connecting shaft 2 on the first connecting shaft 1 is adjusted so that it is parallel to the first swing arm 7. At this time, the laser instrument 6 is also parallel to the first swing arm 7. Then, the installation position of the irregular flange 4 is moved along the direction of the mounting groove 403 so that the axis of the laser beam emitted by the laser instrument 6 coincides with the axis of rotation of the first swing arm drive motor 10. The irregular flange 4 is fixed on the second connecting shaft 2 using bolts through the mounting groove 403 and the fixing threaded hole 202. At this time, the first swing arm drive motor 10 is controlled to drive the first swing arm 7 to rotate. During the rotation, the spot position formed by the laser emitted by the laser instrument 6 on the first swing arm 7 should remain stationary. Finally, the swing angle calibration of the first swing arm 7 begins. The first swing arm drive motor 10 is rotated by the control software to drive the first swing arm 7 to swing at an arbitrary angle. The incremental encoder 5 converts the swing angle into a spin angle using a calibration device. The actual swing angle of the first swing arm 7 will be displayed in the incremental encoder 5. By modifying the parameters of the control software of the artificial joint friction and wear test system, the display value of the first swing angle in the control software is made equal to the display value of the incremental encoder, thus completing one calibration. To eliminate random errors and obtain universal results, the above process is generally repeated five times to complete the calibration of the rotation angle of the tensile and torsion testing machine.

[0048] A schematic diagram of the pendulum angle calibration device of the artificial joint friction and wear testing system described in this invention applied to the pendulum angle calibration of the second pendulum arm 8 is shown below. Figure 3As shown, firstly, the first swing arm drive motor 10 is controlled to rotate the first swing arm 7 to a position perpendicular to the second swing arm 8. Then, the relative position of the second connecting shaft 2 on the first connecting shaft 1 is adjusted so that it is parallel to the second swing arm 7. At this time, the laser instrument 6 is also parallel to the second swing arm 7. Next, the installation position of the irregular flange 4 is moved along the direction of the mounting slot 403 so that the axis of the laser beam emitted by the laser instrument 6 is aligned with the axis of rotation of the second swing arm drive motor 11, and the irregular flange 4 is fixed. At this time, the second swing arm drive motor 11 is controlled to rotate the second swing arm 8. During the rotation, the spot position formed by the laser emitted by the laser instrument 6 on the second swing arm 8 should remain stationary. Finally, the calibration of the swing angle of the second swing arm 8 begins, and the specific calibration process is the same as that of the first swing arm 7.

[0049] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A swing angle measurement and calibration method for an artificial joint friction and wear test system, characterized in that: The swing angle measurement and calibration device comprises a first connecting shaft (1), a second connecting shaft (2), a locking sleeve (3), a special-shaped flange (4), an incremental encoder (5) and a laser instrument (6), the head of the first connecting shaft (1) is used for fixedly connecting a first swing arm (7) of an artificial joint friction and wear test system, the tail of the first connecting shaft (1) is vertically provided with the second connecting shaft (2), the second connecting shaft (2) is installed at the upper end of the special-shaped flange (4), the installation position of the second connecting shaft (2) can be adjusted along a radial direction of the upper end of the special-shaped flange (4), and the lower end of the special-shaped flange (4) is coaxially provided with the incremental encoder (5); the laser instrument (6) is coaxially installed at the center of the upper end of the special-shaped flange (4); The artificial joint friction and wear test system comprises a second swing arm (8) driven by a second swing arm driving motor (11), the cantilever end of the second swing arm (8) is provided with the first swing arm (7), the first swing arm (7) is connected with a first swing arm driving motor (10), and the rotation shafts of the first swing arm driving motor (10) and the second swing arm driving motor (11) are perpendicular to each other; The swing angle measurement and calibration steps of the first swing arm (7) are as follows: Step S1, the cantilever end of the first swing arm (7) is connected with the head of the first connecting shaft (1), the position of the second connecting shaft (2) is adjusted to make the second connecting shaft (2) parallel to the first swing arm (7), and the light beam of the laser instrument (6) is parallel to the first swing arm (7); Step S2, the radial position of the second connecting shaft (2) on the special-shaped flange (4) is adjusted, and the light beam axis of the laser instrument (6) is coincident with the rotation axis of the first swing arm driving motor (10); Step S3, the first swing arm driving motor (10) is started to drive the first swing arm (7) to swing, and the light beam of the laser instrument (6) remains coaxial with the rotation axis of the first swing arm driving motor (10); Step S4, according to a preset swing angle, the rotation of the first swing arm driving motor (10) is controlled to rotate an arbitrary angle by setting parameters of control software, the first swing arm (7) is swung to a corresponding angle, the incremental encoder (5) converts the swing angle of the first swing arm (7) into a self-rotation angle, and the actual swing angle of the first swing arm (7) is measured; Step S5, the step S4 is repeated more than five times, the preset swing angle and the parameters of the control software are adjusted according to the difference between the measured actual swing angle and the preset swing angle, the swing angle displayed by the control software is the same as the actual swing angle, and the calibration is completed; The swing angle measurement and calibration steps of the second swing arm (8) are as follows: Step M1, the cantilever end of the first swing arm (7) is connected with the head of the first connecting shaft (1), the first swing arm driving motor (10) is controlled to drive the first swing arm (7) to rotate to a position perpendicular to the second swing arm (8), the second connecting shaft (2) is adjusted to make it parallel to the second swing arm (8), and the light beam of the laser instrument (6) is parallel to the second swing arm (8); Step M2, after the relative position of the special-shaped flange (4) and the second connecting shaft (2) is adjusted to make the light beam axis of the laser instrument (6) coincident with the rotation axis of the second swing arm (8) driving motor, the special-shaped flange (4) is fixed. Step M3, start the second swing arm drive motor (11) to drive the second swing arm (8) to swing, and the light beam of the laser instrument (6) remains coaxial with the rotation axis of the second swing arm drive motor (11); Step M4, according to the preset swing angle, set the parameters of the control software to control the rotation of the second swing arm drive motor (11) by an arbitrary angle, control the second swing arm (8) to swing to the corresponding angle, and the incremental encoder (5) converts the swing angle of the second swing arm (8) into the self-rotation angle, and measures the actual swing angle of the second swing arm (8); Step M5, repeat step M4 more than five times, according to the difference between the measured actual swing angle and the preset swing angle, adjust the preset swing angle and the parameters of the control software, so that the swing angle displayed by the control software is the same as the actual swing angle, and the calibration is completed.

2. The swing angle measurement and calibration method of the artificial joint friction and wear test system according to claim 1, characterized in that: The head of the first connecting shaft (1) is provided with a key groove (101), and the key groove (101) is used to connect the free end of the first swing arm (7).

3. The method of claim 1, wherein: The tail of the first connecting shaft (1) is coaxially provided with a mounting shaft (102) with a diameter smaller than the middle part of the first connecting shaft (1), the mounting shaft (102) is assembled on the mounting groove (201) of the second connecting shaft (2), the tail of the mounting shaft (102) is provided with external threads and coaxially engages a locking sleeve (3), and the locking sleeve (3) can clamp and fix the second connecting shaft (2).

4. The swing angle measurement and calibration method of the artificial joint friction and wear test system according to claim 3, characterized in that: The mounting groove (201) is a circular arc groove structure, and the second mounting shaft (102) can rotate around the first mounting shaft (102) to adjust the fixed position.

5. The method of claim 1, wherein: The upper end of the special-shaped flange (4) is radially provided with two symmetrically arranged L-shaped supporting plates, and the two L-shaped supporting plates are provided with mounting long grooves, and the mounting long grooves are provided with bolts which can be connected with the second connecting shaft (2).

6. The swing angle measurement and calibration method of the artificial joint friction and wear test system according to claim 5, characterized in that: The two symmetrically arranged L-shaped supporting plates are provided with a radially arranged square long groove, and the square long groove is matched with the square key size of the middle part of the lower end of the second connecting shaft (2).

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