Artificial joint friction wear simulation testing machine and testing method thereof

Abstract

The invention discloses an artificial joint frictional wear simulation testing machine and a testing method thereof. The testing machine comprises a motion loading module, a sample clamping module and a motion coupling module, the motion loading module mainly drives an upper sample of the sample clamping module to generate fundamental frequency swing through a double four-bar-planetary gear train composite mechanism, and the sample clamping module integrates a quick disassembly and assembly clamp and a temperature control lubrication system to fix various joint prostheses and simulate the physiological environment of the human body. And the motion coupling module cooperates with the motion loading module based on the six-degree-of-freedom parallel platform to realize composite action and suppress vibration interference. Through cooperative control of the three modules, the problems that an existing artificial joint friction and wear simulation testing machine is limited to a single joint type and cannot adapt to various artificial joint prostheses, and the degree of freedom of motion is limited, so that various motion forms of the artificial joint cannot be completely restored are solved.

Description

Technical Field

[0001] This invention belongs to the field of medical device testing technology, and relates to an artificial joint friction and wear simulation testing machine. This invention also relates to the testing method of the artificial joint friction and wear simulation testing machine. Background Art

[0002] Against the backdrop of an aging population and a high incidence of osteoarthritis, the demand for artificial joint replacement surgery continues to rise, with an annual demand exceeding two million cases in my country. The long-term service performance of artificial joints is highly dependent on precise in vitro testing. Although the current mainstream equipment for in vitro friction and wear simulation testing is technically mature and widely used, it still has the following problems: (1) The simulation testing equipment lacks versatility. Existing equipment is mostly limited to single joint testing, such as a dedicated simulator for the knee joint or a biaxial testing machine for the hip joint, which is difficult to be compatible with the evaluation needs of diverse prostheses for the ankle and shoulder joints; (2) The coverage of motion dimensions is insufficient. The testing machine can only simulate a limited range of joint motions. For example, the flexion angle range of a multiaxial hip joint testing machine indicates that its working conditions cannot fully cover all types of motions of the human hip joint. These shortcomings make it difficult for existing technologies to meet the requirements of high biomimetic and low-cost testing of various types of joint prostheses. Therefore, it is urgent to develop a universal artificial joint friction and wear simulation testing device that has both multi-joint adaptation capabilities and full-degree-of-freedom motion accuracy. Summary of the Invention

[0003] The purpose of this invention is to provide an artificial joint friction and wear simulation testing machine, which solves the problem that existing artificial joint friction and wear simulation testing machines cannot adapt to various artificial joint prostheses and cannot fully reproduce various movement modes of artificial joints.

[0004] Another object of the present invention is to provide a test method for an artificial joint friction and wear simulation test machine.

[0005] The first technical solution adopted in this invention is an artificial joint friction and wear simulation testing machine, including a profile frame, a motion coupling module provided inside the profile frame, and the motion coupling module connected to the motion loading module through the sample clamping module.

[0006] The first technical solution of this invention is further characterized by: The motion loading module includes a servo motor, the output shaft of which is connected to a planetary reducer. The output shaft of the planetary reducer is connected to a double four-bar-planetary gear train composite mechanism via a coupling. The double four-bar-planetary gear train composite mechanism is fixedly connected to a support base, which is fixedly connected to a profile frame.

[0007] The double four-bar planetary gear train compound mechanism includes an input shaft A, which is supported on a support base by bearings and connected to one end of a crank A via a spline. The other end of crank A is coaxially connected to one end of a connecting rod A, and the other end of connecting rod A is coaxially connected to one end of a rocker arm A. The other fixed end of rocker arm A is supported on the support base by bearings. The shaft connecting one end of rocker arm A to connecting rod A is also coaxially connected to one end of connecting rod B. The other end of connecting rod B is coaxially connected to one end of connecting rod C, and the other end of connecting rod C is coaxially connected to the upper end of rocker arm B. The end and middle parts of rocker arm B are respectively connected to gear A and gear B. Gear A meshes with an arc-shaped rack fixed on the support base, and gear B meshes with gear C fixedly supported on the support base. Gear C is coaxially connected to the end rocker arm.

[0008] Crank A, connecting rod A, rocker A, and support base together constitute the crank-rocker mechanism.

[0009] Rocker A, link B, link C, and rocker B together constitute a four-bar linkage.

[0010] Gear A, gear B, the arc rack, and gear C together constitute a planetary gear train.

[0011] The sample clamping module includes an upper sample connector and a lower sample connector, which are respectively mounted on a pneumatic spring chuck and a centering ring clamp to achieve centering. The pneumatic spring chuck is fixedly connected to the motion loading module, and the centering ring clamp is fixedly connected to the motion coupling module. The lower end of the upper sample connector and the upper end of the lower sample connector are respectively connected to the upper joint mating part and the lower joint mating part of the artificial joint pair.

[0012] A rubber sleeve is installed at the connection between the upper and lower sample connectors.

[0013] The motion coupling module includes a Stewart platform, with a shock-absorbing platform located beneath it.

[0014] The Stewart platform includes an upper rigid platform, the upper end of which is fixedly connected to the bottom of the centering and circumferential clamp in the sample clamping module. The lower end of the upper rigid platform is connected to the upper end of six electric cylinders through six sets of ball joints. The lower end of the six electric cylinders is fixed to the lower rigid platform through six sets of Hooke joints. The ball joints and Hooke joints are arranged in pairs, and the ball joints on the upper rigid platform and the Hooke joints on the lower rigid platform are arranged asymmetrically to form an asymmetrical constraint structure.

[0015] The second technical solution adopted in this invention is a test method for an artificial joint friction and wear simulation testing machine, the specific process of which is as follows: Clamping stage: The pneumatic spring clamp and the centering ring clamp clamp the upper and lower mating parts of the artificial joint to be tested through the standardized connection interfaces at the lower end of the upper sample connector and the upper end of the lower sample connector, respectively, forming a joint mating pair; Friction and wear testing phase: The motion loading module generates fundamental frequency oscillation through a servo motor-driven double four-bar-planetary gear train composite mechanism. Specifically, the servo motor drives the input shaft A to rotate, which in turn drives the crank A to rotate, which in turn drives the rocker arm A to reciprocate via the connecting rod A. The reciprocating oscillation of the rocker arm A simultaneously drives the connecting rods B and C, which in turn drive the rocker arm B to reciprocate. The reciprocating oscillation of the rocker arm B drives the gear A to reciprocate along the track of the arc rack, which in turn drives the gear C to reciprocate. The reciprocating rotation of the gear C drives the end swing arm to oscillate. The Stewart platform of the motion coupling module achieves six degrees of freedom motion of the upper rigid platform through six sets of electric cylinders that extend and retract vertically and rotate freely around six sets of ball joints and six sets of Hooke joints. The shock absorption platform provides shock absorption. During the simulation test, sensors arranged at the artificial joints collect dynamic load and wear data.

[0016] The beneficial effects of this invention are as follows: 1. This artificial joint friction and wear simulation testing machine mainly consists of three modules: a motion loading module, a sample clamping module, and a motion coupling module. The motion loading module drives the upper sample of the sample clamping module to generate fundamental frequency oscillation through a double four-bar-planetary gear composite mechanism. The sample clamping module fixes various types of joint prostheses and simulates the human physiological environment through quick-release clamps and a temperature-controlled lubrication system. The motion coupling module uses a six-degree-of-freedom parallel platform (Stewart platform) to work in conjunction with the motion loading module to achieve composite movements and suppress vibration interference. It can adapt to the reproduction requirements of various human movement forms of various artificial joint prostheses, and at the same time, it fully simulates the internal environment of the joint, realizing highly biomimetic and low-cost friction and wear simulation testing of various types of joint prostheses.

[0017] 2. This invention relies on a dual four-bar-planetary gear train composite mechanism and a master-slave collaborative mechanism of a six-degree-of-freedom parallel platform to achieve full-degree-of-freedom motion simulation of artificial joints, meeting the requirements for reproducing various human movement forms. The dual four-bar-planetary gear train composite mechanism forms a high-rigidity power source through a servo motor directly driving a planetary reducer. The dual four-bar mechanism, combined with an arc-shaped guide rail planetary gear, achieves high-stability motion conversion with large swing angles. The Stewart platform can dynamically decouple clinical gait data into electric cylinder extension and retraction commands. Through the Hooke hinge-ball hinge asymmetric constraint architecture, it accurately reproduces complex human biomechanical behaviors such as tibial internal rotation and femoral posterior rolling and sliding during squats, significantly enhancing the clinical relevance of in vitro tests.

[0018] 3. This invention utilizes an air spring and a magnetorheological damper working in tandem to effectively absorb various vibration interferences generated during artificial joint testing. The air spring relies on real-time adjustment of the airbag pressure to absorb periodic low-frequency impacts from walking, jogging, and other conditions; the magnetorheological damper, based on the intelligent fluid viscosity characteristics, precisely dissipates the high-frequency vibration energy caused by transient joint movements. The two work together to effectively eliminate vibration interference under dynamic loads, significantly improving the accuracy and repeatability of friction and wear data measurements. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the artificial joint friction and wear simulation testing machine of the present invention; Figure 2 This is a schematic diagram of the artificial joint friction and wear simulation testing machine of the present invention after removing the profile frame; Figure 3 This is a schematic diagram of the motion loading module of the artificial joint friction and wear simulation testing machine of the present invention; Figure 4 This is a schematic diagram of the double four-bar-planetary gear train composite mechanism (front view) in the motion loading module of the artificial joint friction and wear simulation test machine of the present invention; Figure 5 This is a schematic diagram of the double four-bar-planetary gear train composite mechanism in the motion loading module of the artificial joint friction and wear simulation test machine of the present invention; Figure 6 This is a schematic diagram of the sample clamping module of the artificial joint friction and wear simulation testing machine of the present invention; Figure 7 This is a schematic diagram of the motion coupling module of the artificial joint friction and wear simulation test machine of the present invention.

[0020] In the diagram, 1. Motion loading module, 1-1. Servo motor, 1-2. Planetary reducer, 1-3. Coupling; 1-4. Double four-bar linkage-planetary gear train compound mechanism, 1-4-1. Input shaft A, 1-4-2. End rocker arm; 1-4-3. Crank-rocker mechanism, 1-4-3-1. Crank A, 1-4-3-2. Connecting rod A, 1-4-3-3. Rocker A; 1-4-4. Four-bar linkage, 1-4-4-1. Connecting rod B, 1-4-4-2. Connecting rod C, 1-4-4-3. Rocker B; 1-4-5. Planetary gear train, 1-4-5-1. Gear A, 1-4-5-2. Gear B, 1-4-5-3. Curved rack, 1-4-5-4. Gear C; 1-5. Support base; 1-6. Connecting flange; 2. Sample clamping module, 2-1. Pneumatic spring chuck, 2-2. Upper sample connector, 2-3. Artificial joint fitting, 2-4. Rubber sleeve, 2-5. Lower sample connector, 2-6. Centering ring clamp; 3. Motion coupling module; 3-1. Stewart platform, 3-1-1. Upper rigid platform, 3-1-2. Ball joint, 3-1-3. Electric cylinder, 3-1-4. Hooke joint, 3-1-5. Lower rigid platform; 3-2. Vibration damping platform; 3-2-1. Upper platform; 3-2-2. Air spring; 3-2-3. Magnetorheological damper; 3-2-4. Base. 4. Profile frame. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] Example 1 The overall structure of the artificial joint friction and wear simulation testing machine of this invention is as follows: Figure 1 As shown, Figure 2 This is a schematic diagram of the testing machine after the profile frame has been removed. The testing machine mainly consists of a motion loading module 1, a sample clamping module 2, and a motion coupling module 3. Both the motion loading module 1 and the motion coupling module 3 are fixedly connected to the profile frame 4. The motion loading module 1 is fixedly connected to the top of the sample clamping module 2 via connecting flanges 1-6 and drives the sample clamping module 2. The sample clamping module 2 fixes the artificial joint prosthesis and simulates the physiological environment. The bottom of the sample clamping module 2 is fixedly connected to the motion coupling module 3. The motion coupling module 3 works in conjunction with the motion loading module 1 to achieve compound movements to simulate different movement forms of various joints.

[0023] Example 2 Figure 3 This is a schematic diagram of the motion loading module 1 of the artificial joint friction and wear simulation test machine of the present invention. Figure 4 and Figure 5This is a schematic diagram of the double four-bar-planetary gear train composite mechanism 1-4 in the motion loading module 1. The motion loading module 1 mainly includes a servo motor 1-1, a planetary reducer 1-2, a coupling 1-3, the double four-bar-planetary gear train composite mechanism 1-4, a support base 1-5, and a connecting flange 1-6. The output shaft of the servo motor 1-1 is connected to the planetary reducer 1-2 via a key. The output shaft of the planetary reducer 1-2 is connected to one end of the coupling 1-3. The other end of the coupling 1-3 is connected to the input shaft A1-4-1 of the double four-bar-planetary gear train composite mechanism 1-4. The input shaft A1-4-1 then passes through the internal crank-rocker mechanism 1-4-3, the four-bar linkage 1-4-4, and the planetary gear train 1-4-5 to the end rocker arm 1-4-2. The end rocker arm 1-4-2 of the double four-bar-planetary gear train composite mechanism 1-4 is connected to the inner hole of a connecting flange 1-6 via an outer spiral connection. The double four-bar-planetary gear system composite mechanism 1-4 is fixedly connected to the support base 1-5, and the support base 1-5 is fixedly connected to the profile frame 4.

[0024] Example 3 The double four-bar linkage-planetary gear train compound mechanism 1-4 includes an input shaft A1-4-1, a crank-rocker mechanism 1-4-3, a four-bar linkage 1-4-4, a planetary gear train 1-4-5, and an end rocker arm 1-4-2. The input shaft A1-4-1 is supported on the support base 1-5 by bearings and is connected to the fixed end of the crank A1-4-3-1 by a spline. The other end of the crank A1-4-3-1 is coaxially connected to one end of the connecting rod A1-4-3-2. The other end of the connecting rod A1-4-3-2 is coaxially connected to one end of the rocker arm A1-4-3-3. The other fixed end of the rocker arm A1-4-3-3 is supported on the support base 1-5 by bearings. The crank A1-4-3-1, connecting rod A1-4-3-2, rocker arm A1-4-3-3, and the support base 1-5 that fixes the fixed ends of the crank A1-4-3-1 and rocker arm A1-4-3-3 together constitute the crank-rocker mechanism 1-4-3. The shaft connecting one end of the rocker arm A1-4-3-3 to one end of the connecting rod A1-4-3-2 is also coaxially connected to one end of the connecting rod B1-4-4-1. The other end of the connecting rod B1-4-4-1 is coaxially connected to one end of the connecting rod C1-4-4-2. The other end of the connecting rod C1-4-4-2 is coaxially connected to the upper end of the rocker arm B1-4-4-3. The rocker arm A1-4-3-3, connecting rod B1-4-4-1, connecting rod C1-4-4-2, and rocker arm B1-4-4-3 together constitute a four-bar linkage 1-4-4. The end and middle sections of rocker arm B1-4-4-3 are connected to gears A1-4-5-1 and B1-4-5-2, respectively. Gear A1-4-5-1 meshes with the arc-shaped rack 1-4-5-3 (tooth profile not shown in the figure) fixed on the support base 1-5, and gear B1-4-5-2 meshes with gear C1-4-5-4 fixed on the support base 1-5. Gears A1-4-5-1, B1-4-5-2, the arc-shaped rack 1-4-5-3, and C1-4-5-4 together constitute the planetary gear train 1-4-5. Gear C1-4-5-4 is coaxially connected to the end lever 1-4-2.

[0025] Example 4 Servo motor 1-1 inputs power to input shaft A1-4-1 of the double four-bar-planetary gear train compound mechanism 1-4 via planetary reducer 1-2 and coupling 1-3. The rotational motion of input shaft A1-4-1 is converted into a large-angle stable oscillation of end rocker arm 1-4-2 via crank-rocker mechanism 1-4-3, four-bar mechanism 1-4-4, and planetary gear train 1-4-5. That is, the rotation of input shaft A1-4-1 drives crank A1-4-3-1 to perform circular motion, which in turn drives rocker arm A1-4-3-3 to perform reciprocating oscillation via connecting rod A1-4-3-2. The reciprocating oscillation of rocker arm A1-4-3-3 simultaneously drives connecting rods B1-4-4-1 and C1-4-4-2, ultimately driving rocker arm B1-4-4-3 to perform reciprocating oscillation. The reciprocating motion of rocker arm B1-4-4-3 drives gear A1-4-5-1 to reciprocate along the track of the arc-shaped rack 1-4-5-3, which in turn drives gear C1-4-5-4 to reciprocate. Gear C1-4-5-4 is coaxially connected to the end rocker arm 1-4-2, so the reciprocating rotation of gear C1-4-5-4 drives the end rocker arm 1-4-2 to reciprocate. Therefore, this double four-bar-planetary gear composite mechanism converts the rotational motion of the input shaft A1-4-1 into a large-angle reciprocating motion of the coaxial end rocker arm 1-4-2, and the angle variation range can be adjusted by changing the component dimensions to suit different joint motion simulations.

[0026] Example 5 Figure 6This is a schematic diagram of the sample clamping module 2 of the artificial joint friction and wear simulation testing machine of the present invention. The sample clamping module 2 mainly consists of a pneumatic spring chuck 2-1, an upper sample connector 2-2, an artificial joint mating pair 2-3, a rubber sleeve 2-4, a lower sample connector 2-5, and a centering ring clamp 2-6. The top of the pneumatic spring chuck 2-1 is fixedly connected to the connecting flange 1-6 of the motion loading module 1, and the bottom of the centering ring clamp 2-6 is fixedly connected to the motion coupling module 3. The upper sample connector 2-2 and the lower sample connector 2-5 are respectively installed on the pneumatic spring chuck 2-1 and the centering ring clamp 2-6 to achieve centering. The lower end of the upper sample connector 2-2 and the upper end of the lower sample connector 2-5 are provided with standardized connection interfaces, which are respectively connected to the upper joint mating pair and the lower joint mating pair of the artificial joint mating pair 2-3. The artificial joint fittings 2-3 can accommodate mating pairs of different artificial joint prostheses, such as hip, knee, ankle, and shoulder joints, to achieve non-destructive and efficient clamping of diverse joint prostheses, thus meeting the friction and wear testing requirements of various artificial joint prostheses. Sensors are simultaneously positioned at the artificial joint fittings 2-3 to collect dynamic loads between the artificial joint mating pairs and monitor friction and wear data. The rubber sleeve 2-4, made of medical-grade silicone, is secured to the upper sample connector 2-2 and lower sample connector 2-5 via upper and lower openings, respectively, forming a closed lubricating environment within its cavity. Its corrugated structure simulates the viscoelastic constraint of the joint capsule. Microchannels are provided inside the lower sample connector 2-5, through which biomimetic synovial fluid (containing 25 g / L protein) circulates into the inner cavity of the rubber sleeve 2-4 at a flow rate of 10~100 mL / min until the artificial joint fitting 2-3 is completely submerged. The artificial joint is equipped with 2-3 integrated PID temperature control units (accuracy ±0.5℃) to maintain a constant temperature environment of 37℃, which fully simulates the internal environment of the artificial joint during operation.

[0027] Example 6 Figure 7This is a schematic diagram of the motion coupling module 3 of the artificial joint friction and wear simulation testing machine of the present invention. The motion coupling module 3 mainly consists of two parts: a Stewart platform 3-1 and a shock-absorbing platform 3-2. The Stewart platform 3-1 mainly includes an upper rigid platform 3-1-1, six sets of ball joints 3-1-2, six sets of electric cylinders 3-1-3, six sets of Hooke joints 3-1-4, and a lower rigid platform 3-1-5. The upper end of the upper rigid platform 3-1-1 is fixedly connected to the bottom of the centering and circumferential clamp 2-6 in the sample clamping module 2. The lower end of the upper rigid platform 3-1-1 is connected to the upper end of the six sets of electric cylinders 3-1-3 through the six sets of ball joints 3-1-2, and the lower end of the six sets of electric cylinders 3-1-3 is fixed to the lower rigid platform 3-1-5 through the six sets of Hooke joints 3-1-4. The ball joints 3-1-2 and Hooke joints 3-1-4 are arranged in pairs, with the ball joints 3-1-2 on the upper rigid platform 3-1-1 and the Hooke joints 3-1-4 on the lower rigid platform 3-1-5 arranged asymmetrically, forming an asymmetrical constraint architecture. The Stewart platform 3-1 can dynamically decouple clinical gait data into extension and retraction commands for six sets of electric cylinders 3-1-3 via a control system. These six sets of electric cylinders 3-1-3 extend and retract vertically and rotate freely around the asymmetrically arranged six sets of ball joints 3-1-2 and six sets of Hooke joints 3-1-4, achieving six degrees of freedom motion of the upper rigid platform 3-1-1, thus meeting the requirements for multi-degree-of-freedom motion simulation of artificial joints. The shock-absorbing platform 3-2 mainly consists of the upper platform 3-2-1, four sets of air springs 3-2-2, four sets of magnetorheological dampers 3-2-3, and the base 3-2-4. The upper platform 3-2-1 is fixedly connected to the lower rigid platform 3-1-5 of the Stewart platform 3-1, and then connected to the base 3-2-4 via four sets of air springs 3-2-2 and four sets of magnetorheological dampers 3-2-3. The base 3-2-4 is fixedly connected to the profile frame 4. The air springs 3-2-2 can be adjusted in real time by controlling the airbag pressure to absorb the periodic low-frequency impacts during walking and jogging. The magnetorheological dampers 3-2-3, based on the intelligent fluid viscosity characteristics, can accurately dissipate the high-frequency vibration energy caused by transient joint movements. The air springs 3-2-2 and the magnetorheological dampers 3-2-3, through passive and active control, can reduce the impact of vibration and improve the dynamic simulation accuracy and measurement reliability of artificial joint wear tests.

[0028] Example 7 The working process of the artificial joint friction and wear simulation test machine of the present invention is as follows: (1) In the clamping stage, the pneumatic spring clamp 2-1 and the centering ring clamp 2-6 clamp the upper and lower pairs of the artificial joint to be tested through the standardized connection interfaces at the lower end of the upper sample connector 2-2 and the upper end of the lower sample connector 2-5, respectively, forming a joint pair. The bionic synovial fluid circulates into the inner cavity of the rubber sleeve 2-4 through the microchannel of the lower sample connector 2-5 and is controlled to maintain a constant temperature of 37 ℃; (2) In the friction and wear test stage, the motion loading module 1 drives the double four-bar-planetary gear composite mechanism 1-4 to generate the fundamental frequency oscillation through the servo motor 1-1, that is, the servo motor 1-1 drives the input shaft A1-4-1 to rotate, and the rotation of the input shaft A1-4-1 drives the crank A1-4-3-1 to perform circular motion, which drives the rocker A1-4-3-3 to perform reciprocating oscillation through the connecting rod A1-4-3-2. The reciprocating oscillation of the rocker A1-4-3-3 is the same as the rotation of the input shaft A1-4-3-1. The drive linkages B1-4-4-1 and C1-4-4-2 move, causing the rocker arm B1-4-4-3 to swing back and forth. The rocker arm B1-4-4-3 swings back and forth, causing gear A1-4-5-1 to move back and forth along the track of the arc-shaped rack 1-4-5-3. Gear B1-4-5-2 then drives gear C1-4-5-4 to rotate back and forth. The rotation of gear C1-4-5-4 drives the end rocker arm 1-4-2 to swing at a large angle stably. The Stewart platform 3-1 of the motion coupling module 3 calculates the extension and retraction of the six sets of electric cylinders 3-1-3 based on clinical gait data. Through the vertical extension and retraction of the six sets of electric cylinders 3-1-3 and their free rotation around the six sets of ball joints 3-1-2 and six sets of Hooke joints 3-1-4, the upper rigid platform 3-1-1 achieves six degrees of freedom motion. The damping platform 3-2 utilizes air springs 3-2-2 and magnetorheological dampers 3-2-3 for damping. The double four-bar-planetary gear train composite mechanism 1-4 works in conjunction with the Stewart platform 3-1 to achieve full-degree-of-freedom motion simulation of the artificial joint pairs, meeting the requirements for reproducing various motion forms of each artificial joint. During the simulation test, sensors arranged at the artificial joint pairs 2-3 collect dynamic load and wear debris data.

Claims

1. An artificial joint friction and wear simulation testing machine, characterized in that: It includes a profile frame (4), and a motion coupling module (3) is provided inside the profile frame (4). The motion coupling module (3) is connected to the motion loading module (1) through the sample clamping module (2).

2. The artificial joint friction and wear simulation testing machine according to claim 1, characterized in that: The motion loading module (1) includes a servo motor (1-1), the output shaft of which is connected to a planetary reducer (1-2), and the output shaft of the planetary reducer (1-2) is connected to a double four-bar-planetary gear train composite mechanism (1-4) via a coupling (1-3). The double four-bar-planetary gear train composite mechanism (1-4) is fixedly connected to a support base (1-5), and the support base (1-5) is fixedly connected to a profile frame (4).

3. The artificial joint friction and wear simulation testing machine according to claim 2, characterized in that: The dual four-bar linkage-planetary gear train composite mechanism (1-4) includes an input shaft A (1-4-1), which is supported on a support base (1-5) by bearings and connected to one end of crank A (1-4-3-1) via a spline. The other end of crank A (1-4-3-1) is coaxially connected to one end of connecting rod A (1-4-3-2), and the other end of connecting rod A (1-4-3-2) is coaxially connected to one end of rocker arm A (1-4-3-3). The other fixed end of rocker arm A (1-4-3-3) is supported on the support base (1-5) by bearings. The shaft connecting rocker arm A (1-4-3-3) to one end of connecting rod A (1-4-3-2) is also coaxially connected to connecting rod B (1-4-4-1). One end of the connecting rod B (1-4-4-1) is coaxially connected to one end of the connecting rod C (1-4-4-2). The other end of the connecting rod C (1-4-4-2) is coaxially connected to the upper end of the rocker arm B (1-4-4-3). The end and middle part of the rocker arm B (1-4-4-3) are respectively connected to gear A (1-4-5-1) and gear B (1-4-5-2). Gear A (1-4-5-1) meshes with the arc-shaped rack (1-4-5-3) fixed on the support base (1-5). Gear B (1-4-5-2) meshes with gear C (1-4-5-4) fixed on the support base (1-5). Gear C (1-4-5-4) is coaxially connected to the end swing arm (1-4-2).

4. The artificial joint friction and wear simulation testing machine according to claim 3, characterized in that: The crank A (1-4-3-1), connecting rod A (1-4-3-2), rocker A (1-4-3-3), and support base (1-5) together constitute the crank-rocker mechanism (1-4-3). The rocker arm A (1-4-3-3), link B (1-4-4-1), link C (1-4-4-2), and rocker arm B (1-4-4-3) together constitute a four-bar linkage (1-4-4).

5. The artificial joint friction and wear simulation testing machine according to claim 3, characterized in that: Gear A (1-4-5-1), gear B (1-4-5-2), arc rack (1-4-5-3), and gear C (1-4-5-4) together constitute the planetary gear train (1-4-5).

6. The artificial joint friction and wear simulation testing machine according to claim 3, characterized in that: The sample clamping module (2) includes an upper sample connector (2-2), and the upper sample connector (2-2) and the lower sample connector (2-5) are respectively mounted on the pneumatic spring chuck (2-1) and the centering ring clamp (2-6) to achieve centering. The pneumatic spring chuck (2-1) is fixedly connected to the motion loading module (1), and the centering ring clamp (2-6) is fixedly connected to the motion coupling module (3). The lower end of the upper sample connector (2-2) and the upper end of the lower sample connector (2-5) are respectively connected to the upper joint pair and the lower joint pair of the artificial joint pair (2-3).

7. The artificial joint friction and wear simulation testing machine according to claim 6, characterized in that: A rubber sleeve (2-4) is installed at the connection between the upper sample connector (2-2) and the lower sample connector (2-5).

8. The artificial joint friction and wear simulation testing machine according to claim 6, characterized in that: The motion coupling module (3) includes a Stewart platform (3-1), and a shock-absorbing platform (3-2) is provided below the Stewart platform (3-1).

9. The artificial joint friction and wear simulation testing machine according to claim 8, characterized in that: The Stewart platform (3-1) includes an upper rigid platform (3-1-1). The upper end of the upper rigid platform (3-1-1) is fixedly connected to the bottom of the centering and circling clamp (2-6) in the sample clamping module (2). The lower end of the upper rigid platform (3-1-1) is connected to the upper end of six electric cylinders (3-1-3) through six sets of ball joints (3-1-2). The lower end of the six sets of electric cylinders (3-1-3) is fixed to the lower rigid platform (3-1-5) through six sets of Hooke joints (3-1-4). The ball joints (3-1-2) and Hooke joints (3-1-4) are arranged in pairs. The ball joints (3-1-2) on the upper rigid platform (3-1-1) and the Hooke joints (3-1-4) on the lower rigid platform (3-1-5) are arranged asymmetrically to form an asymmetrical constraint structure.

10. The test method of the artificial joint friction and wear simulation testing machine according to any one of claims 1 to 9, characterized in that: The specific process is as follows: Clamping stage: The pneumatic spring clamp (2-1) and the centering ring clamp (2-6) clamp the upper and lower mating parts of the artificial joint to be tested through the standardized connection interfaces at the lower end of the upper sample connector (2-2) and the upper end of the lower sample connector (2-5) to form a joint mating pair. Friction and wear test stage: The motion loading module (1) drives the double four-bar-planetary gear train compound mechanism (1-4) to generate the fundamental frequency oscillation through the servo motor (1-1). That is, the servo motor (1-1) drives the input shaft A (1-4-1) to rotate. The rotation of the input shaft A (1-4-1) drives the crank A (1-4-3-1) to make circular motion. Through the connecting rod A (1-4-3-2), the rocker A (1-4-3-3) is driven to reciprocate. The reciprocating oscillation of the rocker A (1-4-3-3) simultaneously drives the connecting rod B (1-4-4-1) and the connecting rod C (1-4-4-2) to move, which drives the rocker B (1-4-4-3) to reciprocate. The reciprocating oscillation of the rocker B (1-4-4-3) drives the gear A (1- 4-5-1) The gear moves back and forth along the track of the arc rack (1-4-5-3), and the gear B (1-4-5-2) drives the gear C (1-4-5-4) to rotate back and forth. The gear C (1-4-5-4) rotates back and forth and drives the end swing rod (1-4-2) to swing. The Stewart platform (3-1) of the motion coupling module (3) extends and retracts up and down through six sets of electric cylinders (3-1-3) and rotates freely around six sets of ball joints (3-1-2) and six sets of Hooke joints (3-1-4), realizing the six degrees of freedom of the upper rigid platform (3-1-1). The shock absorption platform (3-2) performs shock absorption. During the simulation test, the sensors arranged at the artificial joint pair (2-3) collect dynamic load and wear data.

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