A testing method for a robot joint harmonic reducer precision degradation testing device

Abstract

The application discloses a kind of robot joint harmonic reducer precision recession testing device and testing method, including motor assembly being arranged on test platform, for installing harmonic reducer installation assembly, load transmission assembly, cylinder, motor assembly is connected with the input end transmission of harmonic reducer by installation assembly, load transmission group one end is connected with the output end transmission of harmonic reducer by installation assembly, other end is connected with the output end of cylinder, still include the detection component being arranged on load transmission assembly.Based on the principle of slider-crank mechanism, the detection of harmonic reducer loading and transmission precision is carried out simultaneously, the transmission precision recession situation under the simulation of harmonic reducer real working condition is provided different loading mode, according to the load size demand, the load size is parameterized calculation, satisfies the test demand of harmonic reducer high efficiency, accurately, continuous load adjustment is realized by cylinder, high-frequency dynamic response, adjustment precision is promoted, more close to complex working condition demand, improve detection precision.

Description

Technical Field

[0001] This invention relates to a test method for a robot joint harmonic reducer accuracy degradation test device, belonging to the field of harmonic reducer technology. Background Technology

[0002] Harmonic reducers are core components of lightweight joints in industrial robots and humanoid robots. They are characterized by high precision, long lifespan, large transmission ratio, compact structure, and high power density. With the development of the robotics industry, the performance requirements for harmonic reducers are becoming increasingly stringent, demanding not only longer fatigue life but also a higher rate of precision degradation over long-term service.

[0003] To test the accuracy degradation rate of harmonic reducers, it is necessary to record the transmission accuracy of the harmonic reducers at different times under loaded conditions. Patent CN 117147147 A discloses a reducer life test bench considering impact loads. The impact load is adjusted by changing the position of the force-applying column, the force-receiving column, and the distance from the center of the load plate, as well as the weight of the counterweight plate. While this achieves load adjustment, it relies on preset threaded hole positions, making continuous stepless adjustment impossible. The impact force adjustment exhibits step-like jumps, thus limiting its adjustment accuracy. Furthermore, the swing arm-counterweight plate system relies on gravitational potential energy conversion to generate impacts, resulting in inertial delays in load changes, making it difficult to simulate high-frequency instantaneous impacts and causing dynamic response lag. Long-term impact between the swing arm and the column can easily cause wear, affecting test results. The counterweight plate needs to be manually added or removed, and multiple counterweight plates need to be stacked for large loads, leading to insufficient installation space and excessive bearing loads, thus limiting the load range. Additionally, it can only achieve periodic unidirectional impacts and cannot simulate complex working conditions.

[0004] The patent with publication number CN 112326233 A discloses a comprehensive performance test bench for harmonic reducers. It adopts a mechanical loading method of servo motor and planetary reducer. The servo motor is indirectly loaded through the planetary reducer. The transmission chain has inertial delay, which makes it difficult to achieve high-frequency dynamic load switching. It relies on closed-loop control of torque sensor. However, the planetary reducer has backlash, which is prone to nonlinear error when fine-tuning small torque. It requires multiple components such as planetary reducer, coupling, and torque sensor. It occupies a large space and has high requirements for installation alignment. The structure is complex and the installation accuracy requirements are high. Summary of the Invention

[0005] Purpose of the invention: To address the shortcomings of existing technologies, this invention provides a testing method for a robot joint harmonic reducer precision degradation testing device. This invention achieves continuous load adjustment and high-frequency dynamic response through a cylinder, which is closer to the needs of complex working conditions.

[0006] Technical solution: A robot joint harmonic reducer accuracy degradation testing device includes a motor assembly, a mounting assembly for mounting the harmonic reducer, a load transmission assembly, and a cylinder, all mounted on a test platform. The motor assembly is connected to the input end of the harmonic reducer via the mounting assembly. One end of the load transmission assembly is connected to the output end of the harmonic reducer via the mounting assembly, and the other end is connected to the output end of the cylinder. The device also includes a detection assembly mounted on the load transmission assembly.

[0007] This invention drives a harmonic reducer mounted on a mounting assembly via a motor assembly, which in turn drives a load transmission assembly to push a cylinder piston. By changing the cylinder load, the load conditions of the harmonic reducer under different operating conditions can be simulated. The displacement of the cylinder piston is obtained by a detection assembly, thereby obtaining the actual output angle of the harmonic reducer and ultimately the transmission accuracy of the harmonic reducer. This effectively improves the efficiency of accurately characterizing the accuracy degradation of the harmonic reducer under long-term service. The use of a cylinder enables continuous load adjustment and high-frequency dynamic response, which is closer to the needs of complex operating conditions. The testing device has a simple structure.

[0008] In a preferred embodiment, to achieve load transmission, the load transmission assembly includes a crank, a connecting rod, and a cylinder connector. One end of the crank is hinged to the connecting rod, and the other end is connected to a mounting assembly. One end of the cylinder connector is hinged to the connecting rod, and the other end is connected to a cylinder.

[0009] In a preferred embodiment, to improve the installation reliability of the crank and connecting rod, an eccentric shaft is provided on the end of the crank that is hinged to the connecting rod. The eccentric shaft is provided with a bearing and a retaining ring that abuts against the bearing. The bearing is located on the side near the crank. The end of the connecting rod is sleeved on the bearing and hinged to the crank via the eccentric shaft.

[0010] In a preferred embodiment, to obtain the displacement of the cylinder piston, the detection assembly includes a guide rail, a slider, a slider mounting bracket, a grating ruler, and a grating reading head mounted on the test platform. The slider is slidably connected to the guide rail and hinged to the cylinder connector via the slider mounting bracket. The grating ruler is arranged parallel to the guide rail, and the grating reading head is mounted on the slider mounting bracket.

[0011] The connecting rod drives the slider to move back and forth linearly on the guide rail, which in turn drives the cylinder piston to move back and forth. During the movement, the grating reading head moves accordingly, and the displacement of the cylinder piston is obtained through the optical grating ruler.

[0012] In a preferred embodiment, for ease of installation, the slider mounting bracket, cylinder connector, and connecting rod are all hinged together on the same hinge point C on the rotation axis.

[0013] Preferably, to avoid lateral forces exerted by the slider on the guide rail, which would cause wear, the center point A connecting the crank and the mounting assembly is on the same horizontal line as the hinge point C. If the center of the slider deviates from the horizontal line, a lateral force perpendicular to the direction of motion will be generated, which will exacerbate guide rail wear and may even lead to jamming. Horizontal alignment can reduce interference from non-axial forces, improve the durability of the mechanism, and at the same horizontal line, it can simplify kinematic analysis.

[0014] In a preferred embodiment, to improve the reliability of the installation and transmission of the harmonic reducer, the installation assembly includes a first mounting bracket set on a test platform, a connecting shaft with first flanges at both ends, a fixed flange, an input flange connected to the input end of the harmonic reducer, and an output flange connected to the output end of the harmonic reducer. The output flange is also connected to a crank. The harmonic reducer is fixedly installed on the first mounting bracket via the fixed flange. The first flange at one end of the connecting shaft is connected to the input flange, and the first flange at the other end is connected to the motor assembly. The input flange and the output flange are rotatably connected to the fixed flange.

[0015] In a preferred embodiment, to improve the reliability of the motor drive, the motor assembly includes a second mounting bracket and a motor. The motor is mounted on the second mounting bracket, and the output shaft of the motor is provided with a second flange. The output shaft of the motor is coaxial with the connecting shaft and connected through the second flange and the first flange.

[0016] A test method for implementing a robot joint harmonic reducer accuracy degradation test device includes the following steps:

[0017] Step 1: Start the test device: The motor speed is the rated input speed of the harmonic reducer. The motor starts and drives the load transmission component to move through the harmonic reducer.

[0018] Step 2: Select the loading mode to pressurize the cylinder: The loading modes include constant pressure loading mode and compression loading mode. After obtaining the required pressure for the cylinder according to the selected loading mode, pressurize the cylinder; the compression loading mode is to input the initial pressure into the cylinder and then close the cylinder's air inlet.

[0019] Step 3: Obtain the transmission accuracy of the harmonic reducer: Obtain the transmission accuracy of the harmonic reducer by the difference between the theoretical output angle and the actual output angle of the harmonic reducer.

[0020] Step 4: Repeat steps 2-3, recording the equally spaced times t0, t1, t2, t3…t n The transmission accuracy of the harmonic reducer is φ0, φ1, φ2, φ3…φ n The recorded data were fitted to obtain the relationship between the transmission accuracy of the harmonic reducer and time, φ(t).

[0021] Step 5: In step 4, when t n Transmission accuracy φ at any moment n Greater than the transmission accuracy threshold φ T If the harmonic reducer fails due to fatigue, the testing device should be shut down and the test stopped.

[0022] Step two specifically involves:

[0023] Obtain the cylinder force F:

[0024] (1)

[0025] In the formula, , , T is the rated load torque of the harmonic reducer; β is the horizontal angle of the connecting rod; L3 is the distance between center point A and hinge point C; L1 is the distance between center point B and center point A of the eccentric shaft; L2 is the distance between center point B and hinge point C of the eccentric shaft; α is the actual output angle of the harmonic reducer.

[0026] If the constant pressure loading mode is selected, the constant pressure P of the cylinder will be... h for:

[0027] (2)

[0028] In the formula, A is the cross-sectional area of ​​the cylinder. , where r is the nominal radius of the cylinder piston;

[0029] If the compression loading mode is selected, the initial cylinder pressure P1 input is:

[0030] (3)

[0031] In the formula, V0 is the initial volume of the cylinder, and V1 is the compressed volume of the cylinder. L C This refers to the stroke of the cylinder; Δx is the displacement of the cylinder piston;

[0032] Depending on the selected loading mode, at a constant pressure P h Alternatively, the initial pressure P1 can be used to pressurize the cylinder;

[0033] Step three specifically involves:

[0034] The transmission accuracy φ of the harmonic reducer is obtained by the difference between the theoretical output angle θ / N and the actual output angle α.

[0035] (4)

[0036] In the formula, θ is the output angle of the motor, which is given by the angle encoder built into the motor; N is the reduction ratio of the harmonic reducer, and the theoretical output angle of the harmonic reducer is θ / N;

[0037] The actual output angle α of the harmonic reducer is calculated using Equation 5, where the displacement Δx of the cylinder piston is obtained by actual measurement using a grating ruler:

[0038] (5)

[0039] Beneficial effects: Based on the principle of crank-slider mechanism, this invention can simultaneously load and test the transmission accuracy of harmonic reducers, simulating the transmission accuracy degradation under real working conditions of harmonic reducers. It also provides different loading modes and parameterizes the load size according to the loading requirements, meeting the high-efficiency and accurate testing requirements of harmonic reducers. Through the cylinder, it realizes continuous load adjustment, high-frequency dynamic response, and improved adjustment accuracy, which is closer to the requirements of complex working conditions and improves the detection accuracy. The overall structure, installation process, and usage method are simpler. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figure 1 This is an isometric view of the testing device of the present invention;

[0042] Figure 2 This is a front view of the testing device of the present invention;

[0043] Figure 3 This is a left view of the testing device of the present invention;

[0044] Figure 4 This is a structural diagram of the fixed flange, input flange, and output flange of the present invention;

[0045] Figure 5 This is a structural diagram of the connecting shaft of the present invention;

[0046] Figure 6 This is a diagram of the crank structure of the present invention;

[0047] Figure 7 This is a schematic diagram of the motion principle of the testing device of the present invention;

[0048] Figure 8 The following are the motion principle diagrams of the present invention under different rotation angles: (1) is the motion principle diagram when α=0, and (2) is the motion principle diagram when α=π.

[0049] Figure 9 This is a fitted curve of the relationship between transmission accuracy and time φ(t) of the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0052] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0053] like Figure 1 As shown, a robot joint harmonic reducer accuracy degradation testing device includes a motor assembly 2, a mounting assembly 3 for mounting the harmonic reducer, a load transmission assembly 4, and a cylinder 5, all mounted on a test platform 1. The motor assembly 2 is connected to the input end of the harmonic reducer via the mounting assembly 3. One end of the load transmission assembly 4 is connected to the output end of the harmonic reducer via the mounting assembly 3, and the other end is connected to the output end of the cylinder 5. The device also includes a detection assembly 6 mounted on the load transmission assembly 4.

[0054] The motor assembly 2 drives the harmonic reducer mounted on the mounting assembly 3, which in turn drives the load transmission assembly 4 to push the piston of the cylinder 5. By changing the load on the cylinder 5, the load conditions of the harmonic reducer under different working conditions can be simulated. The displacement of the piston of the cylinder 5 is obtained by the detection assembly 6, and the actual output angle of the harmonic reducer is obtained. Finally, the transmission accuracy of the harmonic reducer is obtained, which effectively improves the accuracy characterization efficiency of the harmonic reducer under long-term service. The use of cylinder 5 can realize continuous load adjustment and high-frequency dynamic response, which is closer to the needs of complex working conditions. The test device has a simple structure.

[0055] Furthermore, in this embodiment, a multi-dimensional load system can be constructed through the collaborative layout of multiple cylinders 5, such as a combination of vertical and horizontal cylinders 5, which is closer to the actual working conditions of robot joints.

[0056] like Figure 2 As shown, in order to realize load transmission, the load transmission assembly 4 includes a crank 41, a connecting rod 42, and a cylinder connector 43. One end of the crank 41 is hinged to the connecting rod 42, and the other end is connected to the mounting assembly 3. One end of the cylinder connector 43 is hinged to the connecting rod 42, and the other end is connected to the cylinder 5.

[0057] like Figure 6 As shown, in order to improve the installation reliability of crank 41 and connecting rod 42, an eccentric shaft 411 is provided on the end of crank 41 that is hinged to connecting rod 42. A bearing 412 and a snap ring 413 that abuts against bearing 412 are provided on the eccentric shaft 411. The bearing 412 is located on the side close to crank 41. The end of connecting rod 42 is sleeved on bearing 412 and hinged to crank 41 through eccentric shaft 411.

[0058] like Figures 1-3 As shown, to obtain the piston displacement of cylinder 5, the detection component 6 includes a guide rail 61, a slider 62, a slider mounting bracket 63, a grating ruler 64, and a grating reading head 65 mounted on the test platform 1. The slider 62 is slidably connected to the guide rail 61 and hinged to the cylinder connector 43 via the slider mounting bracket 63. The grating ruler 64 is arranged parallel to the guide rail 61, and the grating reading head 65 is mounted on the slider mounting bracket 63. The connecting rod 42 drives the slider 62 to reciprocate linearly on the guide rail 61, thereby driving the piston of cylinder 5 to reciprocate. During the movement, the grating reading head 65 moves accordingly, and the piston displacement of cylinder 5 is obtained through the grating ruler.

[0059] For ease of installation, the slider mounting bracket 63, cylinder connector 43, and connecting rod 42 are all hinged together on the same hinge point C on the rotation axis.

[0060] In order to avoid the lateral force exerted by the slider 62 on the guide rail 61 and thus cause wear on the guide rail 61, the center point A of the crank 41 connected to the mounting assembly 3 and the hinge point C are on the same horizontal line.

[0061] If the center of slider 62 deviates from the horizontal line, a lateral force perpendicular to the direction of movement will be generated, which will aggravate the wear of guide rail 61 and even cause jamming. Horizontal alignment can reduce the interference of non-axial forces and improve the durability of the mechanism. At the same time, the fact that the two are on the same horizontal line can simplify kinematic analysis.

[0062] like Figures 2-5 As shown, in order to improve the reliability of the installation and transmission of the harmonic reducer, the installation assembly 3 includes a first mounting bracket 31 set on the test platform 1, a connecting shaft 32 with first flanges 321 at both ends, a fixed flange 33, an input flange 34 connected to the input end of the harmonic reducer, and an output flange 35 connected to the output end of the harmonic reducer. The output flange 35 is also connected to the crank 41. The harmonic reducer is fixedly installed on the first mounting bracket 31 through the fixed flange 33. The first flange 321 at one end of the connecting shaft 32 is connected to the input flange 34, and the first flange 321 at the other end is connected to the motor assembly 2. The input flange 34 and the output flange 35 are rotatably connected to the fixed flange 33.

[0063] In this embodiment, the output flange 35 is connected to the steel wheel of the harmonic reducer, the fixed flange 33 is connected to the flexible wheel of the harmonic reducer, and the input flange 34 is connected to the wave generator.

[0064] To improve the reliability of the motor 22 transmission, the motor assembly 2 includes a second mounting bracket 21 and a motor 22. The motor 22 is mounted on the second mounting bracket 21. A second flange 221 is provided on the output shaft of the motor 22. The output shaft of the motor 22 is coaxial with the connecting shaft 32 and connected through the second flange 221 and the first flange 321.

[0065] A test method for implementing a robot joint harmonic reducer accuracy degradation test device includes the following steps:

[0066] Step 1: Start the test device: The speed of motor 22 is the rated input speed of the harmonic reducer. Motor 22 starts and drives the load transmission component 4 to move through the harmonic reducer.

[0067] like Figures 7-8 As shown, step two involves selecting a loading mode to pressurize cylinder 5: the loading modes include constant pressure loading mode and compression loading mode. After obtaining the required pressure for cylinder 5 according to the selected loading mode, cylinder 5 is pressurized; the compression loading mode involves inputting an initial pressure into cylinder 5 and then closing the air inlet of cylinder 5.

[0068] Obtain the force F of cylinder 5:

[0069] (1)

[0070] In the formula, , , T is the rated load torque of the harmonic reducer; β is the horizontal angle of the connecting rod 42; L3 is the distance between the center point A and the hinge point C; L1 is the distance between the center point B and the center point A of the eccentric shaft 411; L2 is the distance between the center point B and the hinge point C of the eccentric shaft 411; α is the actual output angle of the harmonic reducer.

[0071] If the constant pressure loading mode is selected, the constant pressure P of cylinder 5 will be... h for:

[0072] (2)

[0073] In the formula, A is the cross-sectional area of ​​cylinder 5. r is the nominal radius of the piston in cylinder 5;

[0074] If the compression loading mode is selected, the initial pressure P1 of cylinder 5 is:

[0075] (3)

[0076] In the formula, V0 is the initial volume of cylinder 5, and V1 is the compressed volume of cylinder 5. L C This is the stroke of cylinder 5; Δx is the displacement of piston 5 in cylinder 5;

[0077] Depending on the selected loading mode, at a constant pressure P h Alternatively, the initial pressure P1 can be applied to pressurize cylinder 5;

[0078] Step 3: Obtain the transmission accuracy of the harmonic reducer: Obtain the transmission accuracy of the harmonic reducer by the difference between the theoretical output angle and the actual output angle of the harmonic reducer.

[0079] The transmission accuracy φ of the harmonic reducer is obtained by the difference between the theoretical output angle θ / N and the actual output angle α.

[0080] (4)

[0081] In the formula, θ is the output angle of motor 22, which is given by the angle encoder built into motor 22; N is the reduction ratio of harmonic reducer, and the theoretical output angle of harmonic reducer is θ / N;

[0082] The actual output angle α of the harmonic reducer is calculated using Equation 5, where the displacement Δx of the piston in cylinder 5 is measured by the grating ruler 64.

[0083] (5)

[0084] like Figure 9 As shown, in step four, repeat steps two through three, recording the equally spaced times t0, t1, t2, t3…t n The transmission accuracy of the harmonic reducer is φ0, φ1, φ2, φ3…φ n The recorded data were fitted to obtain the relationship between the transmission accuracy of the harmonic reducer and time, φ(t).

[0085] Step 5: In step 4, when t n Transmission accuracy φ at any moment n Greater than the transmission accuracy threshold φ T If the harmonic reducer fails due to fatigue, the testing device should be shut down and the test stopped.

[0086] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0087] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A test method for a robot joint harmonic reducer accuracy degradation test device, the device comprising a motor assembly (2) mounted on a test platform (1), a mounting assembly (3) for mounting the harmonic reducer, a load transmission assembly (4), and a cylinder (5), wherein the motor assembly (2) is connected to the input end of the harmonic reducer via the mounting assembly (3), one end of the load transmission assembly (4) is connected to the output end of the harmonic reducer via the mounting assembly (3), and the other end is connected to the output end of the cylinder (5), and further comprising a detection assembly (6) mounted on the load transmission assembly (4); The load transmission assembly (4) includes a crank (41), a connecting rod (42), and a cylinder connector (43). One end of the crank (41) is hinged to the connecting rod (42), and the other end is connected to the mounting assembly (3). One end of the cylinder connector (43) is hinged to the connecting rod (42), and the other end is connected to the cylinder (5). The detection component (6) includes a guide rail (61), a slider (62), a slider mounting bracket (63), a grating ruler (64), and a grating reading head (65) set on the test platform (1). The slider (62) is slidably connected to the guide rail (61) and is hinged to the cylinder connector (43) through the slider mounting bracket (63). The grating ruler (64) is set parallel to the guide rail (61), and the grating reading head (65) is set on the slider mounting bracket (63). The slider mounting bracket (63), cylinder connector (43), and connecting rod (42) are all hinged together on the rotation axis at the same hinge point C; The center point A connecting the crank (41) and the mounting assembly (3) is on the same horizontal line as the hinge point C; Its features are: The method includes the following steps: Step 1: Start the test device: The motor (22) rotates at the rated input speed of the harmonic reducer. The motor (22) starts and drives the load transmission component (4) to move through the harmonic reducer. Step 2: Select the loading mode to pressurize the cylinder (5): The loading modes include constant pressure loading mode and compression loading mode. After obtaining the required pressure of the cylinder (5) according to the selected loading mode, pressurize the cylinder (5); The compression loading mode is to input the initial pressure into the cylinder (5) and then close the air inlet of the cylinder (5); Step two specifically involves: Obtain the force F of cylinder (5): （1） In the formula, , , T is the rated load torque of the harmonic reducer; β is the horizontal angle of the connecting rod (42); L3 is the distance between the center point A and the hinge point C; L1 is the distance between the center point B and the center point A of the eccentric shaft (411); L2 is the distance between the center point B and the hinge point C of the eccentric shaft (411); α is the actual output angle of the harmonic reducer. If the constant pressure loading mode is selected, the constant pressure P of cylinder (5) will be... h for: （2） In the formula, A is the cross-sectional area of ​​cylinder (5). r is the nominal radius of the piston of cylinder (5); If the compression loading mode is selected, the initial pressure P1 of the cylinder (5) is: （3） In the formula, V0 is the initial volume of cylinder (5), and V1 is the compressed volume of cylinder (5); L C The stroke of cylinder (5); Δx is the displacement of the piston in cylinder (5); Depending on the selected loading mode, at a constant pressure P h Or the initial pressure P1 is used to pressurize the cylinder (5); Step three specifically involves: The transmission accuracy φ of the harmonic reducer is obtained by the difference between the theoretical output angle θ / N and the actual output angle α. （4） In the formula, θ is the output angle of the motor (22), which is given by the angle encoder of the motor (22); N is the reduction ratio of the harmonic reducer, and the theoretical output angle of the harmonic reducer is θ / N; The actual output angle α of the harmonic reducer is calculated using equation (5), where the displacement Δx of the piston in cylinder (5) is measured by the grating ruler (64): （5） Step 3: Obtain the transmission accuracy of the harmonic reducer: Obtain the transmission accuracy of the harmonic reducer by the difference between the theoretical output angle and the actual output angle of the harmonic reducer. Step 4: Repeat steps 2-3, recording the equally spaced times t0, t1, t2, t3…t n The transmission accuracy of the harmonic reducer is φ0, φ1, φ2, φ3…φ n The recorded data were fitted to obtain the relationship between the transmission accuracy of the harmonic reducer and time, φ(t). Step 5: In step 4, when t n Transmission accuracy φ at any moment n Greater than the transmission accuracy threshold φ T If the harmonic reducer fails due to fatigue, the testing device should be shut down and the test stopped.

2. The test method of the robot joint harmonic reducer accuracy degradation test device according to claim 1, characterized in that: An eccentric shaft (411) is provided on one end of the crank (41) that is hinged to the connecting rod (42). A bearing (412) and a snap ring (413) that abuts against the bearing (412) are provided on the eccentric shaft (411). The bearing (412) is located on the side close to the crank (41). The end of the connecting rod (42) is sleeved on the bearing (412) and hinged to the crank (41) through the eccentric shaft (411).

3. The test method of the robot joint harmonic reducer accuracy degradation test device according to claim 1, characterized in that: The mounting assembly (3) includes a first mounting bracket (31) set on the test platform (1), a connecting shaft (32) with first flanges (321) at both ends, a fixed flange (33), an input flange (34) connected to the input end of the harmonic reducer, and an output flange (35) connected to the output end of the harmonic reducer. The output flange (35) is also connected to the crank (41). The harmonic reducer is fixedly mounted on the first mounting bracket (31) through the fixed flange (33). The first flange (321) at one end of the connecting shaft (32) is connected to the input flange (34), and the first flange (321) at the other end is connected to the motor assembly (2). The input flange (34) and the output flange (35) are rotatably connected to the fixed flange (33).

4. The test method of the robot joint harmonic reducer accuracy degradation test device according to claim 3, characterized in that: The motor assembly (2) includes a second mounting bracket (21) and a motor (22). The motor (22) is mounted on the second mounting bracket (21). The output shaft of the motor (22) is provided with a second flange (221). The output shaft of the motor (22) is coaxial with the connecting shaft (32) and connected through the second flange (221) and the first flange (321).

Images