Accuracy attenuation test apparatus and test method for robot joint harmonic reducers

Abstract

This invention discloses a precision attenuation test apparatus and test method for a robot joint harmonic reducer. [Solution] The system includes a motor assembly mounted on a test stand, a first mounting bracket, a harmonic reducer, a load transmission assembly, and a cylinder, wherein the harmonic reducer is mounted on the first mounting bracket, the motor assembly is powered to the input terminal of the harmonic reducer, and the load transmission assembly has one end powered to the output terminal of the harmonic reducer and the other end powered to the output terminal of the cylinder, and further includes a detection assembly mounted on the load transmission assembly. The damping of actual operating conditions is simulated based on the combination of the crank slider mechanism and the cylinder.

Description

[Technical Field]

[0001] This invention relates to a precision attenuation test apparatus and test method for a robot joint harmonic reducer, and belongs to the field of harmonic reducers. [Background technology]

[0002] Harmonic reducers are core components of lightweight joints in industrial robots and humanoid robots. Their characteristics include high precision, long lifespan, high power-to-speed ratio, compact structure, and high power density. With the development of the robotics industry, the demands on the performance of harmonic reducers are increasing, requiring not only longer fatigue life but also higher precision attenuation rates during long-term use.

[0003] To test the accuracy of the decay rate of a harmonic reducer, it is necessary to record the transmission accuracy of the harmonic reducer at different times under load conditions. The patent with publication number CN117147147A discloses a gearbox life test stand that takes impact loads into consideration. By adjusting the position of the biasing column and bearing column from the center of the load disc and the size of the weight disc, adjustment for the magnitude of the impact load is achieved. However, load adjustment is achieved by pre-setting the position depending on the screw hole position and cannot achieve continuous stepless adjustment, and there are stepwise jumps in the impact force adjustment, which limits the adjustment accuracy. Furthermore, the swing arm-weight disc system generates impacts depending on the conversion of gravitational potential energy, and there is an inertial delay in load changes, making it difficult to simulate high-frequency instantaneous impacts. This causes a delay in dynamic response, and long-term impacts between the swing arm and column are prone to causing wear, affecting the test effect. The weight discs need to be manually increased or decreased, and in the case of large loads, multiple weight discs need to be stacked, which has the problem of insufficient mounting space and excessive bearing load, limiting the load range. At the same time, it can only realize periodic unidirectional impacts and cannot simulate complex operating conditions.

[0004] The patent with publication number CN112326233A discloses a comprehensive performance test stand for a harmonic reducer, which employs a servo motor and planetary gearbox mechanical loading method. The servo motor is indirectly loaded by the planetary gearbox, and there is inertial delay in the transmission chain, making it difficult to achieve high-frequency dynamic load switching. It relies on closed-loop control of a torque sensor, however, there is backlash in the planetary gearbox, which makes nonlinear errors likely to occur when fine-tuning small torques. It also requires the combination of multiple assemblies such as the planetary gearbox, coupling, and torque sensor, resulting in a large footprint, high mounting requirements, a complex structure, and high mounting accuracy requirements. [Overview of the project] [Problems that the invention aims to solve]

[0005] In response to the shortcomings of the prior art, the present invention provides a precision attenuation test apparatus and test method for a robot joint harmonic reducer. The present invention achieves continuous load adjustment and high-frequency dynamic response using a cylinder, better meeting the needs of complex operating conditions. [Means for solving the problem]

[0006] The accuracy damping test apparatus for a robot joint harmonic reducer includes a motor assembly, a first mounting bracket, a harmonic reducer, a load transmission assembly, and a cylinder, all mounted on a test stand. The harmonic reducer is mounted on the first mounting bracket, the motor assembly is power-driven to the input terminal of the harmonic reducer, and the load transmission assembly has one end power-driven to the output terminal of the harmonic reducer and the other end power-driven to the output terminal of the cylinder. The apparatus further includes a detection assembly mounted on the load transmission assembly.

[0007] This invention drives a harmonic reducer with a motor assembly, further drives a load transmission assembly to press the piston of a cylinder, obtains the displacement of the cylinder piston with a detection assembly, obtains the actual output angle of the harmonic reducer, and finally obtains the transmission accuracy of the harmonic reducer. This effectively improves the efficiency of accurately characterizing the accuracy decay of the harmonic reducer during long-term use, and by employing a cylinder, continuous load adjustment and high-frequency dynamic response can be achieved, better meeting the needs of complex operating conditions, and the structure of the test apparatus is simple.

[0008] Preferably, to achieve load transmission, the load transmission assembly includes a crank, a link, and a cylinder connecting member, wherein one end of the crank is hinged to the link and the other end is connected to a harmonic reducer, and one end of the cylinder connecting member is hinged to the link and the other end is connected to a cylinder.

[0009] Preferably, in order to improve the mounting reliability between the crank and the link, an eccentric shaft is provided at one end of the crank that is hinged to the link, the eccentric shaft is provided with a bearing and an engaging spring that contacts the bearing, the bearing is located closer to one side of the crank, and the end of the link is fitted into the bearing and hinged to the crank by the eccentric shaft.

[0010] Preferably, to obtain the displacement of the piston of a cylinder, the detection assembly includes a guide rail, a slider, a slider mounting bracket, a diffraction grating scale, and a diffraction grating reading head, wherein the slider is slidably connected to the guide rail and hinged to the cylinder connecting member by the slider mounting bracket, the diffraction grating scale is mounted parallel to the guide rail, and the diffraction grating reading head is mounted on the slider mounting bracket.

[0011] The link drives the slider to reciprocate linearly on the guide rail, and further drives the piston of the cylinder to reciprocate. During the movement process, the diffraction grating reading head follows, and the displacement of the piston of the cylinder is obtained by the diffraction grating scale.

[0012] Preferably, in order to facilitate the installation, the slider mounting bracket, the cylinder connecting member, and the link are all hinged to the rotation axis of the same hinge connection point C.

[0013] Preferably, in order to avoid wearing the guide rail due to the lateral force of the slider on the guide rail, the central point A where the crank and the harmonic reducer are connected is located on the same horizontal line as the hinge connection point C. When the center of the slider deviates from the horizontal line, a lateral force perpendicular to the movement direction is generated, which aggravates the wear of the guide rail and ultimately causes jamming. Aligning the center horizontally can reduce the interference from the non-axial direction force and improve the durability of the mechanism. At the same time, the fact that both are located on the same horizontal line can simplify the kinematic analysis.

[0014] Preferably, in order to improve the reliability of the installation and transmission of the harmonic reducer, it further includes a connecting shaft provided with first flanges at both ends. The harmonic reducer includes a fixed flange, an input flange, and an output flange. The output flange is connected to the crank. The harmonic reducer is fixed and installed on the first mounting bracket by the fixed flange. One end of the connecting shaft has the first flange connected to the input flange, and the other end of the first flange is connected to the motor assembly.

[0015] Preferably, in order to improve the reliability of the motor transmission, the motor assembly includes a second mounting bracket and a motor. The motor is mounted on the second mounting bracket. A second flange is provided on the output shaft of the motor. The output shaft of the motor is coaxial with the connecting shaft and is connected by the second flange and the first flange.

[0016] A test method for realizing a precision attenuation test device of a harmonic reducer for a robot joint is as follows: Step 1 of starting the test device, wherein the rotational speed of the motor is the rated input rotational speed of the harmonic reducer, the motor starts, and the load transmission assembly is driven to move by the harmonic reducer; Step 1 Step 2 of selecting a load mode and pressurizing the cylinder, wherein the load mode includes a constant pressure load mode and a compression load mode. After obtaining the pressure required for the cylinder based on the selected load mode, the cylinder is pressurized. The compression load mode is to seal the air inlet of the cylinder after inputting the initial pressure of the cylinder; Step 2 Step 3 of obtaining the transmission accuracy of the harmonic reducer, wherein the transmission accuracy of the harmonic reducer is obtained based on the difference between the theoretical output angle and the actual output angle of the harmonic reducer; Step 3 Repeat Steps 2 to Step 3, and record the transmission accuracies Δφ0, Δφ1, Δφ2, Δφ3…Δφ of the harmonic reducer at equal interval times t0, t1, t2, t3…t n and perform data approximation on the recorded data to obtain the relationship Δφ(t) between the transmission accuracy of the harmonic reducer and time; Step 4 n In Step 4, when the transmission accuracy Δφ at time t n is greater than the transmission accuracy threshold Δφ n or when fatigue damage occurs to the harmonic reducer, stop the test device and stop the test; Step 5. The method includes the above steps. T

[0017] Specifically, Step 2 is as follows: Based on the rated torque T of the harmonic reducer, obtain the test load torque T L applied to the output end of the harmonic reducer. The peak value of T L is the rated torque T of the harmonic reducer; Obtain the cylinder acting force F. [Number] In the formula [Number] and T L is the test load torque, β is the horizontal included angle of the link, L3 is the distance between the center point A and the hinge connection point C, L1 is the length of the crank AB, that is, the distance between the center point B of the eccentric shaft and the center point A, L2 is the length of the link BC, that is, the distance between the center point B of the eccentric shaft and the hinge connection point C, α is the actual output angle of the harmonic reducer. When the constant pressure load mode is selected, the constant pressure P of the cylinder h is as follows. [Number] In the formula, A1 is the cross-sectional area of the cylinder, A1 = πr 2 where r is the nominal radius of the piston of the cylinder, When the compression load mode is selected, the initial pressure P1 of the cylinder is as follows. [Number] In the formula, V0 is the initial volume of the cylinder, V1 is the volume of the cylinder after compression, V0 = A1·(L C + L0), where L C is the working stroke of the cylinder, L C = 2L1 < L S is satisfied, and L S is the maximum physical stroke of the cylinder, L0 is the clearance length in the maximum compression state of the cylinder, V1 = V0 - A1·Δx, where Δx is the displacement of the piston of the cylinder, [Number] and According to the selected load mode, the cylinder is pressurized with the constant pressure P h or the initial pressure P1, Specifically, step 3 above is as follows: The piston displacement Δx of the cylinder and the output angle θ of the motor, measured using a diffraction grating scale, are recorded in real time, and the geometric relationship is calculated.

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[0018] This invention, based on the principle of a crank slider mechanism, simultaneously detects the load and transmission accuracy of a harmonic reducer and can simulate the transmission accuracy decay under actual operating conditions. By combining its nonlinear kinematic characteristics with cylinder compression, it can simulate both the periodic alternating torque and nonlinear impact torque operating environments of the harmonic reducer, unlike the constant load of conventional test stands. Simultaneously, by parameterizing and calculating the load magnitude, the cylinder achieves continuous load adjustment, high-frequency dynamic response, and improved adjustment accuracy, better meeting the needs of complex operating conditions. Furthermore, by employing a linear guide rail, radial strain interference that conventional circular encoders are prone to is effectively blocked, thereby increasing the measurement accuracy of the linear diffraction grating scale, and the output angle is determined using linear displacement. Overall, this invention provides different load modes, allows parameterized control of applied torque, and can provide an accuracy decay equation, meeting the high-efficiency and accurate testing needs of harmonic reducers, possessing significant engineering application value, and simplifying the overall installation process and usage method of the structure.

[0019] To more clearly illustrate embodiments of the present invention or technical concepts in the prior art, the following briefly describes the drawings necessary for describing the embodiments or prior art. Clearly, the drawings in the following description are merely embodiments of the present invention, and those skilled in the art can obtain other drawings based on the provided drawings without any creative work. [Brief explanation of the drawing]

[0020] [Figure 1] This is an axial view drawing of the test apparatus of the present invention. [Figure 2] This is a front view of the test apparatus of the present invention. [Figure 3] This is a left side view of the test apparatus of the present invention. [Figure 4] This is a structural diagram of the fixed flange, input end flange, and output end flange of the present invention. [Figure 5] This is a structural diagram of the connecting shaft of the present invention. [Figure 6]A structural diagram of the crank of the present invention. [Figure 7] This is a diagram illustrating the principle of motion of the test apparatus of the present invention. [Figure 8] These are diagrams illustrating the principle of motion of the present invention at different rotation angles; (1) is the diagram of the principle of motion when α=0, and (2) is the diagram of the principle of motion when α=π. [Figure 9] This graph shows the relationship between the test load torque and the actual output angle of the present invention. [Figure 10] A graph of the transmission error of the present invention. [Figure 11] This diagram shows the relationship between transmission accuracy and time in the harmonic reducer of the present invention. [Modes for carrying out the invention]

[0021] The technical concepts in the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments, and it will be clear that the embodiments described are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art without creative work based on the embodiments of the present invention are all within the scope of protection of the present invention.

[0022] In the description of this invention, the directions or positional relationships indicated by terms such as "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," and "outside" are based on the directions or positional relationships shown in the drawings and are merely for the convenience and simplification of the description of this invention. They do not indicate or imply that a specified device or element necessarily has a specific direction or must be configured and operated in a specific direction, and should not be understood as limiting the invention.

[0023] In the present invention, unless otherwise specifically defined and limited, the presence of a first feature "above" or "below" a second feature may include direct contact between the first and second features, or it may include contact between the first and second features without direct contact, but through another feature between them. Furthermore, the presence of a first feature "above," "above," and "on the top surface" of a second feature may include the first feature being directly above and diagonally above the second feature, or simply indicating that the horizontal height of the first feature is higher than that of the second feature. The presence of a first feature "below," "below," and "on the bottom surface" of a second feature may include the first feature being directly below and diagonally below the second feature, or simply indicating that the horizontal height of the first feature is lower than that of the second feature.

[0024] As shown in Figure 1, the accuracy damping test apparatus for a robot joint harmonic reducer includes a motor assembly 2, a first mounting bracket 31, a load transmission assembly 4, and a cylinder 5, all mounted on a test stand 1. The harmonic reducer 7 is mounted on the first mounting bracket 31, the motor assembly 2 is power-driven to the input terminal of the harmonic reducer 7, and the load transmission assembly 4 has one end power-driven to the output terminal of the harmonic reducer 7 and the other end power-driven to the output terminal of the cylinder 5. The apparatus further includes a detection assembly 6 mounted on the load transmission assembly 4.

[0025] The cylinder 5 described above is a single-rod dual-acting cylinder. A two-position, two-port solenoid valve 51 is connected to the air vent of the rodless cavity at one end of the cylinder 5 away from the piston rod. This two-position, two-port solenoid valve 51 is used to control the communication or disconnection between the rodless cavity of the cylinder and the external air passage. A vent pipe 52 is attached to the air vent of the rod-equipped cavity at the end of the cylinder 5 closer to the piston rod. The exhaust port of the vent pipe 52 is always in communication with the outside atmosphere, thereby preventing interference back pressure from being generated in the rod-equipped cavity when the cylinder reciprocates. The load mode of the cylinder 5 can be changed by controlling the conduction and disconnection of the two-position, two-port solenoid valve 51, and this is used to simulate the load conditions under different operating conditions of the harmonic reducer 7.

[0026] The motor assembly 2 drives the harmonic reducer 7, the load transmission assembly 4 drives the piston of the cylinder 5 to press, the detection assembly 6 obtains the displacement of the piston of the cylinder 5, the actual output angle of the harmonic reducer 7 is obtained, and finally the transmission accuracy of the harmonic reducer 7 is obtained, effectively improving the efficiency of accurate characterization of the accuracy decay of the harmonic reducer 7 during long-term use, continuous load adjustment and high-frequency dynamic response can be achieved by adopting the cylinder 5, better meeting the needs of complex operating conditions, and the structure of the test equipment is simple.

[0027] Furthermore, in this embodiment, a multidimensional load system can be constructed by the coordinated layout of multiple cylinders 5, for example, a combination of vertical and horizontal cylinders 5, which is closer to the actual operating conditions of a robot joint.

[0028] As shown in Figure 2, in order to achieve load transmission, the load transmission assembly 4 includes a crank 41, a link 42, and a cylinder connecting member 43. The crank 41 is hinged at one end to the link 42 and connected at the other end to a harmonic reducer 7. The cylinder connecting member 43 is hinged at one end to the link 42 and connected at the other end to a cylinder 5.

[0029] As shown in Figure 6, in order to improve the mounting reliability between the crank 41 and the link 42, an eccentric shaft 411 is provided at one end of the crank 41 that is hinged to the link 42, and the eccentric shaft 411 is provided with a bearing 412 and an engaging spring 413 that abuts against the bearing 412, the bearing 412 is provided close to one side of the crank 41, and the end of the link 42 is fitted into the bearing 412 and hinged to the crank 41 by the eccentric shaft 411.

[0030] As shown in Figures 1 to 3, in order to obtain the displacement of the piston of cylinder 5, the detection assembly 6 includes a guide rail 61, a slider 62, a slider mounting bracket 63, a diffraction grating scale 64, and a diffraction grating reading head 65, all mounted on a test stand 1. The slider 62 is slidably connected to the guide rail 61 and hinged to the cylinder connecting member 43 by the slider mounting bracket 63. The diffraction grating scale 64 is mounted parallel to the guide rail 61, and the diffraction grating reading head 65 is mounted on the slider mounting bracket 63. Link 42 drives the slider 62 to reciprocate linearly along the guide rail 61, and further drives the piston of cylinder 5 to reciprocate. During the movement process, the diffraction grating reading head 65 follows, and the displacement of the piston of cylinder 5 is obtained by the diffraction grating scale 64.

[0031] To facilitate installation, the slider mounting bracket 63, cylinder connecting member 43, and link 42 are all hinge-connected to the same pivot axis of the same hinge connection point C.

[0032] To avoid wear on the guide rail 61 due to the lateral force of the slider 62 on the guide rail 61, the center point A where the crank 41 and the harmonic reducer 7 are connected is located on the same horizontal line as the hinge connection point C.

[0033] If the center of the slider 62 is misaligned with the horizontal line, a lateral force perpendicular to the direction of motion is generated, which exacerbates wear on the guide rail 61 and can lead to snagging. Aligning the center horizontally reduces interference from non-axial forces and improves the durability of the mechanism. At the same time, having both on the same horizontal line simplifies kinematic analysis.

[0034] As shown in Figures 2 to 5, in order to improve the reliability of mounting and transmission of the harmonic reducer 7, the system further includes a connecting shaft 32 having first flanges 321 at both ends, the harmonic reducer 7 includes a fixed flange 71, an input flange 72, and an output flange 73, the output flange 73 being connected to the crank 41, the harmonic reducer 7 being fixed and mounted to the first mounting bracket 31 by the fixed flange 71, and the connecting shaft 32 having one end of the first flange 321 connected to the input flange 72 and the other end of the first flange 321 connected to the motor assembly 2.

[0035] To improve the reliability of the motor 22's power transmission, the motor assembly 2 includes a second mounting bracket 21 and a motor 22, the motor 22 being mounted on the second mounting bracket 21, the output shaft of the motor 22 being provided with a second flange 221, the output shaft of the motor 22 being coaxial with the connecting shaft 32 and connected by the second flange 221 and the first flange 321.

[0036] The test method for realizing a precision attenuation test device for robot joint harmonic reducers includes the following steps 1 to 5.

[0037] Step 1 starts the test apparatus: the rotational speed of the motor 22 is the rated input rotational speed of the harmonic reducer 7, the motor 22 starts, and the harmonic reducer 7 drives the load transmission assembly 4 to move. In step 2, a load mode is selected and cylinder 5 is pressurized: the load modes include constant-pressure load mode and compression load mode. The constant-pressure load mode simulates the periodic alternating torque test environment of the harmonic reducer 7, while the compression load mode simulates the nonlinear impact torque test environment of the harmonic reducer 7. Since conventional constant-load test stands for reducers can only provide a single static resistance, the present invention enables the physical reconstruction of complex operating conditions with an extremely simple purely passive pneumatic / mechanical structure: the constant-pressure load mode provides the stable alternating load required for basic fatigue characteristics, while the compression load mode creates the nonlinear impact load required for accelerated damping tests. This "one machine, two-state" environmental reconstruction capability is a capability that conventional ordinary test stands do not possess at all.

[0038] In the constant-pressure load mode described above, the two-position, two-port solenoid valve 51 is controlled and held open, and the rodless cavity of the cylinder 5 is connected to an external constant-pressure air source by this valve. When the slider 62 is driven to compress the cylinder piston, the vent pipe 52 properly discharges the air from the rod cavity, the gas in the rodless cavity stably overflows, and the entire cylinder 5 outputs a constant damping torque to the harmonic reducer 7. This is used to simulate the normal load operating conditions when the equipment is operating stably.

[0039] In the above compression load mode, first, the 2-position 2-port solenoid valve 51 is controlled to open, and by communicating with an external pressure-regulating air source, the pressure in the rodless cavity reaches a predetermined initial pressure. Then, the 2-position 2-port solenoid valve 51 is controlled to close, completely shutting off the gas circuit of the rodless cavity, thereby forming a sealed pressure-receiving cavity inside. As the crank link mechanism continues to press, the gas volume in the sealed cavity rapidly decreases, and the pressure rises rapidly and non-linearly. At the same time, the vent pipe 52 continues to ensure that the rod-equipped cavity does not resist interference. In this case, the cylinder 5 can output a non-linear impact load.

[0040] The selection of the above load mode requires calculating the load conditions based on the rated torque of the harmonic reducer 7.

[0041] As shown in Figure 7, the test load torque T applied by the device of the present invention to the output terminal of the reducer is determined based on the rated torque T of the harmonic reducer 7. L Obtain T L The peak value is the rated torque T of the harmonic reducer 7.

[0042] The force F that needs to be generated by cylinder 5 is calculated.

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[0043] As shown in Figure 8, the motor 22 drives the harmonic reducer 7 to output at a constant speed, drives the load transmission assembly 4 to move, and further drives the piston of cylinder 5 to reciprocate. When the actual output angle α=0, the piston of cylinder 5 has the minimum displacement, and when the actual output angle α=π, it has the maximum displacement. To further illustrate the difference between the two load modes of the present invention, the parameters of the embodiment are: rated torque T=200N·m of the harmonic reducer 7, crank length L1=0.05m, link length BC length L2=0.25m, using a standard cylinder with a cylinder diameter of 100mm, nominal radius r=0.05m of the piston of cylinder 5, and cylinder operating stroke L C The clearance length L0 is set to =0.1m and L0 = 0.022m.

[0044] By combining the above structural parameters, completely different test load operating conditions can be achieved through different control of the gas source pressure. In constant pressure load mode, the constant pressure P of cylinder 5 is controlled according to Equations 1 and 2. h = 0.48 MPa. In compression load mode, according to equations 1 and 3, the initial pressure P1 of the input cylinder 5 is 0.02 MPa. Equation T L The test load torque T is calculated according to =FL3sinβ / cosβ. L The relationship between this and the actual output angle α can be determined, as shown in Figure 9.

[0045] In constant pressure load mode, the test load torque T L The curve exhibits a gentle sinusoidal peak, and this waveform effectively simulates the stable alternating load that the gearbox experiences during steady-state operation. In the compression load mode, the test load torque T L The waveform changes relatively slowly within the interval from 0 to π / 2, reaching a positive peak value as it approaches π, and then rapidly reversing to a negative peak value. This waveform effectively simulates the nonlinear impact load under the alternating impact operation of the harmonic reducer 7.

[0046] In step 3, the transmission accuracy of the harmonic reducer 7 is obtained: the transmission accuracy of the harmonic reducer 7 is obtained by the difference between the theoretical output angle and the actual output angle of the harmonic reducer 7. Step 3 described above specifically includes the following: The piston displacement Δx of cylinder 5 and the output angle θ of motor 22, measured using a diffraction grating scale 64, are recorded in real time, and the geometric relationship is calculated.

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[0047] In step 5, in step 4 above, t n Transmission accuracy Δφ at time n The transmission accuracy threshold Δφ T If the value is greater, or if fatigue damage occurs to the harmonic reducer 7, the test equipment will be stopped and the test will be halted.

[0048] After constructing the transmission accuracy damping parameter model Δφ(t) specified in the above steps, by simply inputting the initial transmission error Δφ0 and an arbitrary target operating time t for a harmonic reducer 7 operating under the same conditions using the same model, it is possible to calculate the transmission accuracy prediction value at the target operating time with high accuracy. This enables quantitative prediction of transmission accuracy and early life warning for the reducer throughout its entire lifecycle.

[0049] In this specification, each embodiment is described progressively, with each embodiment focusing on its differences from the others, and similar and identical parts between embodiments should be referred to alternately. The apparatus disclosed in the embodiments corresponds to the method disclosed in the embodiments, and therefore its description is relatively simple; relevant sections should be referred to in the description of the method.

[0050] Based on the above description of the disclosed examples, those skilled in the art can implement or use the present invention. Various modifications to these examples will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other examples without departing from the spirit or scope of the invention. Accordingly, the present invention is not limited to these examples shown herein, but fits to the broadest extent that is consistent with the principles and novel features disclosed herein. [Explanation of Symbols]

[0051] 1 Test bench 2 Motor Assembly 21 Second mounting bracket 22 motors 221 Second flange 31 First mounting bracket 32 connecting shafts 321 First flange 4. Load transmission assembly 41 Crank 42 links 43 Cylinder connecting member 411 Eccentric shaft 412 Bearing 413 Engaging spring 5 cylinders 51 2-position 2-port solenoid valve 52 Vent 6. Detection Assembly 61 Guide Rail 62 Sliders 63 Slider mounting bracket 64 Diffraction grating scale 65 Diffraction grating reading head 7 Harmonic reducer 71 Fixed flange 72 Input flange 73 Output flange

Claims

1. A precision attenuation test device for a robot joint harmonic reducer, A precision attenuation test apparatus for a robot joint harmonic reducer, comprising a motor assembly (2), a first mounting bracket (31), a harmonic reducer (7), a load transmission assembly (4), and a cylinder (5), wherein the harmonic reducer (7) is mounted on the first mounting bracket (31), the motor assembly (2) is power-driven to the input terminal of the harmonic reducer (7), and the load transmission assembly (4) has one end power-driven to the output terminal of the harmonic reducer (7) and the other end power-driven to the output terminal of the cylinder (5), and further comprises a detection assembly (6) provided on the load transmission assembly (4).

2. The load transmission assembly (4) includes a crank (41), a link (42), and a cylinder connecting member (43), wherein one end of the crank (41) is hinged to the link (42) and the other end is connected to a harmonic reducer (7), and the cylinder connecting member (43) is hinged to the link (42) and the other end is connected to a cylinder (5), characterized in that the accuracy damping test apparatus for a robot joint harmonic reducer according to claim 1.

3. The accuracy damping test apparatus for a robot joint harmonic reducer according to claim 2, characterized in that an eccentric shaft (411) is provided at one end of the crank (41) which is hinged to the link (42), a bearing (412) and an engaging spring (413) that abuts against the bearing (412) are provided on the eccentric shaft (411), the bearing (412) is provided close to one side of the crank (41), and the end of the link (42) is fitted into the bearing (412) and hinged to the crank (41) by the eccentric shaft (411).

4. The detection assembly (6) includes a guide rail (61), a slider (62), a slider mounting bracket (63), a diffraction grating scale (64), and a diffraction grating reading head (65) provided on a test stand (1), wherein the slider (62) is slidably connected to the guide rail (61) and hinged to the cylinder connecting member (43) by the slider mounting bracket (63), the diffraction grating scale (64) is provided parallel to the guide rail (61), and the diffraction grating reading head (65) is provided on the slider mounting bracket (63), characterized in that the accuracy attenuation test apparatus for a robot joint harmonic reducer according to claim 2.

5. The accuracy attenuation test apparatus for a robot joint harmonic reducer according to claim 4, characterized in that the slider mounting bracket (63), cylinder connecting member (43), and link (42) are all hinge-connected to the rotation axis of the same hinge connection point C.

6. The accuracy attenuation test apparatus for a robot joint harmonic reducer according to claim 5, characterized in that the center point A where the crank (41) and the harmonic reducer (7) are connected is located on the same horizontal line as the hinge connection point C.

7. The accuracy damping test apparatus for a robot joint harmonic reducer according to claim 6, further comprising a connecting shaft (32) having first flanges (321) at both ends, the harmonic reducer (7) comprising a fixed flange (71), an input flange (72), and an output flange (73), the output flange (73) being connected to a crank (41), the harmonic reducer (7) being fixed and mounted to a first mounting bracket (31) by the fixed flange (71), and the connecting shaft (32) having one end of the first flange (321) connected to the input flange (72) and the other end of the first flange (321) connected to a motor assembly (2).

8. The accuracy attenuation test apparatus for a robot joint harmonic reducer according to claim 7, characterized in that the motor assembly (2) includes a second mounting bracket (21) and a motor (22), the motor (22) being mounted on the second mounting bracket (21), a second flange (221) being provided on the output shaft of the motor (22), the output shaft of the motor (22) being coaxial with the connecting shaft (32) and connected by the second flange (221) and the first flange (321).

9. A test method for realizing a precision attenuation test apparatus for a robot joint harmonic reducer according to any one of claims 1 to 8, Step 1 involves starting the test apparatus, wherein the rotational speed of the motor (22) is equal to the rated input rotational speed of the harmonic reducer (7), the motor (22) is started, and the harmonic reducer (7) drives the load transmission assembly (4) to move. Step 2 involves selecting a load mode and pressurizing the cylinder (5), wherein the load modes include a constant pressure load mode and a compression load mode, and after obtaining the required pressure in the cylinder (5) based on the selected load mode, the cylinder (5) is pressurized, and in the compression load mode, after inputting the initial pressure in the cylinder (5), the intake port of the cylinder (5) is sealed. Step 3 for obtaining the transmission accuracy of the harmonic reducer (7), wherein the transmission accuracy of the harmonic reducer (7) is obtained by the difference between the theoretical output angle and the actual output angle of the harmonic reducer (7), Repeat steps 2 to step 3 at equally spaced times t ０ , t １ , t ２ , t ３ … t ｎ for the transmission accuracy Δφ ０ , Δφ １ , Δφ ２ , Δφ ３ … Δφ ｎ of the harmonic reducer (7), record it, and perform data approximation on the recorded data to obtain the relationship Δφ(t) between the transmission accuracy and time of the harmonic reducer (7), step 4, and In step 4, t ｎ Transmission accuracy Δφ at time ｎ The transmission accuracy threshold Δφ Ｔ A method for testing a precision attenuation test apparatus for a robot joint harmonic reducer, characterized by comprising step 5, stopping the test apparatus and stopping the test if the value is greater than or if fatigue damage occurs to the harmonic reducer (7).

10. Step 2 is specifically as follows: Based on the rated torque T of the harmonic reducer (7), the test load torque T applied to the output terminal of the harmonic reducer (7) Ｌ Obtained, T Ｌ The peak value is the rated torque T of the harmonic reducer (7), The force F that needs to be generated by the cylinder (5) is calculated. [Number 19] During the ceremony, [Number 20] And, T Ｌ is the test load torque, β is the horizontal clamping angle of the link (42), and L ３ L is the distance between the center point A and the hinge connection point C. １ L is the length of crank AB, that is, the distance between the center point B and center point A of the eccentric shaft (411). ２ is the length of the link BC, i.e., the distance between the center point B of the eccentric shaft (411) and the hinge connection point C, and α is the actual output angle of the harmonic reducer (7). When the constant pressure load mode is selected, the constant pressure P of the cylinder (5) ｈ The following applies: [Math 21] In the formula, A １ The cross-sectional area of ​​the cylinder (5), A １ = πr ２ Here, r is the nominal radius of the piston of cylinder (5), When the compression load mode is selected, the initial pressure P of the cylinder (5) １ The following applies: [Number 22] In the formula, V ０ V is the initial volume of cylinder (5). １ This is the volume of cylinder (5) after compression, V ０ = A １ ・(L Ｃ +L ０ ) and L Ｃ L is the operating stroke of the cylinder (5). Ｃ = 2L １ <L Ｓ Satisfying L Ｓ L is the maximum physical stroke of the cylinder (5). ０ This is the length of the clearance in the cylinder (5) under maximum compression. V １ = V ０ -A １ Δx is the displacement of the piston of cylinder (5). [Number 23] And, Depending on the selected load mode, constant pressure P ｈ or initial pressure P １ Then pressurize the cylinder (5), Step 3 is specifically as follows: The piston displacement Δx of the cylinder (5) and the output angle θ of the motor (22), measured using a diffraction grating scale (64), are recorded in real time, and the geometric relationship is calculated. [Number 24] The actual output angle α of the harmonic reducer (7) is obtained by deriving it according to the formula. [Number 25] The difference between the theoretical output angle and the actual output angle α of the harmonic reducer (7) is the transmission error φ(α) of the harmonic reducer (7). [Number 26] In the equation, 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 (7), and the theoretical output angle of the harmonic reducer (7) is θ / N. Based on the actual output angle α and the transmission error φ(α) of the harmonic reducer (7), which are recorded in real time, a transmission error curve is created with the actual output angle α as the horizontal coordinate and the transmission error φ(α) of the harmonic reducer (7) as the vertical coordinate. The difference between the maximum and minimum values ​​of the vertical coordinate of the transmission error curve is the transmission accuracy Δφ. [Number 27] The method for testing the accuracy attenuation test apparatus for a robot joint harmonic reducer according to feature 9.

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