A harmonic reducer stiffness testing method and system

Abstract

The present invention provides a harmonic reducer stiffness test method and system, and relates to the field of mechanical transmission test technology. The method comprises: connecting the input end of the harmonic reducer to be tested to a stepper motor through a coupling, and connecting the output end to an angle encoder through a loading device; applying a sinusoidal disturbance signal by a control module to control the input end to perform periodic rotational motion; collecting the angle data of the input end and the output end in real time by an angle encoder, and collecting the loading torque by a torque sensor; processing the collected data by a denoising algorithm, calculating the angular velocity and angular acceleration of the input end and the output end; establishing a stiffness calculation model and performing parameter fitting according to the angular velocity, angular acceleration and loading torque, and obtaining the stiffness value and variation law of the harmonic reducer. The system comprises a stepper motor, a coupling, a loading device, an angle encoder, a torque sensor, a control module and a data processing module. The present invention can realize dynamic stiffness testing with high precision and strong environmental adaptability.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical transmission testing, and in particular to a method and system for testing the stiffness of a harmonic reducer. Background Art

[0002] As a high-precision, lightweight mechanical transmission device, harmonic reducers are widely used in robotics, aerospace, and precision instruments. One of its key performances is transmission stiffness, which directly affects the dynamic performance, positioning accuracy, and load capacity of the reducer. Therefore, accurately measuring the stiffness characteristics of harmonic reducers is of great significance for optimizing design and improving performance.

[0003] The existing harmonic reducer stiffness test technology is mainly implemented through static loading method, dynamic frequency response method and torque sensor direct measurement method. The static loading method calculates the transmission stiffness by gradually applying torque and measuring the output angular displacement. This method is simple to operate, but ignores the nonlinear effects (such as hysteresis, friction and clearance) under dynamic conditions, and cannot fully reflect the stiffness characteristics of the reducer in actual operation, especially in scenarios with low stiffness and high precision requirements, which are easily affected by external interference. The dynamic frequency response method can partially reflect the dynamic stiffness characteristics by analyzing the output response after applying a sinusoidal input signal. However, under high-frequency test conditions, due to the limitations of the dynamic response capability of the test equipment and the lack of signal processing accuracy, it is difficult to accurately capture complex nonlinear dynamic characteristics. At the same time, the test equipment is expensive and complicated to operate. The torque sensor direct measurement method calculates stiffness by measuring the relationship between the loading torque and the output angular displacement. This method improves the measurement accuracy to a certain extent, but the torque sensor is prone to nonlinear errors under low torque or high-precision test conditions, and the installation is complicated, which increases the test cost and difficulty.

[0004] There are some common problems in the existing technologies. First, many test methods do not fully consider the nonlinear friction, hysteresis effect and clearance characteristics in the harmonic reducer, and these nonlinear factors have a significant impact on the stiffness characteristics under actual operating conditions. Secondly, under dynamic test conditions, due to the limitations of signal processing capabilities, sensor performance and external environmental interference, it is difficult for existing methods to obtain high-precision dynamic response data, especially the measurement accuracy of key parameters such as output angular acceleration is insufficient, which affects the accuracy of stiffness calculation. In addition, some methods require the use of dedicated high-precision torque sensors or other complex devices, and the design and debugging costs of the test system are high, which is not conducive to large-scale promotion and application. Finally, the existing technology lacks effective compensation for the influence of environmental factors such as temperature, humidity and vibration in the test environment, which makes the test results easily affected by environmental changes, resulting in reduced reliability of the measurement results.

[0005] In summary, the prior art has not yet provided a harmonic reducer stiffness testing method and system that can fully consider nonlinear factors, improve dynamic testing accuracy, reduce equipment complexity, and effectively compensate for environmental impacts. These deficiencies restrict the further development of harmonic reducer performance optimization and application promotion. Summary of the invention

[0006] In order to solve the technical problems in the prior art that nonlinear factors are not fully considered, dynamic test accuracy is insufficient, test equipment is highly complex, and environmental impact compensation is imperfect, the present invention provides a harmonic reducer stiffness testing method and system.

[0007] The technical solution provided by the present invention is as follows:

[0008] First aspect:

[0009] The present invention provides a method for testing the stiffness of a harmonic reducer, comprising:

[0010] S1. Connect the input end of the harmonic reducer to be tested to the stepper motor through a coupling, and connect the output end to the angle encoder through a loading device to form a test system;

[0011] S2, applying a sinusoidal disturbance signal to the stepper motor using a control module to control the input end to perform periodic rotational motion;

[0012] S3, collecting the angle data of the input end and the output end in real time through the angle encoder, and collecting the loading torque through the torque sensor;

[0013] S4, using a denoising algorithm to process the collected angle data, and calculating the angular velocity and angular acceleration of the input end and the output end;

[0014] S5. According to the angular velocity, angular acceleration and loading torque, a stiffness calculation model of the harmonic reducer is established, wherein the nonlinear friction, hysteresis effect and clearance characteristics of the input and output ends are considered in the model;

[0015] S6. Based on the calculation model, the test data is fitted by the least squares method to obtain the stiffness value and stiffness change law of the harmonic reducer.

[0016] Second aspect:

[0017] The present invention provides a harmonic reducer stiffness testing system, comprising:

[0018] A stepper motor for applying rotational motion to the input end;

[0019] Coupling, used to connect the stepper motor and the input end of the harmonic reducer;

[0020] A loading device, used to simulate the working load at the output end of the harmonic reducer;

[0021] Angle encoder, used to measure the angle change between the input and output ends of the harmonic reducer;

[0022] A torque sensor for measuring the torque applied by the loading device;

[0023] Control module, used to coordinate system operation, generate disturbance signals and collect test data;

[0024] The data processing module is used to remove noise, calculate and analyze the collected data and output the stiffness calculation results.

[0025] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0026] (1) In the present invention, the harmonic reducer stiffness test method combines dynamic testing and denoising algorithms, effectively reducing the impact of external noise and measurement errors on the test results. By using high-precision angle encoders and torque sensors, and introducing wavelet transform denoising technology, it is possible to accurately collect input and output angle and loading torque data, and ensure the accuracy of test results under various complex working conditions. This provides reliable data support for the dynamic stiffness characteristics of the harmonic reducer, especially in test environments with large load changes or high frequencies;

[0027] (2) In the present invention, by introducing a temperature and humidity compensation mechanism, the stability of the test results under different environmental conditions is ensured. The system monitors the changes in ambient temperature and humidity in real time, and uses appropriate compensation coefficients to correct the data, effectively eliminating the interference of temperature changes on the test results and ensuring the reliability of the test. This method is suitable for stiffness testing under different loads and working conditions, has strong environmental adaptability, and is widely used in robots, automation equipment, precision machinery and other fields;

[0028] (3) In the present invention, through high-precision dynamic stiffness measurement, the test system can analyze in detail the performance of the harmonic reducer under different loads and working conditions. This method can accurately measure the stiffness change law of the reducer and provide data support for the optimal design of the reducer. Through in-depth analysis of the test data, designers can adjust the structure and material of the reducer according to actual needs, improve its stability and response speed during operation, and thus improve the overall performance and life of the reducer to meet higher requirements of industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A schematic flow chart of a method for testing the stiffness of a harmonic reducer provided in an embodiment of the present invention;

[0031] Figure 2 A structural schematic diagram of a harmonic reducer stiffness testing system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0033] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0034] In the embodiments of the present invention, "image" and "picture" can sometimes be used interchangeably. It should be noted that when the difference between them is not emphasized, the meanings they intend to express are the same. "of", "corresponding, relevant" and "corresponding" can sometimes be used interchangeably. It should be noted that when the difference between them is not emphasized, the meanings they intend to express are the same.

[0035] In the embodiments of the present invention, sometimes the subscripts such as W 1 It may be mistakenly written as a non-subscript form such as W1. When the difference is not emphasized, the meanings they express are the same.

[0036] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0037] Reference Manual Attached Figure 1 , showing a schematic flow chart of a harmonic reducer stiffness testing method provided in an embodiment of the present invention.

[0038] An embodiment of the present invention provides a method for testing the stiffness of a harmonic reducer. The method can be implemented by a harmonic reducer stiffness testing device. The harmonic reducer stiffness testing device can be a terminal or a server. The processing flow of the method for testing the stiffness of a harmonic reducer can include the following steps:

[0039] S1. Connect the input end of the harmonic reducer to be tested to the stepper motor through a coupling, and connect the output end to the angle encoder through a loading device to form a test system.

[0040] In this step, the harmonic reducer to be tested is first connected to the stepper motor through a coupling. The stepper motor is used to generate an accurate periodic disturbance signal to control the input end movement of the harmonic reducer. In order to ensure the accuracy of signal transmission, the coupling uses a high-precision flexible coupling, such as the JS-50 type, which has the characteristics of low friction and high torque transmission efficiency.

[0041] The output end of the harmonic reducer is connected to the inertia loading device (such as an inertia disk) and a high-precision angle encoder. The angle encoder adopts the RENISHAW TONiC series with a resolution of 0.0001°, which is used to collect the angle data of the input and output ends in real time to ensure the accuracy of subsequent data processing. The loading device is designed to simulate the load in actual work and load the inertia moment I load The calculation is performed according to the following formula:

[0042]

[0043] Among them, M represents the mass of the loading disk, in kg, and R is the radius of the loading disk, in m. By changing the moment of inertia of the loading device, the stiffness test under different load conditions can be simulated. Through the above formula, the experimenter can select a suitable loading device to generate the required load during the test, so as to test the dynamic behavior of the harmonic reducer under different loads. For example, if a smaller loading disk (small radius R or lighter mass M) is selected, a smaller moment of inertia will be generated to simulate a low load condition; if a larger loading disk (large radius R or heavier mass M) is selected, a larger moment of inertia will be generated to simulate a high load condition. In this way, the tester can simulate the influence of different load conditions on the stiffness of the harmonic reducer and provide more accurate experimental data for stiffness calculation.

[0044] It is understandable that the above formula calculates the resistance of the loading device (such as the inertia disk) to rotation, which is closely related to the mass and radius of the loading disk. In the stiffness test of the harmonic reducer, this moment of inertia reflects the characteristics of the system load, which in turn affects the relationship between the moment and the angular displacement, thus playing a key role in the calculation of dynamic stiffness.

[0045] In a possible embodiment, the loading device may also use a material having a specific stiffness coefficient K spring For a spring with a load moment of , the calculation method is:

[0046] T spring =K spring ·θ rel

[0047] Among them, T spring Indicates the torque generated by spring loading, in Nm, K spring Indicates the spring stiffness coefficient in Nm / rad, θ rel Represents relative angular displacement in radians.

[0048] It can be understood that the relationship between the torque applied by the spring loading device to the harmonic reducer and the relative angular displacement is described. It shows that the torque of the spring and its stiffness K spring and the relative angular displacement θ rel The above formula is adjusted by adjusting the spring stiffness K spring and the angular displacement θ of the load rel , the torque applied by the loading device to the harmonic reducer can be controlled to simulate different load conditions. This is very important in stiffness testing because the size and type of load directly affects the dynamic response and stiffness characteristics of the harmonic reducer. In this way, testers can provide different load conditions for the harmonic reducer and measure its stiffness changes under various conditions.

[0049] S2. Apply a sinusoidal disturbance signal to the stepper motor using a control module to control the input end to perform periodic rotation. In this step, the control module applies a sinusoidal disturbance signal to the stepper motor to drive the input end to perform periodic rotation. The form of the disturbance signal is:

[0050] θ input =A·sin(ωt+φ)

[0051] Among them, θ input It represents the input angular displacement in radians, A is the signal amplitude, which reflects the maximum disturbance angle in radians, ω is the angular frequency of the signal in radians per second, usually set to 0.1-10rad / s, t is the time in seconds, and φ is the signal phase, which is usually set to zero or adjusted according to demand. Through this disturbance signal, the stepper motor accurately controls the periodic motion of the angular displacement of the input end, thereby simulating the operating state of the harmonic reducer under dynamic conditions.

[0052] It can be understood that the above formula is used to describe the periodic disturbance signal applied to the input end of the stepper motor. Through this formula, the control system can accurately control the angular displacement θ of the input end input, so that it changes over time and presents a sinusoidal waveform. The amplitude A determines the maximum angular displacement of the signal, the frequency ω controls the speed of change of the signal, and the phase φ can adjust the starting position of the signal. In the stiffness test of the harmonic reducer, this periodic disturbance signal is used to simulate the dynamic load encountered by the reducer during operation, so as to analyze the stiffness characteristics of the reducer by measuring the relationship between input and output. By adjusting the amplitude, frequency and phase of the signal, the response ability of the reducer under different working conditions can be tested, and its performance can be evaluated.

[0053] In a possible implementation, a multi-frequency superposition signal may be used for input:

[0054]

[0055] This form is suitable for analyzing the dynamic stiffness characteristics of harmonic reducers under complex working conditions. It should be noted that the above formula is used to describe the synthesis of multi-frequency disturbance signals. By superimposing sine waves of different frequencies, more complex load conditions can be simulated, especially when it is necessary to test the performance of harmonic reducers under non-single frequency conditions. In the test, this multi-frequency signal can more realistically reflect the complex dynamic environment that the reducer may encounter in actual use, thereby helping to analyze its stiffness changes and dynamic response. By adjusting the amplitude A of each frequency component i , frequency ω i and phase φ i , the characteristics of the input signal can be precisely controlled to meet different test requirements.

[0056] S3, collecting the angle data of the input end and the output end in real time through the angle encoder, and collecting the loading torque through the torque sensor.

[0057] It should be noted that in this step, the angle encoder simultaneously collects the input angle θ in real time. input and the output angle θ output , providing data support for subsequent kinematic analysis. The collected angle data is differentially calculated to obtain the angular velocity ω of the input and output ends. input and ω output , and the relative angular displacement θ rel and the relative angular velocity ω rel .

[0058] The relative angular displacement is calculated as follows:

[0059] θ rel =θ input -N·θ output

[0060] Among them, θ relIt represents the relative angular displacement between input and output in radians, and N represents the transmission ratio of the harmonic reducer, which is usually an integer.

[0061] It is important to understand that the above formula is used to express the relative angular displacement between the input and output. The transmission ratio of the harmonic reducer is N, which determines the relationship between the angular displacement of the input and output. Using this formula, we can calculate the difference between the input and output, that is, the relative angular displacement θ rel This relative angular displacement is an important parameter for evaluating the stiffness and dynamic response of the reducer, because it directly affects the relationship between the output torque and the input disturbance. In testing, measuring the relative angular displacement helps to reveal the performance and behavior of the reducer under actual working conditions, especially the impact of nonlinear factors and load changes on stiffness.

[0062] The relative angular velocity is calculated as follows:

[0063] ω rel =ω input -N·ω output

[0064] Among them, ω rel Represents the relative angular velocity. The above parameters are used to calculate the dynamic stiffness model.

[0065] If the test system is equipped with a torque sensor, the sensor will be used to measure the loading torque T in real time. load To ensure the accuracy of the test results. The torque sensor is HBM T22, with a measuring range of 0 to 10 Nm.

[0066] It should be understood that the above formula represents the relative speed between the angular velocity of the input end and the angular velocity of the output end. Since the harmonic reducer has a fixed transmission ratio N, the angular velocity of the input and output has a certain proportional relationship. Through this formula, the relative angular velocity ω between the input and output ends can be calculated rel , which is the difference between the input and output angular velocities after taking into account the gear ratio of the reducer. This relative angular velocity is a key parameter for analyzing the stiffness and dynamic characteristics of the harmonic reducer. It helps to study the response speed and torque changes of the reducer under different load conditions, and then evaluate the performance and stiffness of the reducer.

[0067] S4. Use a denoising algorithm to process the collected angle data and calculate the angular velocity and angular acceleration of the input end and the output end. The denoising algorithm uses wavelet transform technology to remove high-frequency noise and retain effective signal components. After data collection, real-time data often contains noise, which affects the accuracy of subsequent calculations. Therefore, a denoising algorithm is used to process the angle data. Here, a wavelet transform method is used to remove high-frequency noise and retain effective signal components. Through this algorithm, the angle data is smoothed and the instantaneous error caused by motor noise or changes in the external environment is eliminated.

[0068] The denoised angle data is used to further calculate the angular velocity and angular acceleration of the input and output ends. The angular velocity calculation formula of the input and output ends is:

[0069]

[0070] Where Δt is the sampling time interval. The angular acceleration at the output From the angular velocity difference we get:

[0071]

[0072] The purpose of this step is to obtain high-precision kinematic data to facilitate subsequent dynamic stiffness calculations.

[0073] It can be understood that in the angular velocity calculation formulas at the input and output ends, angular velocity is a physical quantity that describes the rotation rate of an object. In practical applications, the input and output angles of stepper motors and harmonic reducers are collected in real time through angle encoders. Through this formula, the angle change can be converted into angular velocity, which is crucial for analyzing the motion response of the harmonic reducer. Specifically, the angular velocity at the input end reflects the rate of change of the disturbance signal applied by the stepper motor, and the angular velocity at the output end indicates the response speed of the reducer to the input signal. These two angular velocities are important parameters for evaluating the transmission efficiency, response characteristics, and stiffness characteristics of the reducer.

[0074] Similarly, the angular acceleration at the output represents the rate of change of angular velocity over time. In practical applications, angular acceleration is very important for understanding the dynamic response of the reducer under load changes or input disturbances. Angular acceleration can reveal the inertial characteristics of the system, especially when starting, stopping or load changes, the system response will produce acceleration or deceleration. By calculating the angular acceleration at the output, the dynamic characteristics of the harmonic reducer can be further analyzed, especially when the load changes, whether the reducer can respond quickly and stably. This is crucial to evaluate whether the reducer can withstand sudden load changes in actual work and the stability of the system.

[0075] S5. According to the angular velocity, angular acceleration and loading torque, a stiffness calculation model of the harmonic reducer is established, and the nonlinear friction, hysteresis effect and gap characteristics of the input and output ends are considered in the model. The stiffness calculation model includes a dynamic model for describing the time correlation between angular displacement and loading torque. In this step, based on the angular velocity, angular acceleration and loading torque data collected above, a stiffness calculation model of the harmonic reducer is established. The nonlinear friction, hysteresis effect and gap characteristics of the input and output ends of the harmonic reducer are considered in the model, and these factors have an important influence on the stiffness characteristics.

[0076] The established kinetic model is:

[0077]

[0078] Where T is the output torque, k 1 is the linear stiffness coefficient, k 2 is the nonlinear stiffness coefficient, A is the hysteresis effect amplitude, α is the hysteresis effect frequency, c is the gap correction parameter, γ is the dynamic damping coefficient, and λ is the inertial coupling coefficient. This model can describe the dynamic response of the harmonic reducer under actual working conditions by establishing the relationship between the input angle, output angle and loading torque as a nonlinear equation.

[0079] It should be noted that the above model is used to describe the relationship between the torque output and input signal of the harmonic reducer under dynamic conditions, and combines nonlinear factors (such as friction, hysteresis effect, clearance, etc.) and dynamic response (such as damping and inertia effect) to accurately simulate the performance of the reducer. Specifically, this model uses multiple parameters to describe the torque T and the relative angular displacement θ rel , relative angular velocity ω rel and angular acceleration These parameters reflect the stiffness, damping and other nonlinear characteristics of the reducer in actual operation.

[0080] Specifically, first, k 1 and k 2 is the stiffness coefficient in the model, k 1 Represents linear stiffness, describing the linear relationship between the input angular displacement and the output torque; k 2 is the nonlinear stiffness coefficient, which describes the nonlinear stiffness effect when the angular displacement is large. In actual testing, k 1 and k 2 By collecting the input angular displacement θ input The data of and output torque T are estimated using parameter identification methods such as the least squares method to obtain these two parameters.

[0081] Secondly, A and α represent the amplitude and frequency of the hysteresis effect, respectively. The hysteresis effect refers to the lag between the output torque of the reducer and the input angular displacement during loading and unloading. This hysteresis effect cannot be ignored in many practical applications, especially when the load changes greatly. By fitting the experimental data, the optimal values ​​of A and α can be obtained.

[0082] Parameter c represents the clearance correction factor of the system. Clearance is an inevitable physical phenomenon in mechanical transmission systems, especially in mechanical connection parts. The existence of clearance will lead to inconsistency between input and output, affecting the stiffness and accuracy of the system. In actual testing, the clearance compensation parameter c can be estimated through the dynamic response data of the system.

[0083] γ is the dynamic damping coefficient, which reflects the resistance of the reducer system during movement and is usually related to friction and other energy consumption factors. Damping force and relative angular velocity ω rel The damping coefficient γ is proportional to the friction or viscous resistance in the system. The damping coefficient γ is usually estimated based on the response data of the actual system by comparing it with the measured torque and angular velocity data.

[0084] Finally, λ is the inertial coupling coefficient, which represents the torque response caused by inertia in the reducer, and is usually proportional to acceleration. By measuring the torque change of the reducer when acceleration is applied, combined with the angular acceleration θ output and the dynamic response of the system, the inertial coupling coefficient λ can be obtained.

[0085] Overall, this model provides a mathematical framework for comprehensively describing the dynamic stiffness of harmonic reducers by combining multiple physical parameters. In practical applications, through the collection of test data and parameter identification, the torque output of the reducer under different working conditions can be accurately calculated, thereby optimizing the design and performance evaluation of the reducer. This is especially important for robots, precision machinery and other fields that require high-precision transmission systems.

[0086] S6. Based on the calculation model, the test data is fitted by the least squares method to obtain the stiffness value and stiffness change law of the harmonic reducer. Use multiple sets of input and output data to verify the stiffness value to ensure the repeatability and accuracy of the test results. In this step, the least squares method is used to identify the parameters of the stiffness calculation model. By fitting the difference between the experimental data and the model output, the optimal value of each parameter in the model is obtained. The specific objective function is:

[0087]

[0088] Among them, T i is the actual output torque of the ith sampling, T model,iThe output torque of the model is calculated for the i-th sampling. The above formula is used to evaluate the error between the output torque predicted by the model and the actual measured output torque. By minimizing this error, the model parameters can be optimized so that the torque calculated by the model is as consistent as possible with the actual test data, thereby improving the accuracy of the reducer stiffness calculation. Specifically, the objective function calculates the actual measured torque T in each experimental data. i The moment T predicted by the stiffness calculation model model,i The smaller the sum of squares of the difference, the stronger the prediction ability of the model and the more accurate the stiffness parameters obtained. Therefore, by optimizing this objective function, the dynamic stiffness and related parameters of the harmonic reducer can be obtained, thereby providing accurate data support for the performance evaluation, design optimization and practical application of the reducer.

[0089] In a possible implementation, in order to improve data processing accuracy, a sliding average filter is used to smooth the kinematic parameters:

[0090]

[0091] Where is the filter window length, usually 5. When the ambient temperature or humidity has a significant impact on the test results, it is corrected by the compensation formula. For example, the temperature compensation T corrected for:

[0092] T corrected =T measured· (1+β·ΔT)

[0093] Among them, T measured is the uncompensated torque, β is the temperature compensation coefficient, and ΔT is the difference between the current temperature and the reference temperature.

[0094] It should be noted that the smoothing formula for diagonal acceleration The data is smoothed and the noise is removed by sliding average filtering to obtain a more stable output result. In practical applications, the measurement of kinematic parameters (such as angular acceleration) may be affected by system noise or sensor errors. Using this filtering method can effectively reduce these errors and make the data smoother and more reliable. By averaging the data at multiple time points, this method helps improve the accuracy of dynamic analysis, especially in high-frequency motion or low signal-to-noise ratio situations, and can ensure the reliability of the calculation results.

[0095] In actual testing, changes in ambient temperature may have a significant impact on the measurement results, especially the changes in the material and friction characteristics of the reducer at different temperatures. Through the temperature compensation formula, the measured torque data T can be calculated based on the current temperature change ΔT and the preset temperature compensation coefficient β. measuredCorrection can be made to obtain more accurate results. This method can ensure the consistency of test results under different temperature environments, thereby improving the reliability and accuracy of the test.

[0096] It should be noted that the temperature compensation coefficient β is obtained through experimental measurement and reflects the impact of temperature changes on torque or system response. In practical applications, the same test is first performed at multiple different temperatures to record the torque changes in the test. Then, through regression analysis or data fitting, a suitable coefficient β is found so that the measured torque data can be compensated at different temperatures. After β is obtained through experimental data, this coefficient can be applied to compensate the measurement results in real time at different ambient temperatures to ensure the consistency and accuracy of the test data.

[0097] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0098] (1) In the present invention, the harmonic reducer stiffness test method combines dynamic testing and denoising algorithms, effectively reducing the impact of external noise and measurement errors on the test results. By using high-precision angle encoders and torque sensors, and introducing wavelet transform denoising technology, it is possible to accurately collect input and output angle and loading torque data, and ensure the accuracy of test results under various complex working conditions. This provides reliable data support for the dynamic stiffness characteristics of the harmonic reducer, especially in test environments with large load changes or high frequencies;

[0099] (2) In the present invention, by introducing a temperature and humidity compensation mechanism, the stability of the test results under different environmental conditions is ensured. The system monitors the changes in ambient temperature and humidity in real time, and uses appropriate compensation coefficients to correct the data, effectively eliminating the interference of temperature changes on the test results and ensuring the reliability of the test. This method is suitable for stiffness testing under different loads and working conditions, has strong environmental adaptability, and is widely used in robots, automation equipment, precision machinery and other fields;

[0100] (3) In the present invention, through high-precision dynamic stiffness measurement, the test system can analyze in detail the performance of the harmonic reducer under different loads and working conditions. This method can accurately measure the stiffness change law of the reducer and provide data support for the optimal design of the reducer. Through in-depth analysis of the test data, designers can adjust the structure and material of the reducer according to actual needs, improve its stability and response speed during operation, and thus improve the overall performance and life of the reducer to meet higher requirements of industrial applications.

[0101] Reference Manual Attached Figure 2 , showing a structural schematic diagram of a harmonic reducer stiffness testing system provided in an embodiment of the present invention.

[0102] The present invention also provides a harmonic reducer stiffness testing system, which is applied to the harmonic reducer stiffness testing method, and comprises:

[0103] Stepper motor, used to apply rotational motion at the input end. This system uses a NEMA 23 stepper motor (model: STP-42D2804) with a step angle of 1.8°, which can be improved to 0.01° through a subdivided driver. The motor is used to apply precise rotational motion at the input end, and the sinusoidal disturbance signal generated by the control module drives the stepper motor to perform periodic motion. The stepper motor is connected to the control module through the RS-485 communication protocol, and the control module adjusts the input signal frequency and amplitude of the stepper motor in real time through a computer or built-in operating system.

[0104] The coupling is used to connect the stepper motor and the input end of the harmonic reducer. The stepper motor and the input end of the harmonic reducer are connected by an elastic coupling (model: RJ-3025-6). The coupling is used to ensure that the torque of the stepper motor can be correctly transmitted to the harmonic reducer, and allows the effective absorption of small axial, radial and angular deviations when the load is uneven. The coupling is installed by keyway and threaded connection to ensure the stability of the connection and high transmission efficiency.

[0105] The loading device is used to simulate the working load at the output end of the harmonic reducer. The loading device is an adjustable inertia wheel that can simulate different inertia loads to meet various test requirements. The system uses an adjustable inertia wheel (model: I-2000-LW) as a loading device to simulate the working load at the output end of the harmonic reducer. The mass and radius of the inertia wheel are adjustable, and the maximum moment of inertia I load 0.1kg·m 2 , the minimum moment of inertia is 0.01kg·m 2 , suitable for different load test requirements. The inertia wheel is installed at the output end of the harmonic reducer through thread and flange connection. By controlling the mass and radius of the inertia wheel, the response characteristics of the reducer under different loads can be accurately simulated. The setting and adjustment of the inertia wheel are adjusted in real time by the control module.

[0106] Angle encoder is used to measure the angular changes at the input and output of the harmonic reducer. The measurement accuracy of the angle encoder is 0.001 degrees, which is used to ensure the accuracy of the collected data. To measure the angular changes at the input and output ends, the system is equipped with a RENISHAW TONiC series (model: RGS-50 / 125) high-precision angle encoder. The resolution of this encoder reaches 0.001°, ensuring the accuracy and stability of the angle data collection. The encoder is connected to the data processing module through an RS-232 interface to transmit the collected input and output angle data in real time for subsequent kinematic calculations and model analysis.

[0107] The torque sensor is used to measure the torque applied by the loading device. In order to accurately measure the torque applied by the loading device, the system is equipped with an HBM T22 torque sensor (measuring range: 0-10Nm). This sensor has high-precision measurement capabilities and can work stably under higher loads and accurately obtain the loading torque T load The torque sensor is connected to the data processing module via the CANopen bus to transmit the measurement results in real time.

[0108] The control module is used to coordinate the operation of the system, generate disturbance signals and collect test data. The control module has the function of adjusting the frequency and amplitude of the input signal in real time, which is used to flexibly test the stiffness response characteristics. The control module is responsible for coordinating the overall operation of the system, generating input signals and adjusting the working state of the stepper motor. The module uses the NIPXI-1075 control system with a built-in high-speed processor to support real-time calculation and signal generation. The control module has the function of adjusting the frequency and amplitude of the input signal in real time to ensure that it can flexibly adapt to different test requirements. Through the connection with the stepper motor, the control module can accurately adjust the signal frequency and amplitude to regulate the dynamic response characteristics of the harmonic reducer. The control module communicates with each sensor through the Modbus TCP protocol to ensure stable and reliable data transmission.

[0109] The data processing module is used to denoise, calculate and analyze the collected data, and output the stiffness calculation results. The data processing module includes an embedded processor for running a parameter identification algorithm, calculating and outputting the stiffness value in real time. The data processing module adopts an embedded processor (model: Raspberry Pi 4B) with a built-in efficient computing platform to support real-time data acquisition, processing and analysis. The data processing module is connected to the angle encoder and torque sensor through a USB interface to obtain real-time data and perform denoising, calculation and analysis. The module runs a parameter identification algorithm, calculates torque and angle data in real time, and outputs dynamic stiffness values ​​and change rules. The data processing module can fit the model using the least squares method or other optimization algorithms according to the relationship between the input signal and the output torque, and accurately obtain the stiffness of the reducer.

[0110] Environmental monitoring module, used to measure the temperature and humidity of the test environment and compensate for it in the stiffness calculation. The environmental monitoring module is used to measure the temperature and humidity of the test environment so as to compensate for it in the stiffness calculation. The module is equipped with Honeywell HIH-4000 series sensors, which can provide high-precision environmental data. The temperature and humidity sensor communicates with the data processing module through the I2C protocol, monitors in real time and transmits data to the data processing module. When performing stiffness calculations, the data processing module will correct the collected data according to the compensation formula to ensure that the test results are not affected by changes in temperature and humidity.

[0111] The entire system is connected through standard interfaces and protocols (such as RS-485, RS-232, CANopen, Modbus TCP, I2C) to achieve real-time data transmission and processing. The stepper motor, angle encoder, torque sensor and environmental monitoring module are coordinated through the control module to collect data in real time and feed it back to the data processing module. The control module can adjust the input signal parameters according to the real-time data to ensure the continuity and stability of the test process. The data processing module is responsible for filtering, calculating, analyzing the data and outputting the final stiffness value.

[0112] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0113] (1) In the present invention, the harmonic reducer stiffness test method combines dynamic testing and denoising algorithms, effectively reducing the impact of external noise and measurement errors on the test results. By using high-precision angle encoders and torque sensors, and introducing wavelet transform denoising technology, it is possible to accurately collect input and output angle and loading torque data, and ensure the accuracy of test results under various complex working conditions. This provides reliable data support for the dynamic stiffness characteristics of the harmonic reducer, especially in test environments with large load changes or high frequencies;

[0114] (2) In the present invention, by introducing a temperature and humidity compensation mechanism, the stability of the test results under different environmental conditions is ensured. The system monitors the changes in ambient temperature and humidity in real time, and uses appropriate compensation coefficients to correct the data, effectively eliminating the interference of temperature changes on the test results and ensuring the reliability of the test. This method is suitable for stiffness testing under different loads and working conditions, has strong environmental adaptability, and is widely used in robots, automation equipment, precision machinery and other fields;

[0115] (3) In the present invention, through high-precision dynamic stiffness measurement, the test system can analyze in detail the performance of the harmonic reducer under different loads and working conditions. This method can accurately measure the stiffness change law of the reducer and provide data support for the optimal design of the reducer. Through in-depth analysis of the test data, designers can adjust the structure and material of the reducer according to actual needs, improve its stability and response speed during operation, and thus improve the overall performance and life of the reducer to meet higher requirements of industrial applications.

[0116] The above contents are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

[0117] There are a few points to note:

[0118] (1) The drawings of the embodiments of the present invention only relate to the structures related to the embodiments of the present invention, and other structures may refer to the general design.

[0119] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present invention, the thickness of the layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or there may be intermediate elements.

[0120] (3) In the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to obtain new embodiments.

[0121] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for testing the stiffness of a harmonic reducer, characterized in that: include: S1. Connect the input end of the harmonic reducer to be tested to the stepper motor through a coupling, and connect the output end to the angle encoder through a loading device to form a test system; S2, applying a sinusoidal disturbance signal to the stepper motor using a control module to control the input end to perform periodic rotational motion; S3, collecting the angle data of the input end and the output end in real time through the angle encoder, and collecting the loading torque through the torque sensor; S4, using a denoising algorithm to process the collected angle data, and calculating the angular velocity and angular acceleration of the input end and the output end; S5. According to the angular velocity, angular acceleration and loading torque, a stiffness calculation model of the harmonic reducer is established, wherein the nonlinear friction, hysteresis effect and clearance characteristics of the input and output ends are considered in the model; S6. Based on the calculation model, the test data is fitted by the least squares method to obtain the stiffness value and stiffness change law of the harmonic reducer.

2. A harmonic reducer stiffness testing method according to claim 1, characterized in that: The S4 further comprises: The denoising algorithm uses wavelet transform technology to remove high-frequency noise and retain effective signal components.

3. A harmonic reducer stiffness testing method according to claim 1, characterized in that: The S5 further comprises: The stiffness calculation model includes a dynamic model for describing the time correlation between the angular displacement and the loading moment.

4. A method for testing the stiffness of a harmonic reducer according to claim 1, characterized in that: The S6 further comprises: Use multiple sets of input and output data to verify the stiffness value to ensure the repeatability and accuracy of the test results.

5. A harmonic reducer stiffness testing system, characterized in that: include: A stepper motor for applying rotational motion to the input end; Coupling, used to connect the stepper motor and the input end of the harmonic reducer; A loading device, used to simulate the working load at the output end of the harmonic reducer; Angle encoder, used to measure the angle change between the input and output ends of the harmonic reducer; A torque sensor for measuring the torque applied by the loading device; Control module, used to coordinate system operation, generate disturbance signals and collect test data; The data processing module is used to remove noise, calculate and analyze the collected data and output the stiffness calculation results.

6. A harmonic reducer stiffness testing system according to claim 5, characterized in that: include: The measuring accuracy of the angle encoder is 0.001 degrees, which is used to ensure the accuracy of the collected data.

7. A harmonic reducer stiffness testing system according to claim 5, characterized in that: include: The loading device is an adjustable inertia wheel, which can simulate different inertia loads to meet various test requirements.

8. A harmonic reducer stiffness testing system according to claim 5, characterized in that: include: The control module has the function of adjusting the frequency and amplitude of the input signal in real time, and is used for flexibly testing the stiffness response characteristics.

9. A harmonic reducer stiffness testing system according to claim 5, characterized in that: include: The data processing module includes an embedded processor for running a parameter identification algorithm to calculate and output stiffness values ​​in real time.

10. A harmonic reducer stiffness testing system according to claim 5, characterized in that: include: The system includes an environmental monitoring module for measuring the temperature and humidity of the test environment and compensating for them in the stiffness calculation.

Images