A robot reducer test platform base and a test method
By using a separate sensor layout and active vibration compensation technology, the problems of environmental vibration interference and manual alignment in speed reducer testing were solved, achieving accuracy and automated positioning in speed reducer performance testing, and ensuring the reliability of test data and structural safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUAQIAO UNIVERSITY
- Filing Date
- 2025-10-31
- Publication Date
- 2026-05-29
AI Technical Summary
In traditional gear reducer performance testing, severe external environmental vibration interference leads to inaccurate test data. Furthermore, the traditional manual alignment method is time-consuming, labor-intensive, and difficult to guarantee accuracy, affecting the accuracy of test results.
By employing a separate sensor layout and active vibration compensation technology, environmental vibrations are separated and canceled through piezoelectric ceramic actuators and an automatic centering mechanism. Combined with a laser displacement sensor and a two-dimensional moving slide driven by a stepper motor, the rapid and automated positioning of the reducer and the accuracy of test data are ensured.
It effectively isolates environmental interference vibrations, ensures the accuracy of test data, improves the reliability of test results, avoids data contamination and positioning errors, provides an ideal dynamic and static test environment, and ensures structural safety.
Smart Images
Figure CN121026480B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of robot testing, specifically to a robot reducer test platform base and testing method. Background Technology
[0002] With the rapid development of robotics technology, the performance and reliability of robot reducers have become a focus of industry attention. As a key component of the robot joint drive system, the real-time monitoring and fault diagnosis of the reducer's operating status are crucial for ensuring the safe operation of the robot and extending its service life. However, in actual operation, due to the complex industrial environment, the vibration signal of the reducer not only includes the vibration generated by the reducer itself but also a large amount of environmental vibration noise transmitted from the ground, air, and other equipment. These vibration signals are superimposed on the signals generated by the reducer itself, resulting in contaminated test data and making it difficult to accurately assess the true vibration characteristics of the reducer.
[0003] Traditional gearbox performance testing typically involves placing the test equipment directly on the ground. This method allows external environmental vibrations to be transmitted to the test equipment through the ground, interfering with the test data and making it difficult for the data to accurately reflect the gearbox's true performance. To address this issue, existing technologies often employ passive vibration isolation solutions, such as using damping pads or vibration isolation springs. However, the isolation effectiveness of these passive solutions is limited by the inherent properties of the materials, and their isolation effect is often unsatisfactory for low-frequency vibrations and dynamic, complex environmental vibrations.
[0004] After completing the vibration isolation foundation construction of the test platform, accurately and efficiently installing the different specifications of the gearboxes under test is another problem that needs to be solved. Traditional manual alignment methods are not only time-consuming and labor-intensive, but also difficult to guarantee accuracy, and alignment errors directly affect the accuracy of test results. This makes test preparation work face challenges of low efficiency and poor positioning repeatability every time the gearbox under test is changed.
[0005] Furthermore, during formal performance testing of the speed reducer, each change to a different weight and size of the tested speed reducer leads to changes in the dynamic characteristics of the entire test system, such as total mass, center of mass, and stiffness. If a single static model is still used for data processing, the model cannot accurately represent the transmission relationship of vibration within the system, thus affecting the accuracy of data decoupling and vibration compensation. This makes it difficult to separate pure speed reducer vibration data from mixed dynamic signals and also makes it impossible to achieve accurate physical cancellation of environmental vibrations. Summary of the Invention
[0006] The purpose of this invention is to provide a robot reducer test platform base and test method to solve the problems mentioned in the background art.
[0007] The technical solution of the present invention includes:
[0008] Heavy-duty main base;
[0009] The secondary platform is independently located above the main base;
[0010] Multiple support components are vertically arranged between the main base and the secondary platform to achieve a rigid connection between the two, wherein each support component is provided with a piezoelectric ceramic actuator.
[0011] The first type of accelerometer and the first type of strain gauge are embedded in the main base, which are used to generate base vibration response data characterizing environmental vibration and main base structural stress;
[0012] The second type of accelerometer and the second type of strain gauge are installed on the secondary platform to generate a mixed dynamic signal of the platform that includes the operating vibration of the reducer, the structural response of the platform, and the environmental vibration.
[0013] Preferably, it also includes an automatic alignment mechanism disposed on the secondary platform, the automatic alignment mechanism being used to support and adjust the position of the speed reducer under test in the horizontal plane.
[0014] Preferably, the automatic alignment mechanism includes a mounting plate, a two-dimensional moving slide, and a laser displacement sensor; wherein, the mounting plate is used to mount the speed reducer under test; the two-dimensional moving slide is used to drive the mounting plate to move in a two-dimensional plane; the laser displacement sensor is fixed on the main base by an independent bracket and is used to measure the spatial position of the mounting plate in real time.
[0015] Preferably, the two-dimensional moving slide is driven by a stepper motor; and the automatic centering mechanism further includes an electromagnetic brake coaxially connected to the stepper motor; wherein the electromagnetic brake is used to lock the two-dimensional moving slide after centering is completed.
[0016] A method for testing robot speed reducers includes:
[0017] The dynamic model establishment step is used to establish a modified dynamic model based on the active excitation signal applied by the piezoelectric ceramic actuator, the vibration response data of the base, and the hybrid dynamic signal of the platform; wherein the modified dynamic model is used to characterize the transmission relationship between the vibration response data of the base and the hybrid dynamic signal of the platform.
[0018] A dynamic signal decoupling step is performed, which is used to decouple the interfering vibration signal from the real-time acquired mixed dynamic signal of the platform based on the modified dynamic model; wherein, the vibration response data of the base is used as the reference noise during decoupling; the interfering vibration signal characterizes the environmental vibration and the platform structural response; the output of this step is pure vibration data that only reflects the working state of the tested reducer;
[0019] An active vibration compensation step is performed, which is used to generate a compensation control command based on the interference vibration signal and drive the piezoelectric ceramic actuator to perform active compensation motion; wherein the compensation control command is equal in magnitude and opposite in phase to the interference vibration signal.
[0020] Preferably, the step of establishing a dynamic model specifically includes establishing a baseline dynamic model and performing model correction; wherein, the baseline dynamic model is established by frequency sweep excitation under the conditions of no load or loading of standard mass blocks on the secondary platform; the model correction refers to calculating the total mass of the assembly by applying instantaneous thrust pulses after installing the reducer under test, and adjusting the parameters of the baseline dynamic model according to the total mass.
[0021] Preferably, the active vibration compensation step further includes: real-time monitoring of structural stress data collected by the first type of strain gauge and the second type of strain gauge; actively limiting the amplitude of the active compensation movement when the structural stress data exceeds a preset safety threshold; and not limiting the amplitude of the active compensation movement when the structural stress data does not exceed the preset safety threshold.
[0022] Preferably, before the step of establishing the dynamic model, an automatic centering step is included; wherein, the automatic centering step is used to adjust the mounting plate of the speed reducer under test to a preset target coordinate based on the real-time position feedback of the laser displacement sensor.
[0023] Preferably, after the automatic alignment step is completed, a locking step is further included; wherein, the locking step is used to rigidly lock the two-dimensional moving slide of the automatic alignment mechanism by means of an electromagnetic brake.
[0024] This invention provides an improved robot reducer test platform base and test method, which, compared with the prior art, has the following improvements and advantages:
[0025] 1. By using a separate sensor layout and dynamic signal decoupling steps, this scheme can effectively separate environmental interference vibrations from the signals of the gearbox under test. Therefore, the final test data only reflects the vibration characteristics of the gearbox itself, thus accurately assessing the true vibration characteristics of the gearbox and avoiding data contamination by environmental noise. The automatic centering mechanism solves the problems of time-consuming, labor-intensive and inaccurate traditional manual centering. By using a laser displacement sensor as the absolute measurement reference and combining it with a two-dimensional moving slide driven by a stepper motor, the gearbox under test is quickly and automatically positioned. After centering, the locking function of the electromagnetic brake ensures that the position of the gearbox remains unchanged throughout the test process, eliminating measurement errors introduced by the movement of the positioning system and improving the reliability of the test results.
[0026] 2. Through the active vibration compensation step, this scheme can physically cancel out the interference vibration, providing a more ideal dynamic-static test environment for the reducer. In addition, because stress is monitored in real time and the amplitude of active compensation motion is actively limited during the compensation process, the structural safety of the platform itself is guaranteed while pursuing the vibration compensation effect, avoiding the risk of structural damage caused by over-compensation. Attached Figure Description
[0027] The present invention will be further explained below with reference to the accompanying drawings and embodiments:
[0028] Figure 1 This is a schematic diagram of the overall structure of the test platform base;
[0029] Figure 2 This is a schematic diagram of the secondary platform and its connection structure;
[0030] Figure 3 This is a schematic diagram of the main base and its connecting structure;
[0031] Figure 4 This is a schematic diagram of the process flow of the method of the present invention.
[0032] In the figure: 100, main base; 110, first type of accelerometer; 120, first type of strain gauge; 130, laser displacement sensor; 200, secondary platform; 210, second type of accelerometer; 220, second type of strain gauge; 300, support assembly; 310, piezoelectric ceramic actuator; 400, automatic centering mechanism; 410, mounting plate; 420, two-dimensional moving slide; 430, stepper motor; 450, electromagnetic brake. Detailed Implementation
[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.
[0034] Example 1
[0035] Please see Figure 1-3 The present invention provides a robot reducer test platform base, comprising:
[0036] Heavy-duty main base 100;
[0037] The secondary platform 200 is independently located above the main base 100;
[0038] Multiple support components 300 are vertically arranged between the main base 100 and the secondary platform 200 to achieve a rigid connection between the two. Each support component 300 is provided with a piezoelectric ceramic actuator 310.
[0039] The first type of acceleration sensor 110 and the first type of strain gauge 120 are embedded in the main base 100 and are used to generate base vibration response data characterizing environmental vibration and structural stress of the main base 100.
[0040] The second type of acceleration sensor 210 and the second type of strain gauge 220 installed on the secondary platform 200 are used to generate a mixed dynamic signal of the platform that includes the operating vibration of the reducer, the response of the platform structure, and the environmental vibration.
[0041] During the performance testing of robot speed reducers, vibrations from the external environment are transmitted to the testing equipment through the ground. These vibrations are superimposed on the vibration signals generated by the speed reducer itself during operation, resulting in contaminated test data and making it difficult to accurately assess the true vibration characteristics of the speed reducer.
[0042] This embodiment provides a robot reducer test platform base. The heavy-duty main base 100 is made of high-density materials such as high-damping concrete or natural granite. The density of high-damping concrete or natural granite typically exceeds 2.7 g / cm³, and its internal damping ratio can reach more than 5%. These physical characteristics enable the main base 100 to effectively absorb and attenuate low-frequency environmental vibrations transmitted from the ground through its own huge inertia and material internal friction, providing a preliminary and stable vibration isolation foundation for the test platform. The large mass and damping characteristics are designed to utilize its own inertia to initially absorb and attenuate most of the vibration energy transmitted from the ground, providing a relatively stable foundation for the entire test system. An independent metal secondary platform 200 is set above the main base 100 to support the reducer under test and its auxiliary equipment. Multiple support components 300 establish a rigid mechanical connection between the main base 100 and the secondary platform 200. Each support component 300 contains a piezoelectric ceramic actuator 310, for example, the Xinmingtian PST1000 / 25 / 400VS45 model, which has a dual function: it can be used as a power source to apply precise excitation signals and as an actuator to perform active compensation motion.
[0043] The piezoelectric ceramic actuator 310 of this model has micron-level displacement resolution, kilonewton-level thrust output capability, and a frequency response range up to kilohertz. These characteristics ensure that it can accurately execute small and fast compensating motions to effectively counteract high-frequency vibration interference.
[0044] The first type of accelerometer 110, such as the PCB352C33 model, and the first type of strain gauge 120 are embedded in the main base 100. Their function is to specifically capture unattenuated environmental vibration information and the stress state of the main base 100 to form base vibration response data. The second type of accelerometer 210 and the second type of strain gauge 220 installed on the secondary platform 200 are used to collect mixed dynamic signals, which include the working vibration of the reducer, the structural response of the secondary platform 200 itself, and the environmental vibration that has been attenuated by the main base 100. Through this separate sensor layout, the platform base has the ability to distinguish between environmental interference and the signal to be measured from the source, providing a basis for subsequent data decoupling and active vibration compensation.
[0045] It also includes an automatic alignment mechanism 400 set on the secondary platform 200, which is used to support and adjust the position of the speed reducer under test in the horizontal plane.
[0046] After completing the vibration isolation foundation construction of the test platform, another problem to be solved is to accurately and efficiently install the speed reducers of different specifications. The traditional manual alignment method is not only time-consuming and laborious, but also difficult to guarantee accuracy. Alignment error will directly affect the accuracy of the test results.
[0047] Therefore, an automatic alignment mechanism 400 is set on the secondary platform 200; the purpose of the automatic alignment mechanism 400 is to achieve rapid and automated positioning of the speed reducer under test; through this mechanism, the operator can move the speed reducer under test to a precise position coaxial with the drive end and load end of the test system in the horizontal two-dimensional plane without tedious manual adjustments, which improves the efficiency of test preparation and the repeatability accuracy of positioning.
[0048] The automatic centering mechanism 400 includes a mounting plate 410, a two-dimensional moving slide 420, and a laser displacement sensor 130; wherein, the mounting plate 410 is used to mount the speed reducer under test; the two-dimensional moving slide 420 is used to drive the mounting plate 410 to move in a two-dimensional plane; the laser displacement sensor 130 is fixed on the main base 100 by an independent bracket and is used to measure the spatial position of the mounting plate 410 in real time.
[0049] The independent support is typically made of high-rigidity materials, such as cast iron or thick steel plates, and is securely mounted on the main base 100 with three or four-point support. Its structural design should avoid any factors that may introduce vibration or thermal deformation to ensure that the laser displacement sensor 130 can always provide an absolute and stable position reference relative to the main base 100.
[0050] To achieve automatic centering, the automatic centering mechanism 400 consists of several core components; the mounting plate 410 provides a standardized mechanical interface for fixing the speed reducer under test; the two-dimensional moving slide 420 is the actuator for position adjustment, driving the mounting plate 410 to move in two mutually perpendicular directions. The structure of this two-dimensional moving slide 420 can be formed by orthogonally stacking two ball screw slides, or it can be implemented using an integrated XY linear motor platform; crucially, the laser displacement sensor 130 used for position determination, for example, the Keyence LK-G5000 series, is not mounted on the moving secondary platform 200, but is fixed to the static heavy-duty main base 100 by an independent rigid bracket.
[0051] The PCB352C33 accelerometer sensor: Its high sensitivity, such as 100mV / g, and wide frequency response range, such as 1Hz-10kHz, enable it to accurately capture weak environmental vibration signals, thereby providing reliable reference noise data for subsequent data decoupling;
[0052] Keyence LK-G5000 series laser displacement sensor 130: Its submicron-level measurement accuracy, such as 0.01μm and high sampling rate, such as 3.9kHz, can ensure high-precision real-time feedback on the position of the mounting plate 410 during automatic alignment, ensuring that the measured reducer is accurately aligned with the target coordinates;
[0053] The purpose of this layout is to establish an absolute measurement benchmark. The measurement data of the laser displacement sensor 130 will not be affected by the minor vibrations or displacements that may occur in the secondary platform 200 during the test, thereby ensuring that the position information fed back to the control system is the true spatial position of the mounting plate 410 relative to the stable geodetic coordinate system.
[0054] The two-dimensional moving slide 420 is driven by a stepper motor 430; and the automatic centering mechanism 400 also includes an electromagnetic brake 450 coaxially connected to the stepper motor 430; wherein the electromagnetic brake 450 is used to lock the two-dimensional moving slide 420 after centering is completed.
[0055] The driving and locking methods of the two-dimensional moving slide 420 are crucial to the stability of the test. The two-dimensional moving slide 420 is driven by a stepper motor 430, such as the NEMA23 series. The stepper motor 430 can achieve precise angle and position control based on pulse signals from the controller. After the alignment process is completed, to eliminate any minor displacement that may be caused by transmission backlash or motor power failure, the automatic alignment mechanism 400 also includes an electromagnetic brake 450. This electromagnetic brake 450 is coaxially connected to the shaft of the stepper motor 430. After the alignment command is completed, the controller sends an energizing or de-energizing signal to the electromagnetic brake 450, depending on whether it is an energized or de-energized brake, to generate braking force and rigidly lock the shaft of the stepper motor 430 and the entire moving part of the two-dimensional moving slide 420. The significance of this locking action is to transform the originally movable alignment mechanism into a temporary rigid structure, ensuring that the position of the tested reducer remains unchanged during subsequent dynamic testing, thereby avoiding measurement errors introduced by the movement of the positioning system.
[0056] Example 2
[0057] Please see Figure 4 A method for testing robot speed reducers, comprising:
[0058] The dynamic model establishment step is used to establish a modified dynamic model based on the active excitation signal applied by the piezoelectric ceramic actuator 310, the vibration response data of the base, and the hybrid dynamic signal of the platform; wherein, the modified dynamic model is used to characterize the transmission relationship between the vibration response data of the base and the hybrid dynamic signal of the platform.
[0059] The dynamic signal decoupling step is performed, which is used to decouple the interfering vibration signal from the mixed dynamic signal of the platform acquired in real time by the second type of accelerometer 210 and the second type of strain gauge 220 based on the modified dynamic model. During decoupling, the vibration response data of the base is used as the reference noise. The interfering vibration signal characterizes the environmental vibration and the platform structural response. The output of this step is pure vibration data that only reflects the working state of the tested reducer.
[0060] An active vibration compensation step is performed, which generates a compensation control command based on the interference vibration signal and drives the piezoelectric ceramic actuator 310 to perform active compensation motion; wherein the compensation control command is equal in magnitude and opposite in phase to the interference vibration signal.
[0061] Considering the signal transmission and actuator response delays in the actual system, the control system will introduce a feedforward control algorithm and a delay compensation module to ensure that the compensation control command can be issued in advance, and that the anti-phase vibration energy is generated simultaneously when the interference signal reaches the secondary platform 200, thereby achieving effective physical cancellation.
[0062] Once a hardware platform capable of separating and acquiring interference signals and mixed signals is available, an effective method is needed to process these signals in order to extract the true vibration data of the speed reducer.
[0063] The core of the testing method in this embodiment lies in a series of data processing and control steps. The dynamic model establishment step is the foundation of the entire method. Its purpose is to obtain the mathematical description, i.e., the transfer function, of the vibration transmitted from the main base 100 to the secondary platform 200 under the current test state. This process involves applying a known excitation signal through the piezoelectric ceramic actuator 310, while simultaneously recording the vibration response data of the base and the sensor group on the secondary platform 200 from the first type of accelerometer 110 and the first type of strain gauge 120. The platform mixes dynamic signals, and the controller establishes a corrected dynamic model characterizing the transmission relationship between the input and output signals by analyzing the relationship between them. The logic of this establishment process is as follows: the controller uses the excitation signal as the system input and the signals collected by the two sensor groups as the system outputs. By performing a fast Fourier transform on the input and output signals, the time-domain signals are converted into frequency-domain signals, and then calculations are performed at each frequency point. The amplitude ratio and phase difference between the output signal and the input signal are used to obtain the transfer function relationship that can quantitatively describe the vibration transmission characteristics. This relationship constitutes the core of the dynamic model. The dynamic signal decoupling step uses this model to clean the data. During the formal testing of the reducer, this step uses the real-time collected vibration response data of the main base 100 as reference noise and inputs it into the corrected dynamic model. The model will calculate the shape that these environmental noises should have after being transmitted to the secondary platform 200. The algorithm subtracts this calculated noise shape from the mixed dynamic signal of the platform collected from the secondary platform 200. The difference obtained is the pure vibration data that has been stripped of the influence of environmental vibration and platform structural response and only reflects the working state of the reducer under test. Specifically, this decoupling process is implemented through an adaptive filtering algorithm, such as the algorithm logic based on least mean square (LMS).
[0064] The algorithm uses the vibration response data of the main base 100 as the reference noise signal and the platform's mixed dynamic signal as the main input signal. Based on the transmission characteristics defined by the modified dynamic model, the algorithm iteratively adjusts its internal filter coefficients. The goal of the adjustment is to make the predicted signal generated by the filter based on the reference noise signal simulate and approximate the environmental vibration and platform structural response components contained in the platform's mixed dynamic signal to the greatest extent. The algorithm subtracts this predicted signal generated by the filter from the real-time main input signal, and the output difference signal is the pure vibration data. Furthermore, an active vibration compensation step is performed to elevate the data purification to vibration cancellation at the physical level. This step takes the decoupled interference vibration signal as the target, and the controller generates compensation control commands of equal magnitude and opposite phase. This constitutes a feedforward control in terms of control principle and drives the piezoelectric ceramic actuator 310 in the support component 300 to perform small and rapid compensation movements. The vibration generated by this movement cancels out the interference vibration, making the secondary platform 200 tend to a dynamic static state, providing a more ideal test environment for the reducer.
[0065] The steps for establishing a dynamic model specifically include establishing a baseline dynamic model and performing model correction. The baseline dynamic model is established by frequency sweep excitation under the conditions of no load or loading standard mass blocks on the secondary platform 200. Model correction refers to calculating the total mass of the assembly by applying instantaneous thrust pulses after installing the reducer under test, and adjusting the parameters of the baseline dynamic model based on the total mass.
[0066] In addition to adjusting the natural frequencies, the model correction process also adjusts the system's damping ratio and mode shapes according to the new total mass. Specifically, the damping ratio can be assumed to be proportional to the total mass or corrected experimentally, while the mode shape matrix can be recalculated by updating the mass matrix and stiffness matrix, thus enabling the entire dynamic model to accurately reflect the actual dynamic characteristics of the system under different loads.
[0067] The accuracy of the dynamic model directly affects the decoupling and compensation effect. Each time the test reducer is replaced with a different weight and size, the dynamic characteristics of the entire test system, such as total mass, center of mass, and stiffness, will change.
[0068] To address this issue, the modified dynamic model aims to accurately reflect the vibration transmission characteristics of the test platform under different load conditions each time the tested reducer is replaced, thereby ensuring the accuracy of subsequent data decoupling and vibration compensation. The model comprises two main components: a baseline dynamic model and model correction logic. The baseline dynamic model is established through frequency sweep excitation, describing the inherent characteristics of the system under no-load or standard load conditions. When a new tested reducer is installed, the total mass of the new assembly is calculated using instantaneous thrust pulses. This total mass data serves as input for mathematical adjustments to key parameters such as natural frequency and damping in the baseline model. Through correction, the model can dynamically reflect changes in the system's natural frequency and damping characteristics caused by variations in mass and stiffness.
[0069] To address this issue, the dynamic model establishment process is broken down into two stages. The first stage involves establishing a baseline dynamic model, a one-time system identification performed when the secondary platform 200 is unloaded or loaded with a standard block of known mass. The controller drives the piezoelectric ceramic actuator 310 to perform a wide-band sweep excitation, comprehensively exciting all modes of the platform to obtain a baseline model describing its inherent characteristics. When a new reducer under test is installed, model correction is performed. This process does not require another time-consuming sweep; instead, the piezoelectric ceramic actuator 310 applies an instantaneous thrust pulse with a known force value. Simultaneously, the acceleration sensor on the secondary platform 200 measures the instantaneous acceleration. Based on Newton's second law (F=ma), the controller uses the known force F and the measured acceleration a to calculate the total mass m of the current secondary platform 200 and reducer assembly. Since the system's natural frequency is inversely proportional to the square root of the total mass, the controller mathematically adjusts key parameters such as the natural frequency and damping in the baseline dynamic model based on the newly calculated total mass. The specific calculation logic for this adjustment follows the following formula:
[0070]
[0071] in, For the adjusted new intrinsic frequency, The reference natural frequency in the reference dynamic model. The total mass of the baseline model is used to establish the baseline model. This is the newly calculated total mass of the combined body; in this way, a corrected dynamic model that matches the current actual load state can be obtained in a short time.
[0072] The active vibration compensation process also includes: real-time monitoring of structural stress data collected by the first type of strain gauge 120 and the second type of strain gauge 220; actively limiting the amplitude of the active compensation motion when the structural stress data exceeds a preset safety threshold; and not limiting the amplitude of the active compensation motion when the structural stress data does not exceed the preset safety threshold.
[0073] This safety threshold is a pre-determined upper limit of stress based on the platform material's yield strength, fatigue limit, and safety factor, using methods such as finite element analysis. For example, for a steel structure platform, the safety threshold can be set to 70% of the yield strength to ensure that the structure will not undergo plastic deformation even in the worst-case scenario.
[0074] This threshold is a pre-set upper limit for stress safety, used to ensure that the structure is not damaged due to excessive stress when the test platform performs active compensation motion; this threshold is determined based on the structural stress data collected by the first type of strain gauge 120 and the second type of strain gauge 220; when the real-time monitored structural stress data exceeds this threshold, the system will trigger a safety mechanism to actively limit the amplitude of the compensation motion in order to avoid structural damage.
[0075] Active vibration compensation systems use high-power actuators to generate reverse motion to counteract vibration. However, under certain specific conditions, such as when approaching the resonance point of the system structure, the compensation motion may be excessively amplified, thereby posing a potential risk of stress damage to the platform structure.
[0076] To ensure the safety of system operation, protective measures are incorporated into the active vibration compensation process. These measures are implemented by real-time monitoring of structural stress data collected by the first type of strain gauge 120 and the second type of strain gauge 220. The controller (e.g., a Siemens PLC with a safety module) continuously compares these real-time stress readings with a preset safety threshold. When the structural stress data exceeds the preset safety threshold, it indicates that the load on the platform structure is approaching its design limit. At this point, the safety logic is triggered, and the controller actively limits the amplitude of the active compensation motion. When the stress data exceeds the threshold, the controller immediately reduces the driving voltage or current output to the piezoelectric ceramic actuator 310, thereby reducing the displacement and force generated and decreasing the amplitude of the compensation motion.
[0077] This limitation can be achieved through strategies such as linear reduction, segmented control, or direct locking to ensure that the structural stress of the platform quickly falls back to a safe range. For example, this can be achieved by reducing the gain of the drive signal of the piezoelectric ceramic actuator 310. Conversely, when the structural stress data does not exceed the preset safety threshold, the system does not limit the amplitude of the active compensation motion, allowing it to perform its full compensation performance. This mechanism ensures that the test platform can achieve vibration compensation while also ensuring its own structural safety.
[0078] Before the dynamic model establishment step, an automatic centering step is also included; wherein, the automatic centering step is used to adjust the mounting plate 410 of the speed reducer under test to the preset target coordinates based on the real-time position feedback of the laser displacement sensor 130.
[0079] The accuracy threshold for the centering process is usually set as the coaxiality requirement of the reducer coupling, for example, less than 50 micrometers. The control algorithm can adopt a closed-loop control strategy based on PID, proportional-integral-derivative, using the real-time position feedback of the laser displacement sensor 130 as the input of the control system. By adjusting the drive pulse of the stepper motor 430, the position of the mounting plate 410 is quickly and smoothly converged to the target coordinates, while avoiding overshoot and oscillation, ensuring the efficiency and accuracy of positioning.
[0080] Before conducting any dynamic characteristic analysis, ensuring that the gearbox under test is mechanically correctly installed is the primary prerequisite; therefore, a positioning step needs to be added at the beginning of the entire testing process.
[0081] Before the dynamic model building step begins, the method performs an automatic centering step. This step is initiated after the operator inputs the target centering coordinates in the control software; the controller drives the stepper motor 430 of the two-dimensional moving slide 420 to start moving the mounting plate 410. At the same time, the laser displacement sensor 130 fixed on the main base 100 feeds back the real-time spatial position of the mounting plate 410 to the controller; based on the deviation between the real-time position feedback of the laser displacement sensor 130 and the target coordinates, the controller continuously adjusts the movement of the stepper motor 430 until the deviation is reduced to an acceptable threshold, thereby completing the adjustment of the mounting plate 410 of the reducer under test to the preset target coordinates.
[0082] After the automatic alignment step is completed, a locking step is also included; wherein, the locking step is used to rigidly lock the two-dimensional moving slide 420 of the automatic alignment mechanism 400 by means of the electromagnetic brake 450.
[0083] After automatic alignment is completed, it must be ensured that the alignment mechanism does not move during subsequent testing to maintain positioning accuracy.
[0084] Therefore, immediately after the automatic alignment step is completed, the method executes a locking step. The purpose of this step is to rigidly lock the two-dimensional moving slide 420 of the automatic alignment mechanism 400 using an electromagnetic brake 450. The controller sends a command to the electromagnetic brake 450, which is coaxial with the stepper motor 430, to generate braking force, thereby locking the entire transmission chain. This locking action transforms the movable two-dimensional slide into a fixed support platform, providing a stable and reliable mechanical reference for all subsequent dynamic testing stages, such as model building, signal decoupling, and vibration compensation.
[0085] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for testing robot speed reducers, characterized in that, The test method is applied to the robot reducer test platform base, which includes: a heavy-duty main base (100). The secondary platform (200) is independently positioned above the main base (100); Multiple support components (300) are vertically arranged between the main base (100) and the secondary platform (200) to achieve a rigid connection between the two, wherein each support component (300) is provided with a piezoelectric ceramic actuator (310). The first type of acceleration sensor (110) and the first type of strain gauge (120) embedded in the main base (100) are used to generate base vibration response data characterizing environmental vibration and structural stress of the main base (100); The second type of acceleration sensor (210) and the second type of strain gauge (220) installed on the secondary platform (200) are used to generate a mixed dynamic signal of the platform that includes the working vibration of the reducer, the response of the platform structure, and the environmental vibration. The robot reducer testing method includes the following steps: The dynamic model establishment step is used to establish a modified dynamic model based on the active excitation signal applied by the piezoelectric ceramic actuator (310), the vibration response data of the base, and the hybrid dynamic signal of the platform; wherein the modified dynamic model is used to characterize the transmission relationship between the vibration response data of the base and the hybrid dynamic signal of the platform. A dynamic signal decoupling step is performed, which is used to decouple the interfering vibration signal from the real-time acquired mixed dynamic signal of the platform based on the modified dynamic model; wherein, the vibration response data of the base is used as the reference noise during decoupling; the interfering vibration signal characterizes the environmental vibration and the platform structural response; the output of this step is pure vibration data that only reflects the working state of the tested reducer; An active vibration compensation step is performed, which is used to generate a compensation control command based on the interference vibration signal and drive the piezoelectric ceramic actuator (310) to perform active compensation motion; wherein the compensation control command is equal in magnitude and opposite in phase to the interference vibration signal.
2. The robot reducer testing method according to claim 1, characterized in that, It also includes an automatic centering mechanism (400) disposed on the secondary platform (200), the automatic centering mechanism (400) being used to carry and adjust the position of the speed reducer under test in the horizontal plane.
3. The robot reducer testing method according to claim 2, characterized in that, The automatic centering mechanism (400) includes a mounting plate (410), a two-dimensional moving slide (420), and a laser displacement sensor (130); wherein, the mounting plate (410) is used to mount the speed reducer under test; the two-dimensional moving slide (420) is used to drive the mounting plate (410) to move in a two-dimensional plane; the laser displacement sensor (130) is fixed on the main base (100) by an independent bracket and is used to measure the spatial position of the mounting plate (410) in real time.
4. The robot reducer testing method according to claim 3, characterized in that, The two-dimensional moving slide (420) is driven by a stepper motor (430); and the automatic centering mechanism (400) further includes an electromagnetic brake (450) coaxially connected to the stepper motor (430); wherein the electromagnetic brake (450) is used to lock the two-dimensional moving slide (420) after centering is completed.
5. The robot reducer testing method according to claim 1, characterized in that, The steps for establishing a dynamic model specifically include establishing a baseline dynamic model and performing model correction; wherein, the baseline dynamic model is established by frequency sweep excitation under the conditions of no load or loading of standard mass blocks on the secondary platform (200); the model correction refers to calculating the total mass of the assembly by applying instantaneous thrust pulses after installing the reducer under test, and adjusting the parameters of the baseline dynamic model according to the total mass.
6. The robot reducer testing method according to claim 1, characterized in that, The active vibration compensation step further includes: real-time monitoring of structural stress data collected by the first type of strain gauge (120) and the second type of strain gauge (220); actively limiting the amplitude of the active compensation movement when the structural stress data exceeds a preset safety threshold; and not limiting the amplitude of the active compensation movement when the structural stress data does not exceed the preset safety threshold.
7. The robot reducer testing method according to claim 3, characterized in that, Before the dynamic model establishment step, an automatic centering step is also included; wherein, the automatic centering step is used to adjust the mounting plate (410) of the speed reducer under test to a preset target coordinate based on the real-time position feedback of the laser displacement sensor (130).
8. The robot reducer testing method according to claim 7, characterized in that, After the automatic alignment step is completed, a locking step is also included; wherein, the locking step is used to rigidly lock the two-dimensional moving slide (420) of the automatic alignment mechanism (400) by means of an electromagnetic brake (450).