A system and method for suppressing angular measurement errors in dynamic testing of precision reducers

Abstract

The present invention relates to the technical field of precision reducer testing, and discloses a system and method for suppressing angular measurement errors in dynamic testing of precision reducers. The system comprises: a servo motor closed-loop control module, a measurement axis motion state monitoring module, a piezoelectric ceramic driver control module, and a joint control module. The method comprises: first performing a first step of control through the servo motor closed-loop control module, then performing a second step of control through the piezoelectric ceramic driver control module, and dynamically adjusting the control ratio of the servo motor closed-loop control module and the piezoelectric ceramic driver control module according to the real-time monitored operating states of the high-speed end motor and the low-speed end motor and the real-time monitored motion state of the measurement axis in combination with preset standards, so that the dynamic angular measurement error is maintained within a preset range, and the angular measurement error caused by dynamic changes in the system structure during the reducer testing process can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of precision reducer testing, and in particular to a system and method for suppressing angular measurement errors in dynamic testing of precision reducers. Background Art

[0002] Precision reducers play a vital role in industrial robots, particularly in motion control and ensuring precision. Reducer performance testing technology, particularly angle measurement accuracy, is crucial for ensuring product quality. Angle, as one of the fundamental parameters for measuring a reducer's overall performance, requires precise measurement systems. However, existing measurement technologies still face challenges, particularly during dynamic transmission testing, where the impact of angle measurement errors cannot be ignored.

[0003] Current precision reducer test instruments typically utilize a multi-stage tandem structure based on national standards. These instruments incorporate angle encoders at the reducer's input and output terminals. In theory, these measurement axes should maintain coaxiality and high precision. However, due to issues such as installation accuracy and axis stiffness, several potential error sources exist. These include: eccentric installation errors of the circular scale and improper fit between the angle encoder and axis, which can lead to measurement errors; and torsional deformation of the axis during static testing. Under static conditions, due to insufficient axis stiffness, minute axis deformation occurs during torque transmission, affecting angular measurement accuracy.

[0004] In actual dynamic transmission testing, the impact of torque fluctuations on angle measurement accuracy becomes particularly significant. Although theoretically, the input shaft, output shaft, and reducer center axes can maintain a coaxial position, due to the insufficient stiffness of the shaft system support structure, torque fluctuations will cause the spatial position of the shaft system to change in real time. These dynamic changes lead to errors in angle measurement, especially during the torque transmission process. Although existing vertical reducer testers have improved the stiffness of the shaft system to a certain extent and reduced the unbalanced torque caused by gravity, and theoretically can avoid the shaft system torsional error caused by radial forces on the support, due to practical factors such as processing and assembly errors, the shaft system still has coaxial errors. This error cannot be completely avoided during the transmission process, especially under high-load and high-speed dynamic conditions. Changes in the friction torque of the shaft system will cause dynamic anomalies in the spatial position, thereby affecting the angle measurement accuracy.

[0005] Reducer inspection instruments typically involve multiple shaft-hole fits, potentially as many as 30 or more. Slight differences in these fits, especially during dynamic transmission, can lead to dynamic changes in the spatial position of the measured shaft due to changes in friction torque and the combined effects of multiple shaft supports, resulting in increased angular measurement errors.

[0006] Therefore, there is an urgent need for a system and method for suppressing the angular measurement error of a precision reducer in dynamic testing, which can suppress the error caused by torque fluctuation and thus improve the angle measurement accuracy in dynamic testing. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a system and method for suppressing angular measurement errors in dynamic testing of precision reducers, thereby suppressing errors caused by torque fluctuations and improving the angle measurement accuracy in dynamic testing.

[0008] The present invention provides a system for suppressing angular measurement errors in dynamic testing of precision reducers, comprising: a servo motor closed-loop control module, a measurement shaft system motion state monitoring module, a piezoelectric ceramic driver control module, and a joint control module;

[0009] The servo motor closed-loop control module includes a high-speed motor servo control subsystem and a low-speed motor servo control subsystem; the high-speed motor servo control subsystem is used to monitor and adjust the operating status of the high-speed motor in real time, and the low-speed motor servo control subsystem is used to monitor and adjust the operating status of the low-speed motor in real time;

[0010] The measuring shaft system motion state monitoring module includes a displacement sensor and a data acquisition and analysis system for real-time monitoring and feedback of the motion state of the measuring shaft system;

[0011] The piezoelectric ceramic driver control module includes a drive controller and a plurality of piezoelectric ceramics; it is used to control the magnitude and direction of the output force of the plurality of piezoelectric ceramics according to the motion state of the measurement axis system detected in real time, and adjust the central axis of the measurement axis system to make it consistent with the theoretical common axis;

[0012] The joint control module is used to use the servo motor closed-loop control module as the first step of control and the piezoelectric ceramic driver control module as the second step of control; and according to the real-time monitored operating status of the high-speed end motor and the low-speed end motor and the real-time monitored motion status of the measurement axis system, combined with preset standards, dynamically adjust the control ratio of the servo motor closed-loop control module and the piezoelectric ceramic driver control module to keep the angular measurement error within a preset range.

[0013] Furthermore, the high-speed end motor servo control subsystem includes a first servo motor, a driver, a high-speed end torque sensor, a high-speed end angle encoder and a first controller, which is used to monitor and adjust the operating state of the high-speed end motor in real time;

[0014] Among them, the first servo motor and driver are used to drive the input end of the reducer under test in a speed mode; the high-speed end torque sensor and the high-speed end angle encoder are arranged at the input end of the reducer under test to obtain the dynamic torque, angular displacement and angular velocity of the input end of the reducer under test in real time; the first controller compensates the current of the first servo motor in real time according to the speed difference between the angular velocity obtained in real time and the speed of the first servo motor, so that the motion state output by the first servo motor is consistent with the preset standard.

[0015] Furthermore, the low-speed end motor servo control subsystem includes a second servo motor, a driver, a low-speed end torque sensor, a low-speed end angle encoder and a second controller for real-time monitoring and adjustment of the operating state of the low-speed end motor;

[0016] Among them, the second servo motor and driver are used to provide a load to the output end of the reducer under test in a torque mode; the low-speed end torque sensor and the low-speed end angle encoder are arranged at the input end of the reducer under test to obtain the dynamic torque, angular displacement and angular velocity of the input end of the reducer under test in real time; the second controller compensates the current of the second servo motor in real time according to the torque difference between the dynamic torque obtained in real time and the torque output by the second servo motor, so that the motion state output by the second servo motor is consistent with the preset standard.

[0017] Furthermore, both the first controller and the second controller adopt an active disturbance rejection control model, and the active disturbance rejection control model compensates the motor current through a tracking differentiator, an extended observer and an error feedback controller.

[0018] Furthermore, two displacement sensors are placed at the supports of the high-speed and low-speed measuring shaft systems, and the two displacement sensors are arranged at a 90° angle to obtain the motion state of the measuring shaft system;

[0019] The data acquisition and analysis system feeds back the motion state of the measurement axis system to the piezoelectric ceramic driver control module.

[0020] Furthermore, the plurality of piezoelectric ceramics are mounted on the outer sides of the supports of the high-speed end and the low-speed end measuring shaft system and are arranged equidistantly in the circumferential direction. The piezoelectric ceramics may be stacked piezoelectric ceramics.

[0021] The drive controller adopts an optimal control theory algorithm to adjust the output force size and direction of a plurality of piezoelectric ceramics in real time according to the motion state of the measurement axis system detected in real time.

[0022] The present invention also provides a method for suppressing angular measurement errors in dynamic testing of a precision reducer, comprising the following steps:

[0023] S1. Assemble the reducer under test with the high-speed and low-speed test components;

[0024] S2, start the first servo motor and the second servo motor, and perform dynamic testing in speed mode and torque mode respectively;

[0025] S3. Obtain the dynamic torque, angular displacement, and angular velocity information of the input and output ends of the measured reducer through the torque sensor and the angle encoder; obtain the motion state of the measured shaft system in real time through the displacement sensor;

[0026] S4. Through the high-speed servo motor auto-disturbance rejection closed-loop control and the low-speed servo motor auto-disturbance rejection closed-loop control, the speed and torque of the servo motor are adjusted in real time using the auto-disturbance rejection control algorithm based on the dynamic torque, angular displacement and angular velocity information at the input and output ends of the measured reducer;

[0027] S5. Dynamically adjust the magnitude and direction of the output force of the piezoelectric ceramic according to the motion state of the measurement axis system through the piezoelectric ceramic driver control module to correct the angular displacement of the measurement axis system;

[0028] S5. The joint control module adjusts the control ratio of the servo motor closed-loop control part and the piezoelectric ceramic driver control part according to the real-time monitored operating status of the high-speed end motor and the low-speed end motor and the real-time monitored motion status of the measurement axis system, combined with the preset standards, so that the angular measurement error remains within the preset range.

[0029] The embodiments of the present invention have the following technical effects:

[0030] 1. Through the closed-loop control of the servo motor and the joint control of the piezoelectric ceramic driver, the dynamic friction torque added to the analog output torque during the dynamic test of the precision reducer, which causes the angular measurement error, is suppressed. The error is handled at the source as much as possible, overcoming the disadvantage that the servo closed loop can only handle low-frequency errors. The piezoelectric ceramic driver can sense the electrical signals generated by tiny force or displacement changes, handle high-frequency errors, and achieve reliable and stable movement during the dynamic test of the measuring shaft system, so as to improve the angle measurement accuracy during the transmission test.

[0031] 2. Through precise control of the high-speed and low-speed servo motors, coupled with the Active Disturbance Rejection Control (ADRC) algorithm, real-time compensation for the motor's dynamic response is achieved. This helps maintain the motion of both high-speed and low-speed motors consistent with preset standards, thereby reducing angular errors caused by insufficient motor control precision. By employing the Active Disturbance Rejection Control (ADRC) model for both the first and second servo motor control systems, external disturbances and internal nonlinearities are effectively eliminated, ensuring precise control of the servo motors at both high and low speeds.

[0032] 3. The piezoelectric ceramic driver control module accurately corrects the angular error of the measurement axis by adjusting the output force of the piezoelectric ceramic based on the real-time feedback of the measurement axis motion state. This can compensate for minor deviations caused by the mechanical transmission and the measurement system itself.

[0033] 4. A displacement sensor monitors the axis's motion in real time and transmits this data to the piezoelectric ceramic driver control module, enabling precise adjustment of the axis's angular displacement. This dynamic correction significantly reduces angular measurement errors caused by changes in the axis's displacement. The high precision of the displacement sensor and its real-time data feedback system ensure that the system can promptly capture and compensate for even the smallest errors during high-speed dynamic testing.

[0034] 5. By coordinating the control modules, the system comprehensively adjusts the control ratios of the servo motor and piezoelectric ceramics to ensure that the angular error fluctuates within a preset range. Compared to traditional single-servo control systems, this multi-control mechanism significantly improves overall measurement accuracy and reduces angular deviation during dynamic testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 Schematic diagram of a system for suppressing angular measurement errors in dynamic testing of a precision reducer provided by an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the system structure of a precision reducer detector provided by an embodiment of the present invention;

[0038] Figure 3 Schematic diagram of the control principle of the high-speed motor servo control subsystem provided by an embodiment of the present invention;

[0039] Figure 4 Schematic diagram of the control principle of the low-speed motor servo control subsystem provided by an embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of a cross section of the piezoelectric ceramics provided by an embodiment of the present invention arranged outside a support;

[0041] Figure 6 Schematic diagram of the arrangement of the dual displacement sensors provided by an embodiment of the present invention at the support of the measuring shaft system;

[0042] Figure 7 This is a flow chart of a method for suppressing angular measurement errors in dynamic testing of a precision reducer provided by an embodiment of the present invention.

[0043] Figure numerals: 1, high-speed end bracket; 2, adapter bracket; 3, low-speed end bracket; 4, motor fixing plate; 5, upper bearing support; 6, lower bearing support; 7, bead bearing outer sleeve; 8, low-speed end torque sensor fixing plate; 9, transmission mechanism fixing plate; 10, first servo motor; 11, coupling; 12, high-speed end locking plate; 13, high-speed end torque sensor; 14, high-speed end angle encoder; 15, high-speed end output shaft; 16, input shaft of the reducer under test; 17, reducer under test ; 18. Reducer output shaft; 19. Low-speed end angle encoder; 20. Bearing; 21. Low-speed end torque sensor; 22. Low-speed end locking plate; 23. Transmission mechanism; 24. Second servo motor; 25. Servo motor closed-loop control module; 26. Piezoelectric ceramic driver control module, 27. Measuring shaft system motion state monitoring module; 28. Piezoelectric ceramics; 29. ​​Support; 30. Support base; 31. Push block; 31. Drive shaft; 32. Drive shaft ground journal; 33. Displacement sensor. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0045] like Figure 2 As shown, a method for determining phase connection of a measuring shaft system based on visual guidance is provided, wherein the detector involved is an existing technology, such as Figure 1-Figure 2 As shown, the present invention provides a system for suppressing angular measurement errors in dynamic testing of precision reducers, comprising: a servo motor closed-loop control module 25, a measurement shaft system motion state monitoring module 26, a piezoelectric ceramic driver control module 27, and a joint control module;

[0046] The servo motor closed-loop control module 25 includes a high-speed motor servo control subsystem and a low-speed motor servo control subsystem; it is used to monitor and adjust the operating status of the high-speed motor and the low-speed motor in real time;

[0047] In some embodiments, the high-speed end motor servo control subsystem includes a first servo motor 10, a driver, a high-speed end torque sensor 13, a high-speed end angle encoder 14 and a first controller, which is used to monitor and adjust the operating status of the high-speed end motor in real time; wherein, the first servo motor 10 and the driver are used to drive the input end of the reducer under test in a speed mode; the high-speed end torque sensor 13 and the high-speed end angle encoder 14 are arranged at the input end of the reducer under test, and obtain the dynamic torque, angular displacement and angular velocity of the input end of the reducer under test in real time; the first controller compensates the current of the first servo motor in real time according to the speed difference between the angular velocity obtained in real time and the speed of the first servo motor, so that the motion state output by the first servo motor is consistent with the preset standard.

[0048] Specifically, the first servo motor 10 and driver are used to drive the input of the reducer under test. Operating in speed mode, the driver is responsible for regulating the motor's speed, controlling the motor's speed and torque by adjusting the current. The high-speed torque sensor 13 monitors the dynamic torque at the reducer's input and provides real-time torque feedback. The high-speed angle encoder 14 monitors the angular displacement at the reducer's input and calculates and provides real-time feedback on changes in angular velocity and displacement. The first controller adjusts the servo motor's current by acquiring the difference between the angular velocity and motor speed in real time, ensuring that the output motion state conforms to preset standards. The high-speed torque sensor 13 feeds dynamic torque data back to the first controller, while the high-speed angle encoder 14 provides real-time angular displacement and angular velocity data. Angular displacement is obtained by integrating angular velocity, while angular velocity is directly acquired via the encoder. The first controller receives real-time feedback on torque, angular displacement, and angular velocity to ensure that the system can adjust according to the actual operating state. Speed ​​difference compensation: The first controller calculates the difference between the motor speed and the angular velocity at the reducer's input. In theory, the motor speed should match the angular velocity at the reducer input. If there is a discrepancy, the controller adjusts the motor current to compensate. Within each cycle, the first controller continuously adjusts the current output based on real-time feedback to ensure that the motor speed and the angular velocity at the reducer input remain consistent. The closed-loop nature of the control system ensures that the motor speed responds quickly to any disturbance or load change, restoring it to the desired standard.

[0049] In some embodiments, the low-speed end motor servo control subsystem includes a second servo motor 24, a driver, a low-speed end torque sensor 21, a low-speed end angle encoder 19 and a second controller, which are used to monitor and adjust the operating status of the low-speed end motor in real time; wherein, the second servo motor and the driver are used to provide a load to the output end of the reducer under test in a torque mode; the low-speed end torque sensor and the low-speed end angle encoder are arranged at the output end of the reducer under test, and the dynamic torque, angular displacement and angular velocity of the output end of the reducer under test are obtained in real time; the second controller compensates the current of the second servo motor in real time according to the torque difference between the dynamic torque obtained in real time and the torque output by the second servo motor, so that the motion state output by the second servo motor is consistent with the preset standard.

[0050] Specifically, the second servo motor 24 is used to provide a load and operates in torque mode. Its output torque is transmitted as a load signal to the output of the reducer under test. The driver provides drive signals to the second servo motor, controlling its speed, torque, and response time. The driver also adjusts the current output according to controller instructions. The low-speed torque sensor 21 is installed at the output of the reducer under test and monitors the dynamic torque at the reducer output in real time. The low-speed angle encoder 19 is installed at the output of the reducer under test and measures angular displacement and angular velocity in real time. The second controller receives signals from the low-speed torque sensor and the low-speed angle encoder in real time. Based on these signals, it calculates the actual torque difference and compensates by adjusting the motor current to ensure that the output torque of the second servo motor is consistent with the preset standard (target torque). The second controller calculates the actual torque difference based on the difference between the real-time dynamic torque (from the torque sensor) and the torque output by the second servo motor. The goal is to adjust the motor current based on the torque difference so that the actual output torque is consistent with the preset standard (target torque). To achieve fast response and high-precision control, a closed-loop control method is typically used. The second controller will continuously adjust the current output based on the real-time feedback of the torque difference and angle information until the motion state of the motor output is consistent with the preset standard (target torque).

[0051] Furthermore, both the first controller and the second controller adopt an active disturbance rejection control model, and the active disturbance rejection control model compensates the motor current through a tracking differentiator, an extended observer and an error feedback controller.

[0052] like Figure 3 As shown, the first controller adopts the anti-disturbance control model and takes the speed difference between the angle encoder and the motor as the tracking control target to compensate the motor current in real time; the compensation current is directly superimposed on the output current of the speed loop of the first servo motor and the driver. Figure 4As shown, the second controller adopts an active disturbance rejection control model and uses the torque difference between the torque sensor output and the motor output as the tracking control target to compensate the motor current in real time; the compensation current is directly superimposed on the output current of the second servo motor and the current loop of the driver.

[0053] The measuring shaft system motion state monitoring module 27 includes a displacement sensor 33 and a data acquisition and analysis system for real-time monitoring and feedback of the motion state of the measuring shaft system. The displacement sensor of the measuring shaft system motion state monitoring module can use a laser displacement sensor or other methods to obtain and detect the motion state of the measuring shaft system.

[0054] Furthermore, the displacement sensors 33 are placed at the support of the high-speed end and the low-speed end measuring shaft system, and two displacement sensors are arranged at a 90° angle to obtain the motion state of the measuring shaft system, such as Figure 6 As shown, this arrangement is designed to provide displacement measurement in both directions;

[0055] The data acquisition and analysis system feeds back the motion state of the measurement axis system to the piezoelectric ceramic driver control module.

[0056] The piezoelectric ceramic driver control module 26 includes a drive controller and a plurality of piezoelectric ceramics 28; it is used to control the magnitude and direction of the output force of the plurality of piezoelectric ceramics 28 according to the motion state of the measurement axis system detected in real time, and adjust the central axis of the measurement axis system to be consistent with the theoretical common axis;

[0057] Alternatively, the theoretical common axis can be determined by the following methods: 1. Determine the common axis based on multi-section circle center fitting. Measure multiple cross sections. On the measured element (such as the rotating component of a reducer) and the reference element, measure circles with multiple cross sections. Construct a 3D line from the center of the circle. Fit the centers of these measured circles to construct a 3D line, which serves as the common axis. 2. Determine the common axis based on the center line connecting the head and tail holes. Determine the head and tail holes. On the rotating component of the reducer, determine the positions of the head and tail holes, measure the center line, measure the centers of the head and tail holes, and connect them into a line. This line serves as the common reference axis. 3. Determine the common axis based on the actual assembly process. Simulate the assembly process. In the actual assembly process of the reducer, there will be a simulated mandrel or assembly reference. This assembly process can be simulated to determine a common axis and adjust the measurement axis system. In dynamic testing, the center axis of the measurement axis system is adjusted to align with this simulated common axis, thereby reducing angular measurement errors.

[0058] Furthermore, the plurality of piezoelectric ceramics 28 are mounted on the outer side of the support of the high-speed end and the low-speed end measuring shaft system and are arranged equidistantly in the circumferential direction. The piezoelectric ceramics can be stacked piezoelectric ceramics, such as Figure 5 As shown;

[0059] The drive controller adopts an optimal control theory algorithm to adjust the output force size and direction of a plurality of piezoelectric ceramics in real time according to the motion state of the measurement axis system detected in real time.

[0060] The piezoelectric ceramic actuator control module receives feedback signals from the data acquisition and analysis system and adjusts the operating state of the piezoelectric ceramic actuator based on this feedback, thereby controlling the movement of the axis system. By applying voltage or changing the electric field, the piezoelectric ceramic actuator can precisely change the attitude, position, or dynamic characteristics of the axis system. This control method has high precision and high response speed, making it particularly suitable for applications such as high-frequency vibration and fine-tuning movement.

[0061] The joint control module is used to use the servo motor closed-loop control module as the first step of control and the piezoelectric ceramic driver control module as the second step of control; and according to the real-time monitored operating status of the high-speed end motor and the low-speed end motor and the real-time monitored motion status of the measurement axis system, combined with preset standards, dynamically adjust the control ratio of the servo motor closed-loop control module and the piezoelectric ceramic driver control module to keep the angular measurement error within a preset range.

[0062] Specifically, the operating status of the high-speed and low-speed motors, as well as the motion of the measurement axis, is monitored in real time, collecting relevant data such as motor speed, acceleration, and position deviation. The first control step—servo motor closed-loop control—is performed using the servo motor's closed-loop control module based on the collected real-time data. This control step adjusts the servo motor's motion through a negative feedback mechanism to ensure it operates within a predetermined parameter range, thereby controlling the coarse adjustment of the measurement axis. The second control step—piezoelectric ceramic driver control—is performed after the servo motor performs coarse adjustment. The piezoelectric ceramic driver's high precision allows for fine-tuning the measurement axis' position to reduce minute angular errors. Based on real-time feedback and preset standards (such as the allowable angular error range), the control ratio of the servo motor and piezoelectric ceramic driver control module is dynamically adjusted. This control ratio is optimized based on the real-time feedback error and speed to maintain the angular error within the preset range. The control strategy is continuously adjusted based on real-time changes in the system's operating status to ensure the system remains in an optimal state and avoid overshoot or undershoot.

[0063] like Figure 7 As shown, the present invention also provides a method for suppressing angular measurement errors in dynamic testing of a precision reducer, comprising the following steps:

[0064] S1. Assemble the reducer to be tested with the high-speed and low-speed test components, such as Figure 2 As shown;

[0065] Connect the input end of the reducer under test to the first servo motor, and the output end of the reducer under test to the second servo motor. Ensure that all sensors (torque sensor, angle encoder, displacement sensor, etc.) are correctly installed on the measuring shaft system to ensure accurate signal transmission.

[0066] S2, start the first servo motor and the second servo motor, and perform dynamic testing in speed mode and torque mode respectively;

[0067] Start the first servo motor and set it to speed mode to control the speed of the input end of the reducer under test; start the second servo motor and set it to torque mode to control the torque of the output end of the reducer under test, ensuring that the two servo motors move in coordination and avoid mutual interference.

[0068] S3. Obtain the dynamic torque, angular displacement, and angular velocity information of the input and output ends of the measured reducer through the torque sensor and the angle encoder; obtain the motion state of the measured shaft system in real time through the displacement sensor;

[0069] The torque sensor obtains the dynamic torque signals of the input and output ends of the measured reducer in real time to determine whether the system is overloaded or unstable. The angle encoder obtains the angular displacement information of the input and output ends of the measured reducer to help determine the motion state of each servo motor. The angular velocity information measures the angular velocity of the input and output ends of the measured reducer. The relationship between angular velocity and angular displacement can be used to calculate the load and adjustment accuracy of the servo motor. The displacement sensor monitors the motion state of the measuring shaft system, obtains the displacement data of the shaft system in real time, and accurately controls the angular displacement.

[0070] S4. Through the high-speed servo motor auto-disturbance rejection closed-loop control and the low-speed servo motor auto-disturbance rejection closed-loop control, the speed and torque of the servo motor are adjusted in real time using the auto-disturbance rejection control algorithm based on the dynamic torque, angular displacement and angular velocity information at the input and output ends of the measured reducer;

[0071] The high-speed servo motor uses an active disturbance rejection control (ADRC) algorithm, which can maintain system stability in the presence of disturbances. It adjusts the speed of the high-speed motor based on real-time feedback of angular velocity information, making the dynamic changes at the input as stable as possible. The low-speed servo motor also uses an ADRC algorithm. Based on the input status and output load of the reducer under test, it adjusts the output torque of the low-speed motor to suppress angular errors caused by the characteristics of the reducer.

[0072] S5. Dynamically adjust the magnitude and direction of the output force of the piezoelectric ceramic according to the motion state of the measurement axis system through the piezoelectric ceramic driver control module to correct the angular displacement of the measurement axis system;

[0073] The output force and direction of the piezoelectric ceramic actuator are dynamically adjusted based on the real-time measurement of the axis's motion state (e.g., angular displacement). The piezoelectric ceramic actuator can provide extremely high-precision fine-tuning and is suitable for compensating for small angular displacement errors in the system, especially during low speed or subtle movements.

[0074] S5. The joint control module adjusts the control ratio of the servo motor closed-loop control part and the piezoelectric ceramic driver control part based on the real-time monitored operating status of the high-speed end motor and the low-speed end motor and the real-time monitored motion status of the measurement axis system in combination with preset standards to keep the angular measurement error within a preset range;

[0075] Based on real-time monitoring of the high- and low-speed servo motor operating conditions (such as speed, load, and torque), as well as the measured axis motion conditions (such as angular displacement, angular velocity, and torque), all necessary feedback data is collected. Preset standards define the allowable range of angular measurement error and other control criteria. These standards can be based on actual application requirements, such as the accuracy requirements of the reducer and the load conditions being tested. During system operation, the joint control module dynamically adjusts the control ratios of the servo motor closed-loop control module and the piezoelectric ceramic driver control module based on the measured errors and real-time monitoring conditions. For example, when the system's angular displacement is large or the error is significant, the servo motor takes priority for coarse control. When the angular displacement error is small or the system is in the fine-tuning stage, the piezoelectric ceramic driver provides fine-tuning compensation. Adjustment of the control ratio can be optimized based on data such as the error magnitude, the system's dynamic response, and torque feedback. Common adjustment methods include gain scheduling and fuzzy logic control, which gradually optimize the control strategy based on real-time feedback.

[0076] It should be noted that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the scope of this application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular and may also include the plural. The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method or device comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of further restrictions, the elements defined by the sentence "comprise a..." do not exclude the presence of other identical elements in the process, method or device comprising the elements.

[0077] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A system for suppressing angular measurement errors in dynamic testing of precision reducers, characterized in that: include: Servo motor closed-loop control module, axis motion status monitoring module, piezoelectric ceramic drive control module and joint control module; The servo motor closed-loop control module includes a high-speed motor servo control subsystem and a low-speed motor servo control subsystem; the high-speed motor servo control subsystem is used to monitor and adjust the operating status of the high-speed motor in real time, and the low-speed motor servo control subsystem is used to monitor and adjust the operating status of the low-speed motor in real time; The measuring shaft system motion state monitoring module includes a laser displacement sensor and a data acquisition and analysis system for real-time monitoring and feedback of the motion state of the measuring shaft system; The piezoelectric ceramic driver control module includes a drive controller and a plurality of piezoelectric ceramics; it is used to control the magnitude and direction of the output force of the plurality of piezoelectric ceramics according to the motion state of the measurement axis system detected in real time, and adjust the central axis of the measurement axis system to make it consistent with the theoretical common axis; The joint control module is used to use the servo motor closed-loop control module as the first step of control and the piezoelectric ceramic driver control module as the second step of control; According to the real-time monitored operating status of the high-speed motor and the low-speed motor and the real-time monitored motion status of the measurement axis system, combined with the preset standards, the control ratio of the servo motor's closed-loop control module and the piezoelectric ceramic driver control module is dynamically adjusted to keep the angular measurement error within the preset range.

2. The system for suppressing angular measurement errors in dynamic testing of a precision reducer according to claim 1, characterized in that: The high-speed end motor servo control subsystem includes a first servo motor, a driver, a high-speed end torque sensor, a high-speed end angle encoder and a first controller, which is used to monitor and adjust the operating state of the high-speed end motor in real time; Among them, the first servo motor and driver are used to drive the input end of the reducer under test in a speed mode; the high-speed end torque sensor and the high-speed end angle encoder are arranged at the input end of the reducer under test to obtain the dynamic torque, angular displacement and angular velocity of the input end of the reducer under test in real time; the first controller compensates the current of the first servo motor in real time according to the speed difference between the angular velocity obtained in real time and the speed of the first servo motor, so that the motion state output by the first servo motor is consistent with the preset standard.

3. The system for suppressing angular measurement errors in dynamic testing of a precision reducer according to claim 2, characterized in that: The low-speed motor servo control subsystem includes a second servo motor, a driver, a low-speed torque sensor, a low-speed angle encoder and a second controller, which is used to monitor and adjust the operating status of the low-speed motor in real time; Among them, the second servo motor and driver are used to provide a load to the output end of the reducer under test in a torque mode; the low-speed end torque sensor and the low-speed end angle encoder are arranged at the input end of the reducer under test to obtain the dynamic torque, angular displacement and angular velocity of the input end of the reducer under test in real time; the second controller compensates the current of the second servo motor in real time according to the torque difference between the dynamic torque obtained in real time and the torque output by the second servo motor, so that the motion state output by the second servo motor is consistent with the preset standard.

4. The system for suppressing angular measurement errors in dynamic testing of a precision reducer according to claim 3, characterized in that: The first controller and the second controller both adopt an active disturbance rejection control model, which compensates the motor current through a tracking differentiator, an extended observer and an error feedback controller.

5. The system for suppressing angular measurement errors in dynamic testing of a precision reducer according to claim 1, characterized in that: The displacement sensors are placed at the support of the high-speed and low-speed measuring shaft systems, two each, and the two displacement sensors are arranged at a 90° angle to obtain the motion state of the measuring shaft system; The data acquisition and analysis system feeds back the motion state of the measurement axis system to the piezoelectric ceramic driver control module.

6. The system for suppressing angular measurement errors in dynamic testing of a precision reducer according to claim 1, characterized in that: The plurality of piezoelectric ceramics are installed on the outer side of the support of the high-speed end and the low-speed end measuring shaft system and are arranged equidistantly in the circumferential direction. The piezoelectric ceramics are stacked piezoelectric ceramics. The drive controller adopts an optimal control theory algorithm to adjust the output force size and direction of a plurality of piezoelectric ceramics in real time according to the motion state of the measurement axis system detected in real time.

7. A method for suppressing angular measurement errors in dynamic testing of precision reducers, characterized in that: The following steps are involved: S1. Assemble the reducer under test with the high-speed and low-speed test components; S2, start the first servo motor and the second servo motor, and perform dynamic testing in speed mode and torque mode respectively; S3. Obtain the dynamic torque, angular displacement, and angular velocity information of the input and output ends of the measured reducer through the torque sensor and the angle encoder; obtain the motion state of the measured shaft system in real time through the displacement sensor; S4. Through the high-speed servo motor auto-disturbance rejection closed-loop control and the low-speed servo motor auto-disturbance rejection closed-loop control, the speed and torque of the servo motor are adjusted in real time using the auto-disturbance rejection control algorithm based on the dynamic torque, angular displacement and angular velocity information at the input and output ends of the measured reducer; S5. Dynamically adjust the magnitude and direction of the output force of the piezoelectric ceramic according to the motion state of the measurement axis system through the piezoelectric ceramic driver control module to correct the angular displacement of the measurement axis system; S6. The joint control module adjusts the control ratio of the servo motor closed-loop control part and the piezoelectric ceramic driver control part according to the real-time monitored operating status of the high-speed end motor and the low-speed end motor and the real-time monitored motion status of the measurement axis system, combined with the preset standards, so that the angular measurement error remains within the preset range.

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