Angle measurement error suppression system and method in dynamic test of precision speed reducer

Abstract

The invention relates to the technical field of precision reducer testing, and discloses an angle measurement error suppression system and method in a precision reducer dynamic test, and the system comprises a servo motor closed-loop regulation and control module, a measurement shafting motion state monitoring module, a piezoelectric ceramic driver regulation and control module, and a combined control module. The method comprises the steps that first-step regulation and control are conducted through the servo motor closed-loop regulation and control module, second-step regulation and control are conducted through the piezoelectric ceramic driver regulation and control module, and according to the running states, monitored in real time, of the high-speed-end motor and the low-speed-end motor and the motion state, monitored in real time, of the measuring shaft system, and in combination with a preset standard, the high-speed-end motor and the low-speed- The control proportion of the closed-loop regulation and control module of the servo motor and the piezoelectric ceramic driver regulation and control module is dynamically adjusted, so that the dynamic angle measurement error is kept within the preset range, and the angle measurement error caused by the dynamic change of the system structure in the speed 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 angle measurement errors in dynamic testing of precision reducers. Background Art

[0002] Precision reducers play a vital role in industrial robots, especially in the robot's motion control and precision assurance. Reducer performance testing technology, especially the accuracy of angle measurement, is the key to ensuring product quality. Angle, as one of the basic parameters to measure the comprehensive performance of reducers, needs to be tested under a precise measurement system. However, existing measurement technology still faces certain challenges, especially in the dynamic transmission test process, the impact of angle measurement error cannot be ignored.

[0003] Current precision reducer test instruments usually adopt a multi-stage series structure based on national standards. These instruments install angle encoders at the input and output ends of the reducer. In theory, these measuring shaft systems should ensure coaxiality and high precision, but due to problems such as installation accuracy and shaft stiffness, there are several potential error sources, including: eccentric installation error of circular scale, improper matching between angle encoder and shaft system, which may lead to measurement error; shaft system torsional deformation in static testing. Under static conditions, due to insufficient shaft stiffness, slight shaft system deformation will occur during torque transmission, affecting the angle measurement accuracy.

[0004] In actual dynamic transmission tests, the impact of torque fluctuations on angle measurement accuracy becomes particularly significant. Although in theory, the input shaft, output shaft and the central axis of the reducer can maintain a coaxial position, due to the insufficient stiffness of the shaft support structure, torque fluctuations will cause the spatial posture of the shaft to change in real time. These dynamic changes lead to errors in angle measurement, especially during torque transmission. Although the existing vertical reducer tester has improved the stiffness of the shaft system to a certain extent, reduced the unbalanced torque caused by gravity, and theoretically can avoid the shaft torsion error caused by the radial force 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, the friction torque change of the shaft system will cause dynamic anomalies in the spatial posture, thereby affecting the angle measurement accuracy.

[0005] Reducer inspection instruments usually involve multiple shaft-hole matching relationships, which may be as many as 30. These slight differences in matching accuracy, especially during dynamic transmission, will cause the spatial position of the measured shaft system to change dynamically due to the changes in friction torque and the combined effects of multiple shaft supports, thus increasing the angle measurement error.

[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, so as to 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 shaft system motion state monitoring module, a piezoelectric ceramic driver control module and a 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 state of the high-speed motor in real time, and the low-speed motor servo control subsystem is used to monitor and adjust the operating state of the low-speed motor in real time; The measuring shaft system motion state monitoring module includes a displacement sensor and a data acquisition and analysis system, which is used 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 measuring axis system detected in real time, and adjust the central axis of the measuring 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; 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.

[0009] Further, 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 the 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.

[0010] Further, 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, which is used to monitor and adjust the operating state of the low-speed end motor in real time; Among them, 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 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.

[0011] 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.

[0012] Furthermore, two displacement sensors are placed at the supports of the measuring shaft system at the high-speed end and the low-speed end, 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.

[0013] Furthermore, 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 can be 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 measuring axis system detected in real time.

[0014] The present invention also provides a method for suppressing angle measurement errors in dynamic testing of a precision reducer, comprising the following steps: S1. Assemble the reducer under test with the high-speed and low-speed test components; S2, starting the first servo motor and the second servo motor, and performing dynamic tests in speed mode and torque mode respectively; S3, obtaining 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; obtaining the motion state of the measuring shaft system in real time through the displacement sensor; S4, through the high-speed servo motor self-disturbance rejection closed-loop control and the low-speed servo motor self-disturbance rejection closed-loop control, according to the dynamic torque, angular displacement and angular velocity information of the input and output ends of the measured reducer, the self-disturbance rejection control algorithm is used to adjust the speed and torque of the servo motor in real time; S5. Dynamically adjust the magnitude and direction of the output force of the piezoelectric ceramic according to the motion state of the measuring axis system through the piezoelectric ceramic driver control module to correct the angular displacement of the measuring axis system; 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 standard, so as to keep the angular measurement error within the preset range.

[0015] The embodiments of the present invention have the following technical effects: 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 can suppress the angular measurement error, and deal with the error from 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, process 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.

[0016] 2. Real-time compensation of the dynamic response of the motor is achieved through precise control of the high-speed and low-speed servo motors in conjunction with the ADRC algorithm. This helps keep the motion state of the high-speed and low-speed motors consistent with the preset standard, thereby reducing the angle error caused by insufficient motor control accuracy. The first and second servo motor control systems using the ADRC model can effectively eliminate external disturbances and internal nonlinear effects of the system, ensuring precise control of the servo motors at high and low speeds.

[0017] 3. The piezoelectric ceramic driver control module adjusts the output force of the piezoelectric ceramic according to the real-time feedback of the measurement axis movement state to accurately correct the angular error of the measurement axis. This can compensate for the slight deviation caused by the mechanical transmission and the measurement system itself.

[0018] 4. The displacement sensor monitors the motion state of the measuring shaft system in real time, and transmits the data feedback to the piezoelectric ceramic driver control module to achieve precise adjustment of the shaft system angular displacement. This dynamic correction greatly reduces the angular measurement error caused by the displacement change of the measuring shaft system. The high precision of the displacement sensor and the real-time data feedback system ensure that the system can capture and compensate for small errors in a timely manner during high-speed dynamic testing.

[0019] 5. Through the coordinated work of the joint control module, the system can comprehensively adjust the control ratio of the servo motor and piezoelectric ceramics to ensure that the angle error fluctuates within the preset range. Compared with the traditional single servo control system, this multiple control mechanism can significantly improve the overall measurement accuracy and reduce the angle deviation in dynamic testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is a 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; Figure 2 It is a schematic diagram of the system structure of a precision reducer detector provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of the control principle of the high-speed end motor servo control subsystem provided by an embodiment of the present invention; Figure 4 Schematic diagram of the control principle of the low-speed motor servo control subsystem provided by an embodiment of the present invention; Figure 5 It is a schematic diagram of a cross section of the piezoelectric ceramic provided by an embodiment of the present invention arranged outside a support; Figure 6 is a schematic diagram of the arrangement of the dual displacement sensor provided by an embodiment of the present invention at the support of the measuring shaft system; Figure 7 It is a flow chart of a method for suppressing angular measurement error in dynamic testing of a precision reducer provided by an embodiment of the present invention.

[0022] 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 seat; 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

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0024] like Figure 2 As shown, a method for determining phase connection of a shaft system based on visual guidance is provided, wherein the detector involved is a prior art, 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, including: a servo motor closed-loop control module 25, a shaft system motion state monitoring module 26, a piezoelectric ceramic driver control module 27 and a joint control module; The servo motor closed-loop control module 25 includes a high-speed motor servo control subsystem and a low-speed motor servo control subsystem; and is used to monitor and adjust the operating status of the high-speed motor and the low-speed motor in real time; 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 are used to monitor and adjust the operating state 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 the dynamic torque, angular displacement and angular velocity of the input end of the reducer under test are obtained 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.

[0025] Specifically, the first servo motor 10 and the driver are used to drive the input end of the measured reducer. When working in the speed mode, the driver is responsible for adjusting the speed of the motor and controlling the speed and torque of the motor by adjusting the current. The high-speed end torque sensor 13 monitors the dynamic torque of the input end of the measured reducer and feeds back the torque value in real time. The high-speed end angle encoder 14 monitors the angular displacement of the input end of the measured reducer, and calculates and feeds back the changes of angular velocity and angular displacement in real time. The first controller adjusts the current of the servo motor by obtaining the difference between the angular velocity and the motor speed in real time to ensure that the output motion state is consistent with the preset standard. The high-speed end torque sensor 13 feeds back the dynamic torque data to the first controller, and the high-speed end angle encoder 14 provides real-time angular displacement and angular velocity data. The angular displacement is obtained by integrating the angular velocity, while the angular velocity is directly obtained by the encoder. The first controller receives the feedback data of torque, angular displacement and angular velocity in real time to ensure that the system can be adjusted according to the actual operating state. Speed ​​difference compensation: The first controller needs to calculate the difference between the motor speed and the angular velocity of the input end of the measured reducer. In theory, the motor speed should match the angular velocity at the reducer input. If there is a difference, the controller will adjust the motor current to compensate. The first controller will continuously adjust the current output based on real-time feedback in each cycle to ensure that the motor speed and the angular velocity at the reducer input remain consistent. The closed-loop nature of the control system allows the motor speed to respond quickly and return to the predetermined standard in the event of any disturbance or load change.

[0026] In some embodiments, the low-speed motor servo control subsystem includes a second servo motor 24, a driver, a low-speed torque sensor 21, a low-speed angle encoder 19 and a second controller, which are used to monitor and adjust the operating state of the low-speed 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 torque sensor and the low-speed 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.

[0027] Specifically, the second servo motor 24 is used to provide a load and is to be operated in a torque mode. Its output torque will be transmitted to the output end of the measured reducer as a load signal. The driver provides a drive signal to the second servo motor to control the motor speed, torque and response time. The driver will also adjust the current output according to the instructions of the controller. The low-speed end torque sensor 21 is installed at the output end of the measured reducer to monitor the dynamic torque at the output end of the reducer in real time. The low-speed end angle encoder 19 is installed at the output end of the measured reducer to measure the angular displacement and angular velocity in real time. The second controller receives the signals obtained from the low-speed end torque sensor and the low-speed end angle encoder in real time. It will calculate the actual torque difference based on the signals and compensate by adjusting the motor current so 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 acquired dynamic torque (from the torque sensor) and the torque output by the second servo motor. The goal is to adjust the motor current according to the torque difference so that the actual output torque is consistent with the preset standard (target torque). In order to achieve fast response and high-precision control, a closed-loop control method is usually adopted. 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).

[0028] 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.

[0029] like Figure 3 As shown, the first controller adopts an anti-disturbance control model and uses 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 anti-disturbance control model, and uses the torque difference between the torque sensor output and the motor output as a 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.

[0030] The measuring shaft system motion state monitoring module 27 includes a displacement sensor 33 and a data acquisition and analysis system, which is used to monitor and feedback the motion state of the measuring shaft system in real time; the displacement sensor of the measuring shaft system motion state monitoring module can use a laser displacement sensor, or other methods can be used to obtain and detect the motion state of the measuring shaft system; Furthermore, two displacement sensors 33 are placed at the support of the high-speed end and the low-speed end of the measuring shaft system, and the 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; The data acquisition and analysis system feeds back the motion state of the measurement axis system to the piezoelectric ceramic driver control module.

[0031] 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 measuring axis system detected in real time, and adjust the central axis of the measuring axis system to make it consistent with the theoretical common axis; Optionally, the theoretical common axis can be determined by the following methods: 1. Determine the common axis based on the fitting of the center of a multi-section circle, measure multiple cross sections, measure circles of multiple cross sections on the measured element (such as the rotating part of the reducer) and the reference element, construct a 3D straight line from the center of the circle, fit the centers of these measured circles, and construct a 3D straight line, which is the common axis. 2. Determine the common axis based on the center line of the head and tail holes, determine the head and tail holes, determine the positions of the head and tail holes on the rotating part of the reducer, measure the center line, measure the centers of the head and tail holes, and connect them into a straight line, which is the common reference axis. 3. Consider the determination of the common axis in 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, you can simulate this assembly process, determine a common axis, adjust the measuring axis system, in the dynamic test, by adjusting the center axis of the measuring axis system to make it consistent with the simulated common axis, so as to reduce the angle measurement error.

[0032] 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; 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 measuring axis system detected in real time.

[0033] The piezoelectric ceramic driver control module receives feedback signals from the data acquisition and analysis system, and adjusts the working state of the piezoelectric ceramic driver according to the feedback information, thereby controlling the movement of the axis system. By applying voltage or changing the electric field, the piezoelectric ceramic driver can accurately change the posture, position or dynamic characteristics of the axis system. This control method has high precision and high response speed, and is particularly suitable for high-frequency vibration and fine-tuning movement.

[0034] 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.

[0035] Specifically, the operating status of the high-speed motor and the low-speed motor and the motion status of the measuring shaft system are monitored in real time, and relevant data such as motor speed, acceleration, position deviation, etc. are collected. The first step of regulation - closed-loop regulation of the servo motor: Based on the real-time data collected, the first step of regulation is performed through the closed-loop control module of the servo motor. This regulation link adjusts the action of the servo motor through a negative feedback mechanism to ensure that it operates within the predetermined parameter range to control the coarse adjustment of the measuring shaft. The second step of regulation - piezoelectric ceramic driver regulation: After the servo motor is coarsely adjusted, the piezoelectric ceramic driver module is started for fine adjustment. The high-precision characteristics of the piezoelectric ceramic driver can be used to fine-tune the position of the measuring shaft to reduce small angular errors. Through the real-time feedback information, combined with the preset standards (such as the allowable range of angular error), the control ratio of the servo motor and the piezoelectric ceramic driver control module is dynamically adjusted. The adjustment of the control ratio is optimized based on the error and speed of the real-time feedback to keep the angular error always within the preset range. According to the real-time changes in the system operation status, the control strategy is continuously adjusted to ensure that the system is always in the optimal state to avoid over-adjustment or under-adjustment.

[0036] like Figure 7 As shown, the present invention also provides a method for suppressing angle measurement errors in dynamic testing of a precision reducer, comprising the following steps: S1. Assemble the reducer under test with the high-speed and low-speed test components, such as Figure 2 As shown; Connect the input end of the measured reducer to the first servo motor, and the output end of the measured reducer to the second servo motor, and ensure that all sensors (torque sensor, angle encoder, displacement sensor, etc.) are correctly installed on the measuring shaft system to ensure accurate signal transmission.

[0037] S2, starting the first servo motor and the second servo motor, and performing dynamic tests in speed mode and torque mode respectively; 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 to ensure the coordinated action of the two servo motors and avoid mutual interference.

[0038] S3, obtaining 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; obtaining the motion state of the measuring shaft system in real time through the displacement sensor; The torque sensor obtains the dynamic torque signal 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. Angular velocity information: measures the angular velocity of the input and output ends of the measured reducer. Through the relationship between angular velocity and angular displacement, the load and adjustment accuracy of the servo motor can be calculated. The displacement sensor monitors and measures the motion state of the shaft system, obtains the displacement data of the shaft system in real time, and accurately controls the angular displacement.

[0039] S4, through the high-speed servo motor self-disturbance rejection closed-loop control and the low-speed servo motor self-disturbance rejection closed-loop control, according to the dynamic torque, angular displacement and angular velocity information of the input and output ends of the measured reducer, the self-disturbance rejection control algorithm is used to adjust the speed and torque of the servo motor in real time; For the high-speed servo motor, the ADRC algorithm is applied. This algorithm can maintain the stability of the system in the presence of disturbances. The speed of the high-speed motor is adjusted through real-time feedback of angular velocity information to make the dynamic changes of the input end as stable as possible. For the low-speed servo motor, the ADRC algorithm is also applied. According to the state of the input end of the measured reducer and the load at the output end, the output torque of the low-speed motor is adjusted to suppress the angular error caused by the characteristics of the reducer.

[0040] S5. Dynamically adjust the magnitude and direction of the output force of the piezoelectric ceramic according to the motion state of the measuring axis system through the piezoelectric ceramic driver control module to correct the angular displacement of the measuring axis system; The output force and direction of the piezoelectric ceramic driver are dynamically adjusted according to the real-time acquired motion state of the measured axis system (such as angular displacement). The piezoelectric ceramic driver 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.

[0041] 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 measuring axis system, combined with the preset standard, so that the angle measurement error is kept within the preset range; Collect all necessary feedback data based on the real-time monitoring of the operating status of the high-speed and low-speed servo motors (such as speed, load, torque) and the motion status of the measured shaft system (such as angular displacement, angular velocity, torque, etc.). Preset standards to set the allowable range of angular measurement errors and other control standards. These standards can be based on actual application requirements, such as the accuracy requirements of the reducer, the load conditions of the test, etc. During the operation of the system, the joint control module needs to dynamically adjust the control ratio of the servo motor closed-loop control module and the piezoelectric ceramic driver control module according to the measured error and the real-time monitoring status. For example, when the angular displacement of the system is large or the error is large, the servo motor is given priority for coarse adjustment; when the angular displacement error is small or the system is in the fine adjustment stage, the piezoelectric ceramic driver provides fine-tuning compensation. The adjustment of the control ratio can be optimized based on the size of the error, the dynamic response of the system, torque feedback and other data. Common adjustment methods include gain scheduling, fuzzy logic control, etc., which gradually optimize the control strategy based on real-time feedback.

[0042] It should be noted that the terms used in the present invention are only for describing specific embodiments, rather than limiting the scope of the present 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, but may also include the plural. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device including 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 more restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method or device including the elements.

[0043] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation 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 it can be an indirect connection through an intermediate medium, or it can be a connection between the 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.

[0044] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by 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 angle 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 state of the high-speed motor in real time, and the low-speed motor servo control subsystem is used to monitor and adjust the operating state 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, which is used 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 measuring axis system detected in real time, and adjust the central axis of the measuring 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 measuring axis system, combined with preset standards, the control ratio of the closed-loop control module of the servo motor and the piezoelectric ceramic driver control module are dynamically adjusted to keep the angular measurement error within the preset range.

2. The system for suppressing angle measurement error in dynamic testing of a precision reducer according to claim 1 is 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 the 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 error in dynamic testing of a precision reducer according to claim 1 is characterized in that: 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, which is used to monitor and adjust the operating state of the low-speed end motor in real time; Among them, 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 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 angle measurement error in dynamic testing of a precision reducer according to claim 3 is characterized in that: The first controller and the second controller both 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.

5. The system for suppressing angle measurement error in dynamic testing of a precision reducer according to claim 1 is characterized in that: The displacement sensors are placed at the support of the high-speed end and the low-speed end of the measuring shaft system, two of 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 angle measurement error 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 measuring axis system detected in real time.

7. A method for suppressing angle measurement error in dynamic testing of a precision reducer, characterized in that: The following steps are involved: S1. Assemble the reducer under test with the high-speed and low-speed test components; S2, starting the first servo motor and the second servo motor, and performing dynamic tests in speed mode and torque mode respectively; S3, obtaining 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; obtaining the motion state of the measuring shaft system in real time through the displacement sensor; S4, through the high-speed servo motor self-disturbance rejection closed-loop control and the low-speed servo motor self-disturbance rejection closed-loop control, according to the dynamic torque, angular displacement and angular velocity information of the input and output ends of the measured reducer, the self-disturbance rejection control algorithm is used to adjust the speed and torque of the servo motor in real time; S5. Dynamically adjust the magnitude and direction of the output force of the piezoelectric ceramics according to the motion state of the measuring axis system through the piezoelectric ceramic driver control module to correct the angular displacement of the measuring 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 standard, so as to keep the angular measurement error within the preset range.

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