Servo motor and inertia matching method thereof

Abstract

This invention discloses a servo motor and its inertia matching method. The servo motor includes a motor body and an inertia adjustment module connected to the first end of the rotor shaft of the motor body. The inertia adjustment module includes a counterweight structure with adjustable position. The matching method includes: acquiring response data information of the servo motor under a set excitation signal; the response data information includes motor torque correlation information and rotor angle information of the servo motor, or load torque correlation information of the load; determining the load inertia based on the response data information; determining the first target inertia of the counterweight structure based on a preset inertia ratio and the load inertia, and determining the target position of the counterweight structure corresponding to the first target inertia. This achieves automated matching of the servo motor inertia, ensures the accuracy and consistency of the matching process, and improves the performance and operational stability of the servo motor.

Description

Technical Field

[0001] This invention relates to the field of servo motor technology, and in particular to a servo motor and its inertia matching method. Background Technology

[0002] In servo drive systems, the ratio of load inertia to motor inertia, i.e., the inertia ratio, is a key parameter affecting the system's dynamic response, stability, and accuracy.

[0003] When the load inertia is much greater than the motor inertia, the system response is sluggish, prone to oscillations, and the motor needs to output greater torque to overcome its own acceleration, resulting in low energy efficiency. When the motor inertia is much greater than the load inertia, although stable, the motor is oversized, leading to wasted cost and energy. Therefore, when a servo motor is working, it is necessary to calculate the appropriate motor inertia to achieve precise inertia matching, so that the servo motor operates in its optimal state.

[0004] However, in the existing technology, when servo motors are dealing with variable loads, their rotational inertia is fixed, which makes them unable to adapt to different loads, resulting in a decrease in the dynamic performance of the system. Alternatively, when the load changes, it is necessary to replace the motor with one of different specifications, which is cumbersome. Summary of the Invention

[0005] This invention provides a servo motor and its inertia matching method, so that the motor-side inertia can adapt to changing loads and improve the dynamic performance of the system.

[0006] According to one aspect of the present invention, an inertia matching method for a servo motor is provided. The servo motor includes a motor body and an inertia adjustment module connected to a first end of the rotor shaft of the motor body. The inertia adjustment module includes a counterweight structure with adjustable position. The inertia matching method for the servo motor includes: Obtain the response data information of the servo motor under a set excitation signal; the response data information includes the motor torque correlation information and rotor angle information of the servo motor, or the load torque correlation information of the load; Determine the load inertia based on the response data information; The first target inertia of the counterweight structure is determined based on the preset inertia ratio and the load inertia, so as to determine the target position of the counterweight structure corresponding to the first target inertia.

[0007] Optionally, determining the load inertia based on the response data information includes: The torque of the servo motor is determined based on the motor torque correlation information; The angular acceleration of the servo motor is determined based on the rotor angle information; The total inertia of the system is determined based on the torque and angular acceleration of the servo motor. The load inertia is determined based on the difference between the total system inertia and the system base inertia; wherein the system base inertia is equal to the sum of the servo motor's own inertia and the counterweight structure's inertia at the current position.

[0008] Optionally, the second end of the rotor shaft of the motor body is connected to the input end of the reducer, and the output end of the reducer is used to connect to the load; the load torque association information includes the torque of the load, or the angle information of the input end of the reducer and the angle information of the output end of the reducer; determining the load inertia based on the response data information includes: The torque of the load can be obtained directly, or the torque of the load can be determined based on the angle information of the input end and the angle information of the output end of the reducer; The angular acceleration of the load is determined based on the angle information at the output end of the reducer; The load inertia is determined based on the load torque and the load angular acceleration.

[0009] Optionally, determining the first target inertia of the counterweight structure based on the preset inertia ratio and the load inertia, and then determining the target position of the counterweight structure corresponding to the first target inertia, includes: The second target inertia of the servo motor is determined based on the ratio of the load inertia to the preset inertia ratio; The first target inertia is determined based on the difference between the second target inertia and the inertia of the servo motor, so as to determine the target position of the counterweight structure corresponding to the first target inertia.

[0010] Optionally, determining the target position of the counterweight structure corresponding to the first target inertia includes: The target position of the counterweight structure is determined based on the first target inertia and a preset correspondence; wherein the preset correspondence is the correspondence between the first target inertia and the position of the counterweight structure.

[0011] Optionally, the preset correspondence is as follows: ; in, Let m be the initial inertia and m be the mass of the counterweight structure. The distance between the counterweight structure and the reference structure in the motor body at the initial position of the counterweight structure. The distance between the counterweight structure and the reference structure in the motor body at the target position of the counterweight structure.

[0012] Optionally, after determining the first target inertia of the counterweight structure based on the preset inertia ratio and the load inertia, and thus determining the target position of the counterweight structure corresponding to the first target inertia, the method further includes: Adjust the counterweight structure to move it to the target position; The process of obtaining the response data information of the servo motor under the set excitation signal is executed again to obtain the total inertia of the system after the counterweight structure is adjusted to the target position; The actual inertia ratio is determined by comparing the total inertia of the system after the counterweight structure is adjusted to the target position with the load inertia. Determine whether the inertia at the current target position matches based on the actual inertia ratio and the preset inertia ratio; If the inertia is mismatched at the current target position, continue with the subsequent step of obtaining the response data information of the servo motor under the set excitation signal.

[0013] Optionally, determining whether the inertia matches at the current target position based on the actual inertia ratio and the preset inertia ratio includes: If the absolute value of the difference between the actual inertia ratio and the preset inertia ratio is greater than or equal to the preset error, then it is determined that the inertia is mismatched at the current target position. If the absolute value of the difference between the actual inertia ratio and the preset inertia ratio is less than the preset error, then inertia matching at the current target position is determined.

[0014] According to another aspect of the present invention, a servo motor is provided, comprising: a motor body, an inertia adjustment module, an information acquisition module, and a control module; The first end of the rotor shaft of the motor body is connected to the inertia adjustment module; The inertia adjustment module includes a counterweight structure, the position of which is adjustable. The information acquisition module is used to acquire response data information of the servo motor under a set excitation signal; the response data information includes the motor torque correlation information and rotor angle information of the servo motor, or the load torque correlation information of the load. The control module is connected to the information acquisition module, and the control module is used to execute the inertia matching method of the servo motor described in any of the above embodiments.

[0015] Optionally, the inertia adjustment module further includes an inertia wheel, a crossbeam, a guide rail, and an adjustment mechanism; the number of the counterweight structures is at least two, and the at least two counterweight structures are symmetrically arranged on both sides of the crossbeam; The center of the inertia wheel is fixedly connected to the first end of the rotor shaft of the servo motor, and the inertia wheel rotates synchronously with the rotor of the servo motor. The crossbeam is arranged along the diameter direction of the inertia wheel, and both ends of the crossbeam are fixedly connected to the frame of the inertia wheel. The guide rail is perpendicular to the crossbeam and passes through the crossbeam and the counterweight structure. Both ends of the guide rail are fixedly connected to the frame of the inertia wheel. The adjustment mechanism is used to adjust the position of the counterweight structure.

[0016] The technical solution of this invention first acquires the response data information of the servo motor under a set excitation signal, then determines the load inertia of the servo motor based on the response data information, and finally determines the first target inertia of the counterweight structure and the target position of the counterweight structure corresponding to the first target inertia based on the preset inertia ratio and the load inertia. This allows the counterweight structure to be adjusted to the target position, achieving accurate calculation of the servo motor inertia. This enables the motor-side inertia to be adjusted by changing the position of the counterweight structure when the load changes, thereby matching the motor-side inertia with the changing load and improving the system's dynamic performance. Furthermore, the motor-side inertia does not rely on empirical estimation, eliminating human error and ensuring the accuracy and consistency of the matching process. This makes it easier for the inertia ratio between the servo motor and the load to always be within the optimal range, ensuring the servo motor operates in its best condition, improving the servo motor's operational stability, and extending its service life.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the structure of a servo motor provided in an embodiment of the present invention; Figure 2 A flowchart of a servo motor inertia matching method provided in an embodiment of the present invention; Figure 3 A detailed flowchart for determining load inertia based on response data information provided in this embodiment of the invention; Figure 4A detailed flowchart for determining load inertia based on response data information provided in this embodiment of the invention; Figure 5 A flowchart illustrating another inertia matching method for a servo motor provided in an embodiment of the present invention; Figure 6 A flowchart illustrating another inertia matching method for a servo motor provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of another servo motor provided in an embodiment of the present invention; Figure 8 A schematic diagram of a speed reducer provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the servo motor inertia adjustment module provided in an embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] Figure 1 This is a schematic diagram of the structure of a servo motor provided in an embodiment of the present invention. Figure 2 This is a flowchart illustrating a servo motor inertia matching method provided in an embodiment of the present invention. This embodiment is applicable to situations where the inertia of a suitable servo motor is matched based on the load inertia. This method can be executed by a servo motor control module, which can be implemented in hardware and / or software. Figure 1As shown, the servo motor 100 includes a motor body 10 and an inertia adjustment module 20 connected to the first end of the rotor shaft of the motor body 10. The inertia adjustment module 20 can be coaxially connected to the rotor shaft of the motor body 10. The inertia adjustment module 20 includes a position-adjustable counterweight structure 21. The counterweight structure 21 is used to provide a suitable inertia for the servo motor 100, matching the load inertia, so that the servo motor 100 is in a good working condition.

[0023] like Figure 2 As shown, the inertia matching method for a servo motor provided in this embodiment of the invention includes the following steps: S110: Obtain the response data information of the servo motor under the set excitation signal.

[0024] Specifically, during the process of a servo motor driving a load, the load inertia and the servo motor inertia need to be matched, meaning the ratio of load inertia to servo motor inertia needs to be within a certain range, typically 1-10. This ensures the stability of the servo motor's dynamic performance, achieving optimal dynamic response, stability, and control precision. Therefore, it is necessary to match the appropriate servo motor inertia to the load inertia. Before matching the servo motor's inertia, a setting excitation signal needs to be sent to the servo motor. Then, the servo motor's response data under the setting excitation signal is obtained. The setting excitation signal can be a trapezoidal wave velocity signal, a sinusoidal sweep frequency signal, etc., which can induce a dynamic response in the servo motor. The dynamic response can include acceleration, deceleration, starting, and braking actions of the servo motor. The response data includes the servo motor's torque correlation information and rotor angle information, or the load torque correlation information. For example, the servo motor's torque correlation information can be three-phase current information related to the servo motor's torque, and the servo motor's rotor angle information can be the servo motor's rotor angular position. The load torque correlation information can be the torque information at the servo motor's output terminal.

[0025] S120. Determine the load inertia based on the response data information.

[0026] Specifically, after acquiring the servo motor's response data under the set excitation signal, the load inertia of the servo motor at this time can be determined based on the corresponding response data. This load inertia can be determined based on the servo motor's torque correlation information and rotor angle information, or it can be determined based solely on the load torque correlation information.

[0027] S130. Determine the first target inertia of the counterweight structure based on the preset inertia ratio and load inertia, so as to determine the target position of the counterweight structure corresponding to the first target inertia.

[0028] Specifically, the position of the counterweight structure can be adjusted. By adjusting the position of the counterweight structure, its inertia can be changed, thereby providing a suitable inertia for the servo motor. After determining the load inertia of the servo motor, the first target inertia of the servo motor counterweight structure can be determined based on the load inertia and a preset inertia ratio. The first target inertia refers to the inertia required by the counterweight structure under the load driven by the servo motor. After determining the first target inertia of the counterweight structure, the target position corresponding to the counterweight structure can be calculated based on the first target inertia, and then the counterweight structure can be adjusted to the target position, so that the inertia ratio between the servo motor and the load is within the optimal range, improving the performance of the servo motor. The preset inertia ratio can be set in advance according to the performance of the servo motor and the parameters of the load. This embodiment of the invention does not specifically limit this and can be set according to the actual situation.

[0029] The servo motor inertia matching method provided in this embodiment first acquires the response data information of the servo motor under a set excitation signal. Then, it determines the load inertia of the servo motor based on the response data information. Finally, it determines the first target inertia of the counterweight structure and the target position of the counterweight structure corresponding to the first target inertia based on the preset inertia ratio and the load inertia. The counterweight structure can then be adjusted to the target position, achieving accurate calculation of the servo motor inertia. This allows the motor-side inertia to be adjusted by changing the position of the counterweight structure when the load changes, thereby matching the motor-side inertia with the changing load and improving the dynamic performance of the system. Furthermore, the motor-side inertia does not rely on empirical estimation, eliminating human error and ensuring the accuracy and consistency of the matching process. This makes it easier for the inertia ratio between the servo motor and the load to always be within the optimal range, ensuring that the servo motor operates in its best condition, improving the operational stability of the servo motor, and extending its service life.

[0030] Optional, Figure 3 A detailed flowchart for determining load inertia based on response data information is provided for embodiments of the present invention. Based on the above embodiments, see also... Figure 3 The inertia matching method for servo motors provided in this embodiment of the invention includes: S210. Determine the torque of the servo motor based on the motor torque correlation information.

[0031] Specifically, after acquiring the servo motor's response data under the set excitation signal, the servo motor's torque can be determined based on its torque correlation information. This torque correlation information can be derived from the collected three-phase current of the servo motor under the set excitation signal. The quadrature-axis current of the servo motor is determined by performing Clarke or Park processing on the three-phase current. Then, the servo motor's torque is determined based on the quadrature-axis current and the torque constant. The torque constant can be obtained from the servo motor's manual.

[0032] The torque of the servo motor is calculated using the following formula: in, For the torque of the servo motor, The torque constant of the servo motor. This is the quadrature-axis current of the servo motor.

[0033] S220. Determine the angular acceleration of the servo motor based on the rotor angle information.

[0034] Specifically, after obtaining the rotor angle information of the servo motor, the angular acceleration of the servo motor can be determined based on this information. The rotor angle information can be obtained by considering the rotor angular position, which is related to the angular velocity of the servo motor rotor. This rotor angular position can be acquired using the servo motor's built-in encoder, and then the angular velocity can be calculated differentially, leading to the calculation of the servo motor's angular acceleration.

[0035] The angular velocity of the servo motor is calculated using the following formula: The angular acceleration of the servo motor is calculated using the following formula: in, Let be the angular velocity of the servo motor at time k. Angular acceleration of servo motors Let be the angular velocity of the servo motor at time k-1. Let be the rotor angular position of the servo motor at time k. Let be the rotor angular position of the servo motor at time k-1. The sampling period.

[0036] S230. Determine the total inertia of the system based on the torque and angular acceleration of the servo motor.

[0037] Specifically, after calculating the torque and angular acceleration of the servo motor, the total inertia of the system can be calculated online using the least squares method or Kalman filtering algorithm based on the torque and angular acceleration of the servo motor.

[0038] The total inertia of the system is calculated using the following formula: in, The total inertia of the system. For the torque of the servo motor, For the angular acceleration of the servo motor, The frictional torque is approximately constant.

[0039] S240. Determine the load inertia based on the difference between the total system inertia and the system's basic inertia.

[0040] Specifically, after determining the total inertia of the system, the load inertia driven by the servo motor can be calculated based on the total system inertia and the system's basic inertia. The system's basic inertia can be equal to the sum of the servo motor's own inertia and the inertia of the counterweight structure at its current position.

[0041] The load inertia is calculated using the following formula: in, For load inertia, The total inertia of the system. This is the system's fundamental inertia.

[0042] Optional, Figure 4 A detailed flowchart for determining load inertia based on response data information is provided for embodiments of the present invention. Based on the above embodiments, see also... Figure 4 The inertia matching method for servo motors provided in this embodiment of the invention includes: S310. Directly obtain the load torque, or determine the load torque based on the angle information of the input end and the angle information of the output end of the reducer.

[0043] Specifically, a reducer can be installed at the second end of the rotor shaft of the servo motor body. The input end of the reducer is connected to the second end of the rotor shaft of the motor body. An encoder is installed at both the output and input ends of the reducer to obtain the angular positions of the output and input ends, respectively. The load torque correlation information can be the angular information of the reducer output end and the angular information of the reducer input end. The angular information of the reducer output end can be the current angular position of the reducer output end, and the angular information of the reducer input end can be the current angular position of the reducer input end. Then, the load torque is determined based on the difference between the angular positions of the output and input ends and the stiffness model of the reducer. In other embodiments, a torque sensor can be installed between the output shaft of the reducer and the load to directly obtain the torque at the load end of the servo motor. Here, the load torque correlation information is the data directly obtained by the torque sensor.

[0044] S320. Determine the angular acceleration of the load based on the angle information at the output end of the reducer.

[0045] Specifically, an encoder is installed at the output end of the reducer, allowing direct acquisition of the angle information at the reducer's output. Angular velocity is determined through differential calculation based on the angular position of the reducer's output at different times, and then the angular acceleration of the load is determined through further differential calculation.

[0046] S330. Determine the load inertia based on the load torque and the load angular acceleration.

[0047] Specifically, after calculating the torque and angular acceleration of the current load, the load inertia can be directly calculated from these values. Once the load torque and angular acceleration are determined, the load torque can be directly determined by the ratio of the load torque to the load angular acceleration. This eliminates the reliance on the three-phase current of the servo motor for calculations, reducing the computational process.

[0048] Optional, Figure 5 A flowchart of another inertia matching method for a servo motor provided in this embodiment of the invention is shown below, based on the above embodiments. Figure 5 The inertia matching method for servo motors provided in this embodiment of the invention includes: S410: Obtain the response data information of the servo motor under the set excitation signal.

[0049] S420. Determine the load inertia based on the response data information.

[0050] S430. Determine the second target inertia of the servo motor based on the ratio of the load inertia to the preset inertia ratio.

[0051] Specifically, after determining the load inertia driven by the servo motor, a second target inertia of the servo motor can be determined based on a preset inertia ratio and the load inertia. The second target inertia can be the servo motor inertia required by the load to achieve optimal inertia matching. The preset inertia ratio can be a pre-set optimal inertia ratio, which can be set according to actual needs in this embodiment of the invention. Then, the second target inertia of the servo motor is determined based on the ratio of the load inertia to the preset inertia ratio.

[0052] The second target inertia is calculated using the following formula: in, This is the second target inertia of the servo motor. For load inertia, This is the preset inertia ratio.

[0053] S440. Determine the first target inertia based on the difference between the second target inertia and the servo motor's own inertia, so as to determine the target position of the counterweight structure corresponding to the first target inertia.

[0054] Specifically, after determining the second target inertia, the first target inertia of the counterweight structure can be calculated based on it. The first target inertia of the counterweight structure can be determined by subtracting the second target inertia from the inertia of the servo motor itself. The inertia of the servo motor refers to its own inertia, which can be obtained by consulting the servo motor's manual.

[0055] The first target inertia is calculated using the following formula: in, The primary objective is inertia. This is the second target inertia of the servo motor. This refers to the inertia of the servo motor itself.

[0056] Optionally, determining the target position of the counterweight structure corresponding to the first target inertia may include determining the target position of the counterweight structure based on the first target inertia and a preset correspondence.

[0057] Specifically, after determining the first target inertia of the counterweight structure, the target position of the counterweight structure can be determined according to the corresponding preset correspondence. The preset correspondence is the relationship between the first target inertia and the position of the counterweight structure.

[0058] Optionally, the default mapping relationship is as follows: in, Let m be the initial inertia and m be the weight of the counterweight structure. Let denoted by , where is the initial position of the counterweight structure and the distance between it and the reference structure within the motor body. Let x represent the target position of the counterweight structure and the distance between it and the reference structure within the motor body. The reference structure within the motor body can be the center position of the inertia adjustment module. For example, a mapping table can be established between the first target inertia and the target position of the counterweight structure. After the first target position is determined, the target position corresponding to the first target inertia can be found directly through the mapping table.

[0059] Optional, Figure 6 A flowchart of another inertia matching method for a servo motor provided in this embodiment of the invention is shown below, based on the above embodiments. Figure 6 The inertia matching method for servo motors provided in this embodiment of the invention includes: S510: Obtain the response data information of the servo motor under the set excitation signal.

[0060] S520. Determine the load inertia based on the response data information.

[0061] S530. Determine the first target inertia of the counterweight structure based on the preset inertia ratio and load inertia, so as to determine the target position of the counterweight structure corresponding to the first target inertia.

[0062] S540, Adjust the counterweight structure to move to the target position.

[0063] Specifically, after determining the target position of the counterweight structure, it can be controlled to slide to that position. The methods for controlling the sliding of the counterweight structure can be varied. Examples include: manual sliding by a worker; automatic drive using a micro servo motor or stepper motor; electromagnetic drive adjustment, where the counterweight structure is designed as a permanent magnet or magnetic conductor, with electromagnetic coils arranged radially on the inertia wheel, and electromagnetic force is generated by controlling the magnitude and direction of the current flowing through the coils to drive the counterweight structure to the target position; passive centrifugal force adjustment, where a spring or elastic element is placed between the counterweight structure and the rotating shaft, and the centrifugal force on the counterweight structure balances with the spring force when the servo motor speed changes, automatically stabilizing it at different positions; and hydraulic or pneumatic drive adjustment, where radial oil or air passages are opened inside the inertia wheel, and the counterweight structure acts as a piston, with high-pressure oil or gas being introduced into the shaft through a rotary joint to drive the counterweight structure to move to the target position.

[0064] S550, execute again to obtain the response data information of the servo motor under the set excitation signal, so as to obtain the total inertia of the system after the counterweight structure is adjusted to the target position.

[0065] Specifically, after adjusting the counterweight structure to the target position, a set excitation signal can be sent to the servo motor again to obtain the servo motor's response data under the set excitation signal. This response data can include the servo motor's torque correlation information and rotor angle information, or the load torque correlation information. Then, the total system inertia after the counterweight structure is adjusted to the target position is calculated based on this data. The total system inertia can be calculated based on the servo motor's torque and angular acceleration. The servo motor's torque can be calculated using the servo motor's torque correlation information or the load torque correlation information, while the angular acceleration can be calculated using the servo motor's rotor angle information or the angle information at the reducer's output end.

[0066] S560. Determine the ratio of the actual inertia to the total inertia of the system after the counterweight structure is adjusted to the target position and the load inertia.

[0067] Specifically, after the counterweight structure slides to the target position and the total system inertia of the counterweight structure at the target position is calculated, the actual inertia ratio of the servo motor can be determined based on the total system inertia of the counterweight structure after it has been adjusted to the target position and the load inertia. The actual inertia ratio is equal to the ratio of the load inertia to the servo motor inertia. The servo motor inertia can be obtained by subtracting the load inertia obtained in step S520 from the total system inertia of the counterweight structure after it has been adjusted to the target position.

[0068] The actual inertia ratio is calculated using the following formula: ; in, This is the actual inertia ratio. For load inertia, This is the total inertia of the system after the counterweight structure has been adjusted to the target position.

[0069] S570. Determine whether the inertia matches at the current target position based on the actual inertia ratio and the preset inertia ratio.

[0070] Specifically, after determining the actual inertia ratio of the servo motor at the target position, the difference between the actual inertia ratio and the preset inertia ratio can be used to determine whether the inertia of the counterweight structure at the current target position matches the load inertia. Specifically, if the absolute value of the difference between the actual inertia ratio and the preset inertia ratio is greater than or equal to a preset error, it is determined that the inertia at the current target position is mismatched. If the absolute value of the difference between the actual inertia ratio and the preset inertia ratio is less than the preset error, it is determined that the inertia at the current target position matches. The preset error is not specifically limited in this embodiment of the invention and can be set according to actual needs.

[0071] In cases where there is an inertia mismatch at the current target position, the subsequent steps of acquiring the response data of the servo motor under the set excitation signal are continued.

[0072] Specifically, when the inertia of the counterweight structure at the current target position is mismatched with the load inertia, that is, when the absolute value of the difference between the actual inertia ratio and the optimal inertia is greater than or equal to the preset error, it may be necessary to continue to match the inertia of the servo motor. The specific matching method is as described in the servo motor inertia matching method in any of the above embodiments. That is, continue to determine the first target inertia of the counterweight structure according to the preset inertia ratio and the load inertia, then determine the target position corresponding to the first target inertia, adjust the counterweight structure to the new target position again, and then verify again whether the inertia of the counterweight structure matches the load at the new target position.

[0073] Optionally, for periodic loads with regular variations, such as those of robotic arms and presses, a trajectory model of the load variation can be established in advance. Before the action is executed, the required inertia of the counterweight structure is pre-calculated based on the trajectory model, and the counterweight structure is adjusted to the target position so that its inertia is close to optimal at each stage of the motion, achieving "proactive" matching and reducing the matching process.

[0074] In addition, a reference model of the servo motor and an adjustable model with the same structure as the reference model but containing the inertia parameters to be estimated can be constructed in advance. The inertia estimate in the adjustable model is continuously updated through an adaptive law, so that the output of the adjustable model tracks the actual output. When the tracking error approaches zero, the inertia estimate converges to the true value, making the output of the reference model consistent with the actual output.

[0075] The inertia matching method for servo motors provided in this invention first determines the load inertia based on the response data of the servo motor, then calculates the target position of the counterweight structure corresponding to the current load inertia, and re-executes inertia identification after adjustment to perform closed-loop verification, thereby achieving stepless and precise inertia matching, realizing automated and intelligent matching, eliminating human error, and significantly improving the dynamic performance of the servo motor.

[0076] This invention also provides a servo motor. Figure 7 This is a schematic diagram of another servo motor provided in an embodiment of the present invention. Based on the above embodiments, see [link to previous section]. Figure 1 and Figure 7 As shown, the servo motor 100 includes a motor body 10, an inertia adjustment module 20, an information acquisition module 30, and a control module 40. The first end of the rotor shaft of the motor body 10 is connected to the inertia adjustment module 20. The inertia adjustment module 20 includes a counterweight structure 21, the position of which is adjustable. The information acquisition module 30 is used to acquire response data information of the servo motor 100 under a set excitation signal. The response data information includes motor torque correlation information and rotor angle information of the servo motor 100, or load torque correlation information of the load. The control module 40 is connected to the information acquisition module 30 and is used to execute the inertia matching method of the servo motor provided in any of the above embodiments.

[0077] in, Figure 8 This is a schematic diagram of a speed reducer provided in an embodiment of the present invention. Figure 1 , Figure 7 and Figure 8As shown, the servo motor 100 may also include a reducer 50. The second end of the rotor shaft of the motor body 10 is connected to the input shaft of the reducer 50, and the first end of the rotor shaft of the motor body 10 is connected to the inertia adjustment module 20. A first encoder is provided at the tail of the servo motor 100. A second encoder can be provided at the input end of the reducer 50, and a third encoder and a torque sensor are provided at the output end of the reducer. The information acquisition module 30 may include a current sampling unit, a first encoder, a second encoder, and a third encoder integrated into the servo motor 100. The current sampling unit and the first encoder may be integrated into the servo motor. The current sampling is used to obtain the motor torque correlation information of the servo motor 100, and the first encoder is used to obtain the rotor angle information of the servo motor. The second encoder is used to obtain the angle information at the input end of the reducer, and the third encoder is used to obtain the angle information at the output end of the reducer. The angle information at the input end and the angle information at the output end of the reducer can be used as the load torque correlation information of the load. The torque sensor can obtain the torque at the load end and use it as the load torque correlation information.

[0078] The control module 40 integrates a servo driver and an inertia matching calculation unit. The servo driver is electrically connected to the power supply interface of the motor body 10 and the first encoder. The servo driver integrates a current loop control unit, a speed loop control unit, and a position loop control unit, used to output three-phase drive signals to the servo motor and to acquire the three-phase current signal, rotor angular velocity signal, and angular position signal of the servo motor in real time. The inertia matching calculation unit communicates with the servo driver via a data bus and is used to receive the motor operation data acquired by the servo driver. The inertia matching calculation unit integrates an inertia identification subunit, a target calculation subunit, and a human-machine interface. The inertia identification subunit calculates the total inertia of the system based on the torque and angular acceleration of the servo motor using a preset algorithm (such as the least squares method). The target calculation subunit determines the load inertia based on the response data information; and determines the first target inertia of the counterweight structure based on the preset inertia ratio and the load inertia, thereby determining the target position of the counterweight structure corresponding to the first target inertia. The human-machine interface is used to output the calculated target position to the human-machine interface (such as a display screen, host computer software, or digital tube) for operators to read. The inertia matching calculation unit is also used to receive load torque correlation information from the load to calculate the load inertia more accurately.

[0079] The control module 40 can be equipped with a Bluetooth communication unit, allowing it to connect to the operator's mobile phone via Bluetooth and push the target position to the phone, enabling the operator to view adjustment instructions via the phone. The control module 40 can also be equipped with a voice interaction unit, which can announce the position of the counterweight structure 21.

[0080] Optional, Figure 9This is a schematic diagram of the servo motor inertia adjustment module provided in an embodiment of the present invention. Based on the above embodiment, see also... Figure 9 The inertia adjustment module 20 also includes an inertia wheel 22, a crossbeam 23, a guide rail 24, and an adjustment mechanism 25. There are at least two counterweight structures 21, symmetrically arranged on both sides of the crossbeam 23. The center of the inertia wheel 22 is fixedly connected to the first end of the rotor shaft of the servo motor 100, and the inertia wheel 22 rotates synchronously with the rotor of the servo motor 100. The crossbeam 23 is arranged along the diameter direction of the inertia wheel 22, and both ends of the crossbeam 23 are fixedly connected to the frame of the inertia wheel 22. The guide rail 24 is perpendicular to the crossbeam 23 and passes through the crossbeam 23 and the counterweight structures 21, with both ends fixedly connected to the frame of the inertia wheel 22. The adjustment mechanism 25 is used to adjust the position of the counterweight structures 21.

[0081] Specifically, the inertia wheel 22 is a ring-shaped disc structure with a mounting hole at its center that mates with the rotor shaft of the servo motor 100. It is fixedly connected to the rotor shaft of the servo motor 100 via a keyway or interference fit, rotating synchronously with the rotor. The crossbeam 23 is arranged along the diameter of the inertia wheel 22, and its two ends are fixed to the frame of the inertia wheel 22. There can be two counterweight structures 21, symmetrically arranged on both sides of the crossbeam 23. The guide rails 24 can include two rails, arranged parallel to each other and perpendicular to the crossbeam 23. Furthermore, the counterweight structure 21 has a through hole through which the guide rails 24 pass. The guide rails 24 are smooth metal rods used to guide the linear motion of the counterweight structure 21.

[0082] The counterweight structure 21 can be a multi-level nested counterweight structure, with multiple coaxial cylindrical counterweights of different diameters, driven by a screw or rack and pinion mechanism. Alternatively, it can be a liquid or particle inertia adjustment structure, where the inertia wheel 22 is designed with radially distributed closed cavities. High-density liquids (such as mercury or liquid metal) or tiny steel balls are injected into these cavities, and a micro-pump or solenoid valve transfers the liquid or particles between different chambers, changing the mass distribution. Finally, it can be a single-slider offset structure, using a single inertia slider, with dynamic balance maintained by counterweights or symmetrically arranged balance blocks.

[0083] For example, a scale 26 can be set in the direction of the vertical beam 23 to indicate the position of the counterweight structure. The position of the counterweight structure can also be detected indirectly based on the servo motor encoder. If the servo motor (such as a lead screw motor) itself has a high-precision encoder, and the connection rigidity between the push rod and the counterweight is high enough, the position of the counterweight can be indirectly calculated by recording the number of rotations of the servo motor, eliminating the need for a separate position sensor. Position detection can also be performed through image recognition. A transparent window and a miniature camera can be set on the tail housing of the servo motor, and image processing algorithms can be used to identify the scale or feature points on the counterweight structure, achieving non-contact position detection. Position detection can also be performed using Hall effect sensors or magnetic gratings. Small magnets are installed on the counterweight structure, and a Hall sensor array or magnetic grating reading head is arranged along the guide rail direction on the inertia wheel housing to obtain the slider position by detecting changes in the magnetic field.

[0084] Specifically, the adjusting mechanism 25 can be an adjusting screw. The counterweight structure 21 has a threaded hole, the central axis of which is parallel to the counterweight structure 21. The adjusting screw passes through the threaded hole into the counterweight structure 21. The middle section of the adjusting screw is a smooth shaft section, which is axially limited to the crossbeam 23 by a retaining ring or a shoulder. The left and right halves of the adjusting screw are respectively provided with external threads in opposite directions, which respectively cooperate with the threaded holes of the two inertia sliders. When the adjusting screw is rotated, the two counterweight structures move synchronously inward (closer to the crossbeam) or outward (away from the crossbeam) along the guide rail under the thread drive, and the movement distance is equal, thereby ensuring that the center of mass of the entire inertia wheel adjusting module 20 is always located on the rotation axis, meeting the dynamic balance requirements during high-speed rotation. Multiple positioning slots or limit blocks can be set on the adjusting screw, and the counterweight structure 21 can switch between several fixed positions. The adjusting mechanism 25 can also be an automatic drive by a screw motor, an electromagnetic drive adjusting mechanism, a centrifugal passive adjusting mechanism, a hydraulic or pneumatic drive adjusting mechanism, etc.

[0085] The servo motor provided in this embodiment of the invention can calculate the target position of the counterweight structure corresponding to the current load inertia through the control module, control the counterweight structure to slide to the target position, and re-execute the inertia identification after adjustment to perform closed-loop verification, thereby achieving stepless and precise inertia matching, realizing automated and intelligent matching, eliminating human error, and significantly improving the dynamic performance of the servo motor.

[0086] The servo motor provided in the embodiments of the present invention can execute the inertia matching method of the servo motor provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0087] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for inertia matching of a servo motor, characterized in that, The servo motor includes a motor body and an inertia adjustment module connected to the first end of the rotor shaft of the motor body. The inertia adjustment module includes a position-adjustable counterweight structure. The inertia matching method of the servo motor includes: Obtain the response data information of the servo motor under a set excitation signal; the response data information includes the motor torque correlation information and rotor angle information of the servo motor, or the load torque correlation information of the load; Determine the load inertia based on the response data information; The first target inertia of the counterweight structure is determined based on the preset inertia ratio and the load inertia, so as to determine the target position of the counterweight structure corresponding to the first target inertia.

2. The inertia matching method for a servo motor according to claim 1, characterized in that, Determining the load inertia based on the response data information includes: The torque of the servo motor is determined based on the motor torque correlation information; the angular acceleration of the servo motor is determined based on the rotor angle information. The total inertia of the system is determined based on the torque and angular acceleration of the servo motor. The load inertia is determined based on the difference between the total system inertia and the system base inertia; wherein the system base inertia is equal to the sum of the servo motor's own inertia and the counterweight structure's inertia at the current position.

3. The inertia matching method for a servo motor according to claim 1, characterized in that, The second end of the rotor shaft of the motor body is connected to the input end of the reducer, and the output end of the reducer is used to connect to the load; the load torque association information includes the torque of the load, or the angle information of the input end of the reducer and the angle information of the output end of the reducer; Determining the load inertia based on the response data information includes: The torque of the load can be obtained directly, or the torque of the load can be determined based on the angle information of the input end and the angle information of the output end of the reducer; The angular acceleration of the load is determined based on the angle information at the output end of the reducer; The load inertia is determined based on the load torque and the load angular acceleration.

4. The inertia matching method for a servo motor according to any one of claims 1-3, characterized in that, The step of determining the first target inertia of the counterweight structure based on the preset inertia ratio and the load inertia, and determining the target position of the counterweight structure corresponding to the first target inertia, includes: The second target inertia of the servo motor is determined based on the ratio of the load inertia to the preset inertia ratio; The first target inertia is determined based on the difference between the second target inertia and the inertia of the servo motor, so as to determine the target position of the counterweight structure corresponding to the first target inertia.

5. The inertia matching method for a servo motor according to claim 4, characterized in that, Determining the target position of the counterweight structure corresponding to the first target inertia includes: The target position of the counterweight structure is determined based on the first target inertia and a preset correspondence; wherein the preset correspondence is the correspondence between the first target inertia and the position of the counterweight structure.

6. The inertia matching method for a servo motor according to claim 5, characterized in that, The preset correspondence is as follows: ； in, Let m be the initial inertia and m be the mass of the counterweight structure. The distance between the counterweight structure and the reference structure in the motor body at the initial position of the counterweight structure. The distance between the counterweight structure and the reference structure in the motor body at the target position of the counterweight structure.

7. The inertia matching method for a servo motor according to claim 1, characterized in that, After determining the first target inertia of the counterweight structure based on the preset inertia ratio and the load inertia, and then determining the target position of the counterweight structure corresponding to the first target inertia, the method further includes: Adjust the counterweight structure to move it to the target position; The process of obtaining the response data information of the servo motor under the set excitation signal is executed again to obtain the total inertia of the system after the counterweight structure is adjusted to the target position; The actual inertia ratio is determined by comparing the total inertia of the system after the counterweight structure is adjusted to the target position with the load inertia. Determine whether the inertia at the current target position matches based on the actual inertia ratio and the preset inertia ratio; If the inertia is mismatched at the current target position, continue with the subsequent step of obtaining the response data information of the servo motor under the set excitation signal.

8. The inertia matching method for a servo motor according to claim 7, characterized in that, The step of determining whether the inertia matches at the current target position based on the actual inertia ratio and the preset inertia ratio includes: If the absolute value of the difference between the actual inertia ratio and the preset inertia ratio is greater than or equal to the preset error, then it is determined that the inertia is mismatched at the current target position. If the absolute value of the difference between the actual inertia ratio and the preset inertia ratio is less than the preset error, then inertia matching at the current target position is determined.

9. A servo motor, characterized in that, include: Motor body, inertia adjustment module, information acquisition module and control module; The first end of the rotor shaft of the motor body is connected to the inertia adjustment module; The inertia adjustment module includes a counterweight structure, the position of which is adjustable. The information acquisition module is used to acquire response data information of the servo motor under a set excitation signal; the response data information includes the motor torque correlation information and rotor angle information of the servo motor, or the load torque correlation information of the load. The control module is connected to the information acquisition module, and the control module is used to execute the inertia matching method of the servo motor according to any one of claims 1-8.

10. The servo motor according to claim 9, characterized in that, The inertia adjustment module also includes an inertia wheel, a crossbeam, a guide rail, and an adjustment mechanism; the number of the counterweight structures is at least two, and the at least two counterweight structures are symmetrically arranged on both sides of the crossbeam; The center of the inertia wheel is fixedly connected to the first end of the rotor shaft of the servo motor, and the inertia wheel rotates synchronously with the rotor of the servo motor. The crossbeam is arranged along the diameter direction of the inertia wheel, and both ends of the crossbeam are fixedly connected to the frame of the inertia wheel. The guide rail is perpendicular to the crossbeam and passes through the crossbeam and the counterweight structure. Both ends of the guide rail are fixedly connected to the frame of the inertia wheel. The adjustment mechanism is used to adjust the position of the counterweight structure.

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