Resonance suppression method and resonance suppression device for dual-inertia servo systems

Abstract

This application provides a resonance suppression method and device for a dual-inertia servo system. The method includes: determining whether the motor of the servo control subsystem is experiencing abnormal operating conditions, including at least one of the following: resonance, the rate of change of shaft current exceeding a rate of change threshold; obtaining an initial position deviation, which is the difference between the actual position of the load and the actual position of the motor; in the event of abnormal motor operating conditions, filtering the initial position deviation according to the target parameters of the motor to obtain the position deviation, and sending the position deviation to the input of the position loop, so that the position loop performs closed-loop control of the motor position based on the position setpoint, the actual position of the motor, and the position deviation, thereby preventing abnormal operating conditions from occurring in the controlled motor. This application solves the problem of large oscillations in existing dual-inertia servo systems.

Description

Technical Field

[0001] This application relates to the field of motor control, and more specifically, to a resonance suppression method, suppression device, computer-readable storage medium, processor, and dual-inertia servo control system for a dual-inertia servo system. Background Technology

[0002] Currently, ball screw drives, with their advantages of high rigidity, low wear, high efficiency, rolling friction, and long life, have become a solution for converting the rotary motion of servo motors into linear feed of the worktable. The control of the position servo system largely depends on the tracking performance of the ball screw drive for the desired trajectory. Unlike rotary motion, linear motion can be achieved not only by using the position information of the rotary motor encoder to realize the position closed loop, but also by using the position information of the linear load-side grating system to form the position closed loop. There are multiple error sources in the feed mechanism: (1) the ball screw will generate thermal expansion during machining, which will lead to positioning errors caused by temperature characteristics; (2) the reverse error caused by the nonlinearity of the gap between the ball and the nut; (3) the nonlinear error caused by the ball screw pitch in converting rotary motion into linear motion; (4) the deformation error caused by mechanical action. The fully closed-loop position loop includes all the mechanical links of the feed drive, so the mechanically caused errors can be detected by the linear grating ruler of the worktable and corrected through the position loop, thereby eliminating multiple error sources. Therefore, as the requirements for accuracy become increasingly stringent, grating systems are becoming more and more important in position closed loops.

[0003] In the mechanical transmission part of the feed servo system, its stiffness is finite, exhibiting a certain degree of elasticity. This introduces a pair of conjugate poles into the system, namely a second-order critical oscillatory element. The ever-expanding servo bandwidth overlaps with the load's natural frequency, thus exciting resonance in the system. This can cause vibration ripples on the machined surface and even severe damage to the machinery. Optimizing the mechanical design, introducing vibration dampers, and reinforcing thrust bearings can suppress resonance to some extent. However, when operating conditions change or the servo bandwidth increases, resonance will reappear.

[0004] Therefore, a method is urgently needed to solve the problem of large oscillations in existing servo systems.

[0005] The information disclosed above in the background section is only intended to enhance the understanding of the background art of the art described herein. Therefore, the background art may contain certain information that does not constitute prior art known to those skilled in the art in this country. Summary of the Invention

[0006] The main objective of this application is to provide a resonance suppression method, suppression device, computer-readable storage medium, processor, and dual-inertia servo control system for a dual-inertia servo system, so as to solve the problem of large oscillations in existing dual-inertia servo systems.

[0007] According to one aspect of the present invention, a resonance suppression method for a dual-inertia servo system is provided. The dual-inertia servo system includes a connected servo control subsystem and a load. The servo control subsystem has a current loop, a speed loop, and a position loop. The method includes: a determination step, determining whether the motor of the servo control subsystem is experiencing an abnormal operating condition, the abnormal operating condition including at least one of the following: resonance, the rate of change of shaft current exceeding a rate of change threshold; an acquisition step, acquiring an initial position deviation, the initial position deviation being the difference between the actual position of the load and the actual position of the motor; and a filtering step, in the case of the abnormal operating condition of the motor, filtering the initial position deviation according to the target parameters of the motor to obtain a position deviation, and sending the position deviation to the input of the position loop, so that the position loop performs closed-loop control of the motor position according to the position setpoint, the actual position of the motor, and the position deviation, so that the controlled motor does not experience the abnormal operating condition. Wherein, when the abnormal operating condition includes resonance, the target parameters include the resonant frequency of the motor; when the abnormal operating condition includes the rate of change exceeding the rate of change threshold, the target parameters include the rate of change.

[0008] Optionally, the initial position deviation is filtered according to the target parameters of the motor to obtain the position deviation, including: determining the filtering time constant according to the resonant frequency and / or the rate of change; and filtering the initial position deviation according to the transfer function corresponding to the time constant to obtain the position deviation.

[0009] Optionally, determining the filtering time constant based on the resonant frequency and / or the rate of change includes: determining an initial filtering time constant and a predetermined step size based on the resonant frequency and / or the rate of change; and increasing and / or decreasing the initial time constant by the predetermined step size starting from the initial time constant to obtain the time constant.

[0010] Optionally, the rate of change is negatively correlated with the time constant.

[0011] Optionally, determining whether the motor of the servo control subsystem exhibits resonance includes: acquiring a frequency threshold; performing a Fourier transform on the shaft current to obtain the motor's spectrum; determining whether the motor exhibits resonance based on the frequency threshold and the spectrum; if there is a frequency point in the spectrum that exceeds the frequency threshold, determining that the motor exhibits resonance, and the frequency of the frequency point is the resonance frequency; if there is no frequency point in the spectrum that exceeds the frequency threshold, determining that the motor does not exhibit resonance.

[0012] Optionally, the filtering step includes: an execution step, in the event that the motor is in the abnormal operating condition, filtering the initial position deviation according to the target parameter to obtain the position deviation, and sending the position deviation to the input of the position loop; and a looping step, sequentially executing the determination step, the acquisition step, and the execution step at least once, until the motor does not resonate.

[0013] Optionally, filtering the initial position deviation includes performing a first-order low-pass filter on the initial position deviation.

[0014] Optionally, prior to the determination step, the method further includes: establishing an analysis model of the system; and obtaining the shaft current, the actual position of the load, and the actual position of the motor from the analysis model.

[0015] According to another aspect of the present invention, a resonance suppression device for a dual-inertia servo system is also provided. The dual-inertia servo system includes a connected servo control subsystem and a load. The servo control subsystem has a current loop, a speed loop, and a position loop. The device includes: a determining unit, configured to determine whether the motor of the servo control subsystem is experiencing an abnormal operating condition, the abnormal operating condition including at least one of the following: resonance, the rate of change of shaft current exceeding a rate of change threshold; a first acquiring unit, configured to acquire an initial position deviation, the initial position deviation being the difference between the actual position of the load and the actual position of the motor; and a filtering unit, configured to filter a step. In the event of the abnormal operating condition of the motor, the initial position deviation is filtered according to the target parameters of the motor to obtain the position deviation, and the position deviation is sent to the input of the position loop. This allows the position loop to perform closed-loop control of the motor's position based on the position setpoint, the actual position of the motor, and the position deviation, ensuring that the controlled motor does not experience the abnormal operating condition. Specifically, when the abnormal operating condition includes resonance, the target parameter includes the resonant frequency of the motor; when the abnormal operating condition includes the rate of change exceeding the rate of change threshold, the target parameter includes the rate of change.

[0016] According to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein the program executes any one of the methods described.

[0017] According to another aspect of the present invention, a processor is also provided, the processor being configured to run a program, wherein the program, when running, executes any one of the methods described.

[0018] According to another aspect of the present invention, a dual-inertia servo control system is also provided, comprising: a dual-inertia servo system, a connected servo control subsystem and a load, wherein the servo control subsystem has a current loop, a speed loop and a position loop; and a resonance suppression device of the dual-inertia servo system for performing any of the methods described herein.

[0019] Optionally, the servo control subsystem includes a ball screw.

[0020] Optionally, the dual-inertia servo control system further includes multiple current sensors, multiple position sensors, and multiple speed sensors, wherein the current sensors, the position sensors, and the speed sensors are respectively mounted on the shaft of the motor of the servo control subsystem and on the load.

[0021] In the harmonic suppression method of the dual-inertia servo system described in this application, it is first determined whether the motor of the servo control subsystem is in an abnormal operating condition such as resonance or the rate of change of shaft current exceeding the rate of change threshold. Then, the initial position deviation between the actual position of the load and the actual position of the motor is obtained. If the motor is in an abnormal operating condition, the initial position deviation is filtered according to the target parameters of the motor to obtain the position deviation, and the position deviation is sent to the input of the position loop. The position loop performs closed-loop control of the motor position according to the position setpoint, the actual position of the motor, and the position deviation, so that the motor does not exhibit the abnormal operating condition after control. Compared to existing dual-inertia servo systems, which suffer from issues such as resonance in the mechanical transmission section that can cause vibration ripples on the machined surface or even serious damage to the machinery, this application addresses these problems by filtering the initial position of the motor during abnormal operating conditions to obtain the position deviation. The position loop then performs full closed-loop dual-position feedback control on the abnormal operating motor based on the position setpoint, the actual motor position, and the position deviation. By detecting the resonant frequency and the rate of change of the shaft current, the application reduces speed oscillations and excessive fluctuations during steady-state and transient processes, thereby achieving adaptive filtering to reduce the oscillation of the full closed-loop system. This solves the problem of large oscillations in existing dual-inertia servo systems. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0023] Figure 1 A schematic flowchart of a resonance suppression method for a dual-inertia servo system according to an embodiment of this application is shown.

[0024] Figure 2 A schematic diagram of dual position feedback control of a dual inertia servo system according to an embodiment of this application is shown;

[0025] Figure 3 A Bird diagram of a dual-inertia servo system according to an embodiment of this application is shown at different time constants;

[0026] Figure 4 A schematic flowchart of a resonance suppression method according to a specific embodiment of this application is shown;

[0027] Figure 5 A schematic diagram of a resonance suppression device for a dual-inertia servo system according to an embodiment of this application is shown. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application 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 for the embodiments of this application 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.

[0031] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Furthermore, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.

[0032] As mentioned in the background section, existing dual-inertia servo systems suffer from significant oscillations. To address this issue, a typical embodiment of this application provides a resonance suppression method, suppression device, computer-readable storage medium, processor, and dual-inertia servo control system for a dual-inertia servo system.

[0033] According to an embodiment of this application, a resonance suppression method for a dual-inertia servo system is provided. The dual-inertia servo system includes a connected servo control subsystem and a load. The servo control subsystem has a current loop, a speed loop, and a position loop.

[0034] Figure 1 This is a flowchart of a resonance suppression method for a dual-inertia servo system according to an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0035] Step S101, Determine step, determine whether the motor of the above servo control subsystem has an abnormal operating condition, the above abnormal operating condition includes at least one of the following: resonance, the rate of change of shaft current exceeds the rate of change threshold.

[0036] Step S102, obtaining the initial position deviation, wherein the initial position deviation is the difference between the actual position of the load and the actual position of the motor;

[0037] Step S103, filtering step: When the motor experiences the aforementioned abnormal operating condition, the initial position deviation is filtered according to the target parameters of the motor to obtain the position deviation, and the position deviation is sent to the input of the position loop so that the position loop performs closed-loop control of the motor position based on the position setpoint, the actual position of the motor, and the position deviation, so that the controlled motor does not experience the aforementioned abnormal operating condition. Wherein, when the abnormal operating condition includes resonance, the target parameter includes the resonant frequency of the motor; when the abnormal operating condition includes the rate of change exceeding the rate of change threshold, the target parameter includes the rate of change.

[0038] In the harmonic suppression method of the dual-inertia servo system described above in this application, firstly, it is determined whether the motor of the servo control subsystem is experiencing abnormal operating conditions such as resonance or the rate of change of shaft current exceeding the rate of change threshold. Then, the initial position deviation between the actual position of the load and the actual position of the motor is obtained. If the motor is experiencing abnormal operating conditions, the initial position deviation is filtered according to the target parameters such as the resonant frequency of the motor and the rate of change of shaft current to obtain the position deviation. The position deviation is then sent to the input of the position loop, so that the position loop performs closed-loop control of the motor position based on the position setpoint, the actual position of the motor, and the position deviation, thereby ensuring that the controlled motor does not experience the aforementioned abnormal operating conditions. Compared to the mechanical transmission part of the existing dual-inertia servo system, which can excite resonance in the system, causing vibration ripples on the machined surface and even serious damage to the machinery, this application filters the initial position of the motor under abnormal operating conditions based on the detected resonant frequency and the rate of change of shaft current to obtain the position deviation. The position loop performs feedback control on the abnormal operating condition motor based on the position setpoint, the actual position of the motor, and the position deviation, reducing the speed oscillation and excessive fluctuations of the motor in steady state and transient state (the process of transitioning from one steady state to another, corresponding to the state of the motor). It realizes adaptive filtering to reduce the oscillation of the system, thereby effectively alleviating the problem of large oscillation in the existing dual-inertia servo system and mitigating the equipment damage caused by abnormal motor operating conditions.

[0039] It should be noted that the above-mentioned servo control subsystem has a current loop, a speed loop, and a position loop from the inside out. That is, the above-mentioned servo control subsystem is a three-loop control system. Among them, the position loop is a control link with the position signal as the feedback signal, the speed loop is a control link with the speed signal as the feedback signal, and the current loop is a control link with the current signal as the feedback signal.

[0040] The input to the current loop is the output of the speed loop PID (Proportion Integration Differentiation) adjustment, called the current loop setpoint. The difference between the current loop setpoint and the current loop feedback value is used for PID adjustment within the current loop and output to the motor. The feedback from the Hall elements installed in each phase inside the driver to the current loop is called the current loop feedback. The phase current of each phase of the motor is called the current loop output. The input to the speed loop is the output of the position loop PID adjustment and the feedforward value of the position setting, called the speed setting. The difference between the speed setting and the speed loop feedback value is used for PID adjustment in the speed loop and output as the current loop setpoint. The speed loop feedback comes from the encoder. The input to the position loop is an external pulse. The external pulse is smoothed, filtered, and calculated by the electronic gear to become the position loop setting. The value of the setting and the pulse signal from the encoder feedback, calculated by the deviation counter, is output after PID adjustment in the position loop. The sum of this value and the feedforward value of the position setpoint constitutes the speed loop setpoint. The position loop feedback also comes from the encoder.

[0041] The aforementioned position setpoint is a preset initial value for the position loop, obtained by smoothing and filtering the external pulse and calculating it using electronic gears. The aforementioned shaft current is an AC shaft current.

[0042] Specifically, the inputs to the aforementioned position loop include the position setpoint and the actual position of the motor. Using the method described in this application, while performing closed-loop adjustment based on the actual position of the motor, closed-loop adjustment is also performed based on the difference between the actual position of the load and the actual position of the motor. In other words, this application achieves closed-loop adjustment of the system based on the dual position feedback of the dual-inertia servo system.

[0043] To further alleviate the problem of large oscillations in existing dual-inertia servo systems, according to a specific embodiment of this application, the initial position deviation is filtered based on the target parameters of the motor to obtain the position deviation. This includes: determining the filtering time constant based on the resonant frequency and / or the rate of change; and filtering the initial position deviation based on the transfer function corresponding to the time constant to obtain the position deviation. By detecting the resonant frequency and / or the rate of change, the filtering time constant is determined. By changing the size of the filter time constant, filters with different time constants are obtained to filter the initial position deviation, removing unwanted frequency signals and obtaining position deviation information. This further suppresses system oscillations and fluctuations. Furthermore, this application only requires obtaining the time constant based on the resonant frequency and / or the rate of change to obtain the position deviation, thereby enabling closed-loop control of the motor's position. This ensures that the controlled motor does not exhibit the aforementioned abnormal operating conditions, and the adjustment process is relatively simple and quick.

[0044] According to another specific embodiment of this application, determining the filtering time constant based on the aforementioned resonant frequency and / or the aforementioned rate of change includes: determining an initial filtering time constant and a predetermined step size based on the aforementioned resonant frequency and / or the aforementioned rate of change; starting from the aforementioned initial time constant, increasing and / or decreasing the aforementioned initial time constant by the aforementioned predetermined step size to obtain the aforementioned time constant. Obtaining the filtering time constant through an adaptive method ensures a high degree of freedom in the control algorithm, while further ensuring a relatively simple and rapid suppression of system resonance and fluctuations.

[0045] In another specific embodiment, the aforementioned rate of change is negatively correlated with the aforementioned time constant. That is, the larger the aforementioned rate of change, the smaller the corresponding time constant; the smaller the aforementioned rate of change, the larger the corresponding time constant. When the aforementioned rate of change is large, a smaller initial time constant and a smaller predetermined step size can be given; when the aforementioned rate of change is small, a larger initial time constant and a larger predetermined step size can be given.

[0046] To further ensure a simpler and more accurate monitoring of whether the motor of the aforementioned servo subsystem is experiencing abnormal operating conditions, and to facilitate timely response and handling in the event of abnormal operating conditions, according to another specific embodiment of this application, determining whether the motor of the aforementioned servo control subsystem is experiencing the aforementioned resonance includes: obtaining a frequency threshold; performing a Fourier transform on the aforementioned shaft current to obtain the spectrum of the aforementioned motor; and determining whether the aforementioned motor is experiencing the aforementioned resonance based on the aforementioned frequency threshold and the aforementioned spectrum. If there is a frequency point in the aforementioned frequency that exceeds the aforementioned frequency threshold, it is determined that the aforementioned motor is experiencing the aforementioned resonance, and the frequency of the aforementioned frequency point is the aforementioned resonance frequency. If there is no frequency point in the aforementioned spectrum that exceeds the aforementioned frequency threshold, it is determined that the aforementioned motor is not experiencing the aforementioned resonance. By determining whether resonance occurs and obtaining the resonance frequency through the shaft current spectrum, it is further ensured that it is possible to determine whether the motor is experiencing abnormal operating conditions in a simpler and more accurate manner.

[0047] Specifically, when the above-mentioned motor exhibits the above-mentioned resonance, in addition to obtaining the above-mentioned resonant frequency, the amplitude corresponding to the above-mentioned frequency point can also be obtained as the resonant amplitude.

[0048] According to a specific embodiment of this application, the filtering step includes: an execution step, in the event of the abnormal operating condition of the motor, filtering the initial position deviation according to the target parameters to obtain the position deviation, and sending the position deviation to the input of the position loop; and a looping step, sequentially executing the determination step, the acquisition step, and the execution step at least once until the motor no longer resonates. By determining the filtering time constant using the obtained resonant frequency and / or rate of change, obtaining the corresponding transfer function, filtering the initial position deviation to obtain the position deviation, and then sending the position deviation to the input of the position loop, the determination step, the acquisition step, and the execution step are looped, further realizing adaptive adjustment of the dual-inertia servo system and further suppressing the impact of abnormal operating conditions on the operation of the dual-inertia servo system.

[0049] To block harmonic emissions that may interfere with the initial position deviation signal, and to ensure a short adjustment period for abnormal operating conditions, according to another specific embodiment of this application, the initial position deviation is filtered, including: performing a first-order low-pass filter on the initial position deviation. The first-order filter can complete the filtering process within the control cycle, suppressing the gain near the resonant frequency, and calculating the time constant based on the resonance characteristic identification result, thereby achieving the effect of suppressing vibration.

[0050] According to another specific embodiment of this application, prior to the above determination step, the method further includes: establishing an analysis model of the system; and obtaining the shaft current, the actual position of the load, and the actual position of the motor from the analysis model.

[0051] In practical applications, the above system can be modeled using MATLAB (Matrix Laboratory) to obtain the above analysis model.

[0052] In one specific embodiment, the elastic connection device of the dual-inertia servo system that needs to suppress vibration is modeled, resulting in the dual-inertia servo system model as follows: Figure 2 As shown.

[0053] Figure 2 The meanings of the variables in the code are explained below:

[0054] θ ref A value is given for the position; θ m θ represents the actual position of the motor. l The actual position of the load; Δθ is the position deviation; ω c A given value for velocity; ω m ω is the actual speed of the motor. l T represents the actual speed of the load.s T is the transmission elastic torque; e T represents the electromagnetic torque of the motor. l K represents the load torque. p For position loop proportional gain; K sp For the velocity loop proportional gain; K si K is the velocity loop integral constant; t K is the torque constant. s 1 / s is the stiffness coefficient; 1 / s is the continuous integral; I q J represents the AC shaft current; 1 / (τs+1) is the transfer function of the first-order low-pass filter, and τ is the time constant; m J1 is the moment of inertia at the motor end, and J2 is the moment of inertia at the load end.

[0055] The aforementioned dual-inertia servo system is equipped with a position sensor at the motor shaft end and a position sensor at the load end, as well as a current sensor and a speed sensor.

[0056] The main difference between the dual-position feedback control strategy in this application and the traditional full closed-loop control lies in the introduction of motor encoder position information into the position closed-loop feedback. Using encoder signals for closed-loop control results in better dynamic response performance because the numerator of the transfer function contains a quadratic term. Including the encoder signal in the position closed loop accelerates the response speed, similar to semi-closed-loop control, and also achieves a higher position gain margin. Simultaneously, the difference between the end-effector grating position signal and the encoder position signal, after passing through a first-order low-pass filter, is compensated into the feedback, further improving control accuracy and achieving a balance between high gain margin and high accuracy. The filtering time constant of the first-order low-pass filter is obtained through adaptive detection, increasing the degree of freedom of the control algorithm. The feedback quantity participating in the position closed loop is denoted as e, and its specific expression is shown in equation (1-1), where τ is the first-order low-pass filter time constant, and Δθ is the position difference between the encoder position and the grating position. When the low-pass filter time constant τ approaches 0, the actual position feedback quantity is the load position, which is equivalent to full closed-loop control; when the low-pass filter time constant τ approaches infinity, the actual position feedback quantity is the motor position, which is equivalent to semi-closed-loop control.

[0057]

[0058] The closed-loop transfer function of the system is derived as shown in equation (1-2). To simplify the expression, the first-order low-pass circuit is replaced by Q, where Q = 1 / (1+τs).

[0059]

[0060] In the formula, a 17 =J1J2,

[0061] a 16=J2 k s k sp ,

[0062] a 15 =J2 k t k si +J2 k t k sp k pos (1-Q)+(J1+J2)k s ,

[0063] a 14 =k s k sp k t +J2 k t k sp k pos (1-Q),

[0064] a 13 =k s k t k si +k s k t k sp k pos ,

[0065] a 12 =k s k t k si k pos ,

[0066] b5=k s k t k sp k pos ,

[0067] b4=k s k t k si k pos ,

[0068] c 10 J1,

[0069] c9=k t k sp ,

[0070] c8⼝k t k si +k t k sp k pos (1-Q)+k s ,

[0071] c7⼝ks k t k si k pos .

[0072] By calculating the steady-state final value error under a unit step disturbance using the final value theorem, as shown in equation (1-3), it can be found that the control accuracy of the dual-position feedback control is not affected by it.

[0073]

[0074] As shown in equation (1-3), when the time constant τ is infinite, the steady-state final value error e dual equal When the time constant τ is 0, the steady-state final value error e dual It equals 0.

[0075] Let the position loop gain be k pos The open-loop transfer function of the dual-position feedback control strategy is derived as shown in (1-4), and the first-order low-pass filter is still replaced by Q.

[0076]

[0077] like Figure 2 As shown, the given value θ at the above position ref Through the position loop proportional gain K p The speed and the given speed constitute the speed loop proportional gain K. sp Combined with the speed setting of the output after PID adjustment of the position loop, a portion of it forms the torque constant K with the AC shaft current. t The moment of inertia J at the motor end is obtained from the electromagnetic torque of the motor. m Then, the motor position feedback θ is obtained based on the motor speed feedback. m The other part is through I q The spectrum is obtained by performing an FFT (Fast Fourier Transform), and the position feedback θ of the motor is used to determine the frequency. m and load position feedback θ l The position feedback difference Δθ is fed back to the position setpoint θ. ref This forms a closed loop. Figure 2 In the position loop, the input is the position setpoint θ ref The actual position θ of the motor m And the position deviation Δθ, through the input value and the position loop proportional gain K p According to (θ) ref -θ m -Δθ)×K p Obtain the velocity setpoint ω c Execute sequentially Figure 2The calculation process continues until the motor position adjustment amount is output, which is then used to adjust the actual position of the motor. The feedback value of the adjusted actual position of the motor is then obtained, and the aforementioned cyclic adjustment is repeated. The principles of the speed loop and current loop are the same as those of the position loop, and will not be elaborated upon here.

[0078] To investigate the effect of the time constant on the system, the Bode (logarithmic frequency response curve) was observed by pre-designing the filter time constant. The filter time constant was set to τ = 0.01s, 0.1s, and 1s, respectively. The system Bode plots for the three filter times are shown below. Figure 3 As shown.

[0079] As can be clearly seen from the Bode plot, changing the filter time constant alters the amplitude-frequency gain of the system near the anti-resonant frequency. A larger filter time constant achieves higher control stiffness, but correspondingly weakens the end-position adjustment capability. When the time constant approaches infinity, it's equivalent to the end no longer participating in the position loop adjustment. Therefore, in engineering applications, the filter time constant needs to be manually adjusted according to the actual system. Initially, the filter time constant should be increased as much as possible to ensure the system no longer oscillates, and then gradually decreased to obtain better response performance.

[0080] Theoretically, we can conclude that a larger time constant results in smaller oscillations, while a smaller time constant leads to larger oscillations. To achieve better dynamic performance while suppressing oscillations, the time constant should be minimized as much as possible. Therefore, according to FFT analysis, the higher the harmonic content, the greater the oscillations, and the more the time constant needs to be increased until the oscillations are suppressed—this is the filter's adaptive rule.

[0081] When the system is in a transient state, an AC shaft current I is detected. q The change in τ causes the time constant to reach its maximum value, making its position feedback the motor end position feedback, achieving the dynamic performance of semi-closed-loop control, reducing speed fluctuations, and enabling it to quickly reach another stable state. When the steady state is reached, it switches back to the steady-state time constant value of the principle.

[0082] This application achieves adaptive filtering to reduce the oscillation of the fully closed-loop system by detecting changes in the amplitude and resonant frequency of the current. Compared with the semi-closed-loop system, which has low positioning accuracy, and the fully closed-loop system, which has inherent oscillation, this application can achieve the advantages of both feedback systems: high accuracy and low oscillation, while reducing speed fluctuations. The required filter parameters are adaptively determined by current detection, requiring no manual adjustment or additional current sensors. The design is simple, the detection is fast, and the application is highly practical.

[0083] In one specific embodiment, according to the above-described method for suppressing resonance in a dual-inertia servo system, such as... Figure 4As shown, the specific process is as follows: First, the motor is started, and the motor current data ia, ib, and ic in the servo control subsystem are detected in real time. Then, through Clark and Park coordinate transformation, the multiple current data ia, ib, and ic are projected onto the d and q axes of the equivalent two coordinate systems to obtain the AC axis current I. q Then cache the equivalent data, and through I q FFT is performed to obtain its spectrum. Based on the AC shaft current spectrum, it is determined whether resonance occurs and the frequency and amplitude of the resonance are obtained. If the motor oscillation increases and a sudden change in current is detected, the time constant of the filter is increased to ensure that the system no longer oscillates. Then, the time constant is gradually reduced until the oscillation is suppressed, ensuring the normal operation of the motor.

[0084] The dual-inertia servo system described in this application is not limited to a dual-inertia servo system; it can also be a triple-inertia or multi-inertia servo system. Furthermore, the rate of change described in this application is not limited to the change amount / change time; the change amount within the same time period can also be used as the rate of change data, i.e., the change rate is obtained by detecting the difference in current before and after the change. This application uses a rotary feed dual-inertia servo system as an example, but it is also applicable to dual-inertia servo systems for robots that also possess resonance and end-effector positioning chattering.

[0085] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0086] This application also provides a resonance suppression device for a dual-inertia servo system. It should be noted that the resonance suppression device for a dual-inertia servo system provided in this application can be used to execute the resonance suppression method for a dual-inertia servo system provided in this application. The resonance suppression device for a dual-inertia servo system provided in this application is described below.

[0087] Figure 5 This is a schematic diagram of a resonance suppression device for a dual-inertia servo system according to an embodiment of this application. Figure 4As shown, the device includes a determining unit 10, a first acquiring unit 20, and a filtering unit 30. The determining unit 10 is used in a determining step to determine whether the motor of the servo control subsystem is experiencing an abnormal operating condition. The abnormal operating condition includes at least one of the following: resonance, or the rate of change of shaft current exceeding a rate of change threshold. The first acquiring unit 20 is used in an acquiring step to acquire an initial position deviation, which is the difference between the actual position of the load and the actual position of the motor. The filtering unit 30 is used in a filtering step to filter the initial position deviation according to the target parameters of the motor when the abnormal operating condition occurs, obtaining a position deviation, and sending the position deviation to the input of the position loop. This allows the position loop to perform closed-loop control of the motor's position based on the position setpoint, the actual position of the motor, and the position deviation, ensuring that the controlled motor does not experience the abnormal operating condition. Specifically, when the abnormal operating condition includes resonance, the target parameter includes the resonant frequency of the motor; when the abnormal operating condition includes the rate of change exceeding the rate of change threshold, the target parameter includes the rate of change.

[0088] This application employs a resonance suppression device for a dual-inertia servo system. The aforementioned determining unit determines whether the motor of the aforementioned servo control subsystem is experiencing abnormal operating conditions such as resonance or the rate of change of shaft current exceeding a threshold. The aforementioned first acquiring unit acquires the initial position deviation between the actual position of the load and the actual position of the motor. If the motor is experiencing abnormal operating conditions, the initial position deviation is filtered based on target parameters such as the motor's resonant frequency and the rate of change of shaft current to obtain the position deviation. The position deviation is then sent to the input of the position loop, enabling the position loop to perform closed-loop control of the motor's position based on the position setpoint, the actual position of the motor, and the position deviation, thereby preventing the aforementioned abnormal operating conditions from occurring in the controlled motor. Compared to the mechanical transmission part of the existing dual-inertia servo system, which can excite resonance in the system, causing vibration ripples on the machined surface and even serious damage to the machinery, this application filters the initial position of the motor under abnormal operating conditions based on the detected resonant frequency and the rate of change of shaft current to obtain the position deviation. The position loop performs feedback control on the abnormal operating condition motor based on the position setpoint, the actual position of the motor, and the position deviation, reducing the speed oscillation and excessive fluctuations of the motor in steady state and transient state (the process of transitioning from one steady state to another, corresponding to the state of the motor). It realizes adaptive filtering to reduce the oscillation of the system, thereby effectively alleviating the problem of large oscillation in the existing dual-inertia servo system and mitigating the equipment damage caused by abnormal motor operating conditions.

[0089] It should be noted that the above-mentioned servo control subsystem has a current loop, a speed loop, and a position loop from the inside out. That is, the above-mentioned servo control subsystem is a three-loop control system. Among them, the position loop is a control link with the position signal as the feedback signal, the speed loop is a control link with the speed signal as the feedback signal, and the current loop is a control link with the current signal as the feedback signal.

[0090] The input to the current loop is the output of the speed loop PID control, called the current loop setpoint. The difference between the current loop setpoint and the current loop feedback value is used for PID control within the current loop and output to the motor. The feedback from the Hall elements installed in each phase inside the driver to the current loop is called the current loop feedback. The phase current of each phase of the motor is called the current loop output. The input to the speed loop is the output of the position loop PID control and the feedforward value of the position setting, called the speed setting. The difference between the speed setting and the speed loop feedback value is used for PID control in the speed loop and output as the current loop setpoint. The speed loop feedback comes from the encoder. The input to the position loop is an external pulse. The external pulse is smoothed, filtered, and calculated by the electronic gears to become the position loop setting. The value of the setting and the pulse signal from the encoder feedback, calculated by the deviation counter, is then output by the position loop PID control and summed with the feedforward value of the position setpoint to form the speed loop setpoint. The position loop feedback also comes from the encoder.

[0091] The aforementioned position setpoint is a preset initial value for the position loop, obtained by smoothing and filtering the external pulse and calculating it using electronic gears. The aforementioned shaft current is an AC shaft current.

[0092] Specifically, the inputs to the aforementioned position loop include a position setpoint and the actual position of the motor. Using the device described in this application, while performing closed-loop adjustment based on the actual position of the motor, closed-loop adjustment is also performed based on the difference between the actual position of the load and the actual position of the motor. In other words, this application achieves closed-loop adjustment of the system based on the dual position feedback of the dual-inertia servo system.

[0093] To further alleviate the problem of large oscillations in existing dual-inertia servo systems, according to a specific embodiment of this application, the filtering unit includes a first determining module and a filtering module. The first determining module determines the filtering time constant based on the resonant frequency and / or the rate of change. The filtering module filters the initial position deviation based on the transfer function corresponding to the time constant to obtain the position deviation. By detecting the resonant frequency and / or the rate of change to determine the filtering time constant, and by changing the size of the filter time constant to obtain filters with different time constants, the initial position deviation is filtered to remove unwanted frequency signals and obtain position deviation information. This further suppresses system oscillations and fluctuations. Furthermore, this application only needs to obtain the time constant based on the resonant frequency and / or the rate of change to obtain the position deviation, thereby enabling closed-loop control of the motor's position. This ensures that the controlled motor does not exhibit the aforementioned abnormal operating conditions, and the adjustment process is relatively simple and quick.

[0094] According to another specific embodiment of this application, the first determining module includes a determining submodule and a predetermined submodule. The determining submodule is used to determine the initial time constant and predetermined step size of the filter based on the resonant frequency and / or the rate of change. The predetermined submodule is used to increase and / or decrease the initial time constant by the predetermined step size, starting from the initial time constant, to obtain the final time constant. Obtaining the filter time constant adaptively ensures a high degree of freedom in the control algorithm, while further ensuring a relatively simple and fast suppression of system resonance and fluctuations.

[0095] In another specific embodiment, the aforementioned rate of change is negatively correlated with the aforementioned time constant. That is, the larger the aforementioned rate of change, the smaller the corresponding time constant; the smaller the aforementioned rate of change, the larger the corresponding time constant. When the aforementioned rate of change is large, a smaller initial time constant and a smaller predetermined step size can be given; when the aforementioned rate of change is small, a larger initial time constant and a larger predetermined step size can be given.

[0096] To further ensure a simpler and more accurate monitoring of whether the motor of the aforementioned servo subsystem is experiencing abnormal operating conditions, and to facilitate timely response and handling in the event of abnormal operating conditions, according to another specific embodiment of this application, the determining unit includes an acquisition module, a transformation module, and a second determining module. The acquisition module is used to acquire a frequency threshold; the transformation module is used to perform a Fourier transform on the shaft current to obtain the motor's spectrum; the second determining module is used to determine whether the motor is experiencing resonance based on the frequency threshold and the spectrum. If a frequency point exceeding the frequency threshold exists in the spectrum, it is determined that the motor is experiencing resonance, and the frequency of that frequency point is the resonant frequency. If no frequency point exceeding the frequency threshold exists in the spectrum, it is determined that the motor is not experiencing resonance. By determining whether resonance occurs and obtaining the resonant frequency through the shaft current spectrum, it is further ensured that the abnormal operating condition of the motor can be determined more simply and accurately.

[0097] Specifically, when the above-mentioned motor exhibits the above-mentioned resonance, in addition to obtaining the above-mentioned resonant frequency, the amplitude corresponding to the above-mentioned frequency point can also be obtained as the resonant amplitude.

[0098] According to a specific embodiment of this application, the filtering unit includes an execution module and a loop module. The execution module is used to filter the initial position deviation according to the target parameters when the motor experiences the abnormal operating condition, obtain the position deviation, and send the position deviation to the input of the position loop. The loop module is used to sequentially execute the determination step, the acquisition step, and the execution step at least once until the motor no longer resonates. By determining the filtering time constant using the obtained resonant frequency and / or rate of change, the corresponding transfer function is obtained. The initial position deviation is then filtered to obtain the position deviation, which is then sent to the input of the position loop. This iterative process of determining, acquiring, and executing the steps further achieves adaptive adjustment of the dual-inertia servo system and further suppresses the impact of abnormal operating conditions on the operation of the dual-inertia servo system.

[0099] To block harmonic emissions that may interfere with the initial position deviation signal, and to ensure a short adjustment period for abnormal operating conditions, according to another specific embodiment of this application, the filtering unit includes a processing module. This processing module performs a first-order low-pass filter on the initial position deviation. The first-order filter completes the filtering process within the control cycle, suppressing the gain near the resonant frequency and calculating the time constant based on the resonance characteristic identification result, thereby achieving vibration suppression.

[0100] According to another specific embodiment of this application, before the above-described determining step, the device further includes a building unit and a second acquisition unit, wherein the building unit is used to build an analysis model of the system; and the second acquisition unit is used to acquire the shaft current, the actual position of the load, and the actual position of the motor from the analysis model.

[0101] In practical applications, the above system can be modeled using MATLAB to obtain the above analysis model.

[0102] In one specific embodiment, the elastic connection device of the dual-inertia servo system that needs to suppress vibration is modeled, resulting in the dual-inertia servo system model as follows: Figure 2 As shown.

[0103] The aforementioned dual-inertia servo system is equipped with a position sensor at the motor shaft end and a position sensor at the load end, as well as a current sensor and a speed sensor.

[0104] The main difference between the dual-position feedback control strategy in this application and the traditional full closed-loop control lies in the introduction of motor encoder position information into the position closed-loop feedback. Using encoder signals for closed-loop control results in better dynamic response performance because the numerator of the transfer function contains a quadratic term. Including the encoder signal in the position closed loop accelerates the response speed, similar to semi-closed-loop control, and also achieves a higher position gain margin. Simultaneously, the difference between the end-effector grating position signal and the encoder position signal, after passing through a first-order low-pass filter, is compensated into the feedback, further improving control accuracy and achieving a balance between high gain margin and high accuracy. The filtering time constant of the first-order low-pass filter is obtained through adaptive detection, increasing the degree of freedom of the control algorithm. The feedback quantity participating in the position closed loop is denoted as e, and its specific expression is shown in equation (1-1), where τ is the first-order low-pass filter time constant, and Δθ is the position difference between the encoder position and the grating position. When the low-pass filter time constant τ approaches 0, the actual position feedback quantity is the load position, which is equivalent to full closed-loop control; when the low-pass filter time constant τ approaches infinity, the actual position feedback quantity is the motor position, which is equivalent to semi-closed-loop control.

[0105] The closed-loop transfer function of the system is derived as shown in equation (1-2). To simplify the expression, the first-order low-pass circuit is replaced by Q, where Q = 1 / (1+τs).

[0106] By calculating the steady-state final value error under a unit step disturbance using the final value theorem, as shown in equation (1-3), it can be found that the control accuracy of the dual-position feedback control is not affected by it.

[0107] As shown in equation (1-3), when the time constant τ is infinite, the steady-state final value error e dual equal When the time constant τ is 0, the steady-state final value error e dual It equals 0.

[0108] Let the position loop gain be k pos The open-loop transfer function of the dual-position feedback control strategy is derived as shown in (1-4), and the first-order low-pass filter is still replaced by Q.

[0109] like Figure 2 As shown, the given value θ at the above position ref Through the position loop proportional gain K p The speed and the given speed constitute the speed loop proportional gain K. sp Combined with the speed setting of the output after PID adjustment of the position loop, a portion of it forms the torque constant K with the AC shaft current. t The moment of inertia J at the motor end is obtained from the electromagnetic torque of the motor. m Then, the motor position feedback θ is obtained based on the motor speed feedback. m The other part is through I q Perform an FFT to obtain its spectrum, and then use the motor position feedback θ m and load position feedback θ l The position feedback difference Δθ is fed back to the position setpoint θ. ref This forms a closed loop. Figure 2 In the position loop, the input is the position setpoint θ ref The actual position θ of the motor m And the position deviation Δθ, through the input value and the position loop proportional gain K p According to (θ) ref -θ m -Δθ)×K p Obtain the velocity setpoint ω c Execute sequentially Figure 2 The calculation process continues until the motor position adjustment amount is output, which is then used to adjust the actual position of the motor. The feedback value of the adjusted actual position of the motor is then obtained, and the aforementioned cyclic adjustment is repeated. The principles of the speed loop and current loop are the same as those of the position loop, and will not be elaborated upon here.

[0110] To investigate the effect of the time constant on the system, the Bode plot was observed by pre-designing the filter time constant. The filter time constant was set to τ = 0.01s, 0.1s, and 1s, respectively. The Bode plots of the system under the three filter time constants are shown below. Figure 3 As shown.

[0111] As can be clearly seen from the Bode plot, changing the filter time constant alters the amplitude-frequency gain of the system near the anti-resonant frequency. A larger filter time constant achieves higher control stiffness, but correspondingly weakens the end-position adjustment capability. When the time constant approaches infinity, it's equivalent to the end no longer participating in the position loop adjustment. Therefore, in engineering applications, the filter time constant needs to be manually adjusted according to the actual system. Initially, the filter time constant should be increased as much as possible to ensure the system no longer oscillates, and then gradually decreased to obtain better response performance.

[0112] Theoretically, we can conclude that a larger time constant results in smaller oscillations, while a smaller time constant leads to larger oscillations. To achieve better dynamic performance while suppressing oscillations, the time constant should be minimized as much as possible. Therefore, according to FFT analysis, the higher the harmonic content, the greater the oscillations, and the more the time constant needs to be increased until the oscillations are suppressed—this is the filter's adaptive rule.

[0113] When the system is in a transient state, an AC shaft current I is detected. q The change in τ causes the time constant to reach its maximum value, making its position feedback the motor end position feedback, achieving the dynamic performance of semi-closed-loop control, reducing speed fluctuations, and enabling it to quickly reach another stable state. When the steady state is reached, it switches back to the steady-state time constant value of the principle.

[0114] This application achieves adaptive filtering to reduce the oscillation of the fully closed-loop system by detecting changes in the amplitude and resonant frequency of the current. Compared with the semi-closed-loop system, which has low positioning accuracy, and the fully closed-loop system, which has inherent oscillation, this application can achieve the advantages of both feedback systems: high accuracy and low oscillation, while reducing speed fluctuations. The required filter parameters are adaptively determined by current detection, requiring no manual adjustment or additional current sensors. The design is simple, the detection is fast, and the application is highly practical.

[0115] In one specific embodiment, according to the above-mentioned dual-inertia servo system resonance suppression device, such as... Figure 4 As shown, the specific process is as follows: First, the motor is started, and the motor current data ia, ib, and ic in the servo control subsystem are detected in real time. Then, through Clark and Park coordinate transformation, the multiple current data ia, ib, and ic are projected onto the d and q axes of the equivalent two coordinate systems to obtain the AC axis current I. q Then cache the equivalent data, and through I q FFT is performed to obtain its spectrum. Based on the AC shaft current spectrum, it is determined whether resonance occurs and the frequency and amplitude of the resonance are obtained. If the motor oscillation increases and a sudden change in current is detected, the time constant of the filter is increased to ensure that the system no longer oscillates. Then, the time constant is gradually reduced until the oscillation is suppressed, ensuring the normal operation of the motor.

[0116] The dual-inertia servo system described in this application is not limited to a dual-inertia servo system; it can also be a triple-inertia or multi-inertia servo system. Furthermore, the rate of change described in this application is not limited to the change amount / change time; the change amount within the same time period can also be used as the rate of change data, i.e., the change rate is obtained by detecting the difference in current before and after the change. This application uses a rotary feed dual-inertia servo system as an example, but it is also applicable to dual-inertia servo systems for robots that also possess resonance and end-effector positioning chattering.

[0117] The resonance suppression device of the aforementioned dual-inertia servo system includes a processor and a memory. The aforementioned determining unit, the aforementioned first acquisition unit, and the aforementioned filtering unit are all stored in the memory as program units, and the processor executes the aforementioned program units stored in the memory to realize the corresponding functions.

[0118] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured, and adjusting kernel parameters can address the problem of excessive oscillation in existing dual-inertia servo systems.

[0119] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0120] This invention provides a computer-readable storage medium storing a program that, when executed by a processor, implements the resonance suppression method for the dual-inertia servo system described above.

[0121] This invention provides a processor for running a program, wherein the program executes the resonance suppression method of the dual-inertia servo system.

[0122] This invention provides a device including a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs at least the following steps:

[0123] Step S101, Determine step, determine whether the motor of the above servo control subsystem has an abnormal operating condition, the above abnormal operating condition includes at least one of the following: resonance, the rate of change of shaft current exceeds the rate of change threshold.

[0124] Step S102, obtaining the initial position deviation, wherein the initial position deviation is the difference between the actual position of the load and the actual position of the motor;

[0125] Step S103, filtering step: When the motor experiences the aforementioned abnormal operating condition, the initial position deviation is filtered according to the target parameters of the motor to obtain the position deviation, and the position deviation is sent to the input of the position loop so that the position loop performs closed-loop control of the motor position based on the position setpoint, the actual position of the motor, and the position deviation, so that the controlled motor does not experience the aforementioned abnormal operating condition. Wherein, when the abnormal operating condition includes resonance, the target parameter includes the resonant frequency of the motor; when the abnormal operating condition includes the rate of change exceeding the rate of change threshold, the target parameter includes the rate of change.

[0126] The devices mentioned in this article can be servers, PCs, tablets, mobile phones, etc.

[0127] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having at least the following method steps:

[0128] Step S101, Determine step, determine whether the motor of the above servo control subsystem has an abnormal operating condition, the above abnormal operating condition includes at least one of the following: resonance, the rate of change of shaft current exceeds the rate of change threshold.

[0129] Step S102, obtaining the initial position deviation, wherein the initial position deviation is the difference between the actual position of the load and the actual position of the motor;

[0130] Step S103, filtering step: When the motor experiences the aforementioned abnormal operating condition, the initial position deviation is filtered according to the target parameters of the motor to obtain the position deviation, and the position deviation is sent to the input of the position loop so that the position loop performs closed-loop control of the motor position based on the position setpoint, the actual position of the motor, and the position deviation, so that the controlled motor does not experience the aforementioned abnormal operating condition. Wherein, when the abnormal operating condition includes resonance, the target parameter includes the resonant frequency of the motor; when the abnormal operating condition includes the rate of change exceeding the rate of change threshold, the target parameter includes the rate of change.

[0131] According to another typical embodiment of this application, a dual-inertia servo control system is also provided, including a dual-inertia servo system and a resonance suppression device for the dual-inertia servo system, wherein the dual-inertia servo system is connected to a servo control subsystem and a load, and the servo control subsystem has a current loop, a speed loop and a position loop; the resonance suppression device is used to perform any of the above-described methods.

[0132] The aforementioned dual-inertia servo control system includes a dual-inertia servo system and its resonance suppression device. The resonance suppression device is used to execute any of the resonance suppression methods described above for the dual-inertia servo system. Compared to the mechanical transmission part of the feed dual-inertia servo system in the prior art, which can excite resonance in the system, causing vibration ripples on the machined surface and even serious damage to the machinery, the dual-inertia servo control system of this application filters the initial position of the motor under abnormal operating conditions through the aforementioned resonance suppression device to obtain the position deviation. The position loop performs full closed-loop dual position feedback control on the motor under abnormal operating conditions based on the position setpoint, the actual position of the motor, and the position deviation. By detecting the resonant frequency and the rate of change of the shaft current, it reduces speed oscillations and excessive fluctuations in steady-state and transient processes, thereby achieving adaptive filtering to reduce the oscillation of the full closed-loop system and solving the problem of large oscillations in the dual-inertia servo system in the prior art.

[0133] In one specific embodiment, the servo control subsystem includes a ball screw. The dual-inertia servo control system further includes multiple current sensors, multiple position sensors, and multiple speed sensors, which are respectively mounted on the shaft of the motor and the load of the servo control subsystem.

[0134] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0135] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units described above can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0136] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0137] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0138] If the aforementioned integrated units are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0139] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0140] 1) In the harmonic suppression method of the dual-inertia servo system described above in this application, it is first determined whether the motor of the servo control subsystem is in an abnormal working condition such as resonance or the rate of change of shaft current exceeding the rate of change threshold. Then, the initial position deviation between the actual position of the load and the actual position of the motor is obtained. If the motor is in an abnormal working condition, the initial position deviation is filtered according to the target parameters of the motor to obtain the position deviation. The position deviation is then sent to the input of the position loop, so that the position loop performs closed-loop control of the motor position according to the position setpoint, the actual position of the motor and the position deviation, so that the motor after control does not experience the above-mentioned abnormal working condition. Compared to existing dual-inertia servo systems, which suffer from issues such as resonance in the mechanical transmission section that can cause vibration ripples on the machined surface or even serious damage to the machinery, this application addresses these problems by filtering the initial position of the motor during abnormal operating conditions to obtain the position deviation. The position loop then performs full closed-loop dual-position feedback control on the abnormal operating motor based on the position setpoint, the actual motor position, and the position deviation. By detecting the resonant frequency and the rate of change of the shaft current, the application reduces speed oscillations and excessive fluctuations during steady-state and transient processes, thereby achieving adaptive filtering to reduce the oscillation of the full closed-loop system. This solves the problem of large oscillations in existing dual-inertia servo systems.

[0141] 2) In the resonance suppression device of the dual inertia servo system described above, the determination unit determines whether the motor of the servo control subsystem is in an abnormal operating condition. The abnormal operating condition includes at least one of the following: resonance, the rate of change of shaft current exceeding the rate of change threshold. The first acquisition unit obtains the initial position deviation, which is the difference between the actual position of the load and the actual position of the motor. When the motor is in an abnormal operating condition, the filtering unit filters the initial position deviation according to the target parameters of the motor to obtain the position deviation, and sends the position deviation to the input of the position loop. The position loop performs closed-loop control of the motor position according to the position setpoint, the actual position of the motor, and the position deviation, so that the motor does not experience the abnormal operating condition after control. Compared to existing dual-inertia servo systems, which suffer from issues such as resonance in the mechanical transmission section that can cause vibration ripples on the machined surface or even serious damage to the machinery, this application addresses these problems by filtering the initial position of the motor during abnormal operating conditions to obtain the position deviation. The position loop then performs full closed-loop dual-position feedback control on the abnormal operating motor based on the position setpoint, the actual motor position, and the position deviation. By detecting the resonant frequency and the rate of change of the shaft current, the application reduces speed oscillations and excessive fluctuations during steady-state and transient processes, thereby achieving adaptive filtering to reduce the oscillation of the full closed-loop system. This solves the problem of large oscillations in existing dual-inertia servo systems.

[0142] 3) The dual-inertia servo control system described in this application includes a dual-inertia servo system and its resonance suppression device. The resonance suppression device is used to execute any of the resonance suppression methods described above for the dual-inertia servo system. Compared with the mechanical transmission part of the feed dual-inertia servo system in the prior art, which can excite resonance in the system, causing vibration ripples on the machined surface and even serious damage to the machinery, the dual-inertia servo control system of this application filters the initial position of the motor under abnormal working conditions through the resonance suppression device to obtain the position deviation. The position loop performs full closed-loop dual position feedback control on the motor under abnormal working conditions based on the position setpoint, the actual position of the motor, and the position deviation. By detecting the resonant frequency and the rate of change of the shaft current, it reduces speed oscillations and excessive fluctuations in steady-state and transient processes, thereby achieving adaptive filtering to reduce the oscillation of the full closed-loop system and solving the problem of large oscillations in the dual-inertia servo system in the prior art.

[0143] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method of resonance suppression for a dual-inertia servo system, the dual-inertia servo system including a connected servo control subsystem and a load, the servo control subsystem having a current loop, a velocity loop, and a position loop, the method comprising: The method comprises: a determining step of determining whether an abnormal condition occurs in a motor of the servo control subsystem, the abnormal condition comprising at least one of the following: resonance, rate of change of shaft current exceeding a rate threshold; an obtaining step of obtaining an initial position deviation, the initial position deviation being a difference between an actual position of the load and an actual position of the motor; a filtering step of filtering the initial position deviation according to a target parameter of the motor to obtain a position deviation, and sending the position deviation to an input end of the position loop, so that the position loop controls the position of the motor according to a position given value, the actual position of the motor and the position deviation, so that the motor after control does not occur the abnormal condition, wherein, in the case that the abnormal condition comprises the resonance, the target parameter comprises a resonance frequency of the motor; in the case that the abnormal condition comprises the rate exceeding the rate threshold, the target parameter comprises the rate; filtering the initial position deviation according to the target parameter of the motor to obtain a position deviation comprises: determining a time constant of filtering according to the resonance frequency and / or the rate; filtering the initial position deviation according to a transfer function corresponding to the time constant to obtain the position deviation.

2. The method of claim 1, wherein, determining a time constant of filtering according to the resonance frequency and / or the rate comprises: determining an initial time constant of filtering and a predetermined step size according to the resonance frequency and / or the rate; increasing and / or decreasing the initial time constant by the predetermined step size from the initial time constant to obtain the time constant.

3. The method of claim 2, wherein, The rate is negatively correlated with the time constant.

4. The method of claim 1, wherein, determining whether the resonance occurs in the motor of the servo control subsystem comprises: obtaining a frequency threshold; performing Fourier transform on the shaft current to obtain a frequency spectrum of the motor; determining whether the resonance occurs in the motor according to the frequency threshold and the frequency spectrum, when a frequency point exceeding the frequency threshold exists in the frequency spectrum, it is determined that the resonance occurs in the motor, and the frequency of the frequency point is the resonance frequency; when no frequency point exceeding the frequency threshold exists in the frequency spectrum, it is determined that the resonance does not occur in the motor.

5. The method of claim 1, wherein, The filtering step comprises: an executing step of filtering the initial position deviation according to the target parameter to obtain the position deviation, and sending the position deviation to the input end of the position loop, when the abnormal condition occurs in the motor; a circulating step of sequentially executing the determining step, the obtaining step and the executing step at least once until the resonance does not occur in the motor.

6. The method according to any one of claims 1 to 5, characterized in that, filtering the initial position deviation comprises: performing first-order low-pass filtering on the initial position deviation.

7. The method according to any one of claims 1 to 5, characterized in that, Before the determining step, the method further comprises: establishing an analysis model of the system; obtaining the shaft current, the actual position of the load and the actual position of the motor from the analysis model.

8. A resonance suppression device for a dual-inertia servo system, the dual-inertia servo system including a connected servo control subsystem and a load, the servo control subsystem having a current loop, a velocity loop, and a position loop, the resonance suppression device comprising: a velocity loop feedforward filter coupled to the velocity loop of the servo control subsystem, the velocity loop feedforward filter configured to receive a velocity loop input signal and to generate a velocity loop feedforward signal; and a position loop feedforward filter coupled to the position loop of the servo control subsystem, the position loop feedforward filter configured to receive a position loop input signal and to generate a position loop feedforward signal. The device comprises: The determining unit is configured to determine whether an abnormal working condition occurs in the motor of the servo control subsystem, the abnormal working condition including at least one of resonance and a rate of change of shaft current exceeding a rate of change threshold. The first obtaining unit is configured to obtain an initial position deviation, the initial position deviation being a difference between an actual position of the load and an actual position of the motor. The filtering unit is configured to filter the initial position deviation according to a target parameter of the motor to obtain a position deviation when the abnormal working condition occurs in the motor, and send the position deviation to an input end of the position loop, so that the position loop performs closed-loop control on the position of the motor according to a position given value, the actual position of the motor, and the position deviation, so that the motor after control does not have the abnormal working condition. In a case where the abnormal working condition includes the resonance, the target parameter includes a resonance frequency of the motor. In a case where the abnormal working condition includes the rate of change exceeding the rate of change threshold, the target parameter includes the rate of change. The filtering unit includes a first determining module and a filtering module. The first determining module is configured to determine a time constant of filtering according to the resonance frequency and / or the rate of change. The filtering module is configured to filter the initial position deviation according to a transfer function corresponding to the time constant to obtain the position deviation.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium includes a stored program, wherein the program executes the method of any one of claims 1 to 7.

10. A processor, comprising: The processor is configured to run a program, wherein the program executes the method of any one of claims 1 to 7 when running.

11. A dual-inertia servo control system characterized by comprising: The double-inertia servo system includes a connected servo control subsystem and a load, the servo control subsystem having a current loop, a speed loop, and a position loop. The resonance suppression device of the double-inertia servo system is configured to execute the method of any one of claims 1 to 7. The servo control subsystem includes a ball screw.

12. The dual inertia servo control system of claim 11, wherein, The double-inertia servo control system further includes a plurality of current sensors, a plurality of position sensors, and a plurality of speed sensors, the current sensors, the position sensors, and the speed sensors being respectively arranged on a shaft of a motor of the servo control subsystem and on the load.

13. The dual inertia servo control system of claim 11, wherein, ​

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