A method for suppressing structural resonance of a flexible system of a low-stiffness and high-load permanent magnet synchronous motor

Abstract

The present invention discloses a method for suppressing structural resonance of a flexible system of a low-rigidity, high-load permanent magnet synchronous motor, which relates to the technical field of permanent magnet synchronous motor control. The method comprises the following steps: dynamically filtering an input position signal by setting a TD tracking differentiator to generate a smooth planning instruction and its differential signal; introducing feedforward compensation in a position closed loop by using a velocity feedforward control method based on the planned instruction differential signal; constructing a disturbance observer based on the electromagnetic torque equation of the motor to estimate the actual wheelbase of the system in real time and perform disturbance compensation; and adopting an IP control method to perform pole configuration based on the resonance characteristics of the system, setting proportional gain and integral gain to suppress structural resonance and optimize closed-loop response. The present invention does not require displacement, velocity, or acceleration signals at the load end, nor does it require very accurate information such as the load resonance frequency, yet can achieve a good resonance suppression effect, have a good dynamic response, and reduce the demand for hardware.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motor control, in particular to a method for suppressing structural resonance of a flexible system of a low-rigidity, high-load permanent magnet synchronous motor. Background Art

[0002] The permanent magnet synchronous motor control system generally includes a servo motor, a transmission mechanism, a connection mechanism, a load, etc. Its simplified block diagram is as follows Figure 2 As shown, where K is the mechanical stiffness of the system, is the motor mass, For the quality of transmission structure and connection mechanism, is the load mass, is the moment of inertia of the motor and transmission mechanism, and x represent the motor rotation angle and linear displacement respectively, and where represents the motor's electromagnetic torque and external load, respectively. Due to constraints in terms of space, volume, and weight, permanent magnet synchronous motor control systems typically utilize lightweight materials, resulting in low mechanical stiffness (K). This can cause structural deformation under high loads, leading to resonance, inaccurate positioning, and even system instability.

[0003] For flexible systems, the load object cannot be simply modeled as a first-order inertial link. The flexible structure allows the load to be split into a series connection of an inertial link and a resonator in the frequency domain. The phase lag characteristic of the resonance point will affect the stability of the control system, and the anti-resonance point will increase the amplitude-frequency of the position closed loop, causing in-position jitter. Usually, a notch filter can be used to suppress resonance, but a fatal disadvantage of the notch filter is that its passband range corresponds to a certain phase lag, and the wider the passband, the more severe the phase lag. Moreover, from the perspective of suppression depth, the wider the passband, the less obvious the suppression effect. Selecting a narrow bandwidth notch filter is often affected by the accuracy of identifying the resonance frequency band.

[0004] Therefore, a method for suppressing structural resonance of a low-stiffness and high-load permanent magnet synchronous motor flexible system is proposed. Summary of the Invention

[0005] The purpose of the present invention is to design a method for suppressing structural resonance of a low-rigidity, high-load permanent magnet synchronous motor flexible system, which is used to solve the problems of system mechanism resonance under low-rigidity, high-load conditions, which in turn leads to low control performance and weak system stability. The purpose is to improve the control accuracy and dynamic response capability of the load end of the permanent magnet synchronous motor flexible system and suppress structural resonance.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In the first aspect, an embodiment of the present invention provides a method for suppressing structural resonance of a low-stiffness, high-load permanent magnet synchronous motor flexible system, including: tracking differentiator path planning: dynamically filtering the input position signal by setting a TD tracking differentiator to generate a smooth planning instruction and its differential signal; speed feedforward control: based on the planned instruction differential signal, a speed feedforward method is used to introduce feedforward compensation in the position closed loop; disturbance observer establishment and compensation: according to the motor electromagnetic torque equation, a disturbance observer is constructed to estimate the actual wheelbase of the system in real time and perform disturbance compensation; IP controller pole configuration: based on the system resonance characteristics, the IP control method is used for pole configuration, and the proportional gain and integral gain are set to suppress structural resonance and optimize the closed-loop response.

[0008] As a preferred solution for the structural resonance suppression method of the low-stiffness, high-load permanent magnet synchronous motor flexible system described in the present invention, the TD tracking differentiator is based on the fastest comprehensive function, combined with the set tracking acceleration factor and filter factor to achieve smooth transition and differential output of the position signal, and reduce the lag error introduced in the planning process through phase compensation.

[0009] As a preferred solution of the method for suppressing structural resonance of a flexible system of a low-stiffness and high-load permanent magnet synchronous motor described in the present invention, the speed feedforward control calculates a feedforward torque signal based on a planned speed signal, and superimposes the feedforward torque with the feedback control torque to compensate for the hysteresis caused by the rotational inertia of the motor.

[0010] As a preferred solution of the method for suppressing structural resonance of a low-stiffness, high-load permanent magnet synchronous motor flexible system described in the present invention, the disturbance observer performs disturbance estimation based on the feedback speed signal and the motor output torque signal, the observer uses a filter frequency parameter to suppress high-frequency noise, and the output observed wheelbase is used to compensate for the low-stiffness effect caused by the flexible structure.

[0011] As an optimal solution for the structural resonance suppression method of the low-stiffness and high-load permanent magnet synchronous motor flexible system described in the present invention, the electromagnetic torque of the motor in the disturbance observer is obtained through shaft current feedback calculation, and the torque coefficient is multiplied by the current signal to obtain the electromagnetic torque signal to participate in the disturbance observation operation.

[0012] As a preferred solution of the method for suppressing structural resonance of a flexible system of a low-rigidity, high-load permanent magnet synchronous motor described in the present invention, the proportional gain and integral gain of the IP controller are determined by calculating the load resonant frequency, the system moment of inertia and the mechanical stiffness parameters, and the pole configuration gives priority to improving the system damping ratio and reducing the resonance peak amplitude, and a trade-off is made between overshoot and response speed according to different application requirements.

[0013] As a preferred solution of the method for suppressing the structural resonance of the flexible system of the low-rigidity and high-load permanent magnet synchronous motor of the present invention, wherein: the resonant frequency is calculated based on the structural stiffness of the servo system and the load mass, specifically by Determine, where K is the structural stiffness of the servo system, The load mass is calculated and the resonance characteristics are corrected according to the total transmission ratio of the servo system to guide the parameter setting of the IP controller.

[0014] Secondly, in order to further solve the problems existing in the control of permanent magnet synchronous motors, the present invention provides a low-stiffness and large-load permanent magnet synchronous motor flexible system structural resonance suppression system, which includes: a path planning module, which uses a tracking differentiator to filter and plan the path of the position command signal; a feedforward and feedback control module, which is used to perform position loop closed-loop control and speed feedforward compensation based on the reference signal generated by the path planning module; a disturbance observation module, which is used to estimate the vibration disturbance of the flexible structure in real time according to the motor operating parameters, and output a disturbance compensation signal; a pole configuration and IP control module, which is used to use an IP controller to configure the poles of the system according to the output result of the disturbance observation module.

[0015] In a third aspect, an embodiment of the present invention provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program is executed by the processor, any step of the method for suppressing structural resonance of a flexible system of a low-stiffness and high-load permanent magnet synchronous motor as described in the first aspect of the present invention is implemented.

[0016] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, any step of the method for suppressing structural resonance of a flexible system of a low-stiffness and high-load permanent magnet synchronous motor as described in the first aspect of the present invention is implemented.

[0017] The beneficial effects of the present invention are:

[0018] 1. This method does not require displacement, velocity or acceleration signals at the load end, nor does it require very accurate information such as the load resonant frequency. It can also achieve good resonance suppression effects and has good dynamic response, reducing hardware requirements.

[0019] 2. This invention is based on the system control principle diagram and can be used for rapid system simulation. At the same time, this solution is easy to adjust parameters. The TD tracking differentiator bandwidth is determined by the system dynamic requirements. IP control takes into account the requirements of overshoot and dynamic response by selecting different coefficients. The dynamic and static performance of the system is improved by the speed feedforward coefficient.

[0020] 3. The present invention is closely integrated with the structural parameters of the servo system, and the resonance characteristics can be obtained during the mechanical design stage of the servo system. At the same time, the dynamic response limit reached by the position closed-loop system can be predicted, providing a reference for mechanical design and controller parameter design. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0022] Figure 1 This is a flow chart for implementing the present invention in Example 1;

[0023] Figure 2 Simplify the model for the permanent magnet synchronous motor system;

[0024] Figure 3 This is the system control schematic diagram;

[0025] Figure 4 This is the block diagram of the disturbance observer. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0029] Example 1

[0030] Reference Figures 1 to 4 , which is the first embodiment of the present invention, provides a method for suppressing structural resonance of a low-rigidity, high-load permanent magnet synchronous motor flexible system. The method aims to improve the control accuracy and dynamic response capability of the load end of the permanent magnet synchronous motor flexible system and suppress structural resonance, and includes the following steps:

[0031] Step S1: Use a tracking differentiator to perform path planning on the position command signal to obtain the planned command and the differential signal of the command.

[0032] Specifically, the TD tracking differentiator is used to perform transition processing on the position signal to obtain the planned The differential signal of the command , which can be specifically expressed by the following formula:

[0033] ;

[0034] ;

[0035] ;

[0036] Where, is the position command, and are the planned instructions at time k+1 and k respectively, and are the command differential signals at time k+1 and time k respectively, and h is the calculation step size.

[0037] For example, the above parameters Using the fastest synthesis function , which can be specifically expressed as:

[0038] ;

[0039] ;

[0040] ;

[0041] ;

[0042] ;

[0043] ;

[0044] ;

[0045] ;

[0046] ;

[0047] Where r is the tracking acceleration factor, which determines the bandwidth of the tracking differentiator. ,in is the position loop bandwidth; is the filter factor, , generally take an integer multiple of the step size, the larger the value, the better the filtering effect; is a symbolic function.

[0048] Since filtering will cause the planned There is a certain phase lag, so the phase of the instruction is compensated, which can be reflected by the following formula: ;

[0049] Wherein, n is an integer.

[0050] It should be noted that this step dynamically filters the input position signal by setting a TD tracking differentiator, achieving a smooth transition and extracting differential information from the original command signal. The TD differentiator is constructed using a fastest synthesis function, with tracking acceleration factors and filtering factors set to ensure that the output position signal planning trajectory is continuous and smooth, and contains velocity and acceleration estimation information that can be used in subsequent control steps. Considering the potential phase lag introduced by filtering, this step also incorporates a phase compensation strategy to reduce planning errors. Ultimately, the reference command and its differential signal are output for closed-loop control, effectively improving the controllability and real-time performance of the system's response feedforward channel.

[0051] Step S2: Use the planned instructions to participate in the position loop closed-loop control, and at the same time adopt speed feedforward control in the speed loop to improve dynamic response.

[0052] Specifically, it can be expressed by the following formula:

[0053] The closed-loop control formula of the position loop is as follows:

[0054] ;

[0055] Where, For position feedback; is the speed instruction; is the magnification factor, .

[0056] The speed feedforward formula is as follows:

[0057] ;

[0058] Where, is the feedforward compensation coefficient, which takes values between [0,1]. The larger the value, the better the phase compensation effect. ;

[0059] It should be noted that after obtaining the path planning signal, this step constructs a velocity feedforward channel based on its differential term, compensating for the system's response lag through a predictive control strategy. Specifically, the velocity feedforward signal is superimposed on the position closed-loop control output to generate a more accurate torque input command, thereby reducing the dynamic lag caused by the system's moment of inertia. The velocity feedforward compensation coefficient can be adjusted between [0, 1] to balance the system's dynamic overshoot and response speed. This step significantly improves the system's responsiveness to rapid target changes, enhancing tracking accuracy and disturbance rejection.

[0060] Step S3: Establish a disturbance observer to obtain the system wheelbase for subsequent pole configuration to improve system damping.

[0061] Specifically, the disturbance observer refers to Figure 4 As shown, the motor electromagnetic torque equation , the disturbance observer formula is as follows:

[0062] ;

[0063] Where, is the actual wheelbase; is the observed wheelbase; For speed feedback; is the moment of inertia of the motor and transmission structure; is the damping coefficient, which is usually 0; is the filter frequency, used to filter the influence of noise;

[0064] For example, the above parameters For the electromagnetic torque of the motor, it can be expressed by the following formula:

[0065] ;

[0066] Where, is the moment coefficient; is the q-axis current feedback.

[0067] It should be noted that this step uses the electromagnetic torque equation of the motor to construct a disturbance observer to estimate the impact of flexible structure vibration on the system wheelbase. The observer input includes the speed feedback signal and the motor output torque signal, and the filter frequency parameter design is used to reduce high-frequency noise interference. The core idea is to calculate the electromagnetic torque through torque and current feedback. , and combined with the inertia model to estimate the disturbance effect, output an observed wheelbase for wheelbase error compensation This compensation mechanism significantly improves the stability and control accuracy of the system under the action of the flexible structure.

[0068] Step S4: Through IP control, the system is pole-configured to suppress structural resonance.

[0069] Specifically, IP control is used to configure the system poles and improve the system damping. Since IP control does not produce zero points, it can better suppress resonance, which can be specifically reflected by the following formula:

[0070] ;

[0071] ;

[0072] Where, is the electromagnetic torque command of the motor; a takes values in the interval [0,1], generally a=0.5. By selecting different values, the requirements of overshoot and dynamic response are taken into account. Increasing a improves the system's resonance suppression capability and reduces overshoot; decreasing a improves the system's dynamic response. and are the amplification coefficient and the integration coefficient respectively; k is the wheelbase compensation coefficient;

[0073] For example, the above parameters can be specifically expressed as:

[0074] ;

[0075] Where, for Axis current command;

[0076] ;

[0077] ;

[0078] Where, is the moment of inertia of the motor and transmission mechanism, is the system resonant frequency, , where K is the structural stiffness of the servo system, is the load mass.

[0079] ;

[0080] Where i is the total transmission ratio of the servo system.

[0081] It should be noted that in order to suppress the structural resonance that may occur in the flexible system under low stiffness and large load, this step introduces an IP controller (proportional-integral control) without zero points, and optimizes the closed-loop response of the system through pole configuration. The proportional gain of the IP controller is With integral gain Based on the system resonant frequency , moment of inertia The system's damping ratio is set based on the mechanical structure's stiffness, K, to ensure a high damping ratio, suppress resonance peaks, and strike a balance between overshoot and response speed. By adjusting controller parameters, resonant frequency matching and dynamic characteristics can be optimized, ensuring stable system operation.

[0082] In summary, this method does not require displacement, velocity or acceleration signals at the load end, does not require very precise information such as the load resonant frequency, and can also achieve good resonance suppression effects, and has good dynamic response, reducing the demand for hardware; in addition, the present invention is based on the system control principle diagram and can be used for fast system simulation. At the same time, this solution is easy to adjust parameters, and the TD tracking differentiator bandwidth is determined by the system dynamic requirements. IP control takes into account the requirements of overshoot and dynamic response by selecting different coefficients. The dynamic and static performance of the system is improved by the speed feedforward coefficient. It is closely integrated with the structural parameters of the servo system, and the resonance characteristics can be obtained in the mechanical design stage of the servo system. At the same time, it can predict the dynamic response limit achieved by the position closed-loop system, providing a reference for mechanical design and controller parameter design.

[0083] Example 2

[0084] Embodiment 2 is the second embodiment of the present invention. This embodiment differs from the first embodiment in that it further provides a low-rigidity, high-load permanent magnet synchronous motor flexible system structure resonance suppression system, including:

[0085] The path planning module is used to filter the position command signal and perform path planning using a tracking differentiator to generate continuous and smooth reference position signals, velocity signals, and acceleration signals;

[0086] A feedforward and feedback control module, configured to perform position loop closed-loop control and velocity feedforward compensation based on the reference signal generated by the path planning module, so as to improve the system dynamic response and tracking accuracy;

[0087] The disturbance observation module is used to estimate the vibration disturbance of the flexible structure in real time based on the motor operating parameters and output a disturbance compensation signal;

[0088] The pole configuration and IP control module is used to configure the poles of the system using the IP controller based on the output results of the disturbance observation module, thereby suppressing resonance and improving system damping.

[0089] This embodiment also provides a computer device, which is suitable for a method for suppressing the structural resonance of a flexible system of a low-stiffness and high-load permanent magnet synchronous motor, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute computer-executable instructions to implement a method for suppressing the structural resonance of a flexible system of a low-stiffness and high-load permanent magnet synchronous motor as proposed in the above embodiment.

[0090] The computer device may be a terminal, comprising a processor, memory, a communication interface, a display, and an input device connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores an operating system and computer programs. The internal memory provides an environment for the operating system and computer programs stored in the non-volatile storage media. The communication interface of the computer device is used to communicate with external terminals via wired or wireless communication. Wireless communication may be achieved via Wi-Fi, a carrier network, NFC (near-field communication), or other technologies. The display of the computer device may be a liquid crystal display or an electronic ink display. The input device may be a touchscreen overlay on the display, buttons, a trackball, or a touchpad on the computer device housing, or an external keyboard, touchpad, or mouse.

[0091] This embodiment also provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for suppressing structural resonance of a flexible system of a low-stiffness and high-load permanent magnet synchronous motor as proposed in the above embodiment; the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0092] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for suppressing structural resonance of a flexible system of a low-rigidity, high-load permanent magnet synchronous motor, characterized by: include: S1, tracking differentiator path planning: By setting the TD tracking differentiator to dynamically filter the input position signal, a smooth planning instruction and its differential signal are generated; S2, speed feedforward control: Based on the planned command differential signal, the speed feedforward control method is used to introduce feedforward compensation in the position closed loop; S3, disturbance observer establishment and compensation: Based on the motor electromagnetic torque equation, a disturbance observer is constructed to estimate the actual wheelbase of the system in real time and perform disturbance compensation; S4, IP controller pole configuration: Based on the system resonance characteristics, the IP control method is used for pole configuration, and the proportional gain and integral gain are set to suppress the structural resonance and optimize the closed-loop response; Among them, the proportional gain and integral gain of the IP controller are determined by calculating the load resonant frequency, system moment of inertia and mechanical structure stiffness parameters. The pole configuration first considers improving the system damping ratio and reducing the resonance peak amplitude, and makes a trade-off between overshoot and response speed according to different application requirements; the resonant frequency is calculated based on the servo system structural stiffness and load mass, specifically by OK, among them is the structural stiffness of the servo system, is the load mass, and the resonance characteristics are calculated and corrected according to the total transmission ratio of the servo system to guide the parameter setting of the IP controller.

2. The method for suppressing structural resonance of a flexible system of a low-rigidity, high-load permanent magnet synchronous motor according to claim 1, characterized in that: The TD tracking differentiator is based on the fastest synthesis function and combines the set tracking acceleration factor and filter factor to achieve smooth transition and differential output of the position signal, and reduce the lag error introduced in the planning process through phase compensation.

3. The method for suppressing structural resonance of a flexible system of a low-rigidity, high-load permanent magnet synchronous motor according to claim 2, characterized in that: The speed feedforward control calculates a feedforward torque signal based on the planned speed signal, and superimposes the feedforward torque with the feedback control torque to compensate for the hysteresis caused by the rotational inertia of the motor.

4. The method for suppressing structural resonance of a flexible system of a low-rigidity, high-load permanent magnet synchronous motor according to claim 3, characterized in that: The disturbance observer estimates disturbances based on the feedback speed signal and the motor output torque signal. The observer uses a filter frequency parameter to suppress high-frequency noise. The output observation wheelbase is used to compensate for the low stiffness effect caused by the flexible structure.

5. The method for suppressing structural resonance of a flexible system of a low-rigidity, high-load permanent magnet synchronous motor according to claim 4, characterized in that: The electromagnetic torque of the motor in the disturbance observer is obtained by shaft current feedback calculation, and the torque coefficient is multiplied by the current signal to obtain the electromagnetic torque signal to participate in the disturbance observation operation.

6. A low-rigidity, high-load permanent magnet synchronous motor flexible system structural resonance suppression system, based on the low-rigidity, high-load permanent magnet synchronous motor flexible system structural resonance suppression method according to any one of claims 1 to 5, characterized in that: include, A path planning module is used to filter the position command signal and perform path planning using a tracking differentiator; A feedforward and feedback control module, configured to perform position loop closed-loop control and speed feedforward compensation based on the reference signal generated by the path planning module; The disturbance observation module is used to estimate the vibration disturbance of the flexible structure in real time based on the motor operating parameters and output a disturbance compensation signal; The pole configuration and IP control module is used to configure the poles of the system using the IP controller according to the output results of the disturbance observation module.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method for suppressing structural resonance of a low-stiffness, high-load permanent magnet synchronous motor flexible system as described in any one of claims 1 to 5 are implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for suppressing structural resonance of a flexible system of a low-rigidity and high-load permanent magnet synchronous motor according to any one of claims 1 to 5 are implemented.

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