Feed-forward compensation device of unknown servo system and feed-forward coefficient self-tuning method

Abstract

The invention discloses a feed-forward compensation device of an unknown servo system and a feed-forward coefficient self-tuning method, and belongs to the technical field of motor servo control. Comprising a position signal differential module, a torque feedforward module, a speed feedforward module, a PID controller, a model identification module and a feedforward coefficient calculation module. The method comprises the following steps: judging an inertia type of an unknown servo system; identifying model parameters; setting calculation of a torque feed-forward coefficient; and setting calculation of a speed feed-forward coefficient. According to the method, judgment of the load inertia type of the servo system and accurate identification of model parameters can be realized in an extremely short time, high-order accurate approximation of a controlled object model is realized, a system delay factor is considered, an accurate feed-forward compensation signal is obtained by utilizing high-order approximation, and the precision of the system is improved. The problems of long feed-forward setting time, poor compatibility of a system load inertia model and insufficient feed-forward compensation precision are solved.

Description

Technical Field

[0001] The invention relates to a feedforward compensation device of an unknown servo system and a feedforward coefficient self-tuning method, belonging to the technical field of motor servo control. Background Art

[0002] In the motor position servo system, in order to make the system output quickly and accurately track the given signal, feedforward signal compensation is often required to eliminate the reference trajectory tracking error and improve the system response speed and accuracy.

[0003] At present, most servo feedforward compensation mainly adopts velocity and acceleration signal feedforward, which is essentially a second-order approximation of the controlled object model. However, this low-order approximation strategy has obvious limitations when facing complex systems, especially when dealing with dual-inertia load models such as flexible transmission systems. The problem of insufficient accuracy is particularly prominent. Specifically, the second-order approximation method ignores the adverse effects of resonance on low-frequency tracking performance and the signal lag caused by system delay, which severely limits the corresponding feedforward compensation effect and makes it difficult to achieve the expected precise tracking control target.

[0004] In order to overcome this limitation, in theory, it is possible to consider using higher-order differential signals for feedforward compensation to more accurately approximate the dynamic characteristics of the controlled object. However, a high-order differential feedforward device means an increase in the feedforward coefficient, which not only increases the complexity of system design, but also greatly increases the difficulty of parameter tuning. Especially when the servo system model parameters are unknown and model identification is required, the parameter tuning process of the high-order feedforward link will become particularly cumbersome and time-consuming. Not only does it extend the tuning time of the overall feedforward link, but it may also reduce the control performance of the system due to improper parameter tuning, which is not conducive to the servo system to achieve fast and accurate feedforward compensation tracking control.

[0005] Therefore, how to effectively simplify the design and implementation of high-order feedforward devices and reduce the difficulty of parameter setting while ensuring the accuracy of feedforward compensation has become an urgent problem to be solved in the current feedforward compensation technology of motor position servo systems. Summary of the invention

[0006] In order to solve the problems existing in the background technology, the present invention provides a feedforward compensation device and a feedforward coefficient self-tuning method for an unknown servo system.

[0007] To achieve the above object, the present invention adopts the following technical scheme: a feedforward compensation device for an unknown servo system, comprising:

[0008] The position signal differential module is used to obtain high-order differential signals of a given position trajectory, including first-order to fifth-order differential signals;

[0009] A torque feedforward module, used for generating a torque feedforward signal according to second-order to fifth-order differential signals of a given position trajectory, and inputting the torque feedforward signal into a current loop of a PID controller;

[0010] A speed feedforward module is used to generate a speed feedforward signal according to first-order to fourth-order differential signals of a given position trajectory, and input the speed feedforward signal into a speed loop of a PID controller;

[0011] A PID controller is used to control the servo motor according to a torque feedforward signal, a speed feedforward signal and a position closed-loop given signal generated by a given position trajectory;

[0012] Model identification module, used to obtain the frequency response characteristic curve of the controlled object of the servo system speed loop and the servo system model parameters;

[0013] The feedforward coefficient calculation module is used to obtain various feedforward coefficients according to the servo system model parameters.

[0014] A method for self-tuning a feedforward coefficient of a feedforward compensation device of an unknown servo system according to the present invention comprises the following steps:

[0015] S1: Determine the inertia type of unknown servo system;

[0016] S101: obtaining a frequency response characteristic curve of a controlled object of a speed loop of a servo system, that is, a load characteristic curve, by means of frequency sweep injection;

[0017] The sweep frequency injection signal in S101 is a Chirp current signal of rated amplitude with a total duration of 0.2s. The sweep frequency injection signal is injected into the q-axis current setting point, and the sweep frequency output signal is a system motor end speed signal.

[0018] The frequency ranges of the swept frequency injection signal and the swept frequency output signal are both 0-1250 Hz.

[0019] S102: using a Savitzky-Golay filtering method to smooth the original load characteristic curve obtained;

[0020] S103: Define the ideal transfer function of the motor load model for a dual inertia load servo system:

[0021]

[0022] In formula (1):

[0023] J=J l +J m is the total moment of inertia of the motor transmission system;

[0024] J l is the load moment of inertia;

[0025] J m is the motor moment of inertia;

[0026] K t is the torque coefficient of the motor transmission system;

[0027] K s is the torsional elastic coefficient of the motor transmission system;

[0028] s is the Laplace operator of the transfer function;

[0029] S104: According to the acquired load characteristic curve, whether there are paired resonant frequency points in the motor load model is automatically detected by double verification of extreme value search of the amplitude-frequency characteristic curve and phase mutation of the phase-frequency characteristic curve, and the load inertia type is determined according to the detection result, that is, a single-inertia load servo system or a dual-inertia load servo system;

[0030] If there are paired resonant frequency points, record the system anti-resonant frequency and the system resonant frequency Otherwise, proceed to S2.

[0031] S2: Model parameter identification;

[0032] S201: Obtain the total moment of inertia of the equivalent system J / K based on the least squares fitting of the low-frequency data in the amplitude-frequency characteristic curve of the acquired load characteristic curve t ;

[0033] S202: Obtain the speed loop equivalent system delay T according to the least squares fitting of the low-frequency data in the phase-frequency characteristic curve in the acquired load characteristic curve s ;

[0034] S203: Calculate and convert the speed loop closed-loop frequency response characteristic curve and the position loop controlled object frequency response characteristic curve according to the acquired load characteristic curve and the written speed loop controller parameters:

[0035]

[0036] In formula (2):

[0037] G p-plant (s) is the transfer function of the position loop controlled object;

[0038] G s (s) is the closed-loop transfer function of the speed loop;

[0039] G c (s) is the transfer function of the speed loop controller;

[0040] G s-plant (s) is the transfer function of the speed loop controlled object;

[0041] S204: When dealing with the problem of outer position loop parameter tuning, the closed-loop characteristics of the inner speed loop are regarded as the overall delay link, so the transfer function expression of the position loop controlled object is converted to Therefore, the equivalent system delay T of the position loop is obtained by least square fitting of the low-frequency data in the phase-frequency characteristic curve of the frequency response characteristic curve of the position loop controlled object. p .

[0042] S3: Setting calculation of torque feedforward coefficient;

[0043] S301: Define the transfer function from the torque feedforward signal compensation to the load end angle output:

[0044]

[0045] In formula (3):

[0046] G ω (s) is the system transfer function from the motor end speed to the load end speed;

[0047] S302: Perform first-order inertia approximation equivalence on the system delay link of the speed loop to obtain the final transfer function:

[0048]

[0049] S303: Perform feedforward control on the servo system, and the system transfer function in the torque feedforward module is:

[0050]

[0051] S304: Obtain corresponding torque feedforward coefficients of each order respectively.

[0052] S30401: Based on the obtained total moment of inertia of the equivalent system J / K t Determine the torque feedforward second-order differential coefficient

[0053] S30402: Based on the obtained total moment of inertia of the equivalent system J / K t And the speed loop equivalent system delay T s Determine the third-order differential coefficient of torque feedforward

[0054] S30403: Based on the obtained total moment of inertia of the equivalent system J / K t and resonant frequency system resonant frequency f N Determine the fourth-order differential coefficient of torque feedforward

[0055] S30404: Based on the obtained total moment of inertia of the equivalent system J / K t , resonant frequency system resonant frequency f N And the speed loop equivalent system delay T s Determine the fifth-order differential coefficient of torque feedforward

[0056]

[0057] S30405: If the load characteristic curve obtained when judging the load inertia type does not detect the resonant frequency point, that is, it is judged to be a single inertia load, then K a4 =K a5 =0.

[0058] S4: Calculation of speed feedforward coefficient.

[0059] S401: Define the transfer function from the speed feedforward signal compensation to the load end angle output:

[0060]

[0061] S402: Perform first-order inertia approximation equivalence on the delay link of the position loop equivalent system to obtain the final transfer function:

[0062]

[0063] S403: Perform feedforward control on the servo system, and the system transfer function in the speed feedforward module is:

[0064]

[0065] S404: Obtain corresponding speed feedforward coefficients of each order respectively.

[0066] S40401: Get the first-order differential coefficient K of the speed feedforward v1 =1;

[0067] S40402: Based on the acquired position loop equivalent system delay T p Determine the speed feedforward second-order differential coefficient K v2 =T p ;

[0068] S40403: According to the obtained resonant frequency system anti-resonant frequency f A Determine the third-order differential coefficient of velocity feedforward

[0069] S40404: According to the obtained resonant frequency system anti-resonant frequency f A and the position loop equivalent system delay T p Determine the fourth-order differential coefficient of velocity feedforward

[0070] S40405: If the load characteristic curve obtained when judging the load inertia type does not detect the resonant frequency point, that is, it is judged to be a single inertia load, then K v3 =K v4 =0.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] The present invention can judge the load inertia type of the servo system and accurately identify the model parameters in a very short time, is compatible with a variety of load inertia models, and thus achieves high-order and accurate approximation of the controlled object model. At the same time, the system delay factor is taken into account when adjusting the feedforward coefficient, and a precise feedforward compensation signal is obtained by using high-order approximation. In addition, the present invention provides the setting formulas of torque feedforward coefficients and speed feedforward coefficients of each order, avoiding complicated manual debugging and greatly shortening the setting time of the feedforward link. The overall process can complete the self-tuning of the feedforward link parameters of the unknown servo system within 0.2 seconds, effectively solving the problems of long feedforward setting time, poor compatibility of system load inertia models, and insufficient feedforward compensation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 is a structural schematic diagram of a feedforward compensation device for an unknown servo system of the present invention;

[0074] Figure 2 is a schematic diagram of swept frequency injection;

[0075] Figure 3 It is a schematic diagram of the original frequency response characteristic curve obtained by frequency sweeping and the smooth curve after filtering;

[0076] Figure 4 It is a schematic diagram of the information result of identifying the speed loop model;

[0077] Figure 5 It is a schematic diagram of the delay result of the equivalent system of the fitted position loop;

[0078] Figure 6 It is a flow chart of a feedforward coefficient self-tuning method of a feedforward compensation device of an unknown servo system of the present invention;

[0079] Figure 7 This is a schematic diagram of the feedforward effect comparison experimental results. DETAILED DESCRIPTION

[0080] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0081] A feedforward compensation device for an unknown servo system, comprising:

[0082] The position signal differential module is used to obtain high-order differential signals of a given position trajectory, including first-order to fifth-order differential signals;

[0083] A torque feedforward module, used for generating a torque feedforward signal according to second-order to fifth-order differential signals of a given position trajectory, and inputting the torque feedforward signal into a current loop of a PID controller;

[0084] A speed feedforward module is used to generate a speed feedforward signal according to first-order to fourth-order differential signals of a given position trajectory, and input the speed feedforward signal into a speed loop of a PID controller;

[0085] A PID controller is used to control the servo motor according to a torque feedforward signal, a speed feedforward signal and a position closed-loop given signal generated by a given position trajectory;

[0086] Model identification module, used to obtain the frequency response characteristic curve of the controlled object of the servo system speed loop and the servo system model parameters;

[0087] The feedforward coefficient calculation module is used to obtain various feedforward coefficients according to the servo system model parameters.

[0088] A method for self-tuning a feedforward coefficient of a feedforward compensation device of an unknown servo system according to the present invention comprises the following steps:

[0089] S1: Determine the inertia type of unknown servo system;

[0090] S101: obtaining a frequency response characteristic curve of a controlled object of a speed loop of a servo system, that is, a load characteristic curve, by means of frequency sweep injection;

[0091] The sweep frequency injection signal in S101 is a Chirp current signal of rated amplitude with a total duration of 0.2s. The sweep frequency injection signal is injected into the q-axis current setting. The sweep frequency output signal is the system motor end speed signal. The overall sweep frequency injection schematic diagram is as follows: Figure 2 shown.

[0092] In order to facilitate the subsequent fitting of system model parameters, the frequency range of the swept frequency injection signal and the swept frequency output signal are both 0-1250Hz. For a permanent magnet synchronous motor dual-inertia load servo system with unknown model parameters, the original frequency response characteristic curve obtained by the frequency sweep and the smoothed curve after filtering are as follows: Figure 3 shown.

[0093] S102: using a Savitzky-Golay filtering method to smooth the original load characteristic curve obtained to eliminate its sawtooth characteristics;

[0094] S103: Define the ideal transfer function of the motor load model for a dual inertia load servo system:

[0095]

[0096] In formula (1):

[0097] J=J l +J m is the total moment of inertia of the motor transmission system;

[0098] J l is the load moment of inertia;

[0099] J m is the motor moment of inertia;

[0100] K t is the torque coefficient of the motor transmission system;

[0101] K s is the torsional elastic coefficient of the motor transmission system;

[0102] s is the Laplace operator of the transfer function;

[0103] S104: According to the acquired load characteristic curve, whether there are paired resonant frequency points in the motor load model is automatically detected by double verification of extreme value search of the amplitude-frequency characteristic curve and phase mutation of the phase-frequency characteristic curve, and the load inertia type is determined according to the detection result, that is, a single-inertia load servo system or a dual-inertia load servo system;

[0104] If there are paired resonant frequency points, record the system anti-resonant frequency (smaller value) and system resonant frequency (larger value) Otherwise, proceed to S2.

[0105] S2: Fast and accurate model parameter identification;

[0106] S201: Obtain the total moment of inertia of the equivalent system J / K based on the least squares fitting of the low-frequency data in the amplitude-frequency characteristic curve of the acquired load characteristic curvet .

[0107] S202: Obtain the speed loop equivalent system delay T according to the least squares fitting of the low-frequency data in the phase-frequency characteristic curve in the acquired load characteristic curve s ;

[0108] S203: Calculate and convert the speed loop closed-loop frequency response characteristic curve and the position loop controlled object frequency response characteristic curve according to the acquired load characteristic curve and the written speed loop controller parameters (the difference between the two is an integral link):

[0109]

[0110] In formula (2):

[0111] G p-plant (s) is the transfer function of the position loop controlled object;

[0112] G s (s) is the closed-loop transfer function of the speed loop;

[0113] G c (s) is the transfer function of the speed loop controller;

[0114] G s-plant (s) is the transfer function of the speed loop controlled object;

[0115] S204: When dealing with the problem of outer position loop parameter tuning, the closed-loop characteristics of the inner speed loop are regarded as the overall delay link, so the transfer function expression of the position loop controlled object is converted to Therefore, the equivalent system delay T of the position loop is obtained by least square fitting of the low-frequency data in the phase-frequency characteristic curve of the frequency response characteristic curve of the position loop controlled object. p .

[0116] S3: Setting calculation of torque feedforward coefficient;

[0117] S301: For a permanent magnet synchronous motor dual inertia load servo system, define the transfer function from the torque feedforward signal compensation to the load end angle output:

[0118]

[0119] In formula (3):

[0120] G ω (s) is the system transfer function from the motor end speed to the load end speed;

[0121] S302: Perform first-order inertia approximation equivalence on the system delay link of the speed loop to obtain the final transfer function:

[0122]

[0123] S303: Feedforward control of the servo system is essentially to compensate the inverse model from the injection point of the feedforward signal to the system output. The system transfer function in the torque feedforward module is:

[0124]

[0125] S304: Obtain corresponding torque feedforward coefficients of each order respectively.

[0126] S30401: Based on the obtained total moment of inertia of the equivalent system J / K t Determine the torque feedforward second-order differential coefficient

[0127] S30402: Based on the obtained total moment of inertia of the equivalent system J / K t And the speed loop equivalent system delay T s Determine the third-order differential coefficient of torque feedforward

[0128] S30403: Based on the obtained total moment of inertia of the equivalent system J / K t and resonant frequency system resonant frequency f N Determine the fourth-order differential coefficient of torque feedforward

[0129] S30404: Based on the obtained total moment of inertia of the equivalent system J / K t , resonant frequency system resonant frequency f N And the speed loop equivalent system delay T s Determine the fifth-order differential coefficient of torque feedforward

[0130]

[0131] S30405: If the load characteristic curve obtained when judging the load inertia type does not detect the resonant frequency point, that is, it is judged to be a single inertia load, then K a4 =K a5 =0.

[0132] S4: Calculation of speed feedforward coefficient.

[0133] S401: Define the transfer function from the speed feedforward signal compensation to the load end angle output:

[0134]

[0135] S402: Perform first-order inertia approximation equivalence on the delay link of the position loop equivalent system to obtain the final transfer function:

[0136]

[0137] S403: Feedforward control of the servo system is essentially to compensate the inverse model from the injection point of the feedforward signal to the system output. The system transfer function in the speed feedforward module is:

[0138]

[0139] S404: Obtain corresponding speed feedforward coefficients of each order respectively.

[0140] S40401: Get the first-order differential coefficient K of the speed feedforward v1 =1;

[0141] S40402: Based on the acquired position loop equivalent system delay T p Determine the speed feedforward second-order differential coefficient K v2 =T p ;

[0142] S40403: According to the obtained resonant frequency system anti-resonant frequency f A Determine the third-order differential coefficient of velocity feedforward

[0143] S40404: According to the obtained resonant frequency system anti-resonant frequency f A and the position loop equivalent system delay T p Determine the fourth-order differential coefficient of velocity feedforward

[0144] S40405: If the load characteristic curve obtained when judging the load inertia type does not detect the resonant frequency point, that is, it is judged to be a single inertia load, then K v3 =K v4 =0.

[0145] In this way, the entire process of feedforward signal compensation and coefficient self-tuning for the unknown permanent magnet synchronous motor servo system is completed. The flow chart of the overall solution is as follows: Figure 6 shown.

[0146] Finally, the feedforward compensation and coefficient self-tuning method disclosed in the present invention is compared with the traditional second-order method through experimental verification, and the results are as follows: Figure 7 As shown, it can be seen that the method disclosed in the present invention has a smaller tracking error, higher tracking accuracy, and no steady-state tracking error under the same position tracking trajectory instruction. At the same time, during the implementation of the overall method, except for the system model identification process, no additional feedforward coefficient setting time and setting operation trajectory are required. The overall process has the significant advantages of fast speed and short operation trajectory, and can quickly and accurately realize the feedforward signal compensation and feedforward coefficient self-tuning of the unknown servo system within 0.2s.

[0147] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0148] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A feedforward compensation device for an unknown servo system, characterized in that: include The position signal differential module is used to obtain high-order differential signals of a given position trajectory, including first-order to fifth-order differential signals; A torque feedforward module, used for generating a torque feedforward signal according to second-order to fifth-order differential signals of a given position trajectory, and inputting the torque feedforward signal into a current loop of a PID controller; A speed feedforward module is used to generate a speed feedforward signal according to first-order to fourth-order differential signals of a given position trajectory, and input the speed feedforward signal into a speed loop of a PID controller; A PID controller is used to control the servo motor according to a torque feedforward signal, a speed feedforward signal and a position closed-loop given signal generated by a given position trajectory; Model identification module, used to obtain the frequency response characteristic curve of the controlled object of the servo system speed loop and the servo system model parameters; The feedforward coefficient calculation module is used to obtain various feedforward coefficients according to the servo system model parameters.

2. A method for self-tuning a feedforward coefficient of a feedforward compensation device of an unknown servo system according to claim 1, characterized in that: The method comprises the following steps: S1: Determine the inertia type of unknown servo system; S2: Model parameter identification; S3: Setting calculation of torque feedforward coefficient; S4: Calculation of speed feedforward coefficient.

3. The method according to claim 2, characterized in that: The S1 comprises the following steps: S101: obtaining a frequency response characteristic curve of a controlled object of a speed loop of a servo system, that is, a load characteristic curve, by means of frequency sweep injection; S102: using a Savitzky-Golay filtering method to smooth the original load characteristic curve obtained; S103: Define the ideal transfer function of the motor load model for a dual inertia load servo system: In formula (1): J=J l +J m is the total moment of inertia of the motor transmission system; J l is the load moment of inertia; J m is the motor moment of inertia; K t is the torque coefficient of the motor transmission system; K s is the torsional elastic coefficient of the motor transmission system; s is the Laplace operator of the transfer function; S104: According to the acquired load characteristic curve, whether there are paired resonant frequency points in the motor load model is automatically detected by double verification of extreme value search of the amplitude-frequency characteristic curve and phase mutation of the phase-frequency characteristic curve, and the load inertia type is determined according to the detection result, that is, a single-inertia load servo system or a dual-inertia load servo system; If there are paired resonant frequency points, record the system anti-resonant frequency and the system resonant frequency Otherwise, proceed to S2.

4. The method according to claim 3, characterized in that: The sweep frequency injection signal in S101 is a Chirp current signal of rated amplitude with a total duration of 0.2s. The sweep frequency injection signal is injected into the q-axis current setting point, and the sweep frequency output signal is a system motor end speed signal.

5. The method according to claim 4, characterized in that: The frequency ranges of the swept frequency injection signal and the swept frequency output signal are both 0-1250 Hz.

6. The method according to claim 2, characterized in that: The S2 comprises the following steps: S201: Obtain the total moment of inertia of the equivalent system J / K based on the least squares fitting of the low-frequency data in the amplitude-frequency characteristic curve of the acquired load characteristic curve t ; S202: Obtain the speed loop equivalent system delay T according to the least squares fitting of the low-frequency data in the phase-frequency characteristic curve in the acquired load characteristic curve s ; S203: Calculate and convert the speed loop closed-loop frequency response characteristic curve and the position loop controlled object frequency response characteristic curve according to the acquired load characteristic curve and the written speed loop controller parameters: In formula (2): G p-plant (s) is the transfer function of the position loop controlled object; G s (s) is the closed-loop transfer function of the speed loop; G c (s) is the transfer function of the speed loop controller; G s-plant (s) is the transfer function of the speed loop controlled object; S204: When dealing with the problem of outer position loop parameter tuning, the closed-loop characteristics of the inner speed loop are regarded as the overall delay link, so the transfer function expression of the position loop controlled object is converted to Therefore, the equivalent system delay T of the position loop is obtained by least square fitting of the low-frequency data in the phase-frequency characteristic curve of the frequency response characteristic curve of the position loop controlled object. p .

7. The method according to claim 2, characterized in that: The S3 comprises the following steps: S301: Define the transfer function from the torque feedforward signal compensation to the load end angle output: In formula (3): G ω (s) is the system transfer function from the motor end speed to the load end speed; S302: Perform first-order inertia approximation equivalence on the system delay link of the speed loop to obtain the final transfer function: S303: Perform feedforward control on the servo system, and the system transfer function in the torque feedforward module is: S304: Obtain corresponding torque feedforward coefficients of each order respectively.

8. The method according to claim 7, characterized in that: The S304 includes the following steps: S30401: Based on the obtained total moment of inertia of the equivalent system J / K t Determine the torque feedforward second-order differential coefficient S30402: Based on the obtained total moment of inertia of the equivalent system J / K t And the speed loop equivalent system delay T s Determine the third-order differential coefficient of torque feedforward S30403: Based on the obtained total moment of inertia of the equivalent system J / K t and resonant frequency system resonant frequency f N Determine the fourth-order differential coefficient of torque feedforward S30404: Based on the obtained total moment of inertia of the equivalent system J / K t , resonant frequency system resonant frequency f N And the speed loop equivalent system delay T s Determine the fifth-order differential coefficient of torque feedforward S30405: If the load characteristic curve obtained when judging the load inertia type does not detect the resonant frequency point, that is, it is judged to be a single inertia load, then K a4 =K a5 =0.

9. The method according to claim 2, characterized in that: The S4 comprises the following steps: S401: Define the transfer function from the speed feedforward signal compensation to the load end angle output: S402: Perform first-order inertia approximation equivalence on the delay link of the position loop equivalent system to obtain the final transfer function: S403: Perform feedforward control on the servo system, and the system transfer function in the speed feedforward module is: S404: Obtain corresponding speed feedforward coefficients of each order respectively.

10. The method according to claim 9, characterized in that: The S404 comprises the following steps: S40401: Get the first-order differential coefficient K of the speed feedforward v1 =1; S40402: Based on the acquired position loop equivalent system delay T p Determine the speed feedforward second-order differential coefficient K v2 =T p ; S40403: According to the obtained resonant frequency system anti-resonant frequency f A Determine the third-order differential coefficient of velocity feedforward S40404: According to the obtained resonant frequency system anti-resonant frequency f A and the position loop equivalent system delay T p Determine the fourth-order differential coefficient of velocity feedforward S40405: If the load characteristic curve obtained when judging the load inertia type does not detect the resonant frequency point, that is, it is judged to be a single inertia load, then K v3 =K v4 =0.

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