Full-closed-loop motorized spindle ternary control method and system, medium and application

Abstract

The invention discloses a full-closed-loop motorized spindle ternary control method and system, a medium and application. The method comprises the following steps of: performing full-closed-loop control by adopting a combined control logic of a feedback controller, a feedforward controller, a first disturbance observer and a second disturbance observer; wherein the first disturbance observer observes the disturbance output of the motor end and outputs a first compensation value, and the second disturbance observer observes the disturbance output of the output end and outputs a second compensation value; and performing control after linear combination. In order to solve the problem that an electric spindle is greatly influenced by uncertain factors such as bearing friction and machining chatter, a double-disturbance observer is designed on the basis of feed-forward control and a feedback controller, and a three-element speed control framework of'feed-forward + feedback + double-disturbance observer 'is formed. Compared with a traditional lumped disturbance observer, the method can achieve the separated estimation and compensation of interference sources with different amplitudes and frequencies, can more accurately remove the disturbance force in the machining process of the motorized spindle, and improves the speed tracking precision and control stability of the motorized spindle.

Description

Technical Field

[0001] The present invention relates to the technical field of mechatronics, and in particular to a full-closed-loop electric spindle ternary control method, system, medium and application. Background Art

[0002] As the core component of high-end composite machining machine tools, the high-speed electric spindle is a mechatronics product with extremely high technical content, involving many fields such as machinery, motors, drive and control, support, lubrication and sealing, material heat treatment and vibration, etc. It is a relatively independent and complete intelligent functional component. However, due to the complex milling process, the speed control of the high-speed electric spindle is easily affected by interference such as friction and machining reaction force, which will further lead to problems such as reduced surface quality and machining accuracy, reduced tool life and productivity. Therefore, how to compensate for the interference of the high-speed electric spindle is very important.

[0003] Chinese invention patent CN 108490789 A discloses a robust active control method for milling chatter of an electric spindle and its active control system, wherein the method comprises the following steps: establishing a milling chatter active control dynamics model; converting the milling process dynamics model into a linear time-invariant model; analyzing modal perturbations and modeling the modal perturbations of the electric spindle; establishing a state augmentation model for active control of milling chatter, and solving the control algorithm using the structural singular value method; and using the designed control algorithm to calculate the active control force of the electric spindle system. Although this method can effectively suppress chatter during milling, it ignores the influence of nonlinear friction, torque fluctuations and other interferences on the motor end, and has limited improvement on control accuracy.

[0004] Chinese invention patent CN110875699A provides a disturbance observer, a control device, a machine tool, and a disturbance estimation method. The disturbance observer performs feedback control on the motor based on instructions, obtains the position information and current information of the motor to estimate the disturbance acting on the motor. The disturbance observer has: a constant calculation unit, which obtains the temperature information of the motor and calculates the torque constant of the motor based on the temperature represented by the obtained temperature information; a torque estimation unit, which estimates the torque of the motor based on the position represented by the obtained position information and the constant of the load machine driven by the motor. However, this single, lumped disturbance estimation method cannot distinguish between disturbances of different frequencies and amplitudes, and the estimation accuracy of multi-source disturbances on the electric spindle is not high.

[0005] Chinese invention patent CN111650952A discloses a hierarchical anti-interference method for quad-rotor drones based on dual interference observers. For a type of quad-rotor drone affected by multi-source interference, a dual interference observer is designed to achieve real-time estimation and compensation of interference. First, a six-degree-of-freedom dynamic model of the quad-rotor drone is established; secondly, for the center of mass motion control loop, the first nonlinear interference observer is designed to estimate the external force of the center of mass motion interference; then, for the attitude control loop, the second nonlinear interference observer is designed to estimate the interference torque; finally, using the estimated values ​​of the two interference observers, the control laws of the center of mass motion control loop and the attitude control loop are designed respectively to ensure the stability of the closed-loop system of the aircraft. Although this method effectively compensates for interference, due to the lack of feedforward control based on the pseudo-dynamic model, its dynamic response is slow, which reduces the trajectory tracking accuracy.

[0006] It can be seen that the existing technology does not provide a comprehensive and accurate solution to the problem that high-speed electric spindles are greatly affected by uncertain factors such as bearing friction and processing chatter, and the speed tracking accuracy and control stability still need to be improved. Summary of the invention

[0007] In view of the deficiencies in the prior art, an object of the present invention is to provide a full-closed-loop electric spindle ternary control method, system, medium and application.

[0008] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0009] In a first aspect, the present invention provides a full-closed-loop electric spindle ternary control method based on feedforward, feedback and dual disturbance observers, wherein the two ends of the electric spindle are respectively a motor end and an output end, and the method comprises:

[0010] For the expected output speed, based on the dynamic model of the electric spindle, a combined control logic of a feedback controller, a feedforward controller, a first disturbance observer and a second disturbance observer is used to perform full closed-loop control on the total input torque of the electric spindle;

[0011] Among them, the first disturbance observer observes the disturbance output of the motor end and a first compensation value, and the second disturbance observer observes the disturbance output of the output end and a second compensation value; the output control value of the feedback controller and the feedforward controller is linearly combined with the first compensation value and the second compensation value to control the input total torque.

[0012] In a second aspect, the present invention further provides a fully closed-loop electric spindle ternary control system based on feedforward, feedback and dual disturbance observers, wherein the two ends of the electric spindle are respectively a motor end and an output end, and the control system comprises: a feedback controller, a feedforward controller, a first disturbance observer and a second disturbance observer;

[0013] Among them, the first disturbance observer observes the disturbance output of the motor end to produce a first compensation value, and the second disturbance observer observes the disturbance output of the output end to produce a second compensation value; the output control value of the feedback controller and the feedforward controller is linearly combined with the first compensation value and the second compensation value to control the total input torque of the motor end.

[0014] In a third aspect, the present invention further provides a readable storage medium, in which a computer program is stored, and when the computer program is executed, the steps of the above-mentioned full-closed-loop electric spindle ternary control method are executed.

[0015] In a fourth aspect, the present invention also provides the application of the above-mentioned full-closed-loop electric spindle ternary control method in the field of mechanical processing.

[0016] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention at least include:

[0017] Aiming at the problem that the high-speed electric spindle is greatly affected by uncertain factors such as bearing friction and machining chatter, the present invention designs a dual disturbance observer based on the dual encoder feedback of the motor end and the output end on the basis of feedforward control and feedback controller, forming a ternary speed control architecture of "feedforward + feedback + dual disturbance observer"; the feedback controller adopts proportional integral (PI) control to eliminate steady-state error, the feedforward controller is used to improve the dynamic response capability of the electric spindle, the motor end disturbance observer compensates for the interference caused by its own factors such as bearing friction and torque fluctuation, the output end disturbance observer observes the frequency and amplitude of the chatter, and specifically designs a shaping filter and a cutoff frequency to compensate for the periodic disturbance of the electric spindle chatter, improve the anti-interference ability, and suppress the jumping of the end of the electric spindle; compared with the traditional lumped disturbance observer, it can perform separate estimation and compensation for interference sources of different amplitudes and frequencies, and can more accurately remove the interference force in the electric spindle machining process, thereby improving the speed tracking accuracy and control stability of the electric spindle.

[0018] The above description is only an overview of the technical solution of the present invention. In order to enable those skilled in the art to more clearly understand the technical means of the present application and implement them according to the contents of the specification, the following is a description of the preferred embodiments of the present invention in conjunction with detailed drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of a fully electric spindle provided by a typical implementation case of the present invention;

[0020] Figure 2 It is a block diagram of a three-element control system of the speed of a fully electric spindle provided by a typical implementation case of the present invention;

[0021] Figure 3It is a reference speed curve diagram of a full-electric spindle in a simulation experiment provided by a typical implementation case of the present invention;

[0022] Figure 4a is a curve diagram of the motor-end disturbance torque applied in a simulation experiment provided by a typical implementation case of the present invention;

[0023] Figure 4b is a curve diagram of the output-end interference torque applied in a simulation experiment provided by a typical implementation case of the present invention;

[0024] Figure 5 This is a comparison diagram of the total interference estimated by the dual interference observer and the actual total interference in a simulation experiment provided by a typical implementation case of the first embodiment of the present invention;

[0025] Figure 6 It is a comparison diagram of speed tracking errors of three speed controllers in a simulation experiment provided by a typical implementation case of the present invention. DETAILED DESCRIPTION

[0026] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

[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. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0028] Moreover, relational terms such as “first” and “second” are merely used to distinguish one component or method step from another with the same name, but do not necessarily require or imply any such actual relationship or order between these components or method steps.

[0029] See also Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a full-closed-loop electric spindle ternary control method based on feedforward, feedback and dual disturbance observers, wherein the two ends of the electric spindle are the motor end and the output end, respectively, and the method comprises the following steps:

[0030] For the expected output speed, based on the dynamic model of the electric spindle, a combined control logic of a feedback controller, a feedforward controller, a first disturbance observer and a second disturbance observer is used to perform full closed-loop control on the total input torque of the electric spindle;

[0031] Among them, the first disturbance observer observes the disturbance output of the motor end and a first compensation value, and the second disturbance observer observes the disturbance output of the output end and a second compensation value; the output control value of the feedback controller and the feedforward controller is linearly combined with the first compensation value and the second compensation value to control the input total torque.

[0032] Machining center machine tools are usually equipped with electric spindles. The electric spindle is a spindle with the motor directly built into it. The spindle and the tool handle are connected by rivets. The tool is tightened by a butterfly spring, and the tool is released by hydraulic or pneumatic drive. The usual electric spindle system includes the spindle, front and rear spindle bearings, housing, spindle front cover, spindle rear cover, stator, rotor and cooling water jacket. Bearing spacers are set between the front and rear spindle bearings. The structure of the electric spindle includes a rotation and support module, a drive module, a tool change module, a cooling module and a signal module. The rotation and support module contains front and rear bearings, a shaft core, a spacer, and a locking nut.

[0033] Of course, the above exemplary electric spindle structure is not the key to the present invention. The key technical contribution of the present invention lies in the three-dimensional closed-loop control of the electric spindle. As some typical examples, in actual applications, for the electric spindle, the following steps can be used to achieve full closed-loop three-dimensional control of the electric spindle:

[0034] (1) Establish a rigid-flexible coupling dynamic model of a high-speed electric spindle;

[0035] (2) Design the feedback controller and feedforward controller of the electric spindle;

[0036] (3) Design a dual disturbance observer to compensate for interference such as friction and reaction of the workpiece being processed. Combined with step (2), a full closed-loop electric spindle ternary control architecture is formed to achieve high-precision control of the electric spindle speed.

[0037] Regarding the specific details of the embodiments provided by the present invention, in some embodiments, the kinetic model is expressed as:

[0038]

[0039] Among them, τ m Represents the total input torque; J m Represents the inertia of the motor end; J l Indicates the inertia of the output end; B m represents the viscous damping of the motor end; B l represents the viscous damping of the output end; q m represents the shaft rotation position of the motor end; q l represents the shaft rotation position of the output end; τ f represents the friction torque at the motor end; τ wrepresents the machining reaction torque; K represents the stiffness of the spindle; · represents the first-order differential; ·· represents the second-order differential.

[0040] As a typical example, the dynamics of the electric spindle is mainly divided into three parts: the motor end mechanical part, the flexible electric spindle and the processing end mechanical part. The motor is divided into two parts, the electrical part and the mechanical part. The electrical part changes the coil current through the closed-loop control of the motor. Since the motor and the processing end are both supported by bearings, the dynamic responses of the motor mechanical part and the processing section mechanical part can be approximated as an inertia and damping system, and the two are coupled through the stiffness of the electric spindle. Figure 2 As shown, the motor end is subjected to the torque τ generated by the permanent magnet torque motor m The inertia of the motor end is J m and output inertia J l Separated by the stiffness K of the electric spindle. In addition, J m and J l During the movement, it will also be subject to viscous damping B m and B l The motor end position encoder measures q m , the position encoder at the processing end measures q l Therefore, the dynamic model of the entire closed-loop electric spindle is:

[0041]

[0042] Among them, τ m is the total input torque provided by the permanent magnet motor, τ f is the friction torque at the motor end, τ w It is the reaction torque that the electric spindle is subjected to during the process of machining workpieces.

[0043] However, the electric spindle system is affected by uncertain factors such as random interference and parameter perturbation in actual operation. In order to achieve precise control of the speed and improve the anti-interference ability of the electric spindle, it is necessary to observe and compensate for the motor-end interference and the processing-end interference in real time. First, in order to achieve basic control of the electric spindle speed, the feedback controller is set to a PI controller. In some implementation schemes, the feedback controller is expressed as:

[0044]

[0045] Wherein, C(s) represents the control value of the feedback controller; k p represents proportional gain; k I represents the integral gain; s represents the complex variable converted from time domain to frequency domain.

[0046] Since the machining trajectory of the tool can be predicted in advance in CNC machining, the feedforward control based on the inverse dynamics model can achieve rapid response of the joint. Therefore, in some embodiments, the feedforward controller is expressed as:

[0047]

[0048] F(s)=G 1 (s) -1

[0049] Among them, G 1 (s) represents the transfer function from the input total torque to the speed of the output end; F(s) represents the control value of the feedforward controller; ·- 1 Represents the inverse function.

[0050] Traditional disturbance observers are based on designing a single observer to observe and compensate for the total disturbance, but this is due to the disturbances such as friction and torque fluctuation at the motor end. In order to observe the friction torque at the motor end, the present invention designs a first disturbance observer at the motor end. In some embodiments, the first disturbance observer is expressed as:

[0051] H 1 =J m s 2 +B m s+K

[0052] H 2 =-K

[0053]

[0054] Among them, H 1 represents the first operator; H 2 represents the second operator; Q 1 Represents the first low-pass filter, with a relative order of H 1 or H 2 above; represents the first compensation value.

[0055] Furthermore, in order to compensate for the interference effect of the machining reaction force and the friction force at the motor end on the workpiece end, the present invention also designs a second interference observer at the machining workpiece end. In some embodiments, the second interference observer is expressed as:

[0056] H 3 =-K

[0057] H 4 =J l s 2 +B l s+K

[0058]

[0059] Among them, H 3 represents the first operator; H 4 represents the second operator; Q 2 Represents the first low-pass filter, with a relative order of H 3 or H 4 above; represents the first compensation value.

[0060] Therefore, the present invention forms a high-dynamic and high-precision ternary control speed control architecture of "feedforward + feedback + dual disturbance observer". In some embodiments, the output control value of the feedback controller and the feedforward controller is linearly combined with the first compensation value and the second compensation value as follows:

[0061]

[0062] Among them, ω r represents the processing speed expected at the output end; Indicates the speed tracking error.

[0063] Based on the feedforward controller and feedback controller, the above technical scheme designs a dual disturbance observer based on the encoder feedback at the motor end and the output end, forming a ternary speed control architecture of "feedforward + feedback + dual disturbance observer", which compensates for the influence of bearing friction, machining chatter and other disturbances on the high-speed electric spindle, and improves the speed tracking accuracy; compared with the traditional lumped disturbance observer, it can perform separate estimation and compensation for interference sources of different amplitudes and frequencies, and can more accurately remove the interference force in the electric spindle machining process, thereby improving the speed tracking accuracy and control stability of the electric spindle.

[0064] Correspondingly, the second aspect of the embodiment of the present invention further provides a full-closed-loop electric spindle ternary control system based on forward feedback and dual disturbance observers, wherein the two ends of the electric spindle are the motor end and the output end, respectively, and the control system comprises: a feedback controller, a feedforward controller, a first disturbance observer and a second disturbance observer;

[0065] Among them, the first disturbance observer observes the disturbance output of the motor end to produce a first compensation value, and the second disturbance observer observes the disturbance output of the output end to produce a second compensation value; the output control value of the feedback controller and the feedforward controller is linearly combined with the first compensation value and the second compensation value to control the total input torque of the motor end.

[0066] In addition, the third aspect of an embodiment of the present invention further provides a readable storage medium, in which a computer program is stored. When the computer program is executed, the steps of the full-closed-loop electric spindle ternary control method provided in any of the above-mentioned embodiments are executed.

[0067] Furthermore, a fourth aspect of the embodiments of the present invention also provides an application of the full-closed-loop electric spindle ternary control method provided by any of the above-mentioned embodiments in the field of mechanical processing.

[0068] The technical solution of the present invention is further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only used to illustrate the present invention, and do not limit the scope of the present invention.

[0069] Example 1

[0070] This embodiment illustrates the process of establishing a three-element closed-loop control method for an electric spindle. Figure 1 As an example of the fully closed-loop electric spindle shown in the figure, a "feedforward + feedback + dual disturbance observer" dual fully closed-loop electric spindle speed control architecture is shown in Figure 2 As shown, the following steps are included:

[0071] In step (1), the specific steps of establishing a fully closed-loop electric spindle dynamics model are as follows:

[0072] (1-1) Based on the Lagrange equation, the high-speed electric spindle is analyzed and the dynamic model of the electric spindle is obtained as follows:

[0073]

[0074] Among them, the inertia J at the motor end m and output inertia J l Separated by the stiffness K of the electric spindle. In addition, J m and J l During the movement, it will also be subject to viscous damping B m and B l The motor end position encoder measures q m , the position encoder of the processing section measures q l , τ m is the total input torque provided by the permanent magnet motor, τ f is the friction torque at the motor end. The reference speed curve expected in the simulation is as follows: Figure 3 As shown; τ w is the reaction torque of the electric spindle during machining. The reaction forces at different ends applied in the simulation are as follows: Figure 4a and Figure 4b shown.

[0075] (1-2) In order to obtain the actual dynamic parameter values ​​of the electric spindle. The dynamic model parameters of the electric spindle can be identified based on the sinusoidal frequency sweep method. First, the driver that controls the electric spindle is debugged into the current loop mode. The amplitude of the input current is constant, and the frequency is a sinusoidal function that increases continuously. The sine wave signal is applied to the system, and the frequency is swept step by step and the response of the system is recorded. The excitation time is long enough for the system to reach a steady state. Ensure that the sampling frequency is high enough to accurately capture the dynamic characteristics of the system. Record the input current, the position information measured by the motor end encoder and the processing end encoder during the frequency sweep process. The speed information can be obtained by passing the position information through a high-pass filter L(s)=s / (0.001s+1). Based on the constructed dynamic model, the transfer function of the input current and the output end speed is obtained. Based on the current and output end speed data measured in the experiment, the least squares method and other parameter estimation methods are used to fit the model parameters. The dynamic parameters obtained by the final frequency sweep are shown in the following table:

[0076] parameter Motor end inertia Jm <![CDATA[Motor terminal damping B m > Stiffness K Numeric 0.2 0.2 28648 unit <![CDATA[kg·m 2 ]]> N·m·s / rad N·m / rad parameter <![CDATA[Output inertia J l > <![CDATA[Output terminal damping B l > Numeric 0.8 0.3 unit <![CDATA[kg·m 2 ]]> N·m·s / rad

[0077] In step (2), the specific steps of designing a fully closed-loop electric spindle feedback and feedforward controller are as follows:

[0078] (2-1) According to the established dynamic model, we know that from the input torque τ m Speed ​​to output The transfer function can be expressed as

[0079]

[0080] (2-2) In order to effectively eliminate the steady-state error of the system and ensure that the system can maintain the set point after reaching it, the feedback controller C(s) of the electric spindle is designed as a PI controller as follows:

[0081]

[0082] Among them, the kp and kI parameters can be obtained by tuning the identified electric spindle based on the PID parameter setter of Simulink.

[0083] (2-3) Since the machining trajectory of the tool can be predicted in advance in CNC machining, the feedforward control based on the inverse dynamics model can achieve rapid response of the joint. Therefore, the feedforward controller can be designed as:

[0084] F(s)=G 1 (s) -1

[0085] In step (3), the specific steps of designing a full closed-loop electric spindle disturbance compensation based on a dual disturbance observer are as follows:

[0086] (3-1) The electric spindle system is affected by uncertain factors such as random interference and parameter perturbation during actual operation. In order to achieve precise control of the speed and improve the anti-interference ability of the electric spindle, it is necessary to observe and compensate for the motor-end interference and the processing-end interference in real time. Traditional interference observers are based on the design of a single observer to observe and compensate for the total interference, but this is due to interference such as friction and torque fluctuations at the motor end. In order to compensate for interference such as friction torque at the motor end, an innovative motor-end interference observer W is designed. 1 as follows:

[0087]

[0088] in: is a low-pass filter, w f It's Q 1 The cutoff frequency. 1 The relative order should be greater than or equal to H 1 or H 2 The relative order of H 1 With H 2 Expressed as

[0089] H 1 =J m s 2 +B m s+K,H 2 = -K,

[0090] (3-2) In order to compensate for the periodic disturbance of the electric spindle vibration, improve the anti-interference ability, and suppress the vibration of the electric spindle end, a workpiece end disturbance observer W is designed. 2 as follows:

[0091]

[0092] in: is a low-pass filter, w w It's Q 2 The cutoff frequency. 2 The relative order should be greater than or equal to H 3 or H 4 The relative order of H 3 With H 4 Expressed as

[0093] H 3 =-K,H 4 =J l s 2 +B l s+K

[0094] (3-3) Therefore, combining (2-2), (2-3), (3-1) and (3-2) forms a high-dynamic, high-precision electric spindle ternary speed control architecture of "feedforward + feedback + dual disturbance observer", and the total torque input to the motor can be expressed as

[0095]

[0096] Among them, ω r is the desired processing speed at the output end, is the speed tracking error.

[0097] Test Case

[0098] The inventor of the present invention simulated and verified a designed dual disturbance observer electric spindle control algorithm based on Matlab / Simulink. The disturbance torque is applied to the motor end and the processing end, such as Figure 2 As shown, a complete ternary full closed-loop controller of "PI speed control + dual disturbance observer" is formed, and three speed control methods are compared:

[0099] E1: Traditional feedforward controller (FF) + feedback controller (FB). The parameter k of the feedback controller is p With k I Set them to 0.4 and 80 respectively.

[0100] E2: Traditional feedforward controller (FF) + feedback controller (FB) + disturbance observer (DOB). The parameter k of the feedback controller is p With k I They are set to 0.4 and 80 respectively. The low-pass filter Q in the disturbance observer W is of third order and has a cutoff frequency of 10 rad / s.

[0101] E3: Proposed feedforward controller (FF) + feedback controller (FB) + dual disturbance observer (DDOB). The parameters kp and k of the feedback controller are I They are set to 0.4 and 80 respectively. Motor end disturbance observer W 1 The low pass filter Q 1 is 2nd order, cutoff frequency w f is 10rad / s; the output disturbance observer W 1 The low pass filter Q 2 is 2nd order, cutoff frequency w w is 10rad / s.

[0102] The total disturbance estimated based on the dual disturbance observer and the actual disturbance force added in the simulation are shown in Figure 5 The tracking errors of the above three speed controllers in tracking the desired output speed are shown in Figure 6From the statistical data of the tracking error, it can be seen that the tracking error obtained by the proposed method E3 is at least 27.88% lower than that of the traditional methods E1 and E2 in terms of the mean index, which proves the advancement of the method proposed in the present invention.

[0103] Based on the above detection results, it can be clearly seen that the embodiment of the present invention aims at the problem that the high-speed electric spindle is greatly affected by uncertain factors such as bearing friction and processing chatter. On the basis of feedforward control and feedback controller, a dual interference observer is designed based on the dual encoder feedback at the motor end and the output end, forming a ternary speed control architecture of "feedforward + feedback + dual interference observer"; the feedback controller adopts PI control to eliminate steady-state errors, the feedforward controller is used to improve the dynamic response capability of the electric spindle, the motor end interference observer compensates for the interference caused by its own factors such as bearing friction and torque fluctuation, the output end interference observer observes the frequency and amplitude of the chatter, and specifically designs a shaping filter and a cutoff frequency to compensate for the periodic disturbance of the electric spindle chatter, improve the anti-interference ability, and suppress the vibration of the electric spindle end; compared with the traditional lumped interference observer, it can perform separate estimation and compensation for interference sources of different amplitudes and frequencies, and can more accurately remove the interference force in the electric spindle machining process, thereby improving the speed tracking accuracy and control stability of the electric spindle.

[0104] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A full-closed-loop electric spindle ternary control method based on feedforward, feedback and dual disturbance observer, the two ends of the electric spindle are the motor end and the output end respectively, characterized in that: include: For the expected output speed, based on the dynamic model of the electric spindle, a combined control logic of a feedback controller, a feedforward controller, a first disturbance observer and a second disturbance observer is used to perform full closed-loop control on the total input torque of the electric spindle; Among them, the first disturbance observer observes the disturbance output of the motor end and a first compensation value, and the second disturbance observer observes the disturbance output of the output end and a second compensation value; the output control value of the feedback controller and the feedforward controller is linearly combined with the first compensation value and the second compensation value to control the input total torque.

2. The full-closed-loop electric spindle ternary control method according to claim 1 is characterized in that: The kinetic model is expressed as: Among them, τ m Represents the total input torque; J m Represents the inertia of the motor end; J l Indicates the inertia of the output end; B m represents the viscous damping of the motor end; B l represents the viscous damping of the output end; q m represents the shaft rotation position of the motor end; q l represents the shaft rotation position of the output end; τ f represents the friction torque at the motor end; τ w represents the machining reaction torque; K represents the stiffness of the spindle; · represents the first-order differential; ·· represents the second-order differential.

3. The full-closed-loop electric spindle ternary control method according to claim 2 is characterized in that: The feedback controller is expressed as: Wherein, C(s) represents the control value of the feedback controller; k p represents proportional gain; k I represents the integral gain; s represents the complex variable converted from time domain to frequency domain.

4. The full-closed-loop electric spindle ternary control method according to claim 2 is characterized in that: The feedforward controller is expressed as: F(s)=G1(s) -1 Wherein, G1(s) represents the transfer function from the input total torque to the speed of the output end; F(s) represents the control value of the feedforward controller;. -1 Represents the inverse function.

5. The full-closed-loop electric spindle ternary control method according to claim 2 is characterized in that: The first disturbance observer is expressed as: H1=J m s 2 +B m s+K H2=-K Wherein, H1 represents the first calculator; H2 represents the second calculator; Q1 represents the first low-pass filter, and the relative order is higher than H1 or H2; represents the first compensation value.

6. The full-closed-loop electric spindle ternary control method according to claim 2 is characterized in that: The second interferer is expressed as: H3=-K H4=J l s 2 +B l s+K Wherein, H3 represents the first calculator; H4 represents the second calculator; Q2 represents the first low-pass filter, and the relative order is higher than H3 or H4; represents the first compensation value.

7. The full-closed-loop electric spindle ternary control method according to any one of claims 2 to 6, characterized in that: The linear combination of the output control value of the feedback controller and the feedforward controller and the first compensation value and the second compensation value is expressed as: Among them, ω r represents the desired processing speed of the output end; Indicates the speed tracking error.

8. A fully closed-loop electric spindle ternary control system based on forward feedback and dual disturbance observers, the two ends of the electric spindle are the motor end and the output end, characterized in that: include: A feedback controller, a feedforward controller, a first disturbance observer, and a second disturbance observer; Among them, the first disturbance observer observes the disturbance output of the motor end to produce a first compensation value, and the second disturbance observer observes the disturbance output of the output end to produce a second compensation value; the output control value of the feedback controller and the feedforward controller is linearly combined with the first compensation value and the second compensation value to control the total input torque of the motor end.

9. A readable storage medium, characterized in that: The readable storage medium stores a computer program, and when the computer program is executed, the steps of the full-closed-loop electric spindle ternary control method according to any one of claims 1 to 7 are executed.

10. Application of the full-closed-loop electric spindle ternary control method according to any one of claims 1 to 7 in the field of mechanical processing.

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