阅读说明：本技术 一种基于扰动观测器的机械数控机床自身振动抑制方法 (Mechanical numerical control machine tool self-vibration suppression method based on disturbance observer ) 是由 顾贤 马继光 刘鹏 朱慧江 于 2020-12-21 设计创作，主要内容包括：本发明提出的一种基于扰动观测器的机械数控机床振动抑制控制方法,首先,永磁同步伺服电机驱动机床某部件后,通过给定转速ω-m～(ref)和编码器采集的电机实际转速ω-m,得到q轴电流的参考值i-q～*并给定d轴电流参考为0；再分别通过编码器和电流传感器得到的电角度θ与电机的三相定子电流i-s(k),从而计算得到q轴的定子电流分量i-q(k),进而可计算电机转矩T-e；确定选取的名义模型G-n(-s)和低通滤波器G-q(-s)结构,计算扭转力矩估计值T-c；再将其与经过低通滤波器之后的电机转矩输入减法器,得到力矩观测值T-(cc)；从而将观测值经过负反馈,进行力矩补偿,达到调节系统的等效惯量,以此实现机械数控机床振动抑制的目的。(The invention provides a mechanical numerical control machine tool vibration suppression control method based on a disturbance observer m ref And the actual rotating speed omega of the motor acquired by the encoder m Obtaining a reference value i of the q-axis current q * And giving the d-axis current reference as 0; and the electrical angle theta and the three-phase stator current i of the motor are obtained by an encoder and a current sensor respectively s (k) Thereby calculating the stator current component i of the q axis q (k) And further can calculate the motor torque T e (ii) a Determining a selected nominal model G n ( s ) And a low-pass filter G q ( s ) Structure for calculating estimated value T of torsional moment c (ii) a Then the sum is low-pass filteredThe motor torque after the device is input into a subtracter to obtain a torque observed value T cc (ii) a Therefore, the observed value is subjected to negative feedback to perform moment compensation, and the equivalent inertia of the system is adjusted, so that the aim of suppressing the vibration of the mechanical numerical control machine tool is fulfilled.)

1. A mechanical numerical control machine tool vibration suppression control method based on a disturbance observer is characterized by comprising the following steps: firstly, after a permanent magnet synchronous servo motor drives a part of a machine tool, a given rotating speed omega is set_m ^refAnd the actual rotating speed omega of the motor acquired by the encoder_mThe deviation value is input into a rotating speed PI controller to obtain a reference value i of the q-axis current_q ^*And given a d-axis current reference i_d ^*0; then according to the electrical angle theta obtained in the encoder, the three-phase stator current i of the motor is measured through the current sensor_s(k) Calculating to obtain the stator current component i of the q axis_q(k) And then the motor torque T can be calculated_e(ii) a Selecting a nominal model G_n(_s) Determining a low-pass filter G_q(_s) Structure for obtaining an estimated value T of a torsional moment_c(ii) a Then will beThe motor torque after passing through the low-pass filter is input into a subtracter to obtain a torque observed value T_cc(ii) a And adding a load moment compensation module Q(s) and a forward gain module F(s) to adjust the equivalent inertia of the system, thereby achieving the purpose of suppressing the vibration of the mechanical numerical control machine.

2. The mechanical numerical control machine tool vibration suppression control method based on the disturbance observer according to claim 1, characterized in that: reference value i of q-axis current_q ^*The acquisition method comprises the following steps: will refer to the rotation speed omega_m ^refWith the actual speed omega measured by the encoder_mDifference e between_nThe input is a rotating speed PI controller G shown in a formula (1)_PI(s) passing through an equivalent low-pass filter G of a torque set value shown in the formula (2)_f(s) to obtain said reference value i of the q-axis current_q ^*；

Wherein k is_pAnd k_iRespectively, proportional gain and integral gain of the rotating speed PI controller, and s is a complex variable.

3. The mechanical numerical control machine tool vibration suppression control method based on the disturbance observer according to claim 1, characterized in that: the motor torque T_eThe calculation method comprises the following steps: obtaining the electrical angle theta of the permanent magnet synchronous motor from the encoder, and measuring the three-phase stator current i of the motor through the current sensor_s(k) Obtaining the alpha-beta axis component i of the stator current after Clark conversion of formula (3)_α(k)、i_β(k) And then obtaining a dq axis component i of the stator current at the moment k through Park conversion of a formula (4)_d(k)、i_q(k) Finally, it can be calculated from equation (5)To motor torque T_e；

Wherein p is_nRepresenting the number of pole pairs; psi_fIt represents the permanent magnet flux linkage of the permanent magnet synchronous servo motor.

4. The mechanical numerical control machine tool vibration suppression control method based on the disturbance observer according to claim 1, characterized in that: the observed value T of the torsional moment_ccThe acquisition method comprises the following steps: selecting a nominal model G_n(_s) And a low-pass filter G_q(_s) The estimated value of the torsional moment T is obtained by the equation (8) as shown in the equations (6) and (7), respectively_cThen, the torque estimated value T is used_cAnd through a low pass filter G_q(_s) Then the motor torque is input into a subtracter to obtain a torque observed value T_cc；

In the formula J_mThe rotational inertia of the motor shaft;

in the formula T_qIs the time constant of the filter;

。

5. the mechanical numerical control machine tool vibration suppression control method based on the disturbance observer according to claim 1, characterized in that: the implementation method of the moment compensation comprises the following steps: observing the torque_ccAfter passing through a moment compensation module Q(s), the reference value i of the input q-axis current is compared with the reference value i of the input q-axis current_q ^*The forward gain module F(s) enters a subtracter and is fed back to the motor torque, so that the aim of increasing the system damping is fulfilled, and the effect of vibration suppression is realized;

in the formula, K is a feedback coefficient,

F(s)＝K(J_L+J_L/K) (11) 。

Technical Field

The invention relates to a mechanical numerical control machine tool vibration suppression control method based on a disturbance observer, which can be applied to the application control occasion of the mechanical numerical control machine tool.

Background

The numerical control machine tool is one of the most widely applied machine tools at present, is directly related to the development of the industrial field in China, and with the continuous updating and development of the numerical control machine tool, the original power mode can not meet the requirements of the current market, and the numerical control machine tool gradually develops to the current servo system. The permanent magnet synchronous servo motor is increasingly applied to a feeding system of a numerical control machine tool due to the excellent control performance of the permanent magnet synchronous servo motor. In order to control the control accuracy of the machine tool position, a traditional automatic control method based on visual conduction is proposed, numerical control gear control is performed by combining photoelectric parameters, the rotational inertia of a gear is accurately corrected, but in the machining process, the traditional automatic control method is still easily influenced by vibration factors of the machine tool, such as the vibration of a sliding table, and is not beneficial to the requirement of high accuracy.

Aiming at the problem, a mechanical numerical control machine tool vibration suppression control method based on a disturbance observer is provided. Firstly, after the permanent magnet synchronous servo motor drives the sliding table, the rotating speed omega is given_m ^refAnd the actual rotating speed omega of the motor acquired by the encoder_mThe deviation value is input into a rotating speed PI controller to obtain a reference value i of the q-axis current_q ^*And given a d-axis current reference i_d ^*0; then according to the electrical angle theta obtained in the encoder, the three-phase stator current i of the motor is measured through the current sensor_s(k) Calculating to obtain the stator current component i of the q axis_q(k) And then the motor torque T can be calculated_e(ii) a Selecting a nominal model G_n(_s) Determining a low-pass filter G_q(_s) Structure for obtaining an estimated value T of a torsional moment_c(ii) a Then inputting the torque and the motor torque after passing through the low-pass filter into a subtracter to obtain a torque observed value T_cc(ii) a And adding a load moment compensation module Q(s) and a forward gain module F(s) to adjust the equivalent inertia of the system, thereby achieving the purpose of suppressing the vibration of the mechanical numerical control machine.

Disclosure of Invention

The technical problem is as follows: in view of the above description, the proposed mechanical numerical control machine tool self-vibration suppression method based on the disturbance observer achieves the purpose of mechanical vibration suppression, so that the requirement of high precision of the numerical control machine tool is met, and the vibration suppression algorithm is simple and is easy to implement in an actual system.

The technical scheme is as follows: a mechanical numerical control machine tool vibration suppression control method based on a disturbance observer comprises the following steps: firstly, after a permanent magnet synchronous servo motor drives a part of a machine tool, a given rotating speed omega is set_m ^refAnd the actual rotating speed omega of the motor acquired by the encoder_mThe deviation value is input into a rotating speed PI controller to obtain a reference value i of the q-axis current_q ^*And given a d-axis current reference i_d ^*0; then according to the electrical angle theta obtained in the encoder, the three-phase stator current i of the motor is measured through the current sensor_s(k) Calculating to obtain the stator current component i of the q axis_q(k) And then the motor torque T can be calculated_e(ii) a Selecting a nominal model G_n(_s) Determining a low-pass filter G_q(_s) Structure for obtaining an estimated value T of a torsional moment_c(ii) a Then inputting the torque and the motor torque after passing through the low-pass filter into a subtracter to obtain a torque observed value T_cc(ii) a And adding a load moment compensation module Q(s) and a forward gain module F(s) to adjust the equivalent inertia of the system, thereby achieving the purpose of suppressing the vibration of the mechanical numerical control machine.

As an optimization, the reference value i of the q-axis current_q ^*The acquisition method comprises the following steps: will refer to the rotation speed omega_m ^refWith the actual speed omega measured by the encoder_mDifference e between_nThe input is a rotating speed PI controller G shown in a formula (1)_PI(s) passing through an equivalent low-pass filter G of a torque set value shown in the formula (2)_f(s) to obtain said reference value i of the q-axis current_q ^*。

Wherein k is_pAnd k_iRespectively, proportional gain and integral gain of the rotating speed PI controller, and s is a complex variable.

As an optimization, the motor torque T_eThe calculation method comprises the following steps: obtaining the electrical angle theta of the permanent magnet synchronous motor from the encoder, and measuring the three-phase stator current i of the motor through the current sensor_s(k) Obtaining the alpha-beta axis component i of the stator current after Clark conversion of formula (3)_α(k)、i_β(k) And then obtaining a dq axis component i of the stator current at the moment k through Park conversion of a formula (4)_d(k)、i_q(k) Finally, the motor torque T can be calculated by the formula (5)_e。

Wherein p is_nRepresenting the number of pole pairs; psi_fIt represents the permanent magnet flux linkage of the permanent magnet synchronous servo motor.

As an optimization, the observed value of the torsional moment T_ccThe acquisition method comprises the following steps: selecting a nominal model G_n(_s) And a low-pass filter G_q(_s) The estimated value of the torsional moment T is obtained by the equation (8) as shown in the equations (6) and (7), respectively_cThen, the torque estimated value T is used_cAnd through a low pass filter G_q(_s) Then the motor torque is input into a subtracter to obtain a torque observed value T_cc。

In the formula J_mThe moment of inertia of the motor shaft.

In the formula T_qIs the time constant of the filter.

As optimization, the implementation method of the moment compensation comprises the following steps: observing the torque_ccAfter passing through a moment compensation module Q(s), the reference value i of the input q-axis current is compared with the reference value i of the input q-axis current_q ^*The forward gain module F(s) enters a subtracter and is fed back to the motor torque, so that the aim of increasing the system damping is fulfilled, and the effect of vibration suppression is realized.

In the formula, K is a feedback coefficient,

F(s)＝K(J_L+J_L/K) (11)。

has the advantages that: the invention relates to a mechanical vibration suppression method based on a disturbance observer, which feeds back a torsional moment from the viewpoint of eliminating the influence of the load moment on the regulation of the rotating speed of a system, namely feeds back the load moment obtained by the motor torque and a torsional moment estimated value to compensate to a motor torque given end, so that the characteristics of a controlled object can be the same as those of a rigidly connected load, and better rotating speed response is achieved, thereby achieving the purpose of suppressing the vibration of a mechanical numerical control machine.

Drawings

FIG. 1 is a diagram of a model of a flexible linkage system for a robotic arm;

FIG. 2 is a control block diagram of a mechanical numerical control machine tool vibration suppression method based on a disturbance observer;

FIG. 3 is a three-phase current waveform and a rotational speed response waveform after a permanent magnet synchronous servo motor drives a flexible joint of an equivalent mechanical arm;

FIG. 4 is a system speed response waveform after applying a vibration suppression strategy.

Detailed Description

The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.

A model diagram of a flexible connecting rod system of a permanent magnet synchronous servo motor driven sliding table in a numerical control machine tool is shown in fig. 1, and the model diagram is subjected to simplified analysis, so that an actual system can be converted into a motor-spring-loaded two-mass system.

As shown in fig. 2, the method comprises the following steps:

step 1: obtaining a reference value i of the q-axis current_q ^*：

Will refer to the rotation speed omega_m ^refWith the actual speed omega measured by the encoder_mDifference e between_nThe input is a rotating speed PI controller G shown in a formula (1)_PI(s) passing through an equivalent low-pass filter G of a torque set value shown in the formula (2)_f(s) to obtain said reference value i of the q-axis current_q ^*。

Wherein k is_pAnd k_iRespectively, proportional gain and integral gain of the rotating speed PI controller, and s is a complex variable.

Step 2: obtaining motor torque T_eThe method of (1):

obtaining the electrical angle theta of the permanent magnet synchronous motor from the encoder, and measuring the three-phase stator current i of the motor through the current sensor_s(k) Obtaining the alpha-beta axis component i of the stator current after Clark conversion of formula (3)_α(k)、i_β(k) And then obtaining a dq axis component i of the stator current at the moment k through Park conversion of a formula (4)_d(k)、i_q(k) Finally, the motor torque T can be calculated by the formula (5)_e。

Wherein p is_nRepresenting the number of pole pairs; psi_fIt represents the permanent magnet flux linkage of the permanent magnet synchronous servo motor.

And step 3: obtaining observed value T of torsion moment_cc：

Selecting a nominal model G_n(_s) And a low-pass filter G_q(_s) The estimated value of the torsional moment T is obtained by the equation (8) as shown in the equations (6) and (7), respectively_cThen, the torque estimated value T is used_cAnd through a low pass filter G_q(_s) Then the motor torque is input into a subtracter to obtain a torque observed value T_cc。

In the formula J_mThe moment of inertia of the motor shaft.

In the formula T_qIs the time constant of the filter.

And 4, step 4: the implementation method of the moment compensation comprises the following steps:

observing the torque_ccAfter passing through a moment compensation module Q(s), the reference value i of the input q-axis current is compared with the reference value i of the input q-axis current_q ^*The forward gain module F(s) enters a subtracter and is fed back to the motor torque, so that the aim of increasing the system damping is fulfilled, and the effect of vibration suppression is realized.

In the formula, K is a feedback coefficient,

F(s)＝K(J_L+J_L/K) (11)

firstly, after a permanent magnet synchronous servo motor drives a sliding table, the rotating speed omega is given_m ^refAnd the actual rotating speed omega of the motor acquired by the encoder_mThe deviation value is input into a rotating speed PI controller to obtain a reference value i of the q-axis current_q ^*And given a d-axis current reference i_d ^*0; then according to the electrical angle theta obtained in the encoder, the three-phase stator current i of the motor is measured through the current sensor_s(k) Calculating to obtain the stator current component i of the q axis_q(k) And then the motor torque T can be calculated_e(ii) a Selecting a nominal model G_n(_s) Determining a low-pass filter G_q(_s) Structure for obtaining an estimated value T of a torsional moment_c(ii) a Then inputting the torque and the motor torque after passing through the low-pass filter into a subtracter to obtain a torque observed value T_cc(ii) a And adding a load moment compensation module Q(s) and a forward gain module F(s) to adjust the equivalent inertia of the system, thereby achieving the purpose of suppressing the vibration of the mechanical numerical control machine.

The three-phase current waveform and the rotating speed response waveform of the permanent magnet synchronous servo motor after driving the flexible joint of the equivalent sliding table are shown in fig. 3, the three-phase current sine degree is good, the rotating speed has an obvious oscillation phenomenon, the rising time is about 0.7s, and the overshoot sigma% is 20.4%. FIG. 4 shows the setting K is 0.3, T_qWhen the system rotation speed waveform is 0.002, the system rotation speed waveform after the control strategy is applied shows that the system jitter phenomenon is basically eliminated, the rising time is reduced to 0.03s, the overshoot phenomenon is basically avoided, and the good vibration suppression performance of the control strategy is reflected.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.