Control system and method of high-speed galvanometer motor

Abstract

The invention provides a control system and method for a high-speed galvanometer motor, and the method comprises the steps: generating a speed instruction signal according to the difference between a position instruction signal and an estimated position signal, generating a current instruction signal according to the difference between the speed instruction signal and the estimated speed signal, generating a drive voltage according to the difference between the current instruction signal and a feedback current, and outputting the drive voltage. A driving current is generated according to the driving voltage, an actual angle is output according to the driving current, the actual angle is converted into a position signal, the position signal output by the grating encoder and the driving voltage output by the current control module are received, and signal processing is carried out by adopting a dynamic adjustment observation noise covariance strategy; according to the invention, filtering processing is carried out by using a dynamic adjustment observation noise covariance strategy, a high-precision feedback signal is provided for the position and speed control module, and then corresponding control is carried out. And high-speed and high-precision position control of the galvanometer motor is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and particularly to a control system and method for a high-speed galvanometer motor. Background Art

[0002] A galvanometer motor is a beam control device based on electromagnetic or piezoelectric drive principles. It realizes dynamic scanning of laser or other light paths by rapidly deflecting a reflecting mirror. Due to its fast response speed and high precision, it is widely used in fields such as laser processing, optical measurement, lidar (LiDAR), 3D printing, and medical equipment. A traditional galvanometer motor system usually consists of an X / Y two-axis galvanometer, a control module, and an optical lens group. Its core performance indicators include scanning speed, positioning accuracy, dynamic response bandwidth, and thermal stability. Among them, a grating encoder is generally used to accurately measure the motor angle and speed. However, due to various interferences on the grating encoder during high-speed operation, especially the significant impact of time-varying factors on its measurement, and the introduction of differential calculation in the motor speed calculation, the noise is further amplified, severely restricting the control accuracy and dynamic response of the system. Traditional filters are difficult to adapt to high-precision and high-dynamic control requirements when dealing with time-varying noise. Summary of the Invention

[0003] The present invention is made to solve the above problems, and aims to provide a control system and method for a high-speed galvanometer motor.

[0004] The present invention provides a control system for a high-speed galvanometer motor, having the following characteristics: including a position control module for generating a speed command signal based on the difference between a position command signal and an estimated position signal, where the initial value of the estimated position signal is 0; a speed control module connected to the position control module for generating a current command signal based on the difference between the speed command signal and an estimated speed signal, where the initial value of the estimated speed signal is 0; a current control module connected to the speed control module for generating a drive voltage based on the difference between the current command signal and a feedback current, where the initial value of the feedback current is 0; a drive circuit connected to the current control module for generating a drive current based on the drive voltage; a galvanometer motor connected to the drive circuit for outputting an actual angle based on the drive current; a grating encoder connected to the galvanometer motor for converting the actual angle into a position signal; and a feedback filtering module connected to the grating encoder, the current control module, the position control module, and the speed control module respectively, for receiving the position signal output by the grating encoder and the drive voltage output by the current control module, and performing signal processing using a dynamic adjustment observation noise covariance strategy to update the estimated position signal and the estimated speed signal, and outputting them to the position control module and the speed control module respectively.

[0005] The present invention provides a control method for a high-speed galvanometer motor, which has the following characteristics and includes the following steps: Step S1, generating a speed command signal based on the difference between the position command signal and the estimated position signal, where the initial value of the estimated position signal is 0; Step S2, generating a current command signal based on the difference between the speed command signal and the estimated speed signal, where the initial value of the estimated speed signal is 0; Step S3, generating a drive voltage based on the difference between the current command signal and the feedback current, where the initial value of the feedback current is 0; Step S4, generating a drive current based on the drive voltage; Step S5, outputting the actual angle based on the drive current; Step S6, converting the actual angle into a position signal; Step S7, receiving the position signal output by the grating encoder and the drive voltage output by the current control module, and performing signal processing using a dynamic adjustment of the observation noise covariance strategy to update the estimated position signal and the estimated speed signal, and respectively outputting them to the position control module and the speed control module.

[0006] In the control method for the high-speed galvanometer motor provided by the present invention, it may further have the following characteristics: Among them, Step S7 includes the following sub-steps: Step S7-1, calculating the original rotational speed of the galvanometer motor based on the position signal at time k, the position signal at time k-1, and the sampling period of the position signal, and obtaining it according to the following formula:

[0007]

[0008] In the formula, θ m (k) represents the position signal at time k, θ m (k-1) represents the position signal at time k-1, T s represents the sampling period of the position signal; Step S7-2, receiving the position signal and the drive voltage, and performing signal processing using a dynamic adjustment of the observation noise covariance strategy to update the estimated position signal and the estimated speed signal, and obtaining them according to the following formula:

[0009]

[0010] In the formula, is the estimated position signal, is the estimated speed signal, k k is the filter gain, H is the observation matrix θ m (k) represents the position signal at time k, ω m (k) represents the rotational speed of the motor at time k, and are respectively the estimated position and the estimated rotational speed of the filter at time k.

[0011] In the control method for the high-speed galvanometer motor provided by the present invention, it may further have the following characteristics: Among them, the estimated position at time k and the estimated rotational speed at time k Obtained according to the following formula:

[0012]

[0013] In the formula, A d is the state matrix of system discretization, B d is the input matrix of system discretization, is the estimated position at time k-1, is the estimated rotational speed at time k-1, u m is the drive voltage, and the given initial value is 0 for the initial calculation.

[0014] In the control method of the high-speed galvanometer motor provided by the present invention, it may further have the following characteristics: Among them, the state matrix A d of system discretization and the input matrix B d of system discretization are obtained according to the following formula:

[0015]

[0016] In the formula, e is the natural constant, T s represents the sampling period of the position signal. In matrices A0 and B0, k a is the motor torque coefficient, k e is the back electromotive force coefficient, R w is the resistance of the motor winding, b m is the motor viscous damping coefficient, J m is the rotor moment of inertia.

[0017] In the control method of the high-speed galvanometer motor provided by the present invention, it may further have the following characteristics: Among them, the filter gain k k is obtained according to the following formula:

[0018]

[0019] In the formula, A d is the state matrix of system discretization, is the prior error covariance matrix, H T is the observation matrix transpose matrix of, and R is the covariance matrix of the observation noise.

[0020] In the control method of the high-speed galvanometer motor provided by the present invention, it may further have the following characteristics: Among them, the prior error covariance matrix is obtained according to the following formula:

[0021]

[0022] In the formula, A d is the state matrix of system discretization, and P k-1 is the error covariance matrix calculated at the (k - 1)th moment. A d T is the transpose matrix of the state matrix of system discretization, and Q is the covariance matrix of process noise.

[0023] In the control method of the high - speed galvanometer motor provided by the present invention, it can also have the following feature: among them, the error covariance matrix calculated at the (k - 1)th moment is obtained according to the following formula:

[0024]

[0025] In the formula, k k-1 is the filter gain calculated at the (k - 1)th moment, is the prior error covariance matrix calculated at the (k - 1)th moment, and I is the identity matrix H is the observation matrix

[0026] In the control method of the high - speed galvanometer motor provided by the present invention, it can also have the following feature: among them, the covariance matrix Q of process noise is obtained according to the following formula:

[0027]

[0028] In the formula, σ θ is the angle represented by the minimum measurement unit of the grating scale, and T s represents the sampling period of the position signal.

[0029] In the control method of the high - speed galvanometer motor provided by the present invention, it can also have the following feature: among them, the covariance matrix R of observation noise is obtained according to the following formula:

[0030]

[0031] In the formula, E1, E2, and E3 are diagonal coefficient matrices ω m (k) represents the motor speed at the kth moment. Then, using the characteristics of the diagonal matrix, the formula for obtaining the covariance matrix R of the observation noise obtained above is decomposed into two equations as follows:

[0032]

[0033] In the formula, r θ is the mean square error of angle measurement noise, and r ω is the mean square error of speed measurement noise. Fitting the mean square error of angle measurement noise and the mean square error of speed measurement noise corresponding to different speed conditions with the above equations, we get e1θ , e 1ω , e 2θ , e 2ω , e 3θ , e 3ω value

[0034] Functions and effects of the invention

[0035] According to the control system and method of the high-speed galvanometer motor involved in the present invention, because in step S1, a speed command signal is generated based on the difference between the position command signal and the estimated position signal, where the initial value of the estimated position signal is 0; in step S2, a current command signal is generated based on the difference between the speed command signal and the estimated speed signal, where the initial value of the estimated speed signal is 0; in step S3, a drive voltage is generated based on the difference between the current command signal and the feedback current, where the initial value of the feedback current is 0; in step S4, a drive current is generated based on the drive voltage; in step S5, an actual angle is output based on the drive current; in step S6, the actual angle is converted into a position signal; in step S7, the position signal output by the grating encoder and the drive voltage output by the current control module are received and signal processing is performed using a dynamic adjustment observation noise covariance strategy to update the estimated position signal and the estimated speed signal, and they are respectively output to the position control module and the speed control module. Therefore, the control system and method of the high-speed galvanometer motor of the present invention use a dynamic adjustment observation noise covariance strategy to filter the speed and position signals of the motor, and provide high-precision feedback signals for the position control and speed control modules, and then perform current, speed, and position control, ultimately achieving high-speed and high-precision position control of the galvanometer motor, enhancing the adaptability and robustness of the galvanometer motor system under high dynamic performance requirements. Description of the drawings

[0036] Figure 1 It is a schematic diagram of the modules of the control system of the high-speed galvanometer motor in Embodiment 1 of the present invention.

[0037] Figure 2 It is a schematic flowchart of the control method of the high-speed galvanometer motor in Embodiment 1 of the present invention. Detailed implementation manners

[0038] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0039] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the following embodiments will specifically elaborate on the control system and method of the high-speed galvanometer motor of the present invention in conjunction with the accompanying drawings.

[0040] Embodiment 1

[0041] Figure 1 It is a schematic diagram of the modules of the control system 100 of the high-speed galvanometer motor in Embodiment 1 of the present invention.

[0042] As Figure 1 shown, the control system 100 of the high-speed galvanometer motor in Embodiment 1 of the present invention includes: a position control module 10, a speed control module 20, a current control module 30, a drive circuit 40, a galvanometer motor 50, a grating encoder 60, and a feedback filtering module 70.

[0043] The position control module 10 generates a speed command signal based on the difference Δθ between the position command signal and the estimated position signal wherein, the initial value of the estimated position signal is 0, and the position control module 10 adopts PID control.

[0044] The speed control module 20 is connected to the position control module 10 and is used to generate a current command signal based on the difference Δω between the speed command signal and the estimated speed signal wherein, the initial value of the estimated speed signal is 0, and the speed control module 20 adopts PID control.

[0045] The current control module 30 is connected to the speed control module 20 and is used to generate a drive voltage u based on the difference Δi between the current command signal m and the feedback current i′, wherein, the initial value of the feedback current i′ is 0, and the current control module 30 adopts PID control.

[0046] The drive circuit 40 is connected to the current control module 30 and is used to generate a drive current i according to the drive voltage u m The drive circuit 40 is also used to generate a feedback current i′ and output it to the current control module 30.

[0047] The galvanometer motor 50 is connected to the drive circuit 40 and is used to output an actual angle θ according to the drive current i.

[0048] The grating encoder 60 is connected to the galvanometer motor 50 and is used to convert the actual angle θ into a position signal θ m .

[0049] The feedback filtering module 70 is respectively connected to the grating encoder 60, the current control module 30, the position control module 10, and the speed control module 20, and is used to receive the position signal θ output by the grating encoder 60 m and the drive voltage u output by the current control module 30 m and performs signal processing by adopting a dynamic adjustment observation noise covariance strategy to update the estimated position signal and the estimated speed signal and respectively outputs them to the position control module 10 and the speed control module 20

[0050] Figure 2 is a schematic flow chart of the control method of the high-speed galvanometer motor in Embodiment 1 of the present invention

[0051] As Figure 2 shown, the control method of the high-speed galvanometer motor in this embodiment is applied to the control system 100 of the high-speed galvanometer motor, and specifically includes the following steps

[0052] Step S1, generating a speed command signal according to the difference Δθ between the position command signal and the estimated position signal wherein, the initial value of the estimated position signal is 0

[0053] The position control module 10 generates a speed command signal using PID control according to the difference Δθ between the position command signal and the estimated position signal and transports it to the speed control module 20

[0054] Step S2, generating a current command signal according to the difference Δω between the speed command signal and the estimated speed signal wherein, the initial value of the estimated speed signal is 0

[0055] The speed control module 20 generates a current command signal using PID control according to the difference Δω between the speed command signal and the estimated speed signal and transports it to the current control module 30

[0056] Step S3, generating a drive voltage u according to the difference Δi between the current command signal m and the feedback current i′, wherein, the initial value of the feedback current i′ is 0

[0057] The current control module 30 generates a drive voltage u according to the current command signal The difference Δi from the feedback current i′ is used to generate a drive voltage u by PID control m , and is delivered to the drive circuit 40.

[0058] Step S4: Generate a drive current i based on the drive voltage u m .

[0059] The drive circuit 40 generates a drive current i according to the drive voltage u m , delivers it to the galvanometer motor 50, and the drive circuit 40 is also used to generate a feedback current i' and output it to the current control module 30.

[0060] Step S5: Output the actual angle θ according to the drive current i

[0061] The galvanometer motor 50 outputs the actual angle θ according to the drive current i

[0062] Step S6: Convert the actual angle θ into a position signal θ m .

[0063] The grating encoder 60 converts the actual angle θ into a position signal θ m , and delivers it to the feedback filter module 70.

[0064] Step S7: Receive the position signal θ output by the grating encoder 60 m and the drive voltage u output by the current control module 30 m and perform signal processing using a dynamic adjustment of the observation noise covariance strategy to update the estimated position signal and the estimated speed signal and output them to the position control module 10 and the speed control module 20 respectively.

[0065] Among them, step S7 includes the following sub-steps:

[0066] Step S7-1: Calculate the original rotational speed of the galvanometer motor 50 according to the position signal at time k, the position signal at time k-1, and the sampling period of the position signal, obtained according to the following formula:

[0067]

[0068] In the formula, θ m (k) represents the position signal at time k, θ m (k-1) represents the position signal at time k-1, and T s represents the sampling period of the position signal.

[0069] Step S7-2: Receive the position signal θ m and the drive voltage u m and perform signal processing using a dynamic adjustment of the observation noise covariance strategy to update the estimated position signal and the estimated speed signal is obtained according to the following formula:

[0070]

[0071] wherein, is the estimated position signal, is the estimated speed signal, and k k is the filter gain, and H is the observation matrix θ m (k) represents the position signal at time k, and ω m (k) represents the motor speed at time k, and are respectively the estimated position and the estimated speed of the filter at time k.

[0072] The estimated position at time k and the estimated speed at time k are obtained according to the following formula:

[0073]

[0074] wherein, A d is the state matrix of system discretization, B d is the input matrix of system discretization, is the estimated position at time k - 1, is the estimated speed at time k - 1, u m is the drive voltage, and the given initial value is 0 for initial calculation.

[0075] The state matrix A of system discretization d and the input matrix B of system discretization d are obtained according to the following formula:

[0076]

[0077] wherein, e is the natural constant, T s represents the sampling period of the position signal. In matrices A0 and B0, k a is the motor torque coefficient, k e is the back electromotive force coefficient, R w is the resistance of the motor winding, b m is the motor viscous damping coefficient, J m is the rotor inertia.

[0078] The filter gain k k is obtained according to the following formula:

[0079]

[0080] In the formula, A d is the state matrix of system discretization, is the prior error covariance matrix, H T is the observation matrix of the transpose matrix, and R is the covariance matrix of the observation noise.

[0081] The prior error covariance matrix is obtained according to the following formula:

[0082]

[0083] In the formula, A d is the state matrix of system discretization, P k-1 is the error covariance matrix calculated at the (k - 1)th moment, A d T is the transpose matrix of the state matrix of system discretization, and Q is the covariance matrix of the process noise.

[0084] The error covariance matrix calculated at the (k - 1)th moment is obtained according to the following formula:

[0085]

[0086] In the formula, k k-1 is the filter gain calculated at the (k - 1)th moment, is the prior error covariance matrix calculated at the (k - 1)th moment, I is the identity matrix H is the observation matrix

[0087] The covariance matrix Q of the process noise is obtained according to the following formula:

[0088]

[0089] In the formula, σ θ is the angle represented by the minimum measurement unit of the grating scale, T s represents the sampling period of the position signal.

[0090] The covariance matrix R of the observation noise is obtained according to the following formula:

[0091]

[0092] In the formula, E1, E2, and E3 are diagonal coefficient matrices ω m (k) represents the motor speed at the kth moment. Then, using the characteristics of the diagonal matrix, the formula for the covariance matrix R of the observation noise obtained above is decomposed into two equations as follows:

[0093]

[0094] where r θ is the mean square error of the angle measurement noise, and r ω is the mean square error of the rotational speed measurement noise. By fitting the mean square error of the angle measurement noise and the mean square error of the rotational speed measurement noise corresponding to different rotational speed conditions to the above equation, the values of e 1θ , e 1ω , e 2θ , e 2ω , e 3θ , e 3ω are obtained.

[0095] Functions and Effects of the Embodiment

[0096] In the control system and method of the high-speed galvanometer motor in Embodiment 1, the dynamic adjustment of the observation noise covariance strategy is used to filter the motor speed and position signals, and high-precision feedback signals are provided for the position control and speed control modules. Subsequently, current, speed, and position control are performed, and finally, high-speed and high-precision position control of the galvanometer motor is achieved, enhancing the adaptability and robustness of the galvanometer motor system under high dynamic performance requirements.

[0097] Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A control system for a high-speed galvanometer motor, characterized in that: include: A position control module, used for generating a speed command signal according to a difference between a position command signal and an estimated position signal, wherein an initial value of the estimated position signal is 0; A speed control module, connected to the position control module, for generating a current command signal according to a difference between the speed command signal and an estimated speed signal, wherein an initial value of the estimated speed signal is 0; A current control module, connected to the speed control module, for generating a driving voltage according to a difference between the current command signal and a feedback current, wherein an initial value of the feedback current is 0; A driving circuit, connected to the current control module, and configured to generate a driving current according to the driving voltage; A galvanometer motor, connected to the drive circuit, and configured to output an actual angle according to the drive current; A grating encoder connected to the galvanometer motor and used for converting the actual angle into a position signal; The feedback filtering module is respectively connected to the grating encoder, the current control module, the position control module and the speed control module, and is used to receive the position signal output by the grating encoder and the driving voltage output by the current control module and adopt a dynamic adjustment observation noise covariance strategy to perform signal processing, update the estimated position signal and the estimated speed signal, and output them to the position control module and the speed control module respectively.

2. A control method for a high-speed galvanometer motor, applied to the control system of the high-speed galvanometer motor as claimed in claim 1, characterized in that: The following steps are involved: Step S1, generating a speed command signal according to the difference between a position command signal and an estimated position signal, wherein the initial value of the estimated position signal is 0; Step S2, generating a current command signal according to the difference between the speed command signal and the estimated speed signal, wherein the estimated speed signal has an initial value of 0; Step S3, generating a driving voltage according to the difference between the current command signal and the feedback current, wherein the initial value of the feedback current is 0; Step S4, generating a driving current according to the driving voltage; Step S5, outputting the actual angle according to the driving current; Step S6, converting the actual angle into a position signal; Step S7, receiving the position signal output by the grating encoder and the driving voltage output by the current control module and adopting a dynamic adjustment observation noise covariance strategy to perform signal processing, update the estimated position signal and the estimated speed signal, and output them to the position control module and the speed control module respectively.

3. The control method of the high-speed galvanometer motor according to claim 2, characterized in that: in, The step S7 comprises the following sub-steps: Step S7-1, calculate the original speed of the galvanometer motor according to the position signal at time k, the position signal at time k-1 and the sampling period of the position signal, and obtain it according to the following formula: In the formula, θ m (k) represents the position signal at time k, θ m (k-1) represents the position signal at time k-1, T s Indicates the sampling period of the position signal; Step S7-2, receiving the position signal and the driving voltage and performing signal processing by adopting a dynamic adjustment strategy for the observed noise covariance, updating the estimated position signal and the estimated speed signal, and obtaining the following formula: In the formula, To estimate the position signal, To estimate the speed signal, k k is the filter gain, H is the measurement matrix θ m (k) represents the position signal at time k, ω m (k) represents the motor speed at time k, and are the estimated position and estimated speed of the filter at time k respectively.

4. The control method of the high-speed galvanometer motor according to claim 3, characterized in that: in, Estimated position at time k and the estimated speed at time k According to the following formula: In the formula, A d is the discretized state matrix of the system, B d is the input matrix of the system discretization, is the estimated position at time k-1, is the estimated speed at time k-1, u m is the driving voltage, given The initial value of is 0 for the initial calculation.

5. The control method of the high-speed galvanometer motor according to claim 4, characterized in that: in, The state matrix A of the system discretization d and the input matrix B of the system discretization d According to the following formula: In the formula, e is a natural constant, T s Represents the sampling period of the position signal. In matrices A0 and B0, k a is the motor torque coefficient, k e is the back electromotive force coefficient, R w is the resistance of the motor winding, b m is the motor viscous damping coefficient, J m is the rotor moment of inertia.

6. The control method of the high-speed galvanometer motor according to claim 3, characterized in that: in, Filter gain k k According to the following formula: In the formula, A d is the discretized state matrix of the system, is the prior error covariance matrix, H T is the observation matrix is the transposed matrix of , and R is the covariance matrix of the observation noise.

7. The control method of the high-speed galvanometer motor according to claim 6, characterized in that: in, Prior error covariance matrix According to the following formula: In the formula, A d is the discretized state matrix of the system, P k-1 is the error covariance matrix calculated at time k-1, A d T is the transposed matrix of the discretized state matrix of the system, and Q is the covariance matrix of the process noise.

8. The control method of the high-speed galvanometer motor according to claim 7, characterized in that: in, The error covariance matrix calculated at time k-1 is obtained according to the following formula: In the formula, k k-1 is the filter gain calculated at time k-1, is the prior error covariance matrix calculated at time k-1, and I is the unit matrix H is the observation matrix 9. The control method of the high-speed galvanometer motor according to claim 7, characterized in that: in, The covariance matrix Q of the process noise is obtained according to the following formula: In the formula, σ θ The angle represented by the smallest measurement unit of the grating ruler, T s Indicates the sampling period of the position signal.

10. The control method of the high-speed galvanometer motor according to claim 6, characterized in that: in, The covariance matrix R of the observation noise is obtained according to the following formula: Where E1, E2, and E3 are diagonal coefficient matrices ω m (k) represents the motor speed at time k. Then, using the diagonal matrix characteristics, the formula for obtaining the covariance matrix R of the observation noise is decomposed into two equations as shown below: In the formula, r θ is the mean square error of angle measurement noise, r ω is the mean square error of the speed measurement noise. The angle measurement noise mean square error and the speed measurement noise mean square error corresponding to different speed conditions are fitted with the above equation to obtain e 1θ 、e 1ω 、e 2θ 、e 2ω 、e 3θ 、e 3ω The value of .

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