LU505458B1

LU505458B1 - FPGA-Based Motor Parameters Adjustment Method and Device to Implement This Method

Info

Publication number: LU505458B1
Application number: LU505458A
Authority: LU
Inventors: Liyu Huang; Zuofang Yao; Haitao Dong
Original assignee: Univ Guangxi
Priority date: 2023-11-09
Filing date: 2023-11-09
Publication date: 2024-05-10

Abstract

The invention provides an FPGA-based motor gain parameters adjustment method and device, the method comprises the following steps: 1) Set the initial gain parameters of the speed and current loops to zero. Given servo motor the step signal to obtain the encoder feedback curve and enter step 2); 2) In the case of disconnecting the speed loop, the current loop gain parameter adjustment commands are sent to the servo driver through the FPGA, Kcp and Kci are adjusted. When the feedback curve reaches the desired effect, go to step 3); 3) In the case of locking the motor spindle, judging whether the feedback signal meets expectations, if the feedback signal meets expectations, enter step 4); 4) After turning on the current loop, the speed loop gain parameters Kvp and Kvi are adjusted by the FPGA until the feedback curve reaches the desired effect.

Description

DESCRIPTION LU505458

FPGA-BASED MOTOR PARAMETERS ADJUSTMENT METHOD AND

DEVICE TO IMPLEMENT THIS METHOD

TECHNICAL FIELD

[001] The invention belongs to the field of servo control, in particular to a gain parameters adjustment technique and device in a servo system.

BACKGROUND

[002] In the existing servo control system, parameters adjustment involves many aspects.

Although the final reflection 1s the gain parameters that 1s the system bandwidth, but the actual adjustment needs to consider and separately adjust many factors such as load inertia, mechanical resonance, friction suppression, etc.

[003] In the prior art, when the gain parameters of the servo system are individually adjusted, it is necessary to establish communication between the servo drive and the host computer using the network interface. Large number of data and commands need to be exchanged between the servo driver and the host computer, and the communication load is large, resulting in communication delay and even failure, which may lead to the adjustment of the gain parameters not being

SUMMARY

[004] In view of the problems existing in the above technology, the invention aims to design and provide a portable method for motor gain parameter adjustment. In the method, no network interface is used to transmit data and commands, which avoids the influence of communication network on gain parameter adjustment and realizes dynamic adjustment of gain parameters.

[005] As far as the motor gain parameter adjustment method is concerned, the technical solution of the invention to solve the above technical problem is an FPGA-based method for adjusting motor gain parameters, which comprises current loop proportional gain parameter

Kcp, current loop integral gain parameter Kci, speed loop proportional gain parameter Ky, and speed loop integral gain parameter Kyi, comprises the following steps:

1) Set the initial gain parameters of the speed and current loops to zero. Given servo LU505458 motor the step signal to obtain the encoder feedback curve and enter step 2). 2) In the case of disconnecting the speed loop, the current loop gain parameter adjustment commands are sent to the servo driver through the FPGA, Kp and Kci are adjusted. When the feedback curve reaches the desired effect, go to step 3). 3) In the case of locking the motor spindle, judging whether the feedback signal meets expectations, if the feedback signal meets expectations, enter step 4). 4) After turning on the speed loop, the speed loop gain parameters Kyp and Ky; are adjusted by the FPGA until the feedback curve reaches the desired effect.

[006] The gain parameters of the motor are adjusted through the FPGA development board and connecting to the host computer and the servo driver through the emulator, which not only avoids the data transmission and commands between the host computer and the servo controller, and reduces the network burden, but also makes the individual debugging of the gain parameters simpler and more convenient and can realize the dynamic adjustment of the gain parameters.

[007] The four buttons of the FPGA respectively control the increase of proportional gain parameters, the reduction of proportional gain parameters, the increase of integral gain parameters, and the decrease of integral gain parameters. And the switching of gain parameters is carried out by the DIP switch of the FPGA. Preferably, the DIP switch switches up to adjust the current loop gain parameters, and the four buttons correspond to Kept, Kep—, Keit, Kei—.

After the current loop gain parameters are adjusted, the DIP switch switches down to adjust the speed loop gain parameters. The four buttons correspond to Kyp+, Kvp—, Kit, and Kyi—, and each time the switch 1s pressed, the corresponding gain parameter increases or decreases by a fixed value.

[008] The gain parameters can be changed by operating the key to the FPGA, which can cause the change of the feedback response curve. As shown in Figure 3, first the proportional gain parameters are adjusted so that the response curve changes continuously until the steady-state value of the response curve reaches about 80% of the command value. Then the integral gain parameters are adjusted so that the response curve changes continuously until the overshoot value of the response curve reaches about 4.3% of the command value.

[009] Figure 1 shows a device implementing the above motor gain parameters adjustment method, the device comprises a servo driver (101), an FPGA (102) connected to the servo driver (101), host computer (103) connected to servo driver (101), a servo motor (104)

connected to the servo driver (101), an emulator (105) connected to the host computer (103) LU505458 and servo driver (101). Wherein the servo driver (101) runs the motor driver to drive the servo motor (104) to respond and obtain the motor operating state. The FPGA (102) adjusts the gain parameters of the motor and sends it to the servo driver (101); host computer (103) obtains operating data from the driver (101) and generates a feedback response curve.

[010] In order to realize the communication of the FPGA (102) and the servo driver (101), the RS485 communication interface is used. RS485 communication interface only occupies two 10s of the FPGA development board, which consumes less resources on the FPGA development board. And one FPGA development board to adjust multiple servo controller parameters at the same time can be realized. The method ensures the stability of data transmission, saves hardware costs, and optimizes the speed of program control, so that the accuracy of motor control is improved.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1: Structural diagram of motor gain parameter adjustment device

Figure 2: Motor gain parameter adjustment step diagram

Figure 3: Motor gain parameter adjustment flowchart

DETAILED DESCRIPTION OF THE INVENTION

[011] In order to have a clearer understanding of the technical features, object and effect of the invention, the specific embodiments of the invention are described in detail with reference to the accompanying figure.

[012] The Figure 1 shows the connection model of the servo driver (101), FPGA development board (102), host computer (103), servo motor (104), and emulator (105).

Wherein, the servo driver (101) runs the servo motor driver and drives the servo motor (104) to run. The FPGA development board (102) and the servo driver (101) are connected through the

RS485 communication interface. The host computer (103) obtains the feedback response curve from the servo driver (101) as the basis for judging the operating state of the motor. Further, the 4 buttons of the FPGA (102) are configured as switches 107, switches 108, switches 109, switches 110. When the FPGA DIP switch (106) 1s dialed up, the four switches represent the increase of the current loop proportional gain parameter Kcp+, the decrease of the current loop proportional gain parameter Kcp —, and the increase of the current loop integral gain parameter by Kit, current loop integral gain parameter reduced Kci—. When the DIP switch is dialed down, 4 switches respectively represent the speed loop proportional gain parameter increases LU505458

Kypt, speed loop proportional gain parameter decreases Kyp— , the velocity loop integral gain parameter is increased Kyit, and the velocity ring integral gain parameter is reduced Kyi—.

[013] According to the prior art, the parameters to be adjusted in the model are speed loop proportional gain parameter Kyp, speed loop integral gain parameter Ki, current loop proportional gain parameter Kcp and current loop integral gain parameter Kci. The object of the invention is to achieve dynamic adjustment of the pending parameters, and to optimize the system gain.

[014] The invention judges the real-time state of the system gain according to the feedback response curve obtained by the host computer and adjusts in the order of the current loop proportional gain parameter Kcp, the current loop integral gain parameter Kci, the speed loop proportional gain parameter Kyp, and the speed loop integral gain parameter Kyi. By clicking a button on the FPGA development board to increase or decrease the gain parameters, the system gain is at its best when the steady-state value of the response curve reaches about 80% of the command value and the overshoot value reaches about 4.3% of the command value.

[015] The speed loop and the current loop gain parameters are adjusted in the same way, and only the adjustment of the current loop gain parameters is detailed here. Referring to Figure 2 and Figure 3, during the operation of the servo system, the gain parameters adjustment of the invention mainly includes the following main steps:

[016] Step 200: First, In the case of disconnecting the speed loop, the FPGA DIP switch (106) is dialed up and run the servo driver (101) and the servo motor (104).

[017] Step 300: The current loop proportional gain parameter and integral gain parameter are adjusted through FPGA (102) so that the observed steady-state value reaches 80% of the command value and the overshoot value reaches 4.3%. Referring to Figure 3, the specific embodiment is: setting the current loop gain parameter to zero and adjusting Kept, Kei—, keeping no overshoot. If the steady-state value is much less than 80% of the command value, tap switch 107, each tap of the switch 107, proportional gain Kcp+1. If the steady-state value is much greater than 80% of the command value, tap switch 108, each tap of the switch 108, proportional gain Kcp — 1 until the desired curve is obtained. Then using the same method, tap switch 109 to increase the integral gain Kci and tap switch 110 to decrease the integral gain Kci, until the overshoot value of the response curve reaches about 4.3% of the command value.

[018] Locking the motor spindle so that it cannot rotate, when there is basically no error between the observed feedback signal and the command, it means that the feedback signal can accurately track the command signal, the current loop adjusting is completed, otherwise LU505458 re-proceed to step 300.

[019] Step 400: After the adjustment of the current loop gain parameters is completed, the servo motor (104) operates according to the adjusted parameters. Turning on the speed loop, the

FPGA DIP switch (106) is dialed down, and the speed loop proportional gain parameter and integral gain parameter are adjusted through the 4 buttons of the FPGA (102), so that the observed steady-state value reaches 80% of the command value, and the overshoot value reaches 4.3%. The speed loop gain parameters are adjusted in the same way as the current loop and can also be implemented with reference to Figure 3, which will not be repeated here.

[020] In summary, the method and apparatus of the present invention can realize the dynamic adjustment of the speed loop and the current loop gain parameters, so that the motor can operates in the optimal gain state.

[021] The embodiments of the invention are described above in conjunction with the accompanying figure, but the invention is not limited to the above specific embodiments, the above specific embodiments are only schematic, not restrictive. Without departing from the scope of protection of the object and claims of the present invention, ordinary skill in the art under the inspiration of the invention can also make many forms, which are within the protection of the invention.

Claims

CLAIMS LU505458

1. An FPGA-based method for adjusting motor gain parameters, which comprises current loop proportional gain parameter Kcp, current loop integral gain parameter Kei, speed loop proportional gain parameter Ky, and speed loop integral gain parameter Ky, comprises the following steps: 1) set the initial gain parameters of the speed and current loops to zero; given servo motor the step signal to obtain the encoder feedback curve and enter step 2); 2) in the case of disconnecting the speed loop, the current loop gain parameter adjustment commands are sent to the servo driver through the FPGA, Kp and Kci are adjusted; when the feedback curve reaches the desired effect, go to step 3); 3) in the case of locking the motor spindle, judging whether the feedback signal meets expectations, if the feedback signal meets expectations, enter step 4); 4) after turning on the speed loop, the speed loop gain parameters Kyp and Ki are adjusted by the FPGA until the feedback curve reaches the desired effect.

2. The gain parameters adjustment method according to claim 1, which is characterized in that the adjustment and switching of the gain parameters is carried out by a DIP switch and 4 buttons on the FPGA; wherein the DIP switch controls the switching of the current loop gain parameters and the speed loop gain parameters, and the 4 buttons respectively control the increase of proportional gain parameters, the reduction of proportional gain parameters, the increase of integral gain parameters, the reduction of integral gain parameters.

3. The gain parameters adjustment method according to claims 1 to 2, which is characterized in that the desired effect of steps 2) and 4) is to firstly adjust the proportional gain parameter so that the steady-state value of the feedback curve reaches about 80% of the command value, and then by adjusting the integral gain parameter so that the overshoot value of the feedback curve reaches about 4.3% of the command value.

4. An FPGA-based motor gain parameters adjustment device, which is characterized | U505458 as follows: the servo driver (101), which executes servo control algorithms, drives the servo motor (104) to run and obtains the motor operating status through the encoder; FPGA (102) is used to adjust the motor gain parameters and sends the parameter adjustment data to the driver (101); host computer (103) is used to acquire and observe motor feedback response curves; servo motor (104) executes the received control command, emulator (105) connects the host computer (103) and the servo driver (101).

5. The motor gain parameters adjustment device according to claim 4, which is characterized in that the FPGA (102) and the servo driver (101) are connected through an RS485 communication interface.