Servo driver and its gain fast self-adjusting method

Abstract

The present application provides a gain quick self-adjusting method, which is applied to a servo driver connected with a motor and includes the following steps: obtaining a current feedback signal of the motor and calculating a torque estimation value; obtaining a position feedback signal of the motor and calculating an acceleration estimation value; calculating a system inertia according to the torque estimation value and the acceleration estimation value, wherein the system inertia represents an inertia of the motor when carrying a specific load; calculating a corresponding estimation control gain according to the system inertia; and adjusting the servo driver according to the estimation control gain.

Description

Technical Field

[0001] This invention relates to a servo driver, and more particularly to a servo driver capable of automatically adjusting control gain, as well as a method for rapid gain self-adjustment used in the servo driver. Background Technology

[0002] Industrial machines typically use one or more motors to move loads, and these machines are equipped with one or more servo drives to control each motor. The servo drives store many parameters, but users often don't know how to set these parameters to ensure the machine operates stably.

[0003] Generally, the machine may be equipped with an automatic gain control (AGC) function (or automatic adjustment function) to assist users in setting the above parameters. The AGC function primarily translates expert experience into computer software as a process, or records this process internally within the servo drive. This allows users without relevant knowledge to follow the steps guided by the user interface (UI) on the computer or servo drive to set the servo drive's gain. As a result, only a small number of machines that cannot be handled by the AGC function require on-site assistance from professionals. This saves significant manpower.

[0004] As mentioned above, in order to enable general users to configure the machine, the automatic machine setup function in related technologies often requires the use of computer software to generate a human-machine interface that guides the user's operation. However, in situations where computer equipment cannot be used, or where computer equipment cannot install software due to security issues (such as in cleanrooms), this automatic machine setup function cannot be implemented.

[0005] Furthermore, the automatic gain control function in related technologies generally requires controlling the machine to move the controlled element back and forth between two points, thus requiring the motor to rotate 1 to 3 revolutions or more. Therefore, this type of automatic gain control function cannot be used for machines where the controlled element has different characteristics at different positions (such as robotic arms), or for machines that can only move the controlled element by a very short distance.

[0006] Furthermore, the aforementioned method of controlling the movement of the controlled components between two points by the machine typically takes 2 to 3 minutes or more to complete a full gain adjustment procedure. For some industrial environments, such a gain adjustment procedure is inefficient. Summary of the Invention

[0007] The main objective of this invention is to provide a servo driver and its rapid gain self-adjustment method, which can complete the gain adjustment program of the servo driver in a very short time, and only requires the motor to make minimal movement when executing the gain adjustment program.

[0008] To achieve the above objectives, the gain fast self-adjustment method of the present invention is mainly applied to a driver connected to a motor, and includes the following steps:

[0009] a) Obtain a current feedback signal from the motor and calculate a torque estimate based on the current feedback signal;

[0010] b) Obtain a position feedback signal of the motor and calculate an acceleration estimate based on the position feedback signal;

[0011] c) Calculate the corresponding system inertia based on the estimated torque and the estimated acceleration, where the system inertia is the inertia of the motor when it is carrying a load;

[0012] d) Calculate an estimated control gain based on the motor's no-load inertia and the system's inertia; and

[0013] e) Adjust the driver based on the estimated control gain.

[0014] To achieve the above objectives, the servo driver of the present invention is electrically connected to a motor, wherein the motor carries a load and together with the load constitutes a controlled system of the servo driver, and the servo driver includes:

[0015] A current sensing element receives an excitation current from the motor and generates a corresponding current feedback signal;

[0016] A central processing unit, connected to the current sensing element and the motor, includes:

[0017] A torque estimation module calculates an estimated torque value based on the current feedback signal;

[0018] An acceleration estimation module receives a position feedback signal from the motor and calculates an acceleration estimation value based on the position feedback signal.

[0019] A gain calculation module calculates a corresponding system inertia based on the estimated torque and acceleration values, and calculates a corresponding estimated control gain based on the motor's no-load inertia and the system inertia, wherein the system inertia is the inertia of the motor when it carries the load; and

[0020] A control module adjusts the servo drive based on the estimated control gain; and

[0021] A storage unit connected to the central processing unit records a data array containing the torque estimate and the acceleration estimate, and the central processing unit is configured to read the data array to obtain the torque estimate and the acceleration estimate.

[0022] Compared with related technologies, the present invention can automatically complete the gain adjustment program after the servo drive is started, and the execution time of the gain adjustment program is extremely short. It does not require the motor to make large displacements, nor does it require storing a large amount of data to execute the gain adjustment program. Attached Figure Description

[0023] Figure 1 This is a block diagram of a servo drive system according to a specific embodiment of the present invention;

[0024] Figure 2 This is a flowchart of an adjustment method according to a specific embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of inertia according to a specific embodiment of the present invention;

[0026] Figure 4 This is a flowchart illustrating the control gain setting process according to a specific embodiment of the present invention.

[0027] Figure 5 This is a flowchart illustrating the stability determination process according to a specific embodiment of the present invention.

[0028] Figure 6 This is a flowchart illustrating the inertia estimation process according to a specific embodiment of the present invention.

[0029] Figure 7 This is a schematic diagram of the control architecture according to a specific embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of the frequency response of a specific embodiment of the present invention.

[0031] Explanation of icon numbers

[0032] 1…Driver

[0033] 11…Central Processing Unit

[0034] 111…Control Module

[0035] 112… Torque Estimation Module

[0036] 113…Acceleration Estimation Module

[0037] 114…Gain Calculation Module

[0038] 115…Speed ​​Estimation Module

[0039] 116… Position Controller

[0040] 117…Speed ​​Controller

[0041] 12… Current sensing element

[0042] 13… storage units

[0043] 14…Power output components

[0044] 2…motor

[0045] 21…Drive Unit

[0046] 22…position detection element

[0047] 3…load

[0048] 4…Controlled System

[0049] 5… Sine wave current

[0050] 6…Motor response curve under no-load conditions

[0051] 7… Response curve of the motor when loaded with twenty times the normal load

[0052] C…Voltage command

[0053] U…motor voltage

[0054] I'…excitation current

[0055] I…current feedback signal

[0056] X…position feedback signal

[0057] V…Speed ​​feedback information

[0058] T…Estimated torque value

[0059] M…data array

[0060] N…gain calculation

[0061] α…acceleration estimation value

[0062] S10~S26…Control Gain Adjustment Steps

[0063] S30~S36…Estimation Steps

[0064] S40~S50…Setting Steps

[0065] S60~S70…Suppression steps Detailed Implementation

[0066] A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0067] Please refer to the first one. Figure 1 and Figure 2 ,in Figure 1 This is a block diagram of a servo drive system according to a specific embodiment of the present invention. Figure 2 This is a flowchart of an adjustment method according to a specific embodiment of the present invention. Figure 1 A servo drive system is disclosed, wherein the servo drive system includes the servo actuator of the present invention (hereinafter referred to as actuator 1 in the specification) and a controlled system electrically connected to actuator 1, wherein the controlled system includes at least a motor 2 electrically connected to actuator 1 and a load 3 carried by motor 2.

[0068] The main technology of this invention is that after the driver 1 is powered on or after the automatic gain adjustment function (or automatic adjustment function) is activated by the user's settings, it can automatically adjust the internal control gain for the currently connected controlled system, thereby enabling the controlled system to work stably when it is controlled by the driver 1.

[0069] In one embodiment, the user can set the automatic tuning parameters inside the driver 1 (e.g., enable the flag) through a user interface (US) or other media. When the driver 1 detects that the automatic tuning parameters are enabled, it can automatically detect the status of the currently connected controlled system and execute the gain fast self-adjustment method of the present invention to realize the automatic gain adjustment function.

[0070] like Figure 1 As shown, the driver 1 of the present invention has at least a central processing unit (CPU) 11, a current sensing element 12, a storage unit 13 and a power output element 14, wherein the current sensing element 12, the storage unit 13 and the power output element 14 are electrically connected to the central processing unit 11.

[0071] In this invention, the central processing unit 11 stores firmware, and based on the functions to be performed by the central processing unit 11, the firmware can be virtually divided into a control module 111, a torque estimation module 112, an acceleration estimation module 113, and a gain calculation module 114. In other words, the control module 111, torque estimation module 112, acceleration estimation module 113, and gain calculation module 114 in this invention can be firmware modules implemented within the central processing unit 11. In this invention, the central processing unit 11 mainly uses the gain calculation module 114 to calculate the corresponding control gain based on the state of the controlled system, and automatically adjusts the driver 1 based on the calculated control gain (details to be described later).

[0072] The motor 2 has at least a drive unit 21 and a position detection element 22, and the motor 2 is directly connected to the load 3, or indirectly connected to the load 3 through a linkage device (e.g., a belt or connecting rod). In one embodiment, the driver 1 is connected to the motor 2 through a central processing unit 11, a current detection element 12, and a power output element 14. Figure 1 As shown, the central processing unit 11 sends a voltage command C to the power output element 14, and the power output element 14 generates a corresponding motor voltage U based on the voltage command C and outputs it to the motor 2, thereby controlling the motor 2.

[0073] Motor 2 receives motor voltage U from driver 1 via drive unit 21 and is driven by drive unit 21 to rotate. After rotating, motor 2 can drive load 3 to move, and motor 2 detects and records position feedback signal X via position detection element 22, and sends position feedback signal X back to driver 1. In addition, motor 2 can also send excitation current I' back to driver 1 via drive unit 21, and driver 1 receives the excitation current I' of motor via current detection element 12 and generates a corresponding current feedback signal I.

[0074] Please also refer to Figure 1 and Figure 2 ,in Figure 2 This is a flowchart of an adjustment method according to a specific embodiment of the present invention. Figure 2 The specific execution steps of the gain fast self-adjustment method of the present invention (hereinafter referred to as the adjustment method) are disclosed, and the adjustment method is applied to, for example... Figure 1 The driver shown is 1.

[0075] In this invention, the driver 1 has a plurality of parameters that can be set and adjusted, including an automatic adjustment parameter. To enable the driver 1 to perform the adjustment method of this invention to achieve automatic gain adjustment, the user needs to enable the automatic adjustment parameter of the driver 1 through a user interface (not shown). After detecting that the automatic adjustment parameter is enabled, the driver 1 automatically inputs a sine wave current corresponding to a single-frequency sine wave to the controlled system, thereby perturbing the controlled system to obtain corresponding information (step S10). Thus, the driver 1 can execute the adjustment method of this invention based on the obtained information.

[0076] After receiving the sinusoidal current, the motor 2 will generate a small displacement. At this time, the driver 1 can receive the excitation current output by the motor 2, and the current detection element 12 generates a corresponding current feedback signal based on the excitation current (step S12). In addition, the driver 1 also obtains the current feedback signal I through the torque estimation module 112 of the central processing unit 11, and calculates the torque estimation value based on the current feedback signal (step S14).

[0077] When the motor 2 generates displacement, the driver 1 also receives the position feedback signal output by the motor 2 through the acceleration estimation module 113 of the central processing unit 11, and calculates the acceleration estimation value based on the position feedback signal (step S16).

[0078] As described above, the controlled system in this embodiment includes a motor 2 and the load 3 it carries. The torque estimation value refers to the torque generated by the motor 2 displacing while carrying the load 3, and the acceleration estimation value refers to the acceleration generated by the motor 2 displacing while carrying the load 3. Furthermore, steps S12, S14, and S16 do not have an execution order; the central processing unit 11 can calculate the torque estimation value and the acceleration estimation value in any order, or it can calculate the torque estimation value and the acceleration estimation value simultaneously based on multiplexing technology, without... Figure 2 The execution order shown is limited.

[0079] After steps S14 and S16, the driver 1 obtains the torque estimate and acceleration estimate through the gain calculation module 114 of the central processing unit 11, and calculates the corresponding system inertia based on the torque estimate and acceleration estimate (step S18). Specifically, in this embodiment, the system inertia refers to the inertia of the motor 2 when carrying the load 3. More specifically, the system inertia refers to the weight of the load 3 currently carried by the motor 2.

[0080] In one embodiment, the gain calculation module 114 can primarily calculate the system inertia based on the following first formula: Where J is the system inertia, T is the estimated torque, and α is the estimated acceleration. However, the above is only one specific embodiment of the present invention, and is not intended to limit it.

[0081] It is worth mentioning that the driver 1 also has a storage unit 13 connected to the central processing unit 11, which may be, for example, various types of memory, but is not limited thereto.

[0082] In one embodiment, after step S14, the torque estimation module 112 stores the calculated torque estimation value in the storage unit 13, and after step S16, the acceleration estimation module 113 stores the calculated acceleration estimation value in the storage unit 13. In this embodiment, the storage unit 113 is used to record a data array containing the torque estimation value and the acceleration estimation value (e.g., ...). Figure 1 The data array M shown. In step S18, the gain calculation module 114 of the central processing unit 11 can read the data array M in the storage unit 113 to obtain the torque estimate and acceleration estimate, thereby calculating the system inertia.

[0083] Please also refer to Figure 3This is a schematic diagram of inertia according to a specific embodiment of the present invention. As described above, in the present invention, the central processing unit 11 calculates the system inertia based on torque estimation and acceleration estimation. However, since the calculation is performed using estimated values, the calculated system inertia may contain errors.

[0084] At Figure 3 In this embodiment, the driver 1 uses a sinusoidal current to cause the motor 2 to move, and the central processing unit 11 obtains multiple torque estimates and multiple acceleration estimates at multiple time points during the displacement of the motor 2. In this embodiment, the gain calculation module 114 of the central processing unit 11 mainly performs a first-order linear regression calculation based on the torque and acceleration estimates at multiple time points, and generates a regression line. Therefore, the gain calculation module 114 of the central processing unit 11 can use the slope of this regression line as the system inertia of the controlled system.

[0085] For example, the sinusoidal current can correspond to a single-frequency sinusoidal wave with a frequency of 5Hz, meaning the time corresponding to this single-frequency sinusoidal wave is 200ms. In this embodiment, the central processing unit 11 can calculate a torque estimate and an acceleration estimate every 20ms after the sinusoidal current is input, and calculate the system inertia of the controlled system using ten torque estimates and ten acceleration estimates. However, the above-mentioned time and number of estimates are for illustrative purposes only and are not intended to limit the technical scope of this application.

[0086] This invention performs first-order linear regression based on multiple torque and acceleration estimates to calculate system inertia, resulting in a more accurate calculated inertia. Furthermore, the driver 1 does not require a large amount of memory to store the data needed to calculate system inertia and control gain. Without the need for extensive storage, this invention allows for self-adjustment of control gain directly by the driver 1 without the need for additional computer equipment.

[0087] Back Figure 2 After step S18, the gain calculation module 114 calculates a corresponding estimated control gain (e.g., based on the no-load inertia of motor 2 and the calculated system inertia). Figure 1 The estimated control gain N is shown in step S20, and the estimated control gain is provided to the control module 111. In one embodiment, the estimated control gain may include, for example, the position gain used by the position controller in the driver 1 and the speed gain used by the speed controller, but is not limited thereto.

[0088] Specifically, the no-load inertia of motor 2 is fixed after motor 2 is manufactured and is known information of driver 1. Based on this, gain calculation module 114 can calculate the parameters that driver 1 should use (i.e., estimate control gain) using the no-load inertia of motor 2 and the estimated system inertia, so that driver 1 can control the controlled system to perform stable motion.

[0089] Please also refer to Figure 4 This is a flowchart illustrating the control gain setting process according to a specific embodiment of the present invention. Figure 4 Used to Figure 2 The following is a further explanation of step S20.

[0090] In one embodiment, the driver 1 may internally establish a bandwidth mapping table (not shown), which pre-records the expected bandwidth corresponding to different system inertias, wherein the system inertia is inversely proportional to its corresponding expected bandwidth. In other words, a smaller system inertia corresponds to a larger expected bandwidth, and a larger system inertia corresponds to a smaller expected bandwidth. For example, the bandwidth mapping table may record that a load 3 with 10 times the inertia corresponds to an expected bandwidth of 100Hz, and a load 3 with 100 times the inertia corresponds to an expected bandwidth of 10Hz. However, the above is only one embodiment of the present invention and is not limited thereto.

[0091] In this embodiment, the gain calculation module 114 first obtains the system inertia estimated in step S18 (step S30), and then queries the bandwidth correspondence table based on the system inertia (step S32) to obtain the expected bandwidth corresponding to this system inertia (step S34). Furthermore, the gain calculation module 114 determines the estimated control gain to be used by the driver 1 based on this expected bandwidth (step S36). In other words, the estimated control gain used by the present invention to adjust the driver 1 is directly related to the expected bandwidth corresponding to the system inertia of the controlled system currently connected to the driver 1. However, the above is only one specific embodiment of the present invention, and is not limited thereto.

[0092] Back Figure 2 After step S20, the central processing unit 11 can adjust the driver 1 according to the estimated control gain provided by the gain calculation module 114 through the control module 111 (step S22).

[0093] With the adjustment method of this invention, users do not need to use additional computer software or be guided through a computer interface to set the gain of the driver 1. Instead, users only need to enable a corresponding parameter in the driver 1 (e.g., check the automatic adjustment parameter) to enable the automatic gain adjustment function, allowing the driver 1 to automatically complete the gain adjustment procedure, which is quite convenient.

[0094] In a preferred scenario, after receiving adjustments from the control module 111, the actuator 1 can automatically complete the setting of multiple parameters and control the controlled system to perform stable motion. However, the central processing unit 11 of this invention calculates the estimated control gain based on the estimated system inertia; therefore, the estimated system inertia in step S20 may have errors compared to the actual system inertia of the controlled system. In view of this, after adjusting the actuator 1, this invention can further test the adjusted actuator 1.

[0095] like Figure 2 As shown, after step S22, the adjusted driver 1 can input a test signal to the controlled system (step S24), thereby causing the motor 2 of the controlled system to perform movement. In this embodiment, the test signal corresponds to a square wave current. By having the adjusted driver 1 generate a square wave current to disturb the motor 2, the present invention can confirm whether the operation of the controlled system is stable under the desired bandwidth currently used by the driver 1. If the operation of the controlled system is stable, the driver 1 can end the current gain adjustment procedure (step S26). If the operation of the controlled system is unstable (for example, the controlled system will vibrate), the driver 1 will then adjust the estimated control gain used through the central processing unit 11 (described in detail later).

[0096] Please refer to the following for further details. Figure 1 , Figure 2 and Figure 5 ,in Figure 5 This is a flowchart illustrating the stability determination process according to a specific embodiment of the present invention. Figure 5 As shown, after the driver 1 receives the estimated control gain adjustment, the adjusted driver 1 can then input the test signal to the controlled system (step S60). At this time, the motor 2 of the controlled system will receive the disturbance and perform motion, and the driver 1 can determine whether the controlled system is stable when the motor 2 performs motion (step S62).

[0097] Specifically, the test signal is a pulse emitted by the driver 1 to the controlled system, which can cause the controlled system (especially the motor 2) to make a small displacement. In one embodiment, in step S62, the driver 1 determines whether the movement of the motor 2 will cause unnecessary vibration in the controlled system when a new control gain (i.e., an estimated control gain) is used to control the controlled system.

[0098] If the controlled system is determined to be stable in step S62, the adjustment method of the present invention can be terminated and the gain adjustment procedure of driver 1 can be completed.

[0099] If it is determined in step S62 that the controlled system is in an unstable state, the driver 1 evaluates the unstable state through the central processing unit 11 to determine whether the unstable state can be resolved by the driver 1 executing the resonance suppression procedure (step S64).

[0100] Specifically, the central processing unit 11 knows the corresponding bandwidth of the estimated control gain calculated by the gain calculation module 114, and the driver 1 can obtain the vibration frequency of the controlled system when it is in an unstable state through a monitoring program. In step S64, the central processing unit 11 can directly determine whether the unstable state of the controlled system can be resolved by a resonance suppression program based on the relationship between the bandwidth of the estimated control gain and the vibration frequency of the controlled system. The resonance suppression program is a common technical means in this field and will not be described in detail here.

[0101] If the central processing unit 11 determines that the controlled system is in an unstable state, but this unstable state can be resolved by a resonance suppression procedure, then the central processing unit 11 controls the driver 1 to execute the resonance suppression procedure (step S66). In this embodiment, the central processing unit 11 can restore the controlled system to stability (e.g., stop vibrating) by having the driver 1 execute the resonance suppression procedure, without needing to adjust the control gain of the driver 1 again.

[0102] If the central processing unit 11 determines that the controlled system is in an unstable state, and this unstable state cannot be resolved by the resonance suppression procedure, it means that the estimated control gain calculated by the gain calculation module 114 is too high. In response, the central processing unit 11 can reduce the bandwidth corresponding to the estimated control gain calculated by the gain calculation module 114 (step S68).

[0103] After step S68, the central processing unit 11 adjusts the driver 1 again based on the reduced estimated control gain through the control module 111, and determines whether the controlled system is stable using the same method as described above (e.g., inputting a test signal) (step S70). If the controlled system is stable, the central processing unit 11 ends the adjustment method of the present invention and completes the gain adjustment procedure of the driver 1. If the controlled system is still unstable, the central processing unit 11 executes step S68 again to reduce the corresponding bandwidth of the estimated control gain again, and adjusts the driver 1 again based on the reduced bandwidth estimated control gain.

[0104] As mentioned above, the test signal emitted by the driver 1 will only cause the controlled system (especially the motor 2) to make a small displacement, and the driver 1 can use this small displacement to determine whether the controlled system is stable. In one embodiment, when the driver 1 performs the adjustment method of the present invention, it only needs to cause the motor 2 to perform a displacement of no more than 1 / 10 of a turn (i.e., less than or equal to 36 degrees), thus allowing the hardware structure of the controlled system to have greater applicability flexibility.

[0105] More specifically, in order to successfully estimate the system inertia, the actuator 1 must ensure that the motor 2 can produce a large velocity response with a small displacement. In this way, the actuator 1 can calculate an effective acceleration estimate in the displacement of the motor 2, and thus be able to estimate the corresponding system inertia.

[0106] Please refer to the following for further details. Figure 1 , Figure 2 , Figure 6 and Figure 7 ,in Figure 6 This is a flowchart illustrating the inertia estimation process according to a specific embodiment of the present invention. Figure 7 This is a schematic diagram of the control architecture of a specific embodiment of the present invention.

[0107] Before the driver 1 executes the gain adjustment procedure, the user can set an initial control gain for the specifications of the motor 2 currently connected to the driver 1, and the control module 111 of the central processing unit 11 can perform initial settings on the driver 1 based on the initial control gain (step S40). In one embodiment, the initial control gain includes at least the position gain set for the position controller 116 in the driver 1 based on the specifications of the motor 2, and the speed gain set for the speed controller 117 in the driver 1 based on the specifications of the motor 2.

[0108] As described above, the present invention sets the initial control gain according to the specifications of motor 2, and after initially setting the driver 1 according to the initial control gain, the controlled system is tested. Therefore, the tuning results will not be affected by the existing parameters inside the driver 1 (such as random parameters set by the user).

[0109] After step S40, the driver 1, after initial setting, inputs the aforementioned sinusoidal current to the controlled system (step S42) to disturb the motor 2 (i.e., to cause the motor 2 to make the aforementioned small displacement). Specifically, step S42 is related to the aforementioned... Figure 2 Step S10 is similar and will not be repeated here.

[0110] It is worth mentioning that, in order to shorten the estimation time of the system inertia, the driver 1 must enable the motor 2 to complete the displacement in a very short time. Therefore, the frequency of the single-frequency sine wave corresponding to the sine wave current cannot be too low. In addition, in order to avoid the motor 2 from vibrating during displacement, the frequency of the single-frequency sine wave corresponding to the sine wave current also cannot be too high (for example, it cannot be greater than the system resonant frequency).

[0111] In one embodiment, the sinusoidal current may correspond to a single-frequency sinusoidal wave with a frequency range of 5Hz to 15Hz, meaning that the disturbance time of the sinusoidal current on the motor 2 is approximately 66ms to 200ms. However, the above is only one specific embodiment of the present invention, and the frequency of the single-frequency sinusoidal wave may be less than 5Hz or greater than 15Hz, and is not limited to the above frequency range.

[0112] By setting the frequency range of the single-frequency sine wave, driver 1 can shorten the estimation time of system inertia, thereby reducing the execution time of the complete gain adjustment procedure to no more than 1 second. This significantly improves the efficiency of driver 1.

[0113] As described above, if a single-frequency sine wave with a frequency too low (e.g., less than 5Hz) is used, the execution time of the complete gain adjustment procedure will be too long, which may not meet the user's needs. In this case, driver 1 can avoid using a complete sine wave, thereby shortening the execution time of the entire gain adjustment procedure. However, the above is only one embodiment of the present invention and is not intended to limit it.

[0114] After step S42, when the motor 2 is moving, the driver 1 can obtain the current feedback signal and position feedback signal of the motor 2 through the current detection element 12, the torque estimation module 112 and the acceleration estimation module 113, and calculate the torque estimation value and acceleration estimation value. Then, the gain calculation module 114 is used to estimate the system inertia of the controlled system (step S44).

[0115] As mentioned above, the gain calculation module 114 estimates the system inertia based on the torque estimate and acceleration estimate. Therefore, if the speed response of the motor 2 is insufficient during the aforementioned disturbance time, the driver 1 may be unable to correctly calculate the acceleration estimate of the motor 2, and thus be unable to estimate the system inertia.

[0116] In this embodiment, after step S44, the central processing unit 11 determines whether the system inertia has been successfully estimated (step S46). If the system inertia is successfully estimated, the central processing unit 11 can continue to execute the remaining gain adjustment procedure (step S50). For example, the central processing unit 11 can continue to execute... Figure 2 Steps S20 to S26 are shown, but are not limited to these steps.

[0117] If the system inertia estimation fails in step S46, the central processing unit 11 can adjust the initial control gain obtained in step S40 based on the feedback information from the motor 2 (e.g., the current feedback signal and the position feedback signal), and the control module 111 will re-initialize the driver according to the adjusted initial control gain (step S48). Furthermore, the central processing unit 11 will execute steps S42 and S44 again to send a sine wave current to the controlled system again from the adjusted driver 1, and receive feedback information from the motor 2 to re-estimate the system inertia.

[0118] Specifically, after receiving the initial settings, the driver 1 inputs a sine wave current to the controlled system and continuously monitors the displacement of the motor 2 after being disturbed, while simultaneously calculating an acceleration estimate based on the position feedback signal of the motor 2. For the driver 1 to successfully calculate the acceleration estimate, the motor 2 needs to perform a sufficiently large displacement within a short period of time after receiving the disturbance. Therefore, the purpose of setting the initial control gain and the frequency of the single-frequency sine wave in this invention is to allow the motor 2 to achieve maximum acceleration characteristics during displacement. Thus, the initial control gain and the single-frequency sine wave will differ when different motors 2 are connected.

[0119] like Figure 7 As shown, the driver 1 of the present invention further includes a speed estimation module 115, a position controller 116, and a speed controller 117, wherein the speed estimation module 115, the position controller 116, and the speed controller 117 may be, for example, firmware modules inside the central processing unit 11, but are not limited thereto.

[0120] like Figure 7 As shown, when the controlled system 4 (i.e., motor 2 and load 3) moves, the position detection element 22 can output a position feedback signal X. After receiving the position feedback signal X, the driver 1 can feed the position feedback signal X back to the position controller 116, and the speed estimation module 115 calculates the speed feedback information V of motor 2 based on the position feedback signal X and feeds it back to the speed controller 117.

[0121] Position controller 116 and speed controller 117 control the controlled system 4 based on feedback signals, and driver 1 can input the sinusoidal current 5 to the controlled system 4. After being disturbed by the sinusoidal current 5, the controlled system 4 can output a current feedback signal I to the torque estimation module 112 of driver 1, and output a position feedback signal X to the acceleration estimation module 113 of driver 1. Thus, the torque estimation module 112 of driver 1 can calculate the estimated torque value T based on the current feedback signal I, and the acceleration estimation module 113 can calculate the estimated acceleration value α based on the position feedback signal X.

[0122] As described above, when the driver 1 cannot obtain the required acceleration estimate through the displacement of the motor 2, it is necessary to execute... Figure 6 Step S48 involves adjusting the initial control gain, including adjusting the position gain used by the position controller 116 and the speed gain used by the speed controller 117. Specifically, the driver 1 amplifies the speed response of the controlled system 4 at the frequency corresponding to the sine wave current 5 by adjusting the initial control gain, thereby enabling the controlled system 4 to generate a sufficiently large acceleration after receiving the sine wave current 5.

[0123] Please also refer to Figure 8 This is a schematic diagram of the frequency response of a specific embodiment of the present invention. Figure 8 The response curves of the controlled system 4 when the motor is unloaded (6) and the response curves of the motor when it is loaded with twenty times the load (7) are disclosed.

[0124] like Figure 8 As shown, when motor 2 is unloaded, the maximum increase (40.37dB) occurs at a frequency of 20.5Hz, while when motor 2 is loaded with twenty times the load, the maximum increase (40.36dB) occurs at a frequency of 6.463Hz. This information is known and can be obtained through testing at the time motor 2 leaves the factory.

[0125] Based on the above information, driver 1 in Figure 6 In step S42, a single-frequency sine wave between 6.4Hz and 20.5Hz can be selected to generate the sine wave current 5. In this case, the motor 2 can have a large speed response when disturbed by the sine wave current 5, whether under no-load or under twenty times load, so that the driver 1 can successfully calculate the acceleration estimate of the motor 2.

[0126] If Figure 6 In step S46, it is determined that the system inertia estimation failed, which means that the load of motor 2 may exceed the above frequency range of the single-frequency sine wave. For example, motor 2 is loaded with a load of thirty times.

[0127] Specifically, Figure 8 The increase shown (i.e., the dB value) is depicted by the speed and position feedback of motor 2, therefore... Figure 6 In step S48, the central processing unit 11 of the driver 1 can adjust the position increment used by the position controller 116 and the speed increment used by the speed controller 117 according to the feedback signal of the motor 2, thereby amplifying the speed response of the motor 2. In this way, it can be ensured that when the driver 1 inputs the sine wave current 5 to the controlled system 4 next time, the acceleration estimation value can be successfully obtained, and the system inertia can be successfully estimated.

[0128] With the technical solution of the present invention, the driver can automatically complete the gain adjustment program after startup. The execution time of the gain adjustment program is extremely short, and the motor does not need to make a large displacement. The driver also does not need to store a large amount of data for the execution of the gain adjustment program.

[0129] The above description is merely a preferred embodiment of the present invention and is not intended to limit the claims of the present invention. Therefore, all equivalent variations made using the content of the present invention are similarly included within the scope of the present invention and are hereby stated.

Claims

1. A method for rapid gain self-adjustment, applied to a driver connected to a motor, comprising: a) Obtain the current feedback signal of the motor and calculate the torque estimate based on the current feedback signal; b) Obtain the position feedback signal of the motor and calculate the acceleration estimate based on the position feedback signal; c) Calculate the corresponding system inertia based on the estimated torque and the estimated acceleration, wherein the system inertia is the inertia of the motor when it is carrying the load; d) Calculate the corresponding estimated control gain based on the motor's no-load inertia and the system's inertia; and e) Adjust the driver based on the estimated control gain; f) A test signal is input from the adjusted driver to a controlled system including the motor and the load, wherein the test signal causes the motor to perform motion; g) Determine whether the controlled system is stable when the motor performs motion; h) If it is determined that the controlled system is in an unstable state, but the unstable state can be resolved by the resonance suppression program, control the driver to execute the resonance suppression program; and i) When it is determined that the controlled system is in the unstable state and the unstable state cannot be resolved by the resonance suppression procedure, the bandwidth corresponding to the estimated control gain is reduced, and the driver is readjusted according to the estimated control gain after the bandwidth is reduced; The driver has a bandwidth correspondence table, which records the desired bandwidth corresponding to different system inertias, and the system inertia is inversely proportional to the desired bandwidth. Step d) involves querying the bandwidth correspondence table based on the system inertia to obtain the corresponding expected bandwidth, and then determining the estimated control gain based on the expected bandwidth.

2. The gain fast self-adjustment method according to claim 1, wherein step h) and step i) are based on the correspondence between the bandwidth corresponding to the estimated control gain and the vibration frequency of the controlled system when it is in the unstable state, to determine whether the unstable state can be resolved by the resonance suppression procedure.

3. The gain fast self-adjustment method according to claim 1, wherein step a) is further included before step a1): inputting a sine wave current to the controlled system to make the motor move, wherein the current feedback signal and the position feedback signal are acquired during the movement of the motor in steps a) and b), and steps b).

4. The gain fast self-adjustment method according to claim 3, wherein the sine wave current corresponds to a single-frequency sine wave with a frequency range of 5~15Hz.

5. The gain fast self-adjustment method according to claim 3, wherein step a1) is further comprising step a0) before step a1): initial setting of the driver according to an initial control gain, wherein the initial control gain includes at least a position gain and a speed gain set based on the specifications of the motor, and step a1) is the input of the sine wave current to the controlled system by the driver after initial setting.

6. The gain fast self-adjustment method according to claim 5, further comprising: c1) After step c), determine whether the system inertia has been successfully estimated; c2) If the system inertia estimation fails, adjust the initial control gain and reset the driver, and repeat steps a0), a1), and steps a) to c). c3) When the system inertia estimation is successful, execute step d) based on the system inertia.

7. The gain fast self-adjustment method according to claim 6, wherein step c2) is to adjust the position gain and the velocity gain to amplify the velocity response of the controlled system at the frequency corresponding to the sinusoidal current.

8. The gain fast self-adjustment method according to claim 1, wherein step c) calculates the system inertia according to the first formula: , where J is the system inertia, T is the estimated torque, and α is the estimated acceleration.

9. The gain fast self-adjustment method according to claim 1, wherein step c) is to perform a first-order linear regression calculation based on the torque estimation value and the acceleration estimation value at multiple time points to generate a regression line, and use the slope of the regression line as the system inertia.

10. A servo driver electrically connected to a motor, wherein the motor carries a load and together with the load constitutes a controlled system of the servo driver, and the servo driver comprises: A current detection element receives the excitation current of the motor and generates a corresponding current feedback signal; Central processing unit, connected to the current detection element and the motor, includes: The torque estimation module calculates the torque estimate based on the current feedback signal; An acceleration estimation module receives the position feedback signal from the motor and calculates an acceleration estimation value based on the position feedback signal. The gain calculation module calculates the corresponding system inertia based on the estimated torque and the estimated acceleration, and calculates the corresponding estimated control gain based on the motor's no-load inertia and the system inertia, wherein the system inertia is the inertia of the motor when it carries the load; and The control module adjusts the servo driver based on the estimated control gain; and A storage unit, connected to the central processing unit, records a data array containing the torque estimate and the acceleration estimate, and the central processing unit is configured to read the data array to obtain the torque estimate and the acceleration estimate. The central processing unit is configured to input a test signal to the controlled system after the servo driver is adjusted to cause the motor to perform motion, and to determine whether the controlled system is stable when the motor performs motion; The central processing unit is configured to determine if the controlled system is in an unstable state, but if the unstable state can be resolved by the resonance suppression procedure, execute the resonance suppression procedure, and if the unstable state cannot be resolved by the resonance suppression procedure, reduce the bandwidth corresponding to the estimated control gain, and readjust the servo driver based on the estimated control gain after the bandwidth reduction. The servo driver has a bandwidth correspondence table that records the expected bandwidth corresponding to different system inertias, wherein the system inertia is inversely proportional to the expected bandwidth, and the gain calculation module is configured to query the bandwidth correspondence table based on the calculated system inertia to obtain the corresponding expected bandwidth, and determine the estimated control gain based on the queried expected bandwidth.

11. The servo driver of claim 10, wherein the central processing unit is configured to input a sine wave current to the controlled system to cause the motor to move, and the torque estimation module is configured to acquire the current feedback signal when the motor moves, and the acceleration estimation module is configured to acquire the position feedback signal when the motor moves.

12. The servo driver of claim 11, wherein the central processing unit is configured to generate the sine wave current based on a single-frequency sine wave with a frequency range of 5 to 15 Hz.

13. The servo drive of claim 11, wherein the control module is configured to initially set the servo drive according to an initial control gain, the initial control gain including at least a position gain and a speed gain set based on the specifications of the motor, and the central processing unit is configured to input the sine wave current to the controlled system after the servo drive has completed the initial setting.

14. The servo driver of claim 13, wherein the central processing unit is configured to adjust the position gain and the velocity gain of the initial control gain to amplify the velocity response of the controlled system at the frequency corresponding to the sine wave current when the system inertia estimation fails, and to re-initialize the servo driver according to the adjusted initial control gain.

15. The servo driver of claim 10, wherein the gain calculation module is configured to calculate the system inertia according to a first formula: , where J is the system inertia, T is the estimated torque, and α is the estimated acceleration.

16. The servo driver according to claim 10, wherein the torque estimation module and the acceleration estimation module are configured to acquire the torque estimation value and the acceleration estimation value at multiple time points after the central processing unit inputs a sinusoidal current to the controlled system, and the gain calculation module is configured to perform a first-order linear regression calculation based on multiple torque estimation values ​​and multiple acceleration estimation values ​​to generate a regression line, and use the slope of the regression line as the system inertia.

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