Motor control device

Abstract

A motor control device is provided which is installed in a position control system for position control of a mechanical end connected to a motor, receives a first speed command from a higher-level system control device, and outputs a position response of a motor shaft to the higher-level system control device, and has a speed controller and an in-system vibration damper controller, the in-system vibration damper controller having a position command estimator which calculates an estimated value of a position command based on the first speed command and the position response of the motor shaft, a parallel vibration damper controller which extracts a frequency component of vibration of the mechanical end included in the first speed command based on the estimated value of the position command and outputs the extracted frequency component, a phase adjuster for improving a response delay caused by the parallel vibration damper controller, a first unit converter which converts an output of the phase adjuster to a dimension of speed, and an arithmetic unit which subtracts an output of the parallel vibration damper controller from the first speed command to remove the frequency component of vibration of the mechanical end from the first speed command as a second speed command, outputs the second speed command as a first actual speed command based on an output of the first unit converter and the second speed command as an output of the in-system vibration damper controller, and outputs the first actual speed command as a command of the speed controller.

Description

Technical Field

[0001] This invention relates to motor control devices. Background Technology

[0002] When a semi-enclosed motor control system drives a controlled machine, if the machine has low rigidity, the ends of the machine (hereinafter referred to as the machine ends) will vibrate at low frequencies of several Hz to 100 Hz due to the machine's resonance / anti-resonance characteristics, resulting in a situation where the required response characteristics cannot be achieved.

[0003] In FA (Fast Moving Equipment) applications where both positioning accuracy and time reduction are crucial for machine operation, vibration damping control is typically employed. Vibration damping control is generally achieved through the processing of control commands, and methods for removing the frequency components that excite vibrations at the machine ends from these control commands are known.

[0004] Patent Document 1 uses two vibration damping filters in a switching manner for position commands, which can dampen the end of the machine even when the resonant / anti-resonant characteristics of the machine change. A notch filter can be cited as an example of a vibration damping filter.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2005-168225 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] When the motor control system is a position control system, vibration reduction control can be achieved by processing position commands using notch filters, etc., but... Figure 2 As shown, there exists a situation where, due to industrial reasons such as machine replacement, the upper-level system control device that generates position commands includes a position controller and a speed control system that is implemented as a small loop by a servo motor control device.

[0010] Furthermore, there exists a situation where, due to reasons such as maintainability and the specifications of each device, vibration reduction control cannot be achieved using a position controller, and it is desired to achieve vibration reduction control within a servo motor control device that serves as a small-loop speed control system.

[0011] In Patent Document 1, the vibration damping filter 3, filter switching unit 9, and command direction detection unit 4 used for vibration damping control are... Figure 2 The structure in Patent Document 1 implements vibration reduction control in the upper-level system control device. Therefore, vibration reduction control is not implemented in the servo motor control device responsible for the speed control system in Patent Document 1.

[0012] Furthermore, when using a line enhancer (LE) as a filter to extract the frequency components of the excitation mechanical end vibration for vibration reduction control, the response delay characteristic of vibration reduction control does not occur, which becomes a technical problem.

[0013] The purpose of this invention is to provide a motor control device in a semi-enclosed motor control system, wherein the upper-level system control device includes a position controller, and a motor control device that implements vibration reduction control within the motor control device responsible for the speed control system, and the motor control device can improve the response delay unique to vibration reduction control.

[0014] Technical means for solving technical problems

[0015] This invention relates to a motor control device, comprising a position control system for controlling the position of a mechanical end connected to a motor. The motor control device is installed in the position control system in a manner that receives a first speed command from a higher-level system control device and outputs a position response of the motor shaft to the higher-level system control device.

[0016] The motor control device includes a speed controller and a vibration damping controller within the speed control system.

[0017] The vibration damping controller within the speed control system has:

[0018] A position command estimator calculates the estimated value of the position command based on the first speed command and the position response of the motor shaft;

[0019] A parallel vibration damping controller extracts the frequency components of the vibration that excites the mechanical end contained in the first speed command based on the calculated value of the position command, and outputs the extracted frequency components.

[0020] A phase adjuster is used to improve the response delay caused by the parallel vibration damping controller;

[0021] A first unit converter that converts the output of the phase adjuster into a velocity dimension; and

[0022] Arithmetic unit,

[0023] The arithmetic unit subtracts the output of the parallel vibration damping controller from the first speed command to remove the frequency component that excites the vibration of the mechanical end, and outputs the second speed command as such.

[0024] The arithmetic unit uses the output of the first unit converter and the output of the second speed command as the first actual speed command for the output of the vibration damping controller within the speed control system, and uses the first actual speed command as the command of the speed controller.

[0025] The effects of the invention

[0026] According to the present invention, the response delay characteristic of vibration reduction control when implementing vibration reduction control in the motor control device responsible for the speed control system can be improved, and the positioning time can be shortened. Attached Figure Description

[0027] Figure 1 This is a diagram showing the first basic structure of Embodiment 1.

[0028] Figure 2 It is a diagram showing the structure including the upper-level system control device and the servo motor control device.

[0029] Figure 3 This is a diagram illustrating the structure that serves as the premise of Example 1.

[0030] Figure 4 This is a graph representing the frequency characteristics of a vibration-excited component extractor.

[0031] Figure 5 This is a graph representing the frequency characteristics of the phase adjuster.

[0032] Figure 6 It is a graph representing the frequency characteristics of the mechanical end.

[0033] Figure 7 This is a diagram showing the first basic structure of Embodiment 2.

[0034] Figure 8 This is a diagram illustrating the structure that serves as the premise for Example 2.

[0035] Figure 9 This is a diagram showing the specific structure of a two-degree-of-freedom controller with an FF controller.

[0036] Figure 10 This is a diagram showing the specific structure of a model-matched two-degree-of-freedom controller.

[0037] Figure 11 This is a diagram representing an AC servo motor control system.

[0038] Figure 12 This is a diagram showing an AC servo motor control system with a vibration damping controller within the speed control system.

[0039] Figure 13A It means Figure 12 The diagram shows the effect of vibration reduction control in the structure.

[0040] Figure 13B yes Figure 13A A magnified view of a portion of the image. Detailed Implementation

[0041] First, regarding the structure that serves as the premise of this embodiment... Figure 3 Please provide an explanation. Figure 3 It is a technology that achieves vibration reduction control within the servo motor control device 301 without processing the position command. Figure 3 The servo motor control device 301 is characterized by having a position command calculator 9, a parallel vibration damping controller 10, a speed controller 20, a position / speed calculator 21, a current control system 207, and an adder / subtractor 304, which processes the speed command 303 obtained from the upper-level system control device 201.

[0042] More specifically, the parallel vibration damping controller 10 includes a vibration excitation component extractor and a unit converter (unit converter). From the position command calculation value 13 obtained by the position command calculator 9, the vibration excitation component extractor extracts the frequency component of the vibration of the excitation mechanical end 204, converts it into the unit of velocity using the unit converter, and removes the vibration excitation component from the velocity command 303, thereby achieving vibration suppression of the mechanical end.

[0043] Figure 3 In the parallel vibration damping controller 10, the vibration excitation component extractor uses a filter equivalent to a line enhancer (LE) that can extract the frequency components of the excitation mechanical end vibration from the position command estimator 9 without phase delay.

[0044] [Number 1]

[0045]

[0046] Where W is the extraction width, L is the parameter responsible for extracting the power level, and ωn is the extracted frequency [rad / s]. Additionally, s is the Laplace operator (hereafter, s denotes the Laplace operator).

[0047] Figure 4 The frequency characteristics of equation (1) are expressed when W = 1, L = 0.1, and ωn = 2π × 10. The amplitude reaches its peak at frequency ωn, and the phase delay is 0, which is a characteristic feature.

[0048] Figure 4 The upper vertical axis represents magnitude (the amplitude of the extracted frequency), and the horizontal axis represents frequency (the frequency of the extracted waveform). Figure 4 The lower vertical axis represents the phase (the phase of the extracted frequency), and the horizontal axis represents the frequency (the frequency of the extracted waveform).

[0049] In vibration reduction control using Equation (1), the response delay characteristic of vibration reduction control becomes a technical problem. Specifically, a phase delay occurs in the frequency band below frequency ωn, which can suppress the vibration of the mechanical end, but cannot obtain sufficient response characteristics, resulting in insufficient shortening of the positioning time.

[0050] The following description applies to an embodiment of the present invention that improves the response delay unique to vibration reduction control, with reference to the accompanying drawings. In addition, in each figure, components with common functions are assigned the same number, and their descriptions are omitted. Furthermore, "feedback" will sometimes be abbreviated as "FB," and "feedforward" as "FF."

[0051] Example 1

[0052] Figure 1 This illustrates the structure of the vibration damping controller 15 within the speed control system of this embodiment. Figure 3 The speed control system and vibration damping controller 302 within the servo motor control device 301 have been newly added with a phase adjuster 1, an adder / subtractor 3, an adder / subtractor 17, and a unit converter 12.

[0053] This embodiment is envisioned as follows: Figure 3 The illustrated motor control system consists of a higher-level system control unit 201 and a servo motor control unit 301. In this embodiment, the servo motor control unit 301 is included in a position control system that performs position control on the mechanical end connected to the motor.

[0054] The upper-level system control device 201 generates a position command 24, including a position controller 22, receives a position response 23 from the servo motor control device 301, and generates a speed command 14 based on the position command 24 and the position response 23, and outputs it to the servo motor control device 301. Alternatively, the position command 24 can also be provided from outside the upper-level system control device 201 by other upper-level devices, etc.

[0055] The servo motor control device 301 in this embodiment includes a speed controller 20, a current control system 207, a position / speed calculator 21, and a vibration damping controller 15 within the speed control system. It receives speed commands 14 from the upper-level system control device 201, performs speed control on the motor, and calculates the position of the motor shaft using the position / speed calculator 21 based on the measurement signals from sensors (e.g., rotary encoders) installed on the motor that can detect position / speed. It uses this position as the position response 23 of the motor shaft and outputs the position response 23 of the motor shaft to the upper-level system control device 201.

[0056] The servo motor control unit 301 has a CPU (Central Processing Unit), which is omitted from the illustration. For the speed control system, including the vibration damping controller 302, speed controller 20, position / speed calculator 21, and current control system 207, which are processed by various processing units such as the position command calculator 9, parallel vibration damping controller 10, and adder / subtractor 304, the CPU can read and execute the program, thus performing the processing of each processing unit. All or part of each processing unit can also be constructed using hardware such as ASIC (Application Specific Integrated Circuit) and FPGA (Field Programmable Gate Array). Furthermore, the upper-level system control unit 201 has a CPU that executes the program corresponding to the position controller 22.

[0057] The technical problem of this embodiment is that the position controller 22 of the upper system control device 201 does not include vibration reduction control, and vibration reduction control is implemented inside the servo motor control device 301, thereby improving the response delay unique to vibration reduction control; the vibration reduction controller 15 in the speed control system is the vibration reduction controller of this embodiment used to implement it.

[0058] Vibration reduction control is achieved by processing speed command 14. This can be accomplished by performing the following steps in principle.

[0059] S1: Master and calculate position commands.

[0060] S2: Extract the frequency components that excite the vibration of the mechanical end from the position commands obtained through understanding and calculation.

[0061] S3: Generate a speed command that does not contain the frequency components extracted in S2, and use it as the speed command for the speed controller.

[0062] Step S1 can be implemented using the position instruction calculator 9.

[0063] An example of its implementation is the following formula. The position command estimator 9 outputs the signal obtained by processing the first speed command 14 with the estimator filter and the position response 23 of the motor shaft using the third adder and subtractor according to formula (2). The result is used as the estimated value of the position command.

[0064] [Number 2]

[0065] r e =F p ·s r +y p (2)

[0066] Where re, sr, and yp are the position prediction command value 13, speed command 14, and motor shaft position response 23, respectively, and Fp is a prediction filter consistent with the inverse characteristic (reverse characteristic) of the position controller 22. For example, if the position controller 22 is a P controller, then Fp is the inverse characteristic of the P controller, i.e., the reciprocal of the P gain. In addition, for the sake of simplicity, it is assumed that the position prediction command value 13 obtained by the position prediction command estimator 9 can predict the position command 24 without error.

[0067] Step S2 can be implemented by the vibration excitation component extractor 11. The vibration excitation component extractor 11 is a line enhancer (LE) as a filter, and the line enhancer has the function of the previously described equation (1).

[0068] Step S3 can be implemented by a unit converter 12 and an adder / subtractor 16. The unit converter 12 converts the output of the vibration excitation component extractor 11 from position to velocity, and the adder / subtractor 16 removes it from the velocity command 14, thereby enabling the velocity command 8 to be implemented without the frequency component that excites the mechanical end vibration. Another example of the unit converter 12 is the position controller 22 included in the upper-level system control device 201.

[0069] The position controller 22 is responsible for generating a speed command based on the position command 24 and the difference between the position command 24 and the position response 23 of the motor shaft. Therefore, within the speed control system, the vibration damping controller 15 can handle the task of the unit converter 12.

[0070] The LE of formula (1) for the vibration-excited component extractor 11, as follows Figure 4 As shown, the frequency components of the excitation mechanical end vibration can be extracted from the position command calculated value 13 without phase delay. However, LE has the characteristic of causing phase advance (lead) in a frequency band lower than the extracted frequency ωn [rad / s] (the maximum phase advance is π / 2 [rad / s]).

[0071] Here, we consider the following treatment for a sine wave with frequency ω minus a sine wave with amplitude α (0<α≤1) and phase advanced by β (0<β<π / 2).

[0072] [Number 3]

[0073] S c (t)=sin(ωt)-αsin(ωt+β)(3)

[0074] The following equation is obtained by transforming the equation.

[0075] [Number 4]

[0076]

[0077] [Number 5]

[0078]

[0079] When α (0 < α ≤ 1) and β (0 < β < π / 2), γ is always negative. Therefore, the sine wave Sc(t) obtained by subtracting a sine wave with amplitude α (0 < α ≤ 1) and phase advanced by β (0 < β < π / 2) from a sine wave with frequency ω is a sine wave with a phase delay relative to the sine wave with frequency ω. The amount of phase delay tends to increase when α is large.

[0080] In addition, consider the following treatment of a sine wave with frequency ω plus an amplitude of α (0<α≤1) and a phase advance of β (0<β<π / 2).

[0081] [Number 6]

[0082] S c (t)=sin(ωt)+αsin(ωt+β) (6)

[0083] The following equation is obtained by transforming the equation.

[0084] [Number 7]

[0085]

[0086] [Number 8]

[0087]

[0088] In equation (8), γ is always positive when α (0 < α ≤ 1) and β (0 < β < π / 2). Therefore, the sine wave Sc(t) obtained by adding a sine wave with amplitude α (0 < α ≤ 1) and phase advanced by β (0 < β < π / 2) to a sine wave with frequency ω is a sine wave with a phase that is necessarily advanced relative to the sine wave with frequency ω.

[0089] This embodiment utilizes the principles of equations (6) to (8) to improve the response delay unique to vibration reduction control.

[0090] Figure 1Equation (1) is used in the parallel vibration damping controller 10. Therefore, in terms of the characteristics of LE, the frequency component below frequency ωn (ωL) is advanced due to LE. Since the frequency component of frequency ωL that is advanced due to LE is subtracted from the frequency component of frequency ωL of speed command 14 by adder / subtractor 16, according to the principles of equations (3) to (5), the frequency component of frequency ωL in the output 8 of adder / subtractor 16 must have a delay relative to the same frequency component of speed command 14. In particular, when ωL is close to ωn, the gain is higher (i.e., α is larger) in terms of the characteristics of LE. Therefore, when ωL is close to ωn, the phase delay becomes significant.

[0091] This is the cause of the response delay unique to the vibration damping control in parallel vibration damping control using LE. This phase delay characteristic delays the frequency components of speed command 14 below ωn, thus delaying the overall speed command.

[0092] This embodiment addresses the phase delay issue of such speed command 14 by using... Figure 1 The phase adjuster 1, adder / subtractor 3, unit converter 12, and adder / subtractor 17.

[0093] The output 2 of the adder / subtractor 3 is the position command (calculated value) after removing the frequency of the vibration of the excitation mechanical end according to the properties of the vibration excitation component extractor 11. However, the frequency components below the frequency ωn are also phase-delayed compared with the position command calculated value 5 (position command calculated value 13), just like the output 8.

[0094] The phase adjuster advances the frequency components delayed by the vibration excitation component extractor 11. After converting the units from position to velocity using the unit converter 12, the output 8 is added using the adder / subtractor 17. As a result, according to the principles of equations (6) to (8), the phase delay of the output 8, which has a phase delay in frequency components below ωn due to the vibration excitation component extractor 11, can be advanced. Consequently, the response delay unique to vibration damping control can be improved. In other words, the purpose of this embodiment is to process the speed command, that is, to generate a speed command 18 (hereinafter referred to as the actual speed command 18) with improved speed command delay by improving the phase delay of the speed command 14 generated by the vibration excitation component extractor 11. The actual speed command 18 is the speed command of the speed controller 20.

[0095] In addition, since output 2 does not contain the frequency component that excites the vibration of the mechanical end, the actual speed command 18 obtained by adding the output 7 of the unit converter 12 to output 8 using the adder / subtractor 17 is also a speed command that does not excite the vibration of the mechanical end and has a vibration reduction effect. This point should be noted.

[0096] An example of phase adjuster 1 is a first-order high-pass filter (HPF) shown below.

[0097] [Number 9]

[0098]

[0099] Where ωh is the cutoff frequency [rad / s], and h(>1) is the adjustment gain.

[0100] exist Figure 5 The frequency characteristics of the HPF are shown in the figure when ωh = 2π × 10 and h = 2.5.

[0101] Figure 5 The upper vertical axis represents magnitude (amplitude of HPF frequency), and the horizontal axis represents frequency (frequency of HPF waveform). Figure 5 The lower vertical axis represents the phase (the phase of the HPF frequency), and the horizontal axis represents the frequency (the frequency of the HPF waveform).

[0102] The characteristics are: phase advance of π / 4 [rad / s] at frequency ωh, and phase advance of up to π / 2 [rad / s] in frequency bands below frequency ωh. Additionally, regarding gain, there is a characteristic of increasing gain by 20 × log10(h) at high frequencies.

[0103] Therefore, by using equation (9), the phase delay of speed command 14 can be improved.

[0104] The parameters ωh and h in equation (9) have design freedom. For example, if the cutoff frequency is consistent with the frequency ωn extracted by LE (ωh = ωn), the rising edge delay of the response to the ramp command can theoretically be improved linearly with the increase of h.

[0105] In addition, the response characteristics of mechanical end vibration are often expressed by the following formula (10).

[0106] [Number 10]

[0107]

[0108] Where ωa is the frequency of the mechanical end vibration [rad / s], and ζa is the attenuation coefficient. Alternatively, to extract the vibration frequency of the mechanical end using LE, we can set ωa = ωn.

[0109] Regarding the parameter design of HPF, if the frequency characteristics of AR in equation (10) are known, then it can be considered.

[0110] exist Figure 6 The frequency characteristics of AR are shown in the figure. Let ωa = 2π × 10, ζa = 0.1.

[0111] Figure 6 The upper vertical axis represents magnitude (amplitude of AR frequency), and the horizontal axis represents frequency (frequency of AR waveform). Figure 6 The lower vertical axis represents the phase (the phase of the AR frequency), and the horizontal axis represents the frequency (the frequency of the AR waveform).

[0112] AR exhibits phase delay and gain attenuation at frequencies higher than ωa. Therefore, in HPF, ωh and h are functions of AR as ωh(ωa,ζa) and h(ωa,ζa), respectively. Making ωh(ωa,ζa) > ωa actively advances the phase at high frequencies, and making h(ωa,ζa) > 2 actively increases the gain at high frequencies. This can be expected to improve not only the response delay inherent in vibration damping control but also the response delay associated with AR characteristics. The filter parameters of the phase adjuster are set based on the vibration characteristics of the mechanical end (vibration frequency and vibration attenuation coefficient).

[0113] The reason for being able to make such an active design of HPF is that the output 2, which is the input of HPF, does not contain the frequency component that excites the vibration of the mechanical end.

[0114] Thus, according to this embodiment, the upper-level system control device includes a position controller and a motor control device that includes a unit for implementing vibration reduction control within the motor servo control device responsible for the speed control system. This allows for a simple improvement in the response delay characteristic of vibration reduction control caused by the parallel vibration reduction controller 10, resulting in a shorter positioning time.

[0115] Example 2

[0116] Figure 7 The structure of the vibration damping controller 71 in the speed control system of this embodiment is shown. Compared with Embodiment 1, the difference is that an FF controller 72, an adder / subtractor 73, and an adder / subtractor 79 are added. Descriptions of contents that are the same as in Embodiment 1 are omitted.

[0117] exist Figure 8 The structure of the vibration damping controller 81 within the speed control system, which is a premise of this embodiment, is shown. Figure 8 In this context, the FF controller 85 is provided to improve response characteristics when the position controller 22 of the upper-level system control device does not include an FF controller. The FF controller 85 is used to improve the response delay of the FB loop caused by the FB controller included in the position controller 22, and is not used to improve the response delay specific to vibration reduction control.

[0118] In this embodiment, the FF controller 72 and Figure 8 The FF controller 85 has the same function and is set up to improve the response delay of the FB loop caused by the FB controller included in the position controller 22.

[0119] In semi-closed position control systems, the controlled object is typically a simple integrator 1 / s. Therefore, the FF controller in the position control system can be simply composed of the product of a scalar gain and a differentiator s. In the position controller, as shown... Figure 9 Simply configure the FF controller as shown.

[0120] Figure 9 This is a diagram showing the specific structure of a two-degree-of-freedom controller with a typical FF controller. Figure 9 In the diagram, input 94 to the FF controller is a position command. The response 96 of the controlled object is from... Figure 8 The position / velocity calculator 21 outputs the response of the controlled object. The input to the FB controller 92 is the difference between the position command 94 and the response 96 of the controlled object. The output 97 of the position controller is the velocity command. Therefore, the FF controller 93 has the property of being able to take the input as the unit of position and the output as the unit of velocity.

[0121] in addition, Figure 9 The FB controller 92 mostly uses a P controller, therefore the FB controller 92 can simply be a scalar gain (denoted as ωp). Furthermore, Figure 7 It is important to note that the position controller 22 is also a P controller with gain ωp at this time.

[0122] When using a position controller to construct a model-matched two-degree-of-freedom control 100, accompanied by a canonical model 101, such as Figure 10 The FF controller 103 can be configured as shown. In this case, the FF controller 103 and the standard model 101 are FFM and M, respectively, and the following formula can be used.

[0123] [Number 11]

[0124]

[0125] [Number 12]

[0126]

[0127] Wherein, ωf is a parameter that specifies the desired response characteristics, and it is generally designed so that ωp < ωf.

[0128] Figure 7 The FF controller 72 in the middle can adopt Figure 9 The FF controller 93. Furthermore, the FF controller 72 can also adopt... Figure 10 The model matches the FF controller in the two-degree-of-freedom control 100. However, in this case, the FF controller 72 is not directly used. Figure 10 Instead of the FF controller 103, the following formula is used. This is to... Figure 10 The modular structure is transformed into Figure 9 The FF controller 93 in this form.

[0129] [Number 13]

[0130]

[0131] According to equation (13), Figure 7 The FF controller 72 in the model-matched two-degree-of-freedom control configuration can be interpreted as a high-pass filter (HPF). F The product of this and position controller 22. Furthermore, it can also be interpreted as the high-pass filter (HPF). F The product of the unit converter 12.

[0132] Regarding high-pass filters (HPF) F Comparing with equation (9), it can be seen that the cutoff frequency is equivalent to ωf, and hf=ωf / ωp is equivalent to adjusting the gain h. The filter parameters of the feedforward controller are set based on the vibration characteristics of the mechanical end (vibration frequency and vibration attenuation coefficient).

[0133] Therefore, it can be seen that when using the FF controller 72 constructed by equation (13), in Figure 7 In the structure, for the speed command 78, which improves the response delay specific to vibration damping control using phase adjuster 1, the speed command 76, which improves the specified phase characteristics using FF controller 72, can be obtained by utilizing the same phase advance characteristic as in equation (9). This phase advance characteristic is responsible for the function of the FF controller of the position control system, and therefore is not used to improve the response delay specific to vibration damping control, but rather to improve the response delay of the FB loop caused by the FB controller included in the position controller 22.

[0134] in addition, Figure 7 In the process, the input 74 of the FF controller is obtained by adding the input 2 and the output 6 of the phase adjuster 1 using the adder-subtractor 73. This is to prevent the output 77 of the FF controller 72 from exciting the mechanical end to vibrate, and to make the output 77, which has the same phase adjustment result as the speed command 78 that has received the phase adjustment result of the phase adjuster 1, act on the speed command 78 via the adder-subtractor 79.

[0135] Therefore, according to this embodiment with FF controller 72, a motor control device is provided that includes a position controller and a motor control device that includes a unit for implementing vibration reduction control within a motor servo control device responsible for the speed control system. This device can improve the response delay unique to vibration reduction control caused by the parallel vibration reduction controller 10 with simple processing, and can also improve the response delay of the FB loop caused by the FB controller, resulting in a shorter positioning time.

[0136] Furthermore, since ωf specifies the desired response characteristics in FF control, and ωp is the control gain of position controller 22, the parameters included in equation (13) are uniquely determined and designed independently of the response characteristics AR of the mechanical end vibration. However, hf in equation (13) can also be regarded as an adjustment gain, and ωp of hf can be intentionally adjusted.

[0137] Therefore, there are cases where the response delay can be further improved. The delay characteristics improved by phase adjuster 1 and FF controller 72 are clearly different. As mentioned above, this is based on independent design. However, there are cases where, by intentionally using ωp of hf as an adjustment element and appropriately designing it in a way that balances with the parameters ωh(ωa,ζa) and h(ωa,ζa) of phase adjuster 1, the overall response delay of the mechanical end can be shortened while suppressing mechanical end vibration.

[0138] This effect can be explained as the result of treating the FF controller 72 as having the same function as the HPF of the phase adjuster 1, and using the phase result of adjusting the speed command 8 using two HPFs.

[0139] Example 3

[0140] The motor control device in this embodiment is as follows: Figure 11 The example shown is an envisioned application to a cascade position FB control system 1100 for an AC servo motor, which consists of a higher-level system control unit and a servo motor control unit.

[0141] Figure 12 This is a diagram illustrating the cascade position FB control system 1200 for the AC servo motor in Embodiment 3. Figure 12 It is Figure 1 The vibration damping controller 15 in the speed control system shown is applied to Figure 11 The same situation as in Example 1 is omitted from the description.

[0142] Figure 12 The cascade position FB control system for the AC servo motor includes: adder / subtractor 1410, adder / subtractor 1411, adder / subtractor 1412, position controller 1315, speed controller 132, current controller 133, a first coordinate transformer 134 that performs coordinate transformation from the dq coordinate system to the three-phase coordinate system, a second coordinate transformer 1310 that performs coordinate transformation from the three-phase coordinate system to the dq coordinate system, a PWM output device 135 that inputs three-phase voltage commands and outputs PWM pulses, an inverter (power converter) with switching elements 136, a current detector 138, a position / speed calculator 1311, a vibration damping controller 15 within the speed control system, an encoder 139 that measures the motor speed, a motor 137, and a mechanical device 1313 driven by the motor as the controlled object.

[0143] The vibration damping controller 15 in the speed control system takes the position response of the motor shaft calculated by the position / speed calculator 1311 based on the output of the encoder 139 and the position operation amount from the position controller 1315 as input, outputs the position response of the motor shaft to the position controller 1315, and outputs the speed command to the speed controller 132.

[0144] In the circuit section where the current controller 133 controls the motor, given that its control cycle is faster than that of the speed controller 132, the current control system is approximated as 1 in the speed control system (the speed controller's input is directly transmitted to the motor's mechanical parts (rotor)). Therefore, the speed controller 132 controls the motor's mechanical parts (rotor) and the mechanical components 1313 connected to the motor's rotor, which is equivalent to... Figure 1 The controlled object of the speed controller 20 in the middle.

[0145] Furthermore, given that the control cycle of the speed controller 132 is faster than the control cycle of the position controller 1315, the speed control system is approximately considered as 1 in the position control system.

[0146] The vibration damping controller 15 in the speed control system is located in the front stage (front end) of the speed control system. It processes the speed command output by the upper system control device and generates commands for the speed controller 132.

[0147] With the inertia number of mechanical 1313 set to 1 and mechanical 1313 elastically coupled to the rotor of the motor, the controlled object can be regarded as a two-inertial system consisting of mechanical 1313 and the rotor of the motor coupled with a spring / damper. The controlled object has frequency characteristics including one set of resonant / anti-resonant characteristics.

[0148] Furthermore, when the number of inertia of mechanical 1313 is 2 and each inertia is combined by a spring / damper, one of which is elastically combined with the rotor of the motor, the controlled object can be regarded as a three-inertial system in which each inertia is combined by a spring / damper, and has frequency characteristics including two sets of resonant / anti-resonant characteristics.

[0149] Assume that mechanical 1313 has low rigidity and exhibits resonant / anti-resonant characteristics in the low-frequency range of several Hz to 100 Hz.

[0150] First, consider the state of the vibration damping controller 15, excluding the speed control system. Figure 11 When the control gain of the position controller is increased to control the motor shaft position response of the motor 137 with high responsiveness from the position command, and a setting is adopted to suppress the vibration caused by the resonance / anti-resonance characteristics of the mechanical 1313, the ends of the mechanical 1313 become vibratory because the rigidity of the mechanical 1313 is low.

[0151] On the other hand, such as Figure 12 As shown, when the vibration damping controller 15 is included in the speed control system, the vibration damping effect of the mechanical end can be achieved as described in Example 1, and the response delay unique to vibration damping control can be improved.

[0152] Figure 13A and Figure 13B This is an explanation Figure 12 The diagram shows the vibration reduction effect of the AC servo motor control system. Figure 12 Structure such as Figure 13A and Figure 13B As shown, it can achieve sufficient vibration reduction and improve response delay.

[0153] exist Figure 13A and Figure 13B In the diagram, the vertical axis represents the mechanical angle (Mech.angle, the position response of the mechanical end), and the horizontal axis represents time. The position response of the mechanical end indicates the position of the end of the machine connected to the motor, i.e., the position moved by the mechanical end due to the rotation of the motor, which is equivalent to the rotation angle (rad) of the motor.

[0154] Figure 13B It is Figure 13A A magnified portion of the image. (For example...) Figure 13A and Figure 13B As shown, compared with "no vibration control" 1402 and "with vibration control but no phase adjustment" 1403, the response performance to "position command" 1401 is higher when using "with vibration control and phase adjustment" 1404 (represented by solid line in this embodiment).

[0155] Therefore, according to this embodiment, a motor control device can be provided. In a semi-enclosed AC servo motor control system, the upper-level system control device includes a position controller, and the motor servo control device responsible for the speed control system includes a unit for implementing vibration reduction control, and also includes a unit for improving the response delay unique to vibration reduction control with simple processing.

[0156] In this embodiment, the case of applying the vibration damping controller 15 in the speed control system of Embodiment 1 to the cascade position FB control system 1100 of the AC servo motor is described as an example. However, the vibration damping controller 71 in the speed control system of Embodiment 2 can also be applied to the cascade position FB control system 1100 of the AC servo motor.

[0157] In addition to AC servo motor control, a cascade control structure based on a speed / position controller is also used in DC motor control. Therefore, according to this embodiment, by setting a vibration damping controller 15 in the speed control system in front of the speed controller, vibration damping at the mechanical end can be achieved in the speed control system.

[0158] Explanation of reference numerals in the attached figures

[0159] 1… Phase adjuster, 9… Position command calculator, 10… Parallel vibration damping controller, 11… Vibration excitation component extractor, 14… Speed ​​command, 15… Vibration damping controller within the speed control system, 18… Actual speed command, 21… Position / speed calculator, 23… Motor shaft position response, 24… Position command, 72… FF controller, 136… Inverter, 137… AC servo motor, 138… Current detector, 139… Encoder, 201… Upper-level system control device, 301… Servo motor control device, 1313… Mechanical control of the controlled object.

Claims

1. A motor control device, comprising a position control system for controlling the position of a mechanical end connected to a motor, characterized in that: The position control system is equipped with a mechanism that enables it to receive a first speed command from a higher-level system control device and output the position response of the motor shaft to the higher-level system control device. The motor control device includes a speed controller and a vibration damping controller within the speed control system. The vibration damping controller within the speed control system has: A position command estimator calculates the estimated value of the position command based on the first speed command and the position response of the motor shaft; A parallel vibration damping controller extracts the frequency components of the vibration that excites the mechanical end contained in the first speed command based on the calculated value of the position command, and outputs the extracted frequency components. A phase adjuster is used to improve the response delay caused by the parallel vibration damping controller; A first unit converter that converts the output of the phase adjuster into a velocity dimension; and Arithmetic unit; The arithmetic unit subtracts the output of the parallel vibration damping controller from the first speed command to remove the frequency component that excites the vibration of the mechanical end, and outputs the second speed command as such. The arithmetic unit outputs a first actual speed command as the output of the vibration damping controller within the speed control system, based on the output of the first unit converter and the second speed command, and uses the first actual speed command as the command of the speed controller.

2. The motor control device as described in claim 1, characterized in that: The arithmetic unit has: A first adder / subtractor subtracts the output of the parallel vibration damping controller from the first speed command; and The second adder / subtractor adds the output of the first unit converter to the second speed command.

3. The motor control device as described in claim 1, characterized in that: The position command estimator has an estimating filter and a third adder / subtractor that are consistent with the inverse characteristics of the position controller included in the upper-level system control device. The third adder / subtractor adds the signal obtained by processing the first speed command with the estimating filter and the phase response of the motor shaft, and outputs the result of the addition as the estimated value of the position command.

4. The motor control device as described in claim 1, characterized in that: The parallel vibration damping controller has the following features: A vibration excitation component extractor extracts the frequency components of the vibration that excites the mechanical end contained in the first velocity command without phase delay from the calculated value of the position command. and The second unit converter converts the units of the vibration excitation component signal extracted by the vibration excitation component extractor into the dimension of velocity. The output of the second unit converter is used as the output of the parallel vibration damping controller. The arithmetic unit calculates the difference between the input and output of the vibration excitation component extractor. The phase adjuster takes the difference as input, adjusts its phase, and outputs it to the first unit converter.

5. The motor control device as described in claim 4, characterized in that: The arithmetic unit has: A first adder / subtractor subtracts the output of the parallel vibration damping controller from the first speed command; The second adder / subtractor adds the output of the first unit converter to the second speed command; and The fourth adder / subtractor subtracts the output from the input of the vibration excitation component extractor.

6. The motor control device as described in claim 1, characterized in that: The vibration damping controller within the speed control system includes a feedforward controller, which is used to improve the response delay of the feedback control of the position controller included in the upper-level system control device. The arithmetic unit calculates the input and output of the phase adjuster, uses the result of the calculation as the input of the feedforward controller, calculates the second actual speed command based on the output of the feedforward controller and the first actual speed command, and uses the second actual speed command as the output of the vibration reduction controller in the speed control system.

7. The motor control device as described in claim 6, characterized in that: The arithmetic unit has: The fifth adder / subtractor adds the input and output of the phase adjuster; and The sixth adder / subtractor adds the output of the feedforward controller to the first actual speed command.

8. The motor control device as described in claim 1, characterized in that: The phase adjuster is a high-pass filter.

9. The motor control device as described in claim 6, characterized in that: The feedforward controller is a high-pass filter.

10. The motor control device as described in claim 1, characterized in that: The filter parameters of the phase adjuster are set based on the vibration characteristics of the mechanical end.

11. The motor control device as described in claim 6, characterized in that: The filter parameters of the feedforward controller are set based on the vibration characteristics of the mechanical end.

12. The motor control device as described in claim 1, characterized in that: The upper-level system control device includes a position controller installed in the position control system, which generates the position command. The position controller generates the first speed command based on the position command and the position response of the motor shaft received from the motor control device.

Images