Control assistance device, control system, and control assistance method

Abstract

A resonance point corresponding to an alias frequency is excluded from targets for filter application.　This control assistance device for assisting adjustment of at least one filter coefficient of a filter provided in a motor control device, includes: a frequency-characteristic measurement portion that measures a frequency characteristic of input / output gain of the motor control device and a phase delay of input / output measured on the basis of an input signal and an output signal whose frequencies change; a resonance detection portion that detects a resonance point in the frequency characteristic; an information acquisition portion that acquires information including a resolution per rotation of a speed sensor of the motor, a motor rotation speed, and a sampling frequency; an alias calculation portion that calculates an alias frequency of an interpolation error component of the speed sensor from the information; and a resonance evaluation portion that evaluates whether or not the filter application to the detected resonance point is necessary on the basis of the alias frequency.

Description

Control support device, control system, and control support method

[0001] The present disclosure relates to a control assistance device, a control system, and a control assistance method that assist in adjusting at least one filter coefficient of a filter provided in a motor control device that controls a motor of a machine tool, a robot, or an industrial machine.

[0002] Patent Documents 1, 2 and 3 describe devices that measure the frequency characteristics of a machine tool or the like and adjust filter coefficients based on the frequency characteristics.

[0003] Japanese Patent Application Laid-Open No. 2006-129999 (Patent Document 1) describes a magnetic disk drive that suppresses vibrations present at frequencies higher than the Nyquist frequency. Specifically, Japanese Patent Application Laid-Open No. 2006-129999 (Patent Document 1) describes introducing a multirate filter having a resonance point at a frequency higher than the target Nyquist frequency into a stage preceding the object to be controlled. Japanese Patent Application Laid-Open No. 2006-129999 (Patent Document 1) also describes designing the multirate filter so that, since the resonance characteristics of the multirate filter are aliased by a sampler, the resonance point after aliasing is phase-stabilized by a following compensator.

[0004] Furthermore, Patent Document 2 describes a servo control device that estimates a transfer function from a measured frequency response and performs filter adjustment. Specifically, Patent Document 2 describes that the servo control device includes a speed control loop including a speed command generation unit, a torque command generation unit, and a speed detection unit, a sinusoidal disturbance input unit, a frequency response calculation unit for estimating gains and phases of speed control loop input / output signals, a resonance frequency detection unit, a resonance mode characteristic estimation unit for estimating resonance characteristics from frequency responses at the resonance frequency and frequencies near the resonance frequency, a rigid body mode characteristic estimation unit for estimating rigid body characteristics from frequency responses in a low frequency band, a filter that attenuates specific frequency band components included in the torque command, and a filter adjustment unit that gives the filter designated filter characteristics, and that the filter adjustment unit further includes filter adjustment means for attenuating frequency band components corresponding to the resonance mode estimated by the resonance mode characteristic estimation unit.

[0005] Furthermore, Patent Document 3 describes a positioning device that ensures high positioning accuracy by actively attenuating resonance near the Nyquist frequency determined by the control variable sampling frequency and simultaneously attenuating high-frequency resonance modes. Specifically, Patent Document 3 describes that the positioning device includes a control target configured with a rigid body mode plus a resonance mode, a digital controller that applies an input in the acceleration dimension, an actuator including a driver that transmits the input to the control target, and a circuit that samples the control variable. It also describes that the positioning device includes a filter that adjusts the phase so that the phase at the frequency of a first resonance mode, which is the lowest frequency among resonance modes whose gain in the open-loop frequency response of the controller, its calculation time delay, the driver, the actuator, and the control target exceeds 0 dB, approaches −270 degrees to −450 degrees.

[0006] JP 2007-4910 A JP 2016-111897 A JP 2002-182703 A

[0007] When adjusting filters for machine tools, etc., it is desirable to measure and evaluate the frequency characteristics while the axis is moving (while the motor is rotating) in order to eliminate the effects of static friction. However, when using a speed sensor with low resolution, alias components (false resonances) of frequencies caused by interpolation errors of the sensor may be measured depending on the motor rotation speed, which may interfere with automatic adjustment, etc.

[0008] Therefore, there is a need for a control assistance device, a control system, and a control assistance method that assist in adjusting filter coefficients while excluding alias components from the filter adjustment targets.

[0009] A first representative aspect of the present disclosure is a control assistance device that assists in adjusting at least one filter coefficient of a filter provided in a motor control device that controls a motor of a machine tool, robot, or industrial machine, and includes: a frequency characteristic measurement unit that measures the frequency characteristics of the input / output gain and input / output phase delay of the motor control device, measured based on an input signal and an output signal whose frequency changes; a resonance detection unit that detects a resonance point in the frequency characteristics; an information acquisition unit that acquires information including the resolution per rotation of a speed sensor of the motor, the motor rotation speed, and a sampling frequency; an alias calculation unit that calculates an alias frequency of an interpolation error component of the speed sensor from the information; and a resonance evaluation unit that evaluates whether or not a filter needs to be applied to the detected resonance point based on the alias frequency.

[0010] A second representative aspect of the present disclosure is a control system comprising the above-mentioned control assistance device, a motor control device including a filter, and an adjustment device that adjusts at least one filter coefficient of the filter, wherein the adjustment device adjusts at least one filter coefficient of the filter so that the filter is applied to a resonance point determined by the control assistance device to be applied to the filter.

[0011] A third representative aspect of the present disclosure is a control assistance method that causes a computer as a control assistance device that assists in adjusting at least one filter coefficient of a filter provided in a motor control device that controls a motor of a machine tool, robot, or industrial machine to perform the following processes: measuring the frequency characteristics of the input / output gain and input / output phase delay of the motor control device, measured based on an input signal and an output signal whose frequency varies; detecting a resonance point in the frequency characteristics; acquiring information including the resolution per rotation of a speed sensor of the motor, the motor rotation speed, and a sampling frequency; calculating an alias frequency of an interpolation error component of the speed sensor from the information; and evaluating, based on the alias frequency, whether or not a filter needs to be applied to the detected resonance point.

[0012] FIG. 1 is a block diagram showing an example of the overall configuration of a control system according to a first embodiment of the present disclosure. FIG. 2 is a block diagram showing example configurations of a motor control device and a control assistance device according to the first embodiment. FIG. 3 is a Bode diagram showing frequency characteristics measured by a frequency characteristic measurement unit and frequencies of first and second resonance points detected by a resonance detection unit in the first embodiment. FIG. 4 is a Bode diagram showing frequency characteristics measured by a frequency characteristic measurement unit and frequencies of the first resonance point detected by the resonance detection unit when a filter is applied to the second resonance point. FIG. 5 is a flowchart showing operation of the control assistance device according to the first embodiment. FIG. 6 is a block diagram showing a modified example of a motor control device and a control assistance device in which the input position of an input signal to the motor control device and the extraction position of an output signal from the motor control device are changed. FIG. 7 is a block diagram showing an example of the overall configuration of a control system according to a second embodiment of the present disclosure. FIG. 8 is a block diagram showing example configurations of a motor control device and a control assistance device according to the second embodiment of the present disclosure. FIG. 9 is a Bode diagram showing frequency characteristics measured by a frequency characteristic measurement unit and a third resonance point detected by the resonance detection unit when a motor is driven at a first motor rotation speed in the second embodiment. 10 is a Bode diagram showing the frequency characteristics measured by the frequency characteristic measuring unit and the first and second resonance points detected by the resonance detecting unit when the motor is driven at a second motor rotation speed in a second embodiment. FIG. 11 is a flowchart showing the operation of the control assistance device in the second embodiment. FIG. 12 is a block diagram showing an example configuration of a motor control device and a control assistance device according to a third embodiment of the present disclosure. FIG. 13 is a diagram showing a display screen of a display unit. FIG. 14 is a diagram showing a table displayed in a first display area of ​​the display screen. FIG. 15 is a characteristic diagram displayed in a second display area of ​​the display screen. FIG. 16 is a block diagram showing an example configuration of a filter formed by directly connecting a plurality of filters.

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. (First Embodiment) Fig. 1 is a block diagram showing an example of the overall configuration of a control system according to a first embodiment of the present disclosure. Fig. 2 is a block diagram showing an example of the configuration of a motor control device and a control assistance device. The control system 10 includes a motor control device 110, a frequency generation device 120, a control assistance device 130, and an adjustment device 140. One or more of the frequency generation device 120, the control assistance device 130, and the adjustment device 140 may be provided within the motor control device 110.

[0014] The motor control device 110 controls the operation of a machine tool, a robot, or an industrial machine. The frequency generating device 120 generates a signal with a variable frequency, for example, a sine wave signal with a variable frequency, as an input signal S ＩＮ The motor control device 110 outputs the input signal S ＩＮ and operates based on the output signal S ＯＵＴ is output to the control assistance device 130.

[0015] The control assistance device 130 receives an input signal S ＩＮ and the output signal S ＯＵＴ The frequency characteristics are calculated using the above formula and the resonance point is detected. The frequency characteristics are the frequency characteristics of the input / output gain and the frequency characteristics of the phase delay of the motor control device 110. Hereinafter, when simply referring to "frequency characteristics", it will refer to the frequency characteristics of the input / output gain and the frequency characteristics of the phase delay. Furthermore, the control assistance device 130 calculates the resolution λ per rotation of the speed sensor, the motor rotation speed S when measuring the frequency characteristics, the sampling frequency f when measuring the frequency characteristics, and the like. Ｓ From this information, the alias frequency f Ａ The alias frequency is the noise frequency of the interpolation error component generated by aliasing. The control assistance device 130 then determines whether the detected resonance point is at the alias frequency f Ａ It is then evaluated whether a resonance point appears based on the above and it is determined whether a filter needs to be applied.

[0016] The control assistance device 130 determines whether the resonance point is at an alias frequency f ＡWhen the adjustment device 140 determines that the resonance point is not a target for applying the filter, the adjustment device 140 determines that the alias frequency f Ａ On the other hand, the control assistance device 130 does not apply the filter 113 to the resonance point that appears based on the alias frequency f Ａ If the adjustment device 140 determines that the resonance point is not a resonance point that appears based on the alias frequency f and determines that the resonance point is a target for filter application, the adjustment device 140 adjusts the filter coefficient of the filter 113 so that the filter 113 of the motor control device 110 is applied to the resonance point. Ａ If the frequency of the resonance point does not appear based on the above equation, the frequency of the resonance point is determined to be a mechanical resonance frequency.

[0017] There are no particular limitations on the configuration by which adjustment device 140 adjusts the filter coefficients of filter 113 of motor control device 110, and any known configuration can be used. For example, adjustment device 140 can use a machine learning device that optimizes the filter coefficients of the filter of the motor control device based on the frequency characteristics of the input / output gain and the frequency characteristics of the phase delay of the motor control device, as described in Japanese Patent Application Laid-Open No. 2020-067874.

[0018] The motor control device 110, the frequency generating device 120, and the control assistance device 130 will be further described below with reference to FIG.

[0019] (Motor Control Device) As shown in FIG. 2 , the motor control device 110 includes a subtractor 111, a speed control unit 112, a filter 113, an adder 114, a subtractor 115, a current control unit 116, an amplifier 117, and a motor 118. The motor 118 is a motor having a rotating shaft, or the like. The object driven by the motor 118 is, for example, a mechanical part of a machine tool, a robot, or an industrial machine. The motor 118 may be provided as part of the machine tool, robot, industrial machine, or the like. The motor control device 110 may be provided as part of the machine tool, robot, industrial machine, or the like.

[0020] The subtractor 111 calculates the difference between the input speed command and the detected speed fed back, and outputs the difference to the speed control section 112 as a speed deviation.

[0021] The speed control unit 112 performs PI control (Proportional-Integral Control), adds together the integrated value obtained by multiplying the speed deviation by integral gain K1v and the value obtained by multiplying the speed deviation by proportional gain K2v, and outputs the result as a torque command to the filter 113. The speed control unit 112 is not particularly limited to PI control, and may use other control, for example, PID control (Proportional-Integral-Differential Control).

[0022] The filter 113 is a filter that attenuates specific frequency components, and for example, a notch filter, a low-pass filter, or a band-stop filter is used. In a machine tool or the like having a mechanical part driven by a motor 118, a resonance point exists, and resonance may increase in the motor control device 110. Resonance can be reduced by using a filter such as a notch filter. The output of the filter 113 is sent to the adder 114 and the control assistance device 130 as an output signal S ＯＵＴ The output signal S is output to the adder 114. ＯＵＴ is the torque command. Equation 1 (hereinafter referred to as Equation 1) is the transfer function G Ｆ (s), where the coefficient δ in Equation 1 is the damping coefficient, and the coefficient ω ｃ is the central angular frequency, and the coefficient τ is the fractional bandwidth. If the central frequency is fc and the bandwidth is fw, then the coefficient ω ｃ ω ｃ = 2πfc, and the coefficient τ is expressed as τ = fw / fc. ｃ and the coefficient τ is the filter coefficient of the filter 113 .

[0023] The adder 114 receives an input signal S, such as a sinusoidal signal with a varying frequency, output from a frequency generator 120. ＩＮ and the output signal S output from the filter 113 ＯＵＴ The adder 114 adds these signals and outputs the result to the subtractor 115. The subtractor 115 finds the difference between the signal output from the adder 114 and the detected current that has been fed back, and outputs the difference to the current control unit 116 as a current deviation.

[0024] The current control unit 116 calculates the value of the current (current value) to be passed through the motor 118 based on the current deviation and outputs this to the amplifier 117. The amplifier 117 calculates the power based on the current value output from the current control unit 116 and inputs this power to the motor 118. The amplifier 117 is equipped with a current detector, and the detected current detected by the current detector is fed back to the subtractor 115.

[0025] The rotation angle position and speed of the motor 118 are detected by a rotary encoder (not shown) provided on the motor 118, and the detected speed is input as speed feedback to the subtractor 111. The rotary encoder serves as a speed sensor.

[0026] (Frequency Generator) The frequency generator 120 receives an input signal S such as a sine wave signal with a variable frequency. ＩＮ to the adder 114 of the motor control device 110 and the frequency characteristic measuring unit 131 of the control assistance device 130. The motor control device 110 receives the input signal S ＩＮ and the output signal S ＯＵＴ is output to the frequency characteristic measuring unit 131 of the control assistance device 130.

[0027] The input signal may be input to another location in the motor control device 110, and the output signal may be output from another location in the motor control device 110. However, if the input signal S ＩＮ is input, and the output signal S ＯＵＴ When the input signal S is output, the following advantages are obtained: The inductance of the motor 118 changes nonlinearly depending on the current flowing through the motor 118 due to the influence of magnetic saturation, etc. ＩＮ is input, changing the filter coefficient of the filter 113 changes the torque command input to the current control unit 116. If the current gain of the current control unit 116 is constant, the current flowing through the motor 118 also changes. When the current flowing through the motor 118 changes and the inductance changes nonlinearly, the characteristics of the current feedback loop also change nonlinearly.

[0028] In the configuration shown in FIG. 2, the frequency generating device 120 outputs a sine wave signal to the adder 114 on the output side of the filter 113 while changing the frequency. ＩＮ The frequency characteristic measuring unit 131 shown in FIG. ＩＮ and the output signal S output from the filter 113 ＯＵＴ The frequency characteristics of the input / output gain and the frequency characteristics of the phase delay of the motor control device 110 are measured from the above. In this way, the input to the current feedback loop becomes constant, and the resonance point can be found by the control assistance device 130 while maintaining the linearity of the current feedback loop characteristics.

[0029] (Control Assistance Device) As shown in FIG. 2 , the control assistance device 130 includes a frequency characteristic measurement unit 131 , a resonance detection unit 132 , a resonance evaluation unit 133 , an information acquisition unit 134 , and an alias calculation unit 135 .

[0030] The frequency characteristic measuring unit 131 measures the input signal S such as a sine wave signal whose frequency is changed, which is output from the frequency generating device 120. ＩＮ and the output of the filter 113 of the motor control device 110 (output signal S ＯＵＴ ) the frequency characteristics of the input / output gain and the frequency characteristics of the phase delay of the motor control device 110 are measured.

[0031] The resonance detection unit 132 detects a resonance point from the frequency characteristics of the input / output gain measured by the frequency characteristic measurement unit 131. Fig. 3 is a Bode diagram showing the frequency characteristics measured by the frequency characteristic measurement unit 131 and the frequencies of the first and second resonance points detected by the resonance detection unit 132. The gain diagram of the input / output gain shown in Fig. 3 shows the frequencies f Ｃ１ , f Ｃ２ In the gain diagram shown in FIG. 3, the frequency f of the first resonance point is Ｃ１ is 1867Hz, the frequency of the second resonance point f Ｃ２ The resonance detection unit 132 detects the frequency f of the first resonance point. Ｃ１ 1867 Hz, the frequency of the second resonance point f Ｃ２ The frequency of 2430 Hz is output to the resonance evaluation unit 133.

[0032] The information acquisition unit 134 acquires the motor rotation speed S at the time of measuring the frequency characteristics from the motor control device 110, and acquires the sampling frequency f at the time of measuring the frequency characteristics from the frequency characteristics measurement unit 131. Ｓ and obtains the resolution λ per rotation of the speed sensor from a numerical control device (not shown). The motor rotation speed S is obtained, for example, from a speed command. The resolution λ per rotation of the speed sensor is stored in the numerical control device. The resolution λ per rotation of the speed sensor may be obtained from the specifications (catalog, etc.) of the rotary encoder used as the motor speed sensor and input to the information acquisition unit 134. Sampling frequency f Ｓ is the sampling frequency of the input signal and the output signal measured by the frequency characteristic measuring unit 131, and the information acquiring unit 134 acquires the sampling frequency f Ｓ The information acquisition unit 134 can acquire the acquired motor rotation speed S, sampling frequency f Ｓ The resolution λ per revolution of the speed sensor is also output to the alias calculation unit 135 .

[0033] The alias calculation unit 135 calculates the alias frequencies. A method for calculating the alias frequencies will be described below, but the method for calculating the alias frequencies is not limited to the method described below.

[0034] The alias calculation unit 135 first calculates the frequency f due to the sensor interpolation error component of the speed sensor during motor rotation, as shown in Equation 2 (hereinafter, Equation 2), using the motor rotation speed S and the resolution per rotation λ of the speed sensor. Ｋ Ask for. In Equation 2, (S / 60) × λ indicates the number of pulses (frequency) output per second. In many cases, the interpolation error is dominated by amplitude error components and phase error components, which correspond to two times per cycle. Therefore, the frequency f Ｋis shown as (S / 60) × λ × 2. Regarding the period of the interpolation error of the amplitude error component and the phase error component, for example, the technical document "High Resolution Technology for Linear Encoders, Sakagami Seiji, Kiriyama Tetsuro, Hagiwara Motonori, Measurement and Control, Vol. 44, No. 10, October issue, p. 666" describes that the period of the interpolation error of the amplitude error component and the phase error component is P / 2 of the signal pitch P, and it can be seen that the frequency is twice (S / 60) × λ.

[0035] In this embodiment, the amplitude error component and the phase error component are taken as the interpolation error, but the above technical document describes an offset error component, an amplitude error component, a phase error component, and an m-th harmonic distortion error component as the interpolation error, and describes that the period of the interpolation error of the offset error component is 1 time / period, and that the period of the interpolation error of the m-th harmonic distortion error component is (m+1) times / period. The offset error component or the m-th harmonic distortion error component may be used as the interpolation error. When the offset error component is used as the interpolation error, Ｋ is 1 / 2 times the value of Equation 2, and when the m-th harmonic distortion error component is used as the interpolation error, the frequency f Ｋ is (m+1) / 2 times the value of Equation 2.

[0036] The alias calculation unit 135 calculates the frequency f Ｋ and sampling frequency f Ｓ and the Nyquist frequency f Ｎ Using the above, the alias frequency f due to the sensor interpolation error component shown in Equation 3 (hereinafter Equation 3) and Equation 4 (hereinafter Equation 4) can be calculated. Ａ Calculate the Nyquist frequency f Ｎ is f Ｎ = f Ｓ / 2. Equation 3 (below) can be calculated as mod(f Ｋ , f ｓ ) <f Ｎ Alias ​​frequency f in the case Ａ and Equation 4 (hereinafter Equation 4) represents mod(f Ｋ , f Ｓ ) ≧ f Ｎ Alias ​​frequency f in the case Ａ mod denotes the modulus function, and the modulus function mod(fＫ , f Ｓ ) is f Ｋ f Ｓ It indicates the remainder (remainder) when divided by .

[0037] Alias ​​frequency f due to sensor interpolation error component Ａ The fact that is expressed by Equation 3 and Equation 4 is described, for example, in Analog Devices APPLICATION NOTE 3716, December 23, 2005, "Folded Frequency Calculator" (https: / / www.analog.com / jp / design notes / foldedfrequencycalculator.html) and JP-T-2010-515069.

[0038] When the frequency characteristic measuring unit 131 measures the frequency characteristic shown in FIG. 3, the motor rotation speed S is 4000 rpm, the resolution λ per rotation of the speed sensor is 256, and the sampling frequency f Ｓ The alias calculation unit 135 calculates the frequency f Ｋ is calculated using Equation 2, Ｋ = 34133 Hz, mod(f Ｋ , f Ｓ ) is 10133 Hz. Nyquist frequency f Ｎ is f Ｎ = f Ｓ / 2, and f Ｎ = 6000 Hz. The remainder function mod(f Ｋ , f Ｓ ) has a value of 10133 Hz, and mod(f Ｋ , f Ｓ ) > f Ｎ Therefore, the alias calculation unit 135 calculates the alias frequency f Ａ The alias calculation unit 135 calculates the alias frequency f Ａ (f Ａ = 1867 Hz) to the resonance evaluation unit 133.

[0039] The resonance evaluation unit 133 calculates the alias frequency f of the interpolation error component of the sensor calculated by the alias calculation unit 135. Ａ is the frequency f of the first and second resonance points detected by the resonance detection unit 132. Ｃ１ , f Ｃ２ The necessity of applying a filter is evaluated depending on whether the alias frequency f Ａ (f Ａ = 1867 Hz) is the frequency f of the first resonance point output from the resonance detection unit 132. Ｃ１ The frequency of the second resonance point f Ｃ２ Therefore, the resonance evaluation unit 133 determines that the first resonance point is not a target for application of the filter, and determines that the second resonance point is a target for application of the filter. The second resonance point is the alias frequency f Ａ Therefore, the frequency of the second resonance point is determined to be the mechanical resonance frequency.

[0040] When the resonance evaluation unit 133 determines that the second resonance point is to be the target of filter application, the resonance evaluation unit 133 transmits to the adjustment device 140 the frequency f of the second resonance point to which the filter is to be applied. Ｃ２ The adjustment device 140 shown in FIG. 1 outputs the frequency f Ｃ２ The filter coefficients (coefficient δ, coefficient ω) of the filter 113 are set so that the filter 113 of the motor control device 110 is applied to 2430 Hz. ｃ 4 is a Bode diagram showing the frequency characteristic measured by the frequency characteristic measuring unit 131 and the frequency of the first resonance point detected by the resonance detecting unit 132 when a filter is applied to the second resonance point. As shown in FIG. 4, in the gain diagram of the input / output gain, the frequency f Ｃ１ In this case, the filter is not applied and the same resonance points as in Figure 3 are observed, but at frequency f Ｃ２ In this case, a filter is applied and no resonance points similar to those in FIG. 3 are observed.

[0041] The above has described the functional blocks included in the control assistance device 130. To realize these functional blocks, the control assistance device 130 includes a processing unit such as a CPU (Central Processing Unit). The control assistance device 130 also includes an auxiliary storage device such as an HDD (Hard Disk Drive) that stores various control programs such as application software and an OS (Operating System), and a main storage device such as a RAM (Random Access Memory) that stores data temporarily required for the processing unit to execute programs.

[0042] In the control assistance device 130, the arithmetic processing unit reads application software or an OS from the auxiliary storage device, and executes arithmetic processing based on the application software or OS while loading the loaded application software or OS into the main storage device. Furthermore, based on the results of this calculation, various pieces of hardware provided in each device are controlled. This realizes the functional blocks of this embodiment. In other words, this embodiment can be realized by the cooperation of hardware and software.

[0043] When the amount of calculation required for the control assistance device 130 is large, for example, a personal computer may be equipped with a GPU (Graphics Processing Unit) and a technology called GPGPU (General-Purpose Computing on Graphics Processing Units) may be used to perform calculations at high speed. Furthermore, in order to achieve even faster processing, a computer cluster may be constructed using multiple computers equipped with such GPUs, and parallel processing may be performed on the multiple computers included in this computer cluster.

[0044] Next, the operation of the control assistance device 130 will be described using a flowchart. Fig. 5 is a flowchart showing the operation of the control assistance device. In step S11, the frequency characteristic measurement unit 131 measures an input signal S such as a sine wave signal whose frequency changes. ＩＮ and the output of the filter 113 of the motor control device 110 (output signal S ＯＵＴ ) the frequency characteristics of the input / output gain and the frequency characteristics of the phase delay of the motor control device 110 are measured.

[0045] In step S12, a resonance point is detected from the frequency characteristics of the input / output gain measured by the frequency characteristic measurement unit 131. In step S13, the information acquisition unit 134 detects the resonance point from the frequency characteristics of the input / output gain measured by the frequency characteristic measurement unit 131. Ｓ and the resolution per rotation λ of the speed sensor, and the alias calculation unit 135 calculates the motor rotation speed S, the sampling frequency f Ｓ and the resolution per revolution of the speed sensor, λ, is used to calculate the alias frequency f of the sensor interpolation error component. Ａ Calculate.

[0046] In step S14, the resonance evaluation unit 133 calculates the alias frequency f of the interpolation error component of the sensor calculated by the alias calculation unit 135. Ａ The necessity of applying a filter is evaluated depending on whether the frequency of the alias frequency coincides with the frequency of the resonance point detected by the resonance detection unit 132, and the resonance point corresponding to the alias frequency is excluded from the target of applying a filter.

[0047] In step S15, the control assistance device 130 determines whether or not to continue the process. If the process is to be continued, the process returns to step S11, and if the process is not to be continued, the process ends.

[0048] In the embodiment described above, resonance points corresponding to alias frequencies can be excluded from filter application, so the adjustment device of the control system can apply filters only to necessary resonance points and does not apply unnecessary filters, thereby reducing the calculation processing time required for filter application.

[0049] (Modification) In the configuration shown in FIG. 2, the frequency generating device 120 receives an input signal S ＩＮ to the adder 114 and the frequency characteristic measuring unit 131 of the motor control device 110, and the motor control device 110 outputs the output signal S ＯＵＴ was output to frequency characteristic measuring unit 131. In this modified example, the input signal is input to a different position in motor control device 110, and the output signal is output from a different position in motor control device 110. Fig. 6 is a block diagram showing a modified example of a motor control device and a control assistance device in which the input position of the input signal to the motor control device and the output position of the output signal from the motor control device are changed. In motor control device 110A shown in Fig. 6, adder 114 of motor control device 110 shown in Fig. 2 is removed and adder 119 is inserted.

[0050] The frequency generator 120 receives an input signal S, such as a sine wave signal whose frequency varies, from the adder 119. ＩＮ The motor controller 110 receives the velocity feedback signal S ＯＵＴ and inputs it to the frequency characteristic measuring unit 131 of the control assistance device 130.

[0051] Second Embodiment Fig. 7 is a block diagram showing an example of the overall configuration of a control system according to a second embodiment of the present disclosure. Fig. 8 is a block diagram showing example configurations of a motor control device and a control assistance device according to a second embodiment of the present disclosure. In a control system 11 according to this embodiment, the control assistance device 130 shown in Figs. 1 and 2 is replaced with a control assistance device 130A shown in Figs. 7 and 8. As shown in Fig. 8, the control assistance device 130A includes a speed command modification unit 136 inserted into the control assistance device 130 shown in Fig. 2, and the speed command modification unit 136 outputs a speed addition value to the subtractor 111 of the motor control device 110. Furthermore, in the control assistance device 130A, the resonance evaluation unit 133 of the control assistance device 130 shown in Fig. 2 is replaced with a resonance evaluation unit 133A.

[0052] When the motor rotation speed changes, the alias frequencies calculated by Equations 3 and 4 also change, so the resonance evaluation unit 133A determines whether or not to apply a filter to a resonance point of the frequency characteristics based on the frequency characteristics measured at different motor rotation speeds. Even if a resonance point corresponds to an alias frequency at the first motor rotation speed, the resonance evaluation unit 133A applies a filter if a resonance point at the same frequency as the first resonance point does not correspond to an alias frequency at the second motor rotation speed and there is a resonance point common to the first and second motor rotation speeds.

[0053] The following describes resonance evaluation unit 133A and speed command modification unit 136. As shown in Fig. 8, speed command modification unit 136 outputs a first speed addition value to be added to the speed command to subtractor 111. Motor control device 110 drives motor 118 at a first motor rotation speed based on a speed command obtained by adding the first speed addition value to the speed command, and frequency characteristic measurement unit 131 measures the frequency characteristic at the first motor rotation speed.

[0054] The resonance detection unit 132 detects a resonance point from the frequency characteristics of the input / output gain measured by the frequency characteristic measurement unit 131. １ 9 is a Bode diagram showing the frequency characteristic measured by the frequency characteristic measuring unit 131 and the third resonance point detected by the resonance detecting unit when the motor 118 is driven at a rotational speed of 1 / 300 rpm (referred to as the first rotational speed in FIG. 9). The gain diagram of the input / output gain shown in FIG. 9 shows the frequency f of the third resonance point detected by the resonance detecting unit 132. Ｃ３ In the gain diagram shown in FIG. 9, the frequency f of the third resonance point is Ｃ３ The resonance detection unit 132 detects the frequency f of the third resonance point. Ｃ３ The frequency of 2430 Hz is output to the resonance evaluation unit 133.

[0055] The information acquisition unit 134 acquires the first motor rotation speed S １ , sampling frequency f when measuring frequency characteristics Ｓand the resolution λ per rotation of the speed sensor, and outputs them to the alias calculation unit 135. As described in the first embodiment, the alias calculation unit 135 calculates the first motor rotation speed S １ , sampling frequency f Ｓ and the resolution per revolution λ of the speed sensor, the alias frequency f Ａ１ is calculated and output to the resonance evaluation unit 133. The first motor rotation speed S when the frequency characteristic measurement unit 131 measures the frequency characteristic shown in FIG. １ is 3934 rpm, the resolution λ per rotation of the speed sensor is 256, and the sampling frequency f Ｓ is 12000 Hz. The alias frequency f Ａ１ is calculated in the same way as in the first embodiment and is found to be 2430 Hz.

[0056] The resonance evaluation unit 133 calculates the alias frequency f of the interpolation error component of the sensor calculated by the alias calculation unit 135. Ａ１ The frequency f of the third resonance point detected by the resonance detection unit 132 is 2430 Hz. Ｃ３ However, the speed command change unit 136 is instructed to change the rotation speed without determining whether or not to apply a filter.

[0057] Speed ​​command change unit 136 outputs a second speed addition value to be added to the speed command to subtractor 111. Motor control device 110 drives motor 118 at a second motor rotation speed based on the speed command obtained by adding the second speed addition value to the speed command, and frequency characteristic measurement unit 131 measures the frequency characteristics at the second motor rotation speed.

[0058] The resonance detection unit 132 detects a resonance point from the frequency characteristics of the input / output gain measured by the frequency characteristic measurement unit 131. ２ 10 is a Bode diagram showing the frequency characteristics measured by the frequency characteristic measuring unit 131 and the first and second resonance points detected by the resonance detecting unit when the motor 118 is driven at a rotational speed f (referred to as the second rotational speed in FIG. 10). The gain diagram of the input / output gain shown in FIG. 10 shows the frequency f of the first resonance point detected by the resonance detecting unit 132. Ｃ１and the frequency of the first resonance point f Ｃ２ The frequency of the first resonance point f Ｃ１ is 1867Hz, the frequency of the second resonance point f Ｃ２ is 2430 Hz, which is the same value as in the first embodiment.

[0059] The resonance detector 132 detects the frequency f of the first resonance point. Ｃ１ 1867 Hz, the frequency of the second resonance point f Ｃ２ The frequency of 2430 Hz is output to the resonance evaluation unit 133.

[0060] The information acquisition unit 134 acquires the second motor rotation speed S ２ , sampling frequency f when measuring frequency characteristics Ｓ and the resolution λ per rotation of the speed sensor are acquired and output to the alias calculation unit 135. As in the first embodiment, the second motor rotation speed S ２ is 4000 rpm, the resolution λ per rotation of the speed sensor is 256, and the sampling frequency f Ｓ The alias frequency f is 12000 Hz. The alias frequency calculation unit 135 calculates the alias frequency f Ａ２ is calculated and output to the resonance evaluation unit 133. Ａ２ becomes 1867 Hz.

[0061] The resonance evaluation unit 133 calculates the alias frequency f of the interpolation error component of the sensor calculated by the alias calculation unit 135. Ａ２ The frequency f of the first resonance point detected by the resonance detection unit 132 is 1867 Hz. Ｃ１ Since the frequency of the first resonance point coincides with 1867 Hz as the frequency of the first resonance point, it is determined that the first resonance point is not subject to application of the filter.

[0062] The resonance evaluation unit 133 calculates the first motor rotation speed S １ When the motor 118 is driven at , the alias frequency f of the interpolation error component of the sensor calculated by the alias calculation unit 135 is Ａ１ The frequency f of the third resonance point detected by the resonance detection unit 132 is 2430 Hz. Ｃ３ The second motor rotation speed S ２When the motor control device 110 is controlled at the frequency f Ｃ３ If a resonance point having the same frequency as the first motor rotation speed S (2430 Hz) is not detected, the third resonance point is excluded from the filter application. １ The frequency f of the third resonance point when the motor 118 is driven at Ｃ３ 2430 Hz, and the second motor rotation speed S ２ When the motor control device 110 is controlled at Ｃ２ Since the first motor rotation speed S is equal to 2430 Hz, it is determined that the filter is applied to the third resonance point. １ The frequency f of the third resonance point when the motor 118 is driven at Ｃ３ is the alias frequency f Ａ１ Even if the third resonance point is not a mechanical resonance point, the first motor rotation speed S １ to the second motor rotation speed S ２ As a result, the alias frequency is shifted to the frequency f of the second resonance point, which is the same frequency as the frequency of the third resonance point. Ｃ２ This is because it is believed that mechanical resonance occurred.

[0063] Next, the operation of the control assistance device 130A will be described using a flowchart. Fig. 11 is a flowchart showing the operation of the control assistance device. In step S21, the speed command change unit 136 outputs a first speed addition value to be added to the speed command to the motor control device 110, and the frequency characteristic measurement unit 131 measures the input signal S, such as a sine wave signal, whose frequency changes. ＩＮ and the output of the filter 113 of the motor control device 110 (output signal S ＯＵＴ ) and the first motor rotation speed S １ The frequency characteristics of the input / output gain and the frequency characteristics of the phase delay of the motor control device 110 operating at the first rotation speed (referred to as the first rotation speed in FIG. 11) are measured.

[0064] In step S22, a third resonance point is detected from the frequency characteristics of the input / output gain measured by the frequency characteristic measuring unit 131.

[0065] In step S23, the information acquisition unit 134 acquires the first motor rotation speed S １ , sampling frequency f when measuring frequency characteristics Ｓ and the resolution per rotation λ of the speed sensor, and the alias calculation unit 135 calculates the first motor rotation speed S １ , sampling frequency f Ｓ and the resolution per revolution of the speed sensor, λ, is used to calculate the alias frequency f of the sensor interpolation error component. Ａ１ Calculate.

[0066] In step S24, the speed command change unit 136 outputs a second speed addition value to be added to the speed command to the motor control device 110, and the frequency characteristic measurement unit 131 measures the input signal S ＩＮ and the second motor rotation speed S ２ The output of the filter 113 of the motor control device 110 operating at a rotation speed (referred to as the second rotation speed in FIG. 11) (output signal S ＯＵＴ ) the frequency characteristics of the input / output gain and the frequency characteristics of the phase delay of the motor control device 110 are measured.

[0067] In step S25, the first and second resonance points are detected from the frequency characteristics of the input / output gain measured by the frequency characteristic measurement unit 131. In step S26, the information acquisition unit 134 acquires the second motor rotation speed S ２ , sampling frequency f when measuring frequency characteristics Ｓ and the resolution per rotation λ of the speed sensor, and the alias calculation unit 135 calculates the second motor rotation speed S ２ , sampling frequency f Ｓ and the resolution per revolution of the speed sensor, λ, is used to calculate the alias frequency f of the sensor interpolation error component. Ａ２ Calculate.

[0068] In step S26, the resonance evaluation unit 133 calculates the first motor rotation speed S １ and the frequency of the third resonance point at the second motor rotation speed S ２Unless the frequencies of the first and second resonance points at the first motor rotation speed S coincide, i.e., unless there is a common resonance point at the first and second motor rotation speeds, １ If the frequency of the resonance point at is an alias frequency, the third resonance point is excluded from the filter application.

[0069] In step S27, the control assistance device 130A determines whether to continue the process. If the process is to be continued, the process returns to step S21. If the process is not to be continued, the process ends.

[0070] In the embodiment described above, in addition to the effects of the first embodiment, when the motor rotation speed is changed, it is possible to determine whether or not a filter should be applied by determining whether or not the resonance point corresponds to an alias frequency.

[0071] Third Embodiment Fig. 12 is a block diagram showing an example configuration of a motor control device and a control assistance device according to a third embodiment of the present disclosure. As shown in Fig. 12, a control assistance device 130B of this embodiment is configured by adding a display unit 137 to the control assistance device 130A shown in Fig. 8. The display unit 137 acquires information indicating the alias frequency evaluation results and the filter application results from the resonance evaluation unit 133 to create the table shown in Fig. 14, acquires frequency characteristics before and after application of the filter and the frequencies of the resonance points from the resonance evaluation unit 133, creates characteristic diagrams shown in Fig. 15 and Fig. 16, and displays them on a display screen 138 shown in Fig. 13.

[0072] 13 is a diagram showing a display screen 138 of the display unit 137. The display screen 138 has a first display area 138A, a second display area 138B, and a third display area 138C.

[0073] Fig. 14 is a diagram showing a table displayed in the first display area 138A, Fig. 15 is a characteristics diagram displayed in the second display area 138B, and Fig. 16 is a characteristics diagram displayed in the third display area 138C. The first display area 138A displays a table showing the alias frequency evaluation results and filter application results shown in Fig. 14. The table shows two resonance point frequencies, 1867 Hz and 2430 Hz, and indicates that the frequency 1867 Hz is an alias frequency and the frequency 2430 Hz is a mechanical resonance frequency. The table also shows that no filter is applied to the resonance point frequency 1867 Hz, but that a filter is applied to the resonance point frequency 2430 Hz, and that the applied filter is a notch filter with a center frequency of 2430 Hz, a bandwidth of 400 Hz, and a damping rate of 10%.

[0074] Second display area 138B shows a Bode diagram of the frequency characteristics measured by frequency characteristic measurement unit 131 and two resonance points (1867 Hz and 2430 Hz) detected by resonance detection unit 132 when motor control device 110 is operated at the second motor rotation speed without applying a filter, as shown in Fig. 15. The black arrow and white arrow shown in Fig. 15 indicate the positions of the frequencies 1867 Hz and 2430 Hz, respectively.

[0075] Third display area 138C shows a Bode diagram of the frequency characteristics measured by frequency characteristic measurement unit 131 and the resonance point (1867 Hz) detected by resonance detection unit 132 when adjustment device 140 adjusts the filter coefficient of filter 113, applies the filter, and operates motor control device 110 at the second motor rotation speed, as shown in Fig. 16. The black arrow and white arrow shown in Fig. 16 indicate the positions of the frequencies of 1867 Hz and 2430 Hz, respectively.

[0076] By looking at first display area 138A on display screen 138 of display unit 137, the user can know how many resonance points have been detected, which resonance points' frequencies correspond to alias frequencies, and which resonance points' frequencies correspond to mechanical resonance frequencies. The user can also know whether a filter has been applied to the detected resonance points and the type of filter. By looking at second display area 138B and third display area 138C on display screen 138 of display unit 137, the user can see that two resonance points were observed before the filter was applied, but that this becomes a single resonance point after the filter is applied, and can visually know whether a filter has been applied.

[0077] In the embodiment described above, in addition to the effects of the second embodiment, the user can know whether the resonance point is due to an alias frequency or a mechanical resonance frequency, whether a filter is applied at the detected resonance point, and the type of filter. Also, the user can visually know whether a filter is applied.

[0078] In order to realize the functional blocks included in the control assistance device in each embodiment described above, the control assistance device can be realized by hardware, software, or a combination of these. Here, being realized by software means being realized by a computer reading and executing a program.

[0079] In this embodiment, in order to realize the functional blocks included in the control assistance device by software or a combination thereof, specifically, each control assistance device includes a processing unit such as a CPU (Central Processing Unit), an auxiliary storage device such as an HDD (Hard Disk Drive) that stores various control programs such as application software or an OS (Operating System), and a main storage device such as a RAM (Random Access Memory) that stores data temporarily required for the processing unit to execute the programs.

[0080] In the control assistance device, the arithmetic processing unit reads application software or an OS from the auxiliary storage device, and executes arithmetic processing based on the application software or the OS while loading the read application software or the OS into the main storage device. Furthermore, based on the results of this calculation, various hardware components of each device are controlled. This realizes the functional blocks of this embodiment.

[0081] Each component included in the control assistance device can be realized by hardware including electronic circuits, etc. When the control assistance device is configured by hardware, some or all of the functions of each component included in the control assistance device can be configured by an integrated circuit (IC), such as an ASIC (Application Specific Integrated Circuit), a gate array, an FPGA (Field Programmable Gate Array), or a CPLD (Complex Programmable Logic Device).

[0082] The program can be stored and supplied to a computer using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)). The program may also be supplied to the computer by various types of transient computer readable media.

[0083] According to the control assistance device, control system, and control assistance method of the present disclosure including each embodiment, resonance points corresponding to alias frequencies can be excluded from the target of filter application.

[0084] Although the above-described embodiments are preferred embodiments of the present invention, the scope of the present invention is not limited to the above-described embodiments, and the present invention can be implemented in various modified forms within the scope that does not deviate from the gist of the present invention.

[0085] For example, in each of the above-described embodiments, the case where one filter is provided has been described, but the filter 113 may be configured by connecting in series a plurality of filters each corresponding to a different frequency band. Fig. 17 is a block diagram showing an example of a filter configured by directly connecting a plurality of filters. In Fig. 17, when there are m resonance points (m is a natural number of 2 or more), the filter 113 is configured by connecting m filters 113-1 to 113-m in series. The coefficients ω of each of the m filters 113-1 to 113-m are ｃ , τ, and δ are optimally determined by the adjustment device 140.

[0086] The following supplementary note is further disclosed regarding the above embodiment: (Supplementary Note 1) A control assistance device (130, 130A, 130B) that assists in adjusting at least one filter coefficient of a filter (113) provided in a motor control device (110, 110A) that controls a motor of a machine tool, a robot, or an industrial machine, comprising: a frequency characteristic measurement unit (131) that measures frequency characteristics of an input / output gain and an input / output phase delay of the motor control device, measured based on an input signal and an output signal having varying frequencies, a resonance detection unit (132) that detects a resonance point in the frequency characteristics, an information acquisition unit (134) that acquires information including a resolution per rotation of a speed sensor of the motor, the motor rotation speed, and a sampling frequency, an alias calculation unit (135) that calculates an alias frequency of an interpolation error component of the speed sensor from the information, and a resonance evaluation unit (133, 133A) that evaluates whether or not a filter needs to be applied to the detected resonance point based on the alias frequency.

[0087] (Supplementary Note 2) The control assistance device according to Supplementary Note 1 further comprises a speed command change unit (136) that outputs a speed command to the motor control device to change the rotation of the motor from a first motor rotation speed to a second motor rotation speed, and the resonance evaluation unit (133A) determines whether or not a filter needs to be applied to the resonance point of the frequency characteristic measured at the first motor rotation speed, based on the resonance point of the frequency characteristic measured at the first motor rotation speed and the second motor rotation speed.

[0088] (Supplementary Note 3) The control assistance device according to Supplementary Note 1 or 2, further comprising a display unit (137) that displays the alias frequency and whether or not the filter needs to be applied.

[0089] (Supplementary Note 4) A control system (10) comprising: a control assistance device (130, 130A, 130B) according to any one of Supplementary Notes 1 to 3; a motor control device (110, 110A) including a filter (113); and an adjustment device (140) that adjusts at least one filter coefficient of the filter (113), wherein the adjustment device (140) adjusts at least one filter coefficient of the filter (113) so that the filter is applied to a resonance point determined by the control assistance device (110, 110A) to apply the filter.

[0090] (Supplementary Note 5) A control assistance method that causes a computer as a control assistance device (130, 130A, 130B) that assists in adjusting at least one filter coefficient of a filter (113) provided in a motor control device (110, 110A) that controls a motor of a machine tool, robot, or industrial machine to execute the following processes: measuring frequency characteristics of input / output gain and input / output phase delay of the motor control device, measured based on an input signal and an output signal whose frequency changes; detecting a resonance point in the frequency characteristics; acquiring information including the resolution per rotation of a speed sensor of the motor, the motor rotation speed, and a sampling frequency; calculating an alias frequency of an interpolation error component of the speed sensor from the information; and evaluating, based on the alias frequency, whether or not a filter needs to be applied to the detected resonance point.

[0091] 10, 11 Control system 110, 110A Motor control device 111 Subtractor 112 Speed ​​control unit 113 Filter 114, 119 Adder 115 Subtractor 116 Current control unit 117 Amplifier 118 Motor 120 Frequency generation device 130, 130A, 130B Control assistance device 131 Frequency characteristic measurement unit 132 Resonance detection unit 133, 133A Resonance evaluation unit 134 Information acquisition unit 135 Alias ​​calculation unit 136 Speed ​​command change unit 137 Display unit 140 Adjustment device

Claims

1. A control support device that assists in adjusting at least one filter coefficient of a filter provided in a motor control device that controls a motor of a machine tool, robot, or industrial machine, A frequency response measurement unit measures the frequency characteristics of the input / output gain and input / output phase delay of the motor control device, based on input and output signals with varying frequencies. A resonance detection unit for detecting the resonance point in the frequency characteristics, An information acquisition unit that acquires information including the resolution per revolution of the motor speed sensor, the motor rotation speed, and the sampling frequency, An alias calculation unit calculates the alias frequency of the interpolation error component of the speed sensor from the aforementioned information, A control support device comprising: a resonance evaluation unit that evaluates whether or not a filter is necessary for the detected resonance point based on the alias frequency.

2. The system includes a speed command changing unit that outputs a speed command to the motor control device for changing the rotation of the motor from a first motor rotation speed to a second motor rotation speed. The control support device according to claim 1, wherein the resonance evaluation unit determines whether or not to apply a filter to the resonance point of the frequency characteristics measured at the first motor rotation speed, based on the resonance point of the frequency characteristics measured at the first motor rotation speed and the second motor rotation speed.

3. The control support device according to claim 1, further comprising a display unit that displays the alias frequency and whether or not the filter needs to be applied.

4. A control system comprising a control support device according to any one of claims 1 to 3, a motor control device including a filter, and an adjustment device for adjusting at least one filter coefficient of the filter, The adjustment device is a control system that adjusts at least one filter coefficient of the filter so that the filter is applied to the resonance point where the control support device has determined the filter application.

5. A computer, which serves as a control support device, assists in adjusting at least one filter coefficient of a filter installed in a motor control device that controls the motor of a machine tool, robot, or industrial machine, A process for measuring the frequency characteristics of the input / output gain and input / output phase delay of the motor control device, measured based on input and output signals with varying frequencies, A process for detecting the resonance point in the frequency characteristics. A process for acquiring information including the resolution per revolution of the motor speed sensor, the motor rotation speed, and the sampling frequency, A process to calculate the alias frequency of the interpolation error component of the speed sensor from the aforementioned information, A process to evaluate whether or not a filter should be applied to the detected resonance point based on the alias frequency, A control support method for executing this action.