TWI678065B - Motor control - Google Patents

Abstract

In order to provide a motor control device capable of detecting abnormality of a machine.

The speed controller (110) generates and outputs a first torque command based on a deviation between the speed command and the speed feedback. The torque command notch filter (115) generates and outputs a second torque command by removing the signal component of the resonance frequency of the machine (300) from the first torque command. The power converter (125) drives a motor for driving the machine (300) based on the second torque command. The resonance frequency estimator (135) estimates a resonance frequency of the machine (300) based on speed feedback, thereby generating an estimated resonance frequency. The mechanical abnormality detection unit (150) detects a mechanical abnormality based on the estimated resonance frequency.

Description

Motor control

The present invention relates to a motor control device.

A working machine equipped with a stage which is moved linearly by a ball screw is known. The ball screw is mounted on the output shaft of the motor through a coupling. When the motor rotates, the stage moves linearly.

The coupling is rigid. The working machine is affected by the rigidity of the coupling and generates resonance. When resonance occurs in a work machine, it may adversely affect the control characteristics of the work machine. Therefore, a torque command for controlling the operation of the working machine is passed through a notch filter. The torque command after passing the notch filter is used to control the operation of the machine, thereby suppressing the occurrence of resonance.

In mechanical systems such as work machines, physical characteristics such as rigidity may vary. When this variation becomes large, the resonance frequency changes greatly, and it is difficult to suppress resonance by a common notch filter. An adaptive notch filter capable of suppressing resonance even if the resonance frequency is greatly changed has been developed. The adaptive notch filter estimates the resonance frequency, and automatically sets the frequency of the notch filter.

However, when the resonance frequency greatly deviates from the reference value, it is considered that an abnormality has occurred in the mechanical system, and a problem may occur if the operation is continued as it is. For example, when the fixing portion is loosened due to incorrect assembly of the machine, the resonance frequency decreases and the estimated frequency of the adaptive notch filter decreases. When the estimated frequency decreases, the phase delay of the adaptive notch filter causes adverse effects related to the control characteristics such as an increase in the hump of the speed control response. As a result, the processing accuracy is lowered and the production tact time is increased. As a result, not only production efficiency is deteriorated, but also the machine itself may be adversely affected in extreme cases.

Techniques for detecting mechanical abnormalities include various techniques such as a technique for detecting an abnormality using an external sensor, a technique for detecting an abnormality based on a motor current, and a technique for detecting an abnormality based on a motor position.

A technique for detecting an abnormality using an external sensor is described in, for example, Japanese Patent Application Laid-Open No. 2002-22617. In the technique described in this document, the vibration acceleration of the bearing portion is measured using an accelerometer provided in the bearing portion. FFT (High-Speed Fourier Transform) processing is performed on the measured vibration acceleration, thereby extracting a signal of a frequency at which vibration occurs. This is used to detect anomalies.

A technique for detecting an abnormality based on a motor current is described in, for example, Japanese Patent Application Laid-Open No. 11-83686. The technique described in this document is a spectrum analysis of a load current signal (a power source frequency and a high frequency thereof) of a motor driving a mechanical device. Calculate the diagnostic parameters used to identify mechanical equipment abnormalities based on the results of the spectrum analysis. The calculated diagnostic parameters and the judgment base set in advance for each machine and equipment to be diagnosed Comparison. When the calculated diagnostic parameter is larger than the determination reference value, it is determined that an abnormality has occurred in the mechanical equipment.

A technique for detecting an abnormality based on a motor position is described in, for example, Japanese Patent Application Laid-Open No. 2013-81282. In the technology described in this document, a servo system includes a motor, a position detector that detects the position of the motor, a servo driver that drives the motor, and a servo controller that controls the servo driver. In this servo system, an abnormality of a driven part driven by a motor is detected. That is, the system includes an input unit, a frequency conversion unit, and a comparison determination unit. The input unit obtains the position information of the motor from the position detector. The frequency conversion unit performs frequency conversion on the position information of the motor when the motor rotates at a substantially constant speed. The comparison determination unit compares the amplitude of a predetermined frequency obtained through frequency conversion with a threshold value for determining an abnormality of the driven unit. An abnormal part of the driven part is detected based on a frequency having a larger amplitude than a threshold value.

However, the technologies described in Japanese Patent Application Laid-Open No. 2002-22617, Japanese Patent Application Laid-Open No. 11-83686, and Japanese Patent Application Laid-Open No. 2013-81282 have the following problems.

In the technique of Japanese Patent Application Laid-Open No. 2002-22617, an accelerometer must be provided in the bearing portion. In addition, it is necessary to perform complicated arithmetic processing on the measured signal. Therefore, there is a problem that the cost increases.

Technology, machinery in Japanese Patent Application Laid-Open No. 11-83686 The abnormality is detected using the load current signal of the motor. Therefore, the abnormality can be detected only at a specific rotation speed at which the power supply frequency of the motor and its high frequency coincide with the resonance frequency of the mechanical system.

In the technique of Japanese Patent Application Laid-Open No. 2013-81282, when an abnormality is detected, the motor must be rotated at a substantially constant speed. Therefore, when an acceleration / deceleration operation is performed in accordance with a command from the controller, an abnormality cannot be accurately detected. In addition, in the frequency conversion using high-speed Fourier transform or wavelet transform, the amount of processing performed by the software increases, and a CPU capable of high-speed processing must be used. Therefore, there is a problem that the cost of the motor control device increases.

The present invention has been developed to solve the problems of the conventional techniques. An object of the present invention is to provide a motor control device capable of detecting a mechanical abnormality during a motor operation. The motor control device does not need to be provided with a special sensor in order to detect abnormalities, does not need to limit the rotation speed or operation mode of the motor during abnormality detection, and does not need to perform complicated calculation processing when performing abnormality detection. However, the adverse effect on the control characteristics can be suppressed within a certain range.

In order to achieve the above object, a motor control device according to an embodiment of the present invention includes a speed controller, a torque command notch filter, a power converter, a resonance frequency estimator, and a mechanical abnormality detection unit. The speed controller is The first torque command is generated based on the deviation of the speed command and the speed feedback; this torque command notch filter is to remove the signal component of the resonance frequency of the machine from the first torque command to generate a second torque command Let; the power converter drive the motor for driving the machine according to the second torque command; the resonance frequency estimator estimates the resonance frequency of the machine based on the speed feedback, thereby generating an estimated resonance frequency This mechanical abnormality detection unit detects a mechanical abnormality based on the estimated resonance frequency.

According to the motor control device having the above structure, no special sensor is required to detect a mechanical abnormality, and it is not necessary to limit the rotation speed or operation mode of the motor when detecting a mechanical abnormality, and when detecting a mechanical abnormality It is not necessary to implement complicated arithmetic processing, and can suppress the adverse effect on the control characteristics within a certain range.

100‧‧‧ Motor control device

105‧‧‧speed calculator

110‧‧‧speed controller

115‧‧‧Torque command notch filter

120‧‧‧Torque controller

125‧‧‧ Power Converter

130‧‧‧High-pass filter

135‧‧‧Resonant frequency estimator

150‧‧‧Mechanical anomaly detection department

155‧‧‧ Upper limit detector

160‧‧‧ lower limit detector

165, 170‧‧‧continue status confirmer

175‧‧‧OR circuit

180‧‧‧Switch

185‧‧‧Initial motion detector

FIG. 1 is a block diagram of a motor control device according to this embodiment.

Fig. 2 is a diagram for explaining the operation of the motor control device according to this embodiment.

Next, a motor control device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a motor control device according to this embodiment.

[Configuration of Motor Control Device]

The motor control device 100 includes a speed calculator 105, a speed controller 110, a torque command notch filter 115, a torque controller 120, a power converter 125, a high-pass filter 130, a resonance frequency estimator 135, and a mechanical abnormality. Detector 150.

The motor control device 100 is electrically connected to the motor 200. The motor 200 is mechanically connected to the machine 300 and is used to drive the machine 300. The encoder 210 is mechanically connected to the motor 200. The encoder 210 outputs a signal (motor position) related to the position of the motor 200.

The speed calculator 105 obtains and differentiates the motor position output from the encoder 210, thereby generating and outputting a speed feedback. The speed controller 110 obtains a deviation between a speed command and a speed feedback output from a controller (not shown), and generates and outputs a first torque command based on the deviation. The torque command notch filter 115 obtains a first torque command, removes the signal component of the resonance frequency of the machine 300 from the first torque command, and generates and outputs a second torque command. The resonance frequency set by the torque command notch filter 115 is the resonance frequency (estimated resonance frequency) of the machine 300 estimated by the resonance frequency estimator 135. That is, the torque command notch filter 115 generates a second torque command by removing a signal component of the estimated resonance frequency from the first torque command.

The torque controller 120 obtains a second torque command and outputs a motor drive signal. The motor drive signal is a signal for outputting a torque corresponding to the second torque command to the motor 200. The power converter 125 obtains the motor drive signal. The power converter 125 is generated based on the motor drive signal so that the torque corresponding to the second torque command is output to the motor 200. The voltage and current are supplied to the motor 200. That is, the power converter drives the motor 200 for driving the machine 300 in accordance with the second torque command.

The high-pass filter 130 obtains speed feedback, passes signals of high-frequency components (high-frequency feedback signals) included in the speed feedback, and attenuates signals of other frequency components. The frequency of the high-frequency feedback signal passing through the high-pass filter 130 is higher than the response frequency of the speed controller 110. That is, the high-pass filter 130 passes signals having a high frequency component higher in frequency than the response frequency of the speed controller 110 included in the speed feedback, and attenuates signals of other frequency components.

The resonance frequency estimator 135 estimates a resonance frequency of the machine 300 based on a high-frequency feedback signal. The resonance frequency (estimated resonance frequency) of the machine 300 estimated by the resonance frequency estimator 135 is set in the torque command notch filter 115. The mechanical abnormality detection unit 150 detects an abnormality of the machine 300 based on the estimated resonance frequency. Therefore, the resonance frequency estimator 135 and the mechanical abnormality detection unit 150 function as sensors for detecting an abnormality of the machine 300.

The mechanical abnormality detection unit 150 includes an upper limit detector 155, a lower limit detector 160, continuity checkers 165 and 170, an OR circuit 175, a switch 180, and an initial operation detector 185.

The upper limit detector 155 detects whether or not the estimated resonance frequency estimated by the resonance frequency estimator 135 is higher than the frequency of the upper limit shown in FIG. 2 set by the upper limit detector 155. The lower limit detector 160 detects whether the estimated resonance frequency is lower than the frequency of the lower limit shown in FIG. 2 set by the lower limit detector 160. As The upper limit frequency is set, for example, as a maximum allowable resonance frequency that is a reference resonance frequency of the machine 300. The frequency serving as the lower limit limit is set, for example, as a minimum allowable resonance frequency that is a reference resonance frequency of the machine 300.

The continuation state checker 165 outputs a mechanical abnormality when the estimated resonance frequency is maintained for a certain period of time or more and the frequency of the upper limit is exceeded. The continuation state checker 170 outputs a mechanical abnormality when the estimated resonance frequency is maintained for a certain period of time or more and the frequency of the lower limit limit or less.

The OR circuit 175 outputs a mechanical abnormality to at least one of the continuation state confirmers 165 and 170, and outputs the mechanical abnormality to the outside. The initial operation detector 185 acquires the operation start (for example, a signal (operation start signal) outputted in response to the operation start) and a speed command, and detects whether the resonance frequency estimator 135 can operate appropriately. The switch 180 is provided on the output side of the OR circuit 175 at the subsequent stage of the continuation state confirmers 165 and 170. The switch 180 is used to switch whether a mechanical abnormality can be output to the outside.

When the initial operation detector 185 detects that the resonance frequency estimator 135 cannot operate properly, the switch 180 is turned on to prevent mechanical abnormalities from being output to the outside. When the initial operation detector 185 detects that the resonance frequency estimator 135 can operate appropriately, the switch 180 is turned off to enable external output of a mechanical abnormality.

According to the operation of the initial motion detector 185 as described above, the following effects can be obtained. That is, when the motor 200 starts to run, the speed command is 0, and the motor 200 may be stopped. At this time, subject to the mechanical system Under the influence of friction, the resonance frequency estimator 135 may not be able to estimate the resonance frequency (that is, the resonance frequency estimator 135 may not operate properly). In this case, the above-mentioned operation of the initial motion detector 185 can prevent or suppress the output of a mechanical abnormality. In other words, the case where the resonance frequency estimator 135 cannot operate appropriately means that when the machine 300 starts to operate, the estimated resonance frequency estimated based on the initial value of the speed command is above the upper limit frequency or below the lower limit frequency. Happening. In this case, erroneous detection of a mechanical abnormality can be prevented or suppressed.

The frequency component of the motor operation generated according to a speed command output from a controller (not shown) is within the range of the response frequency of the speed controller 110. The cut-off frequency set in the high-pass filter 130 is higher than the response frequency of the speed controller 110. Therefore, in the output of the high-pass filter 130, the frequency component of the motor operation according to the speed command does not appear. Even if the acceleration / deceleration operation is performed in accordance with a command from the controller, the abnormality of the machine 300 can be appropriately detected.

The frequency set at the upper limit of the upper limit detector 155 and the frequency set at the lower limit of the lower limit detector 160 are set to a frequency that prevents or suppresses damage to the machine 300, thereby preventing or suppressing damage to the machine 300 Yu Weiran.

In addition, by setting the frequency of the lower limit to a frequency in a region that does not cause the control characteristics of the motor control device 100 to be extremely deteriorated (not to adversely affect the processing), the deterioration of the control characteristics can be prevented or suppressed even if the resonance frequency is reduced.

[Motion of the motor control device]

Next, the operation of the motor control device will be described with reference to FIGS. 1 and 2. Fig. 2 is an operation explanatory diagram of the motor control device according to this embodiment. FIG. 2 is a diagram showing the relationship between the gain and the frequency of the estimated resonance frequency of the machine 300 estimated by the resonance frequency estimator 135.

When the operation is started without outputting a speed command from a controller (not shown), the initial motion detector 185 obtains the operation start and speed command, and turns on the switch 180 to prevent or suppress erroneous detection by the mechanical abnormality detection unit 150. On the other hand, when the operation is started and the speed command is raised, the resonance frequency estimator 135 can operate appropriately. At this time, the initial operation detector 185 turns off the switch 180 so that the mechanical abnormality detection unit 150 detects a mechanical abnormality.

The speed controller 110 generates and outputs a first torque command based on a deviation between the speed feedback output from the speed calculator 105 and the speed command output from the controller. The high-pass filter 130 passes a high-frequency component signal (high-frequency feedback signal) included in the speed feedback. The resonance frequency estimator 135 estimates a resonance frequency of the machine 300 based on a high-frequency feedback signal, thereby generating an estimated resonance frequency.

An estimated resonance frequency is set in the torque command notch filter 115. The torque command notch filter 115 obtains a first torque command output from the speed controller 110, and removes the signal component of the estimated resonance frequency of the machine 300 from the first torque command, thereby generating and outputting a second torque instruction. The torque controller 120 obtains the second torque command output from the torque command notch filter 115 and outputs a motor drive signal. The motor drive signal is A signal for outputting the torque corresponding to the second torque command to the motor 200. The power converter 125 generates a voltage and a current for outputting the torque corresponding to the second torque command to the motor 200 based on a motor drive signal output from the torque controller 120 and supplies the voltage and current to the motor 200.

The motor 200 rotates in accordance with the voltage and current supplied from the power converter 125 to drive the machine 300. The motor position indicating the rotation position of the motor 200 is detected by the encoder 210 and output to the speed calculator 105.

When the resonance frequency (estimated resonance frequency) of the machine 300 is between the frequency of the upper limit and the frequency of the lower limit shown in FIG. 2, neither the upper limit detector 155 nor the lower limit detector 160 outputs a mechanical abnormality. Therefore, the mechanical abnormality detection unit 150 does not output a mechanical abnormality.

On the other hand, when the resonance frequency (estimated resonance frequency) of the machine 300 becomes higher than the frequency of the upper limit limit or lower than the frequency of the lower limit limit shown in FIG. 2, the upper limit detector 155 or the lower limit detector 160 outputs a mechanical abnormality.

When the continuation state confirmer 165 confirms that a mechanical abnormality is output from the upper limit detector 155 for a certain period of time, or when the continuation state confirmer 170 confirms that a mechanical abnormality is output from the lower limit detector 160 for a certain period of time, the continuation state confirmer 165 OR 170 outputs a mechanical error to the OR circuit 175. The OR circuit 175 outputs a mechanical abnormality to the outside through the switch 180.

In addition, after the output of the mechanical abnormality, when the upper limit detector 155 or the lower limit detector 160 does not continue to output for more than a certain time When a mechanical abnormality occurs, the mechanical abnormality output of the state checkers 165 and 170 to the OR circuit 175 may be stopped.

For example, when the resonance frequency of the machine 300 is between the upper limit (380 Hz) and the lower limit (210 Hz) shown in FIG. 2, no mechanical abnormality is output. On the other hand, when the resonance frequency of the machine 300 is more than 380 Hz or less than 210 Hz, and this state continues for more than a certain time, the output machine is abnormal.

As described above, the motor control device 100 according to this embodiment is a frequency that sets the upper limit limit and the lower limit limit to the resonance frequency estimator 135. When the estimated resonance frequency estimated by the resonance frequency estimator 135 continues for more than a certain time, the frequency becomes equal to or higher than the frequency of the upper limit or the frequency of the lower limit or lower, and a mechanical abnormality is output.

Therefore, even if the machine 300 is incorrectly assembled and / or the resonance frequency of the machine 300 is reduced as the mechanical parts deteriorate, it is possible to prevent or suppress the deterioration of the control characteristics of the motor control device 100. In addition, breakage of the machine 300 can be prevented or suppressed.

In the above embodiment, both the upper limit detector 155 and the lower limit detector 160 are provided in the motor control device 100 (mechanical abnormality detection unit 150). Depending on the resonance characteristics of the machine 300, in order to detect a mechanical abnormality, it may be sufficient to detect any one of the frequency where the estimated resonance frequency becomes the upper limit limit or the frequency where the estimated resonance frequency becomes the lower limit limit. In this case, either the upper limit detector 155 or the lower limit detector 160 may be provided in the motor control device 100 (mechanical abnormality detection unit 150).

In order to detect an abnormality of the machine 300, the motor control device 100 of this embodiment includes a resonance frequency estimator 135 and a mechanical abnormality detection unit 150. Therefore, in order to detect the abnormality, an abnormality of the machine 300 can be detected without using a special sensor.

In the motor control device 100 according to this embodiment, the high-pass filter 130 generates a high-frequency feedback signal by removing frequency components below the response frequency of the speed controller 110 from the speed feedback. The resonance frequency estimator 135 estimates the resonance frequency of the machine 300 based on the high-frequency feedback signal. Therefore, in order to detect an abnormality of the machine 300, it is possible to prevent the rotation speed and the operation mode of the motor 200 from being restricted.

The motor control device 100 detects a mechanical abnormality based on the frequency of the upper limit and the frequency of the lower limit. Therefore, it is not necessary to perform complicated arithmetic processing when performing abnormality detection.

The foregoing is a description of a preferred embodiment of the present invention. However, these are merely examples for explaining the present invention, and do not limit the scope of the present invention. The present invention can be implemented in various aspects other than the above-described embodiments without departing from the scope of the invention.

In this embodiment, the resonance frequency estimator 135 estimates the resonance frequency of the machine 300 based on the high-frequency feedback signal. However, the motor control device 100 may not include the high-pass filter 130. In this case, the resonance frequency estimator 135 may estimate the resonance frequency of the machine 300 based on the speed feedback, thereby generating and outputting the estimated resonance frequency.

The speed calculator 105 may input the motor position output from the encoder 210, differentiate it, and output speed feedback. Speed controller 110, will The deviation input of the speed command and speed feedback output by the controller (not shown) can also be used to output the torque command. The torque command notch filter 115 may input a torque command and output a torque command after removing the signal component of the resonance frequency of the machine 300 from the torque command. The resonance frequency set in the torque command notch filter 115 may also be a resonance frequency estimated by the resonance frequency estimator 135. The torque controller 120 may input a torque command excluding the signal component of the resonance frequency of the machine 300 and output a signal for the motor 200 to output a torque corresponding to the torque command. The power converter 125 may input a signal for outputting the torque, and may also supply necessary voltage and current to the motor 200.

The high-pass filter 130 is configured to input the speed feedback and pass the signals of the high frequency components included in the speed feedback, and attenuate the signals of the other frequency components. The signal passing the high-frequency component of the high-pass filter 130 may be a higher frequency than the response frequency of the speed controller 110. The resonance frequency estimator 135 may estimate the resonance frequency of the machine 300 from a speed feedback having a frequency component higher than the response frequency of the speed controller 110. The resonance frequency estimated by the resonance frequency estimator 135 may be set in the torque command notch filter 115. The mechanical abnormality detection unit 150 may detect an abnormality of the machine 300 using the resonance frequency estimated by the resonance frequency estimator 135.

The initial motion detector 185 prevents the resonance frequency estimator 135 from estimating the resonance frequency when the speed command is 0 and stops the motor 200 when the motor 200 starts to run. This prevents or suppresses the output of machinery. Abnormal can also be. In other words, the initial motion detector 185. When the estimated resonance frequency before the start of the operation of the machine 300 becomes a frequency higher than the frequency of the upper limit or a frequency lower than the frequency of the lower limit, erroneous detection of a mechanical abnormality may be prevented or suppressed.

The upper limit frequency may be set to the allowable maximum resonance frequency for the resonance frequency serving as a reference for the machine 300. The frequency of the lower limit may be set to a minimum allowable resonance frequency for the resonance frequency serving as a reference for the machine 300. The frequency component of the motor operation according to the speed command output by the controller (not shown) may be within the range of the response frequency of the speed controller 110. When the upper limit detector 155 or the lower limit detector 160 does not output a mechanical abnormality for a certain period of time or longer, the continuation state checkers 165 and 170 may not output a mechanical abnormality to the OR circuit 175.

The present invention can also be a motor control device capable of detecting an abnormality of a machine.

The first motor control device includes a speed controller, a torque command notch filter, a power converter, a resonance frequency estimator, and a mechanical abnormality detection unit. The speed controller outputs data based on the deviation of the speed command and speed feedback. Torque command; This torque command notch filter outputs the torque command after removing the signal component of the machine's resonance frequency from the aforementioned torque command; the power converter uses the signal component of the machine's resonance frequency after removing it The torque command is used to drive the motor; the resonance frequency estimator uses the speed feedback to estimate the resonance frequency of the machine driven by the motor; and the mechanical abnormality detection unit uses the estimated resonance frequency of the machine to detect a mechanical abnormality.

The second motor control device is the first motor control device. The resonance frequency of the machine estimated by the resonance frequency estimator is set in the torque command notch filter.

The third motor control device is the first or second motor control device, wherein the mechanical abnormality detection unit is provided with at least either an upper limit detector or a lower limit detector; the upper limit detector is based on the estimated When the mechanical resonance frequency is a frequency higher than the set upper limit frequency, a mechanical abnormality is output; the lower limit detector outputs a mechanical abnormality when the estimated resonance frequency of the machine is a frequency lower than the set lower limit frequency. .

The fourth motor control device is the third motor control device, wherein the mechanical abnormality detection unit further includes a continuation state confirmer that confirms that the continuity condition continues from the upper limit detector or the lower limit detector for a certain period of time. When a mechanical abnormality is output during the above time, the mechanical abnormality is output to the outside.

The fifth motor control device is the fourth motor control device, wherein the mechanical abnormality detection unit further includes a switch and an initial motion detector; the switch can be switched to prevent the mechanical abnormality from being output to the outside or output it; The motion detector detects whether the resonance frequency estimator can operate properly by inputting the start of operation and the speed command. The initial motion detector detects the situation where the resonance frequency estimator cannot operate properly and switches the switch. Turn on to prevent the mechanical abnormality from being output to the outside. When it is detected that the resonance frequency estimator can operate properly, turn off the switch to output the mechanical abnormality to the outside.

The sixth motor control device is the fifth motor control device, wherein The switch is set at the rear of the aforementioned continuation state confirmer.

The seventh motor control device is the case where the fifth or sixth motor control device detects that the resonance frequency estimator cannot operate properly, and is estimated by using the initial value of the speed command when the machine starts to operate. The resonance frequency is a frequency higher than the frequency of the upper limit or a frequency lower than the frequency of the lower limit.

The eighth motor control device is a motor control device according to any one of the first to seventh. A high-pass filter is provided in front of the resonance frequency estimator. The high-pass filter allows the speed feedback The response frequency of the speed controller is higher, that is, signals with high frequency components pass through, and signals with other frequency components are attenuated.

Claims (11)

A motor control device includes a speed controller, a torque command notch filter, a power converter, a resonance frequency estimator, and a mechanical abnormality detection unit. The speed controller generates a first 1 torque command; the torque command notch filter generates a second torque command by removing the signal component of the resonance frequency of the machine from the first torque command; the power converter is based on the second torque A command is used to drive a motor for driving the aforementioned machine; the resonance frequency estimator estimates the resonance frequency of the machine based on the speed feedback, thereby generating an estimated resonance frequency; and the mechanical abnormality detection unit is based on the estimated resonance frequency. Detects a mechanical abnormality. The mechanical abnormality detecting unit further includes a switch and an initial motion detector. The switch is used to switch whether to output the mechanical abnormality to the outside. The initial motion detector is to obtain the start of operation and the speed command to detect Whether the aforementioned resonance frequency estimator can operate properly; It is detected that the resonance frequency estimator cannot operate properly, and the switch is turned on to avoid external output of the mechanical abnormality. On the other hand, when it is detected that the resonance frequency estimator can operate properly, the switch is turned off. The aforementioned mechanical abnormality can be output to the outside. The motor control device according to item 1 of the scope of patent application, wherein the torque command notch filter generates the second torque by removing a signal component of the estimated resonance frequency from the first torque command. instruction. The motor control device according to item 1 of the scope of patent application, wherein the mechanical abnormality detection unit is provided with at least either an upper limit detector or a lower limit detector; the upper limit detector is at the estimated resonance frequency. A mechanical abnormality is output at a frequency higher than the frequency set by the upper limit; the lower limit detector outputs a mechanical abnormality when the estimated resonance frequency is lower than the frequency set by the lower limit. The motor control device according to item 2 of the scope of patent application, wherein the mechanical abnormality detection unit is provided with at least one of an upper limit detector and a lower limit detector; the upper limit detector is at the estimated resonance frequency. A mechanical abnormality is output at a frequency higher than the frequency set by the upper limit; the lower limit detector outputs a mechanical abnormality when the estimated resonance frequency is lower than the frequency set by the lower limit. The motor control device according to item 3 of the scope of the patent application, wherein the mechanical abnormality detection unit further includes a continuation state confirmer that confirms that the continuity from the upper limit detector or the lower limit detector continues to be constant. When a mechanical abnormality is output for more than time, the aforementioned mechanical abnormality is output. The motor control device according to item 4 of the scope of patent application, wherein the mechanical abnormality detection section further includes a continuation state confirmer, which confirms that the continuity from the upper limit detector or the lower limit detector is constant for a certain period When a mechanical abnormality is output for more than time, the aforementioned mechanical abnormality is output. The motor control device according to item 5 of the scope of patent application, wherein the switch is disposed at a rear stage of the continuation state confirmer. The motor control device according to item 6 of the scope of patent application, wherein the switch is disposed at a rear stage of the continuation state confirmer. According to the motor control device described in item 1 or 7 or 8 of the scope of the patent application, wherein the case where the resonance frequency estimator cannot be properly operated is detected, when the machine starts to operate, the initial value according to the speed command When the estimated resonance frequency is above the frequency of the upper limit or below the frequency of the lower limit. The motor control device according to any one of claims 1 to 8, further comprising a high-pass filter provided at a front stage of the resonance frequency estimator, the high-pass filter is included in the speed feedback A frequency higher than the response frequency of the speed controller, that is, a signal of a high frequency component passes through, and a signal of other frequency components is attenuated. The motor control device according to item 9 of the scope of the patent application, further comprising a high-pass filter provided at a front stage of the resonance frequency estimator, the high-pass filter allows the speed feedback A signal with a higher response frequency, that is, a signal with a high frequency component passes, and attenuates signals of other frequency components.