JP2022073001A - Protection apparatus - Google Patents

Abstract

To provide a structure of a protection apparatus for protecting a drive unit including a torque detector for detecting a torque induced on a rotation shaft to which a rotation drive force is transmitted, which structure can be readily mounted in the drive unit, and highly precisely protect the drive unit without affected by an adverse effect such as a noise derived from torque detection.SOLUTION: A protection apparatus 10 protects a testing apparatus 1 including: an electric motor 4 that generates a rotation drive force; a rotation shaft 6 that rotates with the rotation drive force; and a torque detector 7 that detects a torque induced on the rotation shaft 6. The protection apparatus 10 includes: a torque saturation detection unit 20 that detects based on the torque which is detected by the torque detector 7, whether or not a frequency that the torque exceeds a predetermined value is equal to or larger than a certain value; and a control unit 70 that, when the torque saturation detection unit 20 detects that the frequency that the torque exceeds the predetermined value is equal to or larger than the certain value, produces and outputs a suspend signal which suspends the rotation by the electric motor 4, of the rotation shaft 6.SELECTED DRAWING: Figure 1

Description

The present invention relates to a protective device for protecting a drive device in which a rotary shaft is rotated by a rotary drive force generated by a drive source.

The torque generated on the rotating shaft by the rotational driving force generated by the drive source is detected by the torque detection unit. A device that detects a predetermined signal based on the output of the torque detection unit is known. As such a device, for example, Patent Document 1 discloses a physical quantity detection circuit including a detection circuit in which a signal from a physical quantity detection element is input and a detection signal is output, and an abnormality diagnosis circuit.

In the physical quantity detection circuit, the abnormality diagnosis circuit has a monitoring determination circuit for monitoring the magnitude of a signal input to a circuit located after the amplifier circuit of the detection circuit. The monitoring determination circuit outputs a high-level signal when the signal is saturated.

Further, as an abnormality diagnosis device for performing abnormality diagnosis, for example, Patent Document 2 describes a device for diagnosing an abnormality in the feed shaft in a machine having a feed shaft for moving a moving body via a ball screw rotated by a servomotor. It has been disclosed.

In this device, the presence or absence of a peak of the damage frequency of the feed shaft is confirmed by frequency analysis of the servo information related to the control of the servo motor during the shaft operation of the feed shaft, and if there is the peak, the above is described. Judge that the feed axis is abnormal.

Japanese Unexamined Patent Publication No. 2016-183912 International Publication No. 2018/025634

By the way, the abnormality diagnosis device disclosed in the above-mentioned Patent Document 2 analyzes the servo information by frequency, and determines the occurrence of an abnormality by using the analysis result. Therefore, in the abnormality diagnosis device, it is necessary to acquire frequency information generated in the event of an abnormality in advance, and a data processing technique for frequency analysis is required. Therefore, the abnormality diagnosis device has a problem that it cannot be easily mounted on another device.

On the other hand, although the physical quantity detection circuit disclosed in Patent Document 1 described above can be easily mounted on another device, it outputs a high-level signal when the signal is saturated, so that the signal is used. Even if it is temporarily saturated due to noise or the like, the high level signal is output. That is, the physical quantity detection circuit disclosed in Patent Document 1 may react sensitively to noise and the like of the signal.

Therefore, when the physical quantity detection circuit is used as a protection device for a drive device including a torque detection unit, for example, the drive of the device is frequently stopped based on a high level signal output in response to noise or the like of the signal. As such, there is a possibility of excessively protecting the drive device. Further, in this case, since the chance of stopping the device increases, the operating rate of the device may decrease.

As described above, the physical quantity detection circuit disclosed in Patent Document 1 described above is susceptible to noise and the like. Therefore, it is difficult to accurately protect the drive device provided with the torque detection unit without excessively protecting it.

An object of the present invention is a protective device for protecting a drive device including a torque detection unit that detects torque generated on a rotary shaft to which a rotational drive force is transmitted, which can be easily mounted on the drive device and for torque detection. An object of the present invention is to provide a configuration capable of accurately protecting the drive device without being affected by noise or the like.

A protective device according to an embodiment of the present invention includes a drive source that generates a rotational drive force, a rotary shaft that is rotated by the rotary drive force, and a torque detection unit that detects torque generated in the rotary drive force. It is a protective device for protecting. This protection device includes a torque saturation detection unit that detects whether or not the frequency of the torque exceeding a predetermined value exceeds a certain level based on the torque detected by the torque detection unit, and the torque saturation detection unit. It includes a control unit that generates and outputs a stop signal for stopping the rotation of the rotating shaft by the drive source when it is detected that the frequency at which the torque exceeds the predetermined value exceeds a certain level. (First configuration).

When the frequency at which the torque detected by the torque detection unit exceeds a predetermined value exceeds a certain frequency in this way, the rotation of the rotating shaft by the drive source is stopped, so that the component of the drive device including the torque detection unit can be used. It is possible to prevent excessive torque from continuously acting. Therefore, the drive device can be protected. On the other hand, when the torque detected by the torque detection unit temporarily exceeds a predetermined value, the rotation of the rotating shaft by the drive source is not stopped, so that the torque signal detected by the torque detection unit is noisy or the like. Even when the above is included, it is possible to prevent the drive device from being stopped unnecessarily. Therefore, it is possible to accurately protect the components of the drive device including the torque detection unit while efficiently operating the drive device.

Moreover, in the protection device having the above-mentioned configuration, since the rotation of the rotating shaft by the drive source is stopped by detecting the abnormality of the drive device without using the frequency analysis or the like online, it can be easily mounted on the drive device. Can be done.

Therefore, with the above configuration, it is possible to realize a protective device that can be easily mounted on the drive device and that can accurately protect the drive device without being affected by torque detection noise or the like.

In the first configuration, the torque saturation detection unit is an absolute value of the total of the maximum value and the minimum value in the difference between the moving average of the torque detected by the torque detection unit and the torque detection value by the torque detection unit. Is equal to or greater than the first threshold value, it is detected that the torque exceeds the predetermined value (second configuration).

As a result, the torque saturation detection unit does not detect that the torque exceeds the predetermined value when the torque detected by the torque detection unit momentarily exceeds the predetermined value. The torque saturation detection unit uses the difference between the moving average of the torque detected by the torque detection unit and the torque detection value, so that the torque exceeds a predetermined value at a certain frequency or more. Is detected to exceed the predetermined value. Therefore, it is possible to accurately detect that the torque continuously exceeds a predetermined value without being affected by the torque noise detected by the torque detection unit.

Therefore, the drive device can be accurately protected without being affected by torque detection noise or the like.

In the first or second configuration, based on the torque detected by the torque detecting unit, tooth striking occurs at the coupling portion that transmits the rotational driving force from the driving source to the rotating shaft in the driving device. A tooth striking detection unit for detecting the presence or absence is further provided (third configuration).

When the drive device has a coupling portion that transmits a rotational driving force to the rotary shaft and the coupling portion has a meshing portion, the meshing portion is formed by a change in the rotational direction of the rotary shaft, a change in the rotational driving force, or the like. A tooth striking phenomenon may occur in which members repeatedly contact and separate from each other. When such a tooth striking phenomenon occurs, excessive vibration may occur in the drive device.

On the other hand, as in the above configuration, when the tooth striking of the coupling portion that transmits the rotational driving force generated by the driving source to the rotating shaft is detected, the rotation of the rotating shaft by the driving source is stopped. It is possible to prevent the vibration generated in the drive device from increasing. This makes it possible to protect the components of the drive device including the torque detection unit.

In the third configuration, when the absolute value of the difference between the effective value of the torque detected by the torque detection unit and the moving average is equal to or greater than the tooth striking threshold value, the tooth striking detection unit performs tooth striking at the joint portion. Is detected (fourth configuration).

As a result, the control unit can accurately detect the tooth striking at the joint portion. Therefore, the protective device can stop the rotation of the rotation shaft by the drive source when the tooth striking of the joint portion is detected by the control unit. Therefore, the drive device can be protected with high accuracy.

In any one of the first to fourth configurations, the protection device further includes a control validity determination unit for determining whether control for a control target including the drive source is valid. The drive device includes a plurality of feedback loops that negatively feed back the output of the torque detection unit to the input side corresponding to the plurality of vibration modes of the controlled object. Each of the plurality of feedback loops has a bandpass filter, a phase compensation unit, and an amplitude adjusting unit that extract a part of the vibration modes from the plurality of vibration modes. The bandpass filter and the phase compensator function as a differentiator. The control validity determination unit controls the control target based on the difference between the phase of the manipulated variable with respect to the control target and the phase of the negative feedback signal of the feedback loop, and the amplitude change of the negative feedback signal. It is determined whether it is valid (fifth configuration).

Thereby, the protective device can determine whether or not the control for the controlled object including the drive source is effective. Therefore, when the protection device stops the rotation of the rotating shaft by the drive source, the cause of the stop by the protection device is the effectiveness of the control and the effect of the control by determining whether the control for the control target is effective. You can see if it is related to invalidation.

The protection device according to the embodiment of the present invention is the protection device according to the drive source when it is detected that the frequency of the torque exceeding a predetermined value is more than a certain frequency based on the torque detected by the torque detection unit. It is equipped with a control unit that stops the rotation of the rotating shaft. As a result, it is possible to obtain a protective device that can be easily mounted on the drive device and that can accurately protect the drive device without being affected by torque detection noise or the like.

FIG. 1 is a diagram showing a schematic configuration of a test device provided with a protective device according to an embodiment of the present invention in functional blocks. FIG. 2 is a functional block diagram showing a schematic configuration of a control device and a protection device. FIG. 3 is a functional block diagram showing a schematic configuration of a torque saturation detection unit. FIG. 4 is a functional block diagram showing a schematic configuration of a tooth striking detection unit. FIG. 5 is a diagram showing an example of the output of the torque detector. FIG. 6 is a diagram showing an example of the moving average of the output of the torque detector, the maximum value and the minimum value of the difference. FIG. 7 is a diagram showing an example of the output of the torque detector when the tooth striking phenomenon of the joint portion occurs. FIG. 8 is a diagram showing an example of a moving average, an effective value, and a tooth striking flag of the output of the torque detector. FIG. 9 is a flowchart showing the operation of the control unit when the torque saturation signal is output from the torque saturation detection unit and when the torque saturation signal is output from the tooth striking detection unit. FIG. 10 is a functional block diagram showing a schematic configuration of a control effect determination unit. FIG. 11 is a diagram showing an example of the signal waveform of the step response to be controlled. FIG. 12 is a diagram showing an example of a signal waveform when a sine wave having a first-order resonance frequency is input to a controlled object. FIG. 13 is a diagram showing an example of a signal waveform when the vibration characteristic of the controlled object changes due to the non-linear characteristic. FIG. 14 is a flowchart showing a modified example 1 of the operation of the control device when the torque saturation signal is output from the torque saturation detection unit and when the torque saturation signal is output from the tooth striking detection unit. FIG. 15 is a flowchart showing a modified example 2 of the operation of the control device when the torque saturation signal is output from the torque saturation detection unit and when the torque saturation signal is output from the tooth striking detection unit. FIG. 16 is a flowchart showing a modified example 3 of the operation of the control device when the torque saturation signal is output from the torque saturation detection unit and when the torque saturation signal is output from the tooth striking detection unit. FIG. 17 is a flowchart showing a modified example 4 of the operation of the control device when the torque saturation signal is output from the torque saturation detection unit and when the torque saturation signal is output from the tooth striking detection unit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the figure are designated by the same reference numerals and the description thereof will not be repeated.

(overall structure)
FIG. 1 is a diagram showing a schematic configuration of a test device 1 (driving device) provided with a protective device 10 according to an embodiment of the present invention in functional blocks. This test device 1 is a test device for testing the characteristics of a specimen M such as an automobile motor. The specimen M to be tested by the test apparatus 1 may be a rotating body other than the motor.

Specifically, the test device 1 includes a control device 2, a motor drive circuit 3, an electric motor 4 (drive source), a coupling portion 5, a rotary shaft 6, and a torque detector 7 (torque detector). To prepare for.

The control device 2 generates a drive command for the motor drive circuit 3 by using the motor torque command r which is an input command and the feedback value described later. The control device 2 has a plurality of feedback loops 11 and 12 that negatively feed back to the motor torque command r using the output of the torque detector 7 (see FIG. 2). Since the configuration in which the control device 2 generates the drive command is the same as in the conventional case, detailed description of the control device 2 will be omitted. The configuration of the feedback loops 11 and 12 will be described later.

Although not particularly shown, the motor drive circuit 3 has a plurality of switching elements. The motor drive circuit 3 supplies electric power to a coil (not shown) of the electric motor 4 by driving the plurality of switching elements based on the drive command.

The electric motor 4 has a rotor and a stator (not shown). By supplying electric power from the motor drive circuit 3 to the coil of the stator, the rotor rotates with respect to the stator. The rotor is rotatably connected to the test piece M with the test piece M via the coupling portion 5 and the rotation shaft 6. As a result, torque can be output from the electric motor 4 to the specimen M by the rotation of the rotor. Since the configuration of the electric motor 4 is the same as the configuration of a general motor, detailed description of the electric motor 4 will be omitted.

The coupling portion 5 integrally rotatably connects the rotor of the electric motor 4 and the rotary shaft 6. The coupling portion 5 includes a structure capable of meshing, for example, a spline coupling. That is, the coupling portion 5 has a meshing portion. The coupling portion may be provided between the rotating shaft 6 and the specimen M. Further, the test device 1 does not have to have a joint portion. In this case, the protective device 10 described later does not have to have a tooth striking detection unit for detecting the tooth striking phenomenon of the joint portion.

The torque detector 7 is provided on a rotating shaft 6 that connects the electric motor 4 and the specimen M. The torque detector 7 detects the torque generated by the rotating shaft 6. The output of the torque detected by the torque detector 7 is input to the control device 2 as an input value of the feedback loops 11 and 12 (see FIG. 2), and is also input to the protection device 10 described later. That is, the output of the torque detector 7 is used for feedback control and also for protection control of the test device 1. Since the configuration of the torque detector 7 is the same as the conventional configuration, a detailed description of the torque detector 7 will be omitted.

The test device 1 having the above configuration has mechanical resonance (simply) when the electric motor 4 rotates due to the rigidity of the shaft system including the electric motor 4, the coupling portion 5, the rotating shaft 6, the torque detector 7, and the specimen M. Resonance) occurs. In the test of the test piece M, when the resonance occurs within the frequency measurement range, the torque detector 7 detects the torque (for example, shaft torque) obtained by adding the vibration component of the resonance to the output torque of the electric motor 4. To torque. Therefore, it is desired to remove the vibration component of the resonance.

On the other hand, in the present embodiment, as shown in FIG. 2, the control device 2 has a plurality of feedback loops 11 and 12 that feed back the output of the torque detector 7 to the motor torque command r which is an input command. .. That is, the test device 1 of the present embodiment is electrically driven by a control system including a control device 2, a motor drive circuit 3, an electric motor 4, a coupling portion 5, a rotary shaft 6 and a torque detector 7, and does not include a test piece M. It controls the drive of the motor 4.

In FIGS. 1 and 2, r is a target value as a motor torque command, and y is an output of the torque detector 7.

Further, the reference numeral P in FIG. 2 is a control target, and in the present embodiment, the control target P includes a motor drive circuit 3, an electric motor 4, a coupling portion 5, a rotary shaft 6, and a torque detector 7. The controlled object P also includes a portion of the rotating shaft 6 connecting the electric motor 4 and the specimen M in the range from the electric motor 4 to the torque detector 7.

Each of the plurality of feedback loops 11 and 12 is a differential feedback system including a differential element. The output of the torque detector 7 is input to each of the plurality of feedback loops 11 and 12, respectively. The feedback loop 11 includes a bandpass filter 51, a phase compensation unit 52, and an amplitude adjusting unit 53. The feedback loop 12 includes a bandpass filter 61, a phase compensation unit 62, and an amplitude adjusting unit 63.

The bandpass filter 51 of the feedback loop 11 has the same configuration as the bandpass filter 61 of the feedback loop 12. The phase compensation unit 52 of the feedback loop 11 has the same configuration as the phase compensation unit 62 of the feedback loop 12. The amplitude adjusting unit 53 of the feedback loop 11 has the same configuration as the amplitude adjusting unit 63 of the feedback loop 12.

As will be described later, the feedback loop 11 and the feedback loop 12 differ in the band of the signal passing through the output of the torque detector 7.

The bandpass filters 51 and 61 form a part of the differential element. The bandpass filters 51 and 61 have the same functions as the high-pass filter in the conventional differentiator, and also have the function of a low-pass filter that cuts high-frequency noise.

The phase compensation units 52 and 62 form a part of the differential element. The phase compensation units 52 and 62 have the same function as the phase adjustment in the conventional differentiator. The phase compensation units 52 and 62 have both functions of phase lead compensation and phase lag compensation when generating a signal for suppressing vibration caused by resonance (vibration suppression signal). The phase compensation units 52 and 62 can adjust the phase of the vibration suppression signal to an arbitrary phase as phase lead compensation or phase delay compensation.

Since the phase of the vibration suppression signal can be adjusted to an arbitrary phase by the phase compensation units 52 and 62 in this way, the phase of the vibration suppression signal can be easily set when the phase of the dead time is also taken into consideration.

The bandpass filter 51 and the phase compensation unit 52 form a differential element of the feedback loop 11. The bandpass filter 61 and the phase compensation unit 62 constitute a differential element of the feedback loop 12.

The amplitude adjusting units 53 and 63 adjust the gain of the vibration suppression signal. That is, the amplitude adjusting units 53 and 63 adjust the amplitude of the vibration suppression signal.

With the above configuration, in the feedback loop 11, the phase and amplitude of the feedback signal are adjusted to generate a vibration suppression signal that suppresses vibration caused by resonance. Similarly, in the feedback loop 12, the phase and amplitude of the feedback signal are adjusted to generate a vibration suppression signal that suppresses vibration caused by resonance.

Each of the plurality of feedback loops 11 and 12 is configured to suppress vibration at the resonance frequency of each vibration mode. The bandpass filters 51 and 61 in the plurality of feedback loops 11 and 12 are configured to be able to pass signals in different bands so that different vibration modes can be extracted.

Further, in the plurality of feedback loops 11 and 12, the phase compensation units 52 and 62 are at the resonance frequency of the vibration mode extracted by the band path filters 51 and 61 of the same feedback loops 11 and 12 as the phase compensation units 52 and 62. The phase of the vibration suppression signal is adjusted so as to suppress the vibration.

In the plurality of feedback loops 11 and 12, the amplitude adjusting units 53 and 63 generate vibrations at the resonance frequency of the vibration mode extracted by the band path filters 51 and 61 of the same feedback loops 11 and 12 as the amplitude adjusting units 53 and 63. Adjust the amplitude of the vibration suppression signal so that it is suppressed.

As a result, vibration at the resonance frequency of each vibration mode can be suppressed by the plurality of feedback loops 11 and 12. Therefore, it is possible to suppress vibration at the resonance frequency of each vibration mode of the controlled object P having a plurality of vibration modes.

Further, the test apparatus 1 having the above-mentioned configuration includes the resonance generated in the shaft system including the electric motor 4, the coupling portion 5, the rotating shaft 6, the torque detector 7, and the specimen M, and the electric motor 4 and the specimen. The torque detected by the torque detector 7 fluctuates due to the ripple generated in M.

When the torque measured by the torque detector 7 exceeds the rated measured value, it is preferable to stop the driving of the electric motor 4 of the test device 1 in order to protect the torque detector 7. However, the torque detected by the torque detector 7 may temporarily exceed the rated measured value due to the influence of noise or the like. Even in such a case, if the drive of the electric motor 4 of the test device 1 is stopped, the operating rate of the test device 1 decreases.

Further, in the test apparatus 1 having the above-mentioned configuration, for example, ripples generated in the electric motor 4 and the specimen M may cause a tooth striking phenomenon caused by backlash of the meshing portion of the coupling portion 5. When such a tooth striking phenomenon occurs, excessive vibration may occur and the load on the torque detector 7 may increase.

On the other hand, the test device 1 of the present embodiment has a protective device 10. The protection device 10 protects the torque detector 7 by stopping the drive of the electric motor 4 of the test device 1 when the torque detector 7 is loaded as described above.

Specifically, the protection device 10 includes a torque saturation detection unit 20, a tooth striking detection unit 30, a control effect determination unit 40, and a control unit 70. FIG. 3 is a functional block diagram showing a schematic configuration of the torque saturation detection unit 20. FIG. 4 is a functional block diagram showing a schematic configuration of the tooth striking detection unit 30.

The torque saturation detection unit 20 uses the output y of the torque detector 7 to detect whether or not the frequency at which the output y exceeds a predetermined value is at least a certain level. Specifically, as shown in FIG. 3, the torque saturation detection unit 20 includes a moving average calculation unit 21, a difference calculation unit 22, a difference range calculation unit 23, an effective value calculation unit 24, and a torque saturation signal output unit 25. And have.

FIG. 5 is a diagram showing an example of the output of the torque detector 7. In the example shown in FIG. 5, the output of the torque detector 7 exceeds the permissible value (“X” on the vertical axis). The torque saturation detection unit 20 detects whether or not the frequency at which the output y of the torque detector 7 exceeds the allowable value, which is the predetermined value, is constant or higher. The allowable value may be the rating of the torque detector 7 or may be lower than the rating of the torque detector 7.

The moving average calculation unit 21 uses the output y of the torque detector 7 to obtain the moving average y _movement of the output y. Specifically, the moving average calculation unit 21 obtains the moving average y _movement using the output y of the torque detector 7 or the predetermined number of outputs y of the torque detector 7 within a predetermined time. Since the method of obtaining the moving average y _movement is the same as the conventional method, detailed description thereof will be omitted.

The difference calculation unit 22 _obtains the difference y _AC between the output y of the torque detector 7 and the moving average y motion calculated by the moving average calculation unit 21. The difference range calculation unit 23 obtains the maximum value y _ACMAX and the minimum value y _ACMIN of the difference y _AC calculated by the difference calculation unit 22 at regular intervals, and is the sum of the maximum value y _ACMAX and the minimum value y _ACMIN y _ACMAX + y _ACMIN. Find the absolute value of. Note that FIG. 6 is a diagram showing an example of a moving average y _movement of the output y of the torque detector 7, a maximum value y _ACMAX and a minimum value y _ACMIN of the difference y _AC .

The effective value calculation unit 24 sets the difference flag FLAG _Diff to 1 when the absolute value of the sum of the maximum value y _ACMAX and the minimum value y _ACMIN of the difference y _AC calculated by the difference range calculation unit 23 is the first threshold value T1 or more. On the other hand, when the absolute value is smaller than the first threshold value T1, the difference flag FLAG _Diff is set to 0. The effective value calculation unit 24 obtains the effective value FLAG _RMS of the difference flag FLAG _Diff by using the equation (1).

In addition, N is the number of data for which an effective value is obtained. The number of data is determined according to the sampling time and the resonance frequency.

In FIG. 5, an example of the difference flag FLAG _Diff is shown by a thick solid line. In the example shown in FIG. 5, the frequency that the output y of the torque detector 7 exceeds the predetermined value is more than a certain frequency, so that the difference flag FLAG _Diff is 1.

The torque saturation signal output unit 25 outputs a torque saturation signal when the effective value FLAG _RMS of the difference flag FLAG _Diff calculated by the effective value calculation unit 24 is equal to or higher than the second threshold value T2, and outputs the torque saturation signal, and the effective value of the difference flag FLAG _Diff . When FLAG _RMS is smaller than the second threshold value T2, the torque saturation signal is not output.

With the above configuration, it is possible to detect whether or not the frequency with which the torque detected by the torque detector 7 exceeds a predetermined value exceeds a certain level. The torque saturation signal output when the torque saturation detection unit 20 detects that the frequency at which the torque exceeds a predetermined value exceeds a certain value is input to the control unit 70. When the torque saturation signal is input to the control unit 70, the control unit 70 generates a stop signal for stopping the driving of the electric motor 4. When the generated stop signal is input to the control device 2, the control device 2 stops driving the electric motor 4. In this way, the drive of the electric motor 4 of the test device 1 can be controlled according to the detection result of the torque saturation detection unit 20.

Moreover, since the torque saturation detection unit 20 has the above-mentioned configuration, even if the output y of the torque detector 7 momentarily exceeds the predetermined value, the torque saturation detection unit 20 does not generate a torque saturation signal. It is possible to suppress a decrease in the operating rate of the test device 1.

The tooth striking detection unit 30 detects the tooth striking phenomenon of the coupling portion 5 by using the output y of the torque detector 7. Specifically, as shown in FIG. 4, the tooth striking detection unit 30 includes a moving average calculation unit 31, an effective value calculation unit 32, a difference calculation unit 33, and a tooth striking signal output unit 34.

FIG. 7 is a diagram showing an example of the output y of the torque detector 7 when the tooth striking phenomenon of the coupling portion 5 occurs. In the example shown in FIG. 7, the output y of the torque detector 7 has a large amplitude.

Similar to the moving average calculation unit 21 of the torque saturation detection unit 20, the moving average calculation unit 31 uses the output y of the torque detector 7 to obtain the moving average y _movement of the output y. The torque saturation detection unit 20 and the tooth striking detection unit 30 may use one moving average calculation unit to obtain the moving average y _movement of the output y of the torque detector 7.

The effective value calculation unit 32 obtains the effective value y _RMS of the output y of the torque detector 7. The effective value calculation unit 32 is different from the effective value calculation unit 24 of the torque saturation detection unit 20 in that the target for obtaining the effective value is different, but the effective value of the output y of the torque detector 7 is obtained by the same method as the effective value calculation unit 24. y Find the _RMS .

The difference calculation unit 33 calculates the absolute value of the difference y _movement -y _RMS between the effective value y _RMS calculated by the effective value calculation unit 32 and the moving average y _movement calculated by the moving average calculation unit 31.

The tooth striking signal output unit 34 sets the tooth striking flag to 1 when the absolute value of the difference y _movement -y _RMS calculated by the difference calculation unit 33 is equal to or greater than the tooth striking threshold value T3, while the difference y _movement -y _RMS . When the absolute value of is smaller than the tooth striking threshold value T3, the tooth striking flag is set to 0. The tooth striking signal output unit 34 generates and outputs a tooth striking signal when the tooth striking flag is 1.

Note that FIG. 8 is a diagram showing an example of a moving average y _movement of the output y of the torque detector 7, an effective value y _RMS , and a tooth striking flag. In the example shown in FIG. 8, since the absolute value of the difference y _movement − y _RMS between the effective value y _RMS and the moving average y _movement exceeds the tooth striking threshold value T3, the tooth striking flag is 1.

With the above configuration, the tooth striking detection unit 30 can detect that the tooth striking phenomenon of the joint portion 5 has occurred. The tooth striking signal output when the tooth striking phenomenon of the coupling portion 5 is detected by the tooth striking detection unit 30 is input to the control unit 70, and the control unit 70 receives a stop signal for stopping the drive of the electric motor 4. Generated. When the generated stop signal is input to the control device 2, the control device 2 stops driving the electric motor 4. In this way, the drive of the electric motor 4 of the test device 1 can be controlled according to the detection result of the tooth striking detection unit 30.

The operation of the control unit 70 when the torque saturation signal is output from the torque saturation detection unit 20 and when the tooth striking signal is output from the tooth striking detection unit 30 will be described with reference to FIG.

As shown in FIG. 9, when the flow starts (START), in step SA1, the control unit 70 outputs a torque saturation signal from the torque saturation detection unit 20 or a tooth striking signal from the tooth striking detection unit 30. Is output.

When it is determined that any of the signals is output (YES in step SA1), the control unit 70 generates a stop signal for stopping the drive of the electric motor 4 and outputs the stop signal to the control device 2. (Step SA2). As a result, the control device 2 stops driving the electric motor 4. After that, this flow is terminated (END).

On the other hand, when it is determined that neither signal is output (NO in step SA1), the control unit 70 performs the determination in step SA1 again.

When the frequency at which the torque detected by the torque detector 7 exceeds a predetermined value exceeds a certain frequency in this way, the drive of the electric motor 4 is stopped to form a component of the test device 1 including the torque detector 7. It is possible to prevent excessive torque from continuously acting. Therefore, the test apparatus 1 can be protected. On the other hand, when the torque detected by the torque detector 7 temporarily exceeds a predetermined value, the drive of the electric motor 4 is not stopped, so that the torque signal detected by the torque detector 7 contains noise and the like. Even in such a case, it is possible to prevent the test device 1 from being stopped unnecessarily. Therefore, it is possible to accurately protect the components of the test device 1 including the torque detector 7 while efficiently operating the test device 1.

Further, when the tooth striking of the coupling portion 5 that transmits the rotational driving force generated by the electric motor 4 to the rotating shaft 6 is detected, the rotation of the rotating shaft 6 by the electric motor 4 is stopped, so that the vibration generated in the test device 1 is generated. Can be prevented from increasing. Thereby, the components of the test apparatus 1 including the torque detector 7 can be protected.

Moreover, in the protection device 10 of the present embodiment, since the abnormality of the test device 1 is detected and the rotation of the rotating shaft 6 by the electric motor 4 is stopped without using the frequency analysis or the like online, the test device 1 can easily be used. Can be implemented.

Therefore, with the above configuration, it is possible to realize a protection device 10 that can be easily mounted on the test device 1 and can accurately protect the test device 1 without being affected by torque detection noise or the like.

The protection device 10 of the present embodiment has a control effect determination unit 40. The control effect determination unit 40 determines whether or not the control for the control target P is effective. FIG. 10 is a functional block diagram showing a schematic configuration of the control effect determination unit 40. As shown in FIG. 10, the control effect determination unit 40 includes a phase comparison unit 41, an amplitude determination unit 42, and a determination signal generation unit 43. The operation signal and feedback signal (hereinafter referred to as FB signal) of the control device 2 are input to the control effect determination unit 40.

The phase comparison unit 41 compares the phase of the operation signal input to the control effect determination unit 40 with the phase of the FB signal. Although not particularly shown, the phase comparison unit 41 uses a feedback loop bandpass filter that generates the FB signal as the phase of the operation signal when comparing the phase of the operation signal with the phase of the FB signal. The phase of the signal extracted from the operation signal using a bandpass filter having the same characteristics is used.

The phase comparison unit 41 determines whether or not the difference between the phase of the operation signal and the phase of the FB signal is within a predetermined range. The predetermined range is, for example, a case where the difference between the time at which the operation signal zero-crosses and the time at which the FB signal crosses zero is within a desired time.

The desired time is determined, for example, as follows. Assuming that the period of the resonance frequency is 1 / F, zero cross occurs twice in one cycle, so zero cross is detected once in 1 / 2F. Assuming that the permissible deviation of the detection time is 50%, the desired time is 0.5 / 2F.

In the following description, when the difference between the phase of the operation signal and the phase of the FB signal is within the predetermined range, it is also said that the phase of the operation signal and the phase of the FB signal are the same phase. ..

In the configuration of the control device 2 having the feedback loop as shown in FIG. 2, the phase of the operation signal extracted by using the bandpass filter having the same characteristics and the phase of the FB signal are the same phase. Therefore, the phase comparison unit 41 compares the phase of the operation signal with the phase of the FB signal, and if the phases are different, it is determined that the control of the control device 2 with respect to the control target P is not effective. Can be done.

The amplitude determination unit 42 determines the attenuation of the amplitude of the FB signal. The amplitude determination unit 42 detects a change in the amplitude of the FB signal and determines whether or not the amplitude does not change or decreases.

In the determination signal generation unit 43, the phase comparison unit 41 determines that the phase of the operation signal and the phase of the FB signal are the same phase, and the amplitude determination unit 42 maintains or attenuates the amplitude of the FB signal. If it is determined that the control device 2 is controlled, a determination signal indicating that the control of the control device 2 with respect to the control target P is effective is generated.

FIG. 11 is a diagram showing an example of the signal waveform of the step response of the controlled object P. In the example shown in FIG. 11, the timing of zero crossing of the operation signal and the FB signal is close, and the amplitudes of those signals are attenuated. Therefore, in the example shown in FIG. 11, the determination signal generation unit 43 generates a determination signal that the control of the control device 2 with respect to the control target P is effective.

FIG. 12 is a diagram showing an example of a signal waveform when a sine wave having a first-order resonance frequency is input to the controlled object P. In the example shown in FIG. 12, the timing of zero crossing of the operation signal and the FB signal is close, and the amplitudes of those signals are maintained. Therefore, in the example shown in FIG. 12, the determination signal generation unit 43 generates a determination signal that the control of the control device 2 with respect to the control target P is effective.

The determination signal generation unit 43 determines that the phase of the operation signal and the phase of the FB signal are the same phase by the phase comparison unit 41, and the amplitude of the FB signal is increased by the amplitude determination unit 42. If it is determined, the control of the control device 2 with respect to the controlled object P is effective, but a determination signal indicating that the vibration is increasing is generated.

In the determination signal generation unit 43, the phase comparison unit 41 determines that the phase of the operation signal and the phase of the FB signal are not the same phase, and the amplitude determination unit 42 maintains or attenuates the amplitude of the FB signal. If it is determined that the signal is present, the vibration generated in the controlled object P is a vibration having a frequency different from that of the feedback loop, so that a determination signal is generated that the control device 2 is not subject to control.

The determination signal generation unit 43 determines that the phase of the operation signal and the phase of the FB signal are not the same phase by the phase comparison unit 41, and the amplitude determination unit 42 increases the amplitude of the FB signal. If it is determined, the determination signal that the vibration is increasing and the vibration characteristic of the control target P may be changed, that is, the determination signal that the control of the control device 2 with respect to the control target P is not effective. To generate.

The determination signal generated by the determination signal generation unit 43 is input to the control unit 70. The control unit 70 outputs the input determination signal as an output signal to an output device (not shown). As a result, it is possible to output whether or not the control of the control device 2 with respect to the control target P is effective. The determination signal may be input to the control device 2 and used to generate a control signal of the control device 2.

FIG. 13 is a diagram showing an example of a signal waveform when the vibration characteristic of the controlled object P changes due to the non-linear characteristic. In the example shown in FIG. 13, the timings of zero crossing of the operation signal and the FB signal are significantly different, and their amplitudes are also increasing. Therefore, in the example shown in FIG. 13, the determination signal generation unit 43 generates a determination signal that the control of the control device 2 with respect to the control target P is not effective.

With the above configuration, the protection device 10 can determine whether or not the control for the control target P including the electric motor 4 is effective. Therefore, when the protection device 10 stops driving the electric motor 4, it is determined whether or not the control for the control target P is effective, and the cause of the drive stop of the electric motor 4 by the protection device 10 is the control target. It is possible to grasp whether it is related to the validity and invalidity of the control for P.

Moreover, by combining the determination result of the control effect determination unit 40 and the other determination result of the control for the control target P, it can be used for investigating the cause of the drive stop of the electric motor 4 by the protection device 10.

(Modification 1)
FIG. 14 shows a modified example 1 of the operation of the control unit 70 when the torque saturation signal is output from the torque saturation detection unit 20 and when the tooth striking signal is output from the tooth striking detection unit 30 in the above-described embodiment. It will be explained using. In this modification, when the torque saturation signal and the tooth striking signal are output, the control unit 70 generates a stop signal for stopping the drive of the electric motor 4.

As shown in FIG. 14, when the flow starts (START), in step SB1, the control unit 70 determines whether both the torque saturation signal and the tooth striking signal are output.

When it is determined that both the torque saturation signal and the tooth striking signal are output (YES in step SB1), the control unit 70 generates a stop signal for stopping the drive of the electric motor 4. And output to the control device 2 (step SB2). As a result, the control device 2 stops driving the electric motor 4. After that, this flow is terminated (END).

On the other hand, when it is determined that both the torque saturation signal and the tooth striking signal are not output (NO in step SB1), that is, whether neither the torque saturation signal nor the tooth striking signal is output. If only one of the signals is output, the control unit 70 re-determines step SB1.

As a result, the protection device 10 can stop the drive of the electric motor 4 in a state where a large load is applied to the torque detector 7. Therefore, it is possible to more reliably prevent the electric motor 4 from being driven and stopped frequently.

(Modification 2)
A modification 2 of the operation of the control unit 70 will be described with reference to FIG. In this modification, the control unit 70 stops driving the electric motor 4 in either the case where the torque saturation signal is output, the case where the tooth striking signal is output, or the case where the determination signal is output. Generate a stop signal.

The determination signal is a signal other than the torque saturation signal and the tooth striking signal, and is a signal capable of estimating the load of the torque detector 7. In the present embodiment, the determination signal is a signal output by the control effect determination unit 40.

As shown in FIG. 15, when the flow starts (START), in step SC1, the control unit 70 determines whether the torque saturation signal is output, the tooth striking signal is output, or the determination signal is output. judge.

When it is determined that any of the signals is output (YES in step SC1), the control unit 70 generates a stop signal for stopping the drive of the electric motor 4 and outputs the stop signal to the control device 2. (Step SC2). As a result, the control device 2 stops driving the electric motor 4. After that, this flow is terminated (END).

On the other hand, when it is determined that neither signal is output (NO in step SC1), the control unit 70 re-determines step SC1.

As a result, the protection device 10 can more reliably stop the drive of the electric motor 4 in response to the increase in the load of the torque detector 7.

(Modification 3)
A modified example 3 of the operation of the control unit 70 will be described with reference to FIG. In this modification, the control unit 70 generates a stop signal for stopping the drive of the electric motor 4 when a torque saturation signal is output or a tooth striking signal is output, and a determination signal is output. Also, the stop signal is generated.

As shown in FIG. 16, when the flow starts (START), in step SD1, the control unit 70 determines whether a torque saturation signal is output or a tooth striking signal is output.

When it is determined that any of the signals is output (YES in step SD1), the control unit 70 generates a stop signal for stopping the drive of the electric motor 4 and outputs the stop signal to the control device 2. (Step SD3). As a result, the control device 2 stops driving the electric motor 4. After that, this flow is terminated (END).

On the other hand, if it is determined that neither signal is output (NO in step SD1), the process proceeds to step SD2, and the control unit 70 determines whether or not the determination signal is output.

When it is determined that the determination signal has been output (YES in step SD2), the control unit 70 generates a stop signal for stopping the drive of the electric motor 4 and outputs it to the control device 2 (when it is determined to be YES). Step SD3). As a result, the control device 2 stops driving the electric motor 4. After that, this flow is terminated (END).

On the other hand, when it is determined that the determination signal is not output (NO in step SD1), the control unit 70 performs the determination in step SD1 again.

As a result, the protection device 10 can more reliably stop the drive of the electric motor 4 in response to the increase in the load of the torque detector 7.

(Modification example 4)
A modified example 4 of the operation of the control unit 70 will be described with reference to FIG. In this modification, the control unit 70 stops driving the electric motor 4 when a torque saturation signal is output or a tooth striking signal is output, and outputs a signal to a higher-level controller.

As shown in FIG. 17, when the flow starts (START), in step SE1, the control unit 70 determines whether a torque saturation signal is output or a tooth striking signal is output.

When it is determined that any of the signals is output (YES in step SE1), the control unit 70 generates a stop signal for stopping the drive of the electric motor 4 and outputs the stop signal to the control device 2. (Step SE2). As a result, the control device 2 stops driving the electric motor 4. In the following step SE3, the control unit 70 outputs a signal notifying the upper controller of the stop. After that, this flow is terminated (END).

On the other hand, when it is determined that neither signal is output (NO in step SE1), the control unit 70 performs the determination in step SE1 again.

As a result, the control unit 70 can notify the upper controller of the drive stop of the electric motor 4.

In addition, also in the configuration of the above-described embodiment and the configuration of other modifications, as in this modification, the control unit 70 stops driving the electric motor 4 and then causes the electric motor 4 to be referred to the upper controller. A signal for notifying the stop of driving may be output.

(Other embodiments)
Although the embodiment of the present invention has been described above, the above-described embodiment is merely an example for carrying out the present invention. Therefore, the embodiment is not limited to the above-described embodiment, and the above-described embodiment can be appropriately modified and implemented within a range that does not deviate from the gist thereof.

In the embodiment, the control device 2 has two feedback loops. However, the controller may have three or more feedback loops.

In the embodiment, the control device 2 may perform other controls such as servo control and feedforward control. Further, the control device 2 may perform waste time control and the like.

In the embodiment, the controlled object P includes a motor drive circuit 3, an electric motor 4, and a torque detector 7. However, the controlled object may include other configurations or may include an axis system having other configurations.

In the above embodiment, the feedback loops 11 and 12 of the control device 2 include bandpass filters 51 and 61, phase compensation units 52 and 62, and amplitude adjustment units 53 and 63. However, the feedback loop of the controller may include other configurations. Also, the control device may not have a feedback loop.

In the above embodiment, the protection device 10 includes a torque saturation detection unit 20, a tooth striking detection unit 30, and a control effect determination unit 40. However, the protective device may not have a tooth striking detection unit. In this case, the protection device stops driving the electric motor when the frequency at which the output of the torque detector exceeds a predetermined value by the torque saturation detection unit exceeds a certain frequency. Further, the protective device may not have a control effect determination unit. In this case, the controller may not have a feedback loop.

In the above embodiment, the protection device 10 controls the drive of the electric motor 4 so as to protect the torque detector 7 of the test device 1. However, the protective device may control the drive of the electric motor to protect components other than the torque detector of the test device.

In the above embodiment, the moving average calculation units 21 and 31 use the output y of the torque detector 7 to obtain the moving average y _movement of the output y. However, instead of the moving average calculation unit, the DC component of the output of the torque detector may be cut by a bypass filter.

INDUSTRIAL APPLICABILITY The present invention can be used as a protective device for protecting a drive device including a torque detection unit that detects torque generated on a rotating shaft by a drive source.

1 Test device (drive device)
2 Control device 3 Motor drive circuit 4 Electric motor (drive source)
5 Coupling part 6 Rotating shaft 7 Torque detector (torque detector)
10 Protective devices 11, 12 Feedback loop 20 Torque saturation detection unit 21, 31 Moving average calculation unit 22, 33 Difference calculation unit 23 Difference range calculation unit 24, 32 Effective value calculation unit 25 Torque saturation signal output unit 30 Toothing detection unit 34 Toothing signal output unit 40 Control effect determination unit 41 Phase comparison unit 42 Amplitude determination unit 43 Judgment signal generation unit 51, 61 Band path filter 52, 62 Phase compensation unit 53, 63 Amplitude adjustment unit 70 Control unit M Specimen

Claims (5)

The drive source that produces the rotational driving force and
The rotating shaft rotated by the rotational driving force and
A torque detector that detects the torque generated on the rotating shaft,
A protective device for protecting a drive device provided with
Based on the torque detected by the torque detection unit, a torque saturation detection unit that detects whether or not the frequency at which the torque exceeds a predetermined value exceeds a certain value is equal to or higher than a certain value.
A control unit that generates and outputs a stop signal for stopping the rotation of the rotating shaft by the drive source when the torque saturation detection unit detects that the frequency at which the torque exceeds a predetermined value exceeds a certain level. ,
It is equipped with a protective device. In the protective device according to claim 1,
The torque saturation detection unit is used when the absolute value of the total of the maximum and minimum values in the difference between the moving average of the torque detected by the torque detection unit and the torque detection value by the torque detection unit is equal to or higher than the first threshold value. In addition, a protective device that detects that the torque exceeds the predetermined value. In the protective device according to claim 1 or 2.
Based on the torque detected by the torque detection unit, the tooth striking detection unit that detects whether or not tooth striking occurs at the coupling portion that transmits the rotational driving force from the drive source to the rotation shaft in the drive device. Further equipped, protective device. In the protective device according to claim 3,
The tooth striking detection unit detects that tooth striking has occurred at the joint portion when the absolute value of the difference between the effective value of the torque detected by the torque detection unit and the moving average is equal to or greater than the tooth striking threshold value. , Protective device. In the protective device according to any one of claims 1 to 4.
Further, a control validity determination unit for determining whether or not control for a control target including the drive source is valid is provided.
The drive device is
A plurality of feedback loops that negatively feed back the output of the torque detection unit to the input side are provided corresponding to the plurality of vibration modes of the controlled object.
Each of the plurality of feedback loops has a bandpass filter, a phase compensation unit, and an amplitude adjusting unit that extract a part of the vibration modes from the plurality of vibration modes.
The bandpass filter and the phase compensator function as a differentiator, and the bandpass filter and the phase compensation unit function as a differentiator.
The control validity determination unit controls the control target based on the difference between the phase of the manipulated variable with respect to the control target and the phase of the negative feedback signal of the feedback loop, and the amplitude change of the negative feedback signal. A protective device that determines whether it is valid.

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