JP6901688B2 - Vibration system control device and work transfer device - Google Patents

Description

The present invention relates to a vibration system control device and a work transfer device capable of appropriately controlling the phase of the vibration system even in a high frequency region.

Conventionally, a work transfer device that conveys a work using a traveling wave has been known (for example, Patent Document 1). As shown in FIG. 8, this type of work transfer device has a structure in which the transfer portion a has a vibrating portion that can orbit, and has a standing wave mode (vibration mode) that undulates along this orbital path. doing. Of these, the first vibrating section b1 and the second vibrating section b2, which are spatially out of phase by 90 °, are subjected to two standing wave modes (0 ° mode and 90 ° mode) as shown in FIG. In order to vibrate in the ultrasonic region with a phase shift of 90 °, vibration units c1 and c2 using piezoelectric elements are provided in the vibrating parts b1 and b2, respectively, to provide the first vibration system D1 and the second vibration. It constitutes the system D2. Then, a sine wave is input from the drive command generation unit e to the first and second vibration systems D1 and D2 via the amplifiers A1 and A2, respectively, and at that time, one of the vibration systems (second vibration in the illustrated example). By shifting the phase shift by 90 ° with respect to the system D2) and inputting a drive command, a traveling wave is generated in the transport unit a.

Japanese Unexamined Patent Publication No. 2017-34331

In such a work transfer device, the resonance frequencies of the two standing wave modes that are spatially out of phase by 90 ° are close but do not match, and therefore the phase difference (mechanical) of the response to the excitation signal. There is a deviation (phase difference) (see FIG. 10). Due to this deviation, even if the phase of the excitation signal to each mode is shifted by 90 °, the phase of the vibration of each mode generated as a response is not necessarily 90 °. Further, during continuous driving, there is a phenomenon that the resonance frequency changes due to a temperature change or the like, and the phase relationship of each vibration mode also changes accordingly. For stable workpiece transfer, it is necessary to adjust the phase difference of the vibration signal so that the phase difference of the vibration in each mode becomes 90 ° in response to such a phase shift or change. ..

However, in the past, such adjustment has not been made, and the traveling wave may deteriorate without an appropriate phase difference, making it impossible to convey the work. This deterioration of the traveling wave can be regarded as a decrease in the traveling wave ratio. In general, the traveling wave ratio is an index showing how close to an ideal traveling wave is, and is defined by the following equation. A traveling wave ratio of 1 indicates a complete traveling wave, a value of 0 indicates a standing wave, and a value in between indicates a wave in which a traveling wave and a standing wave are mixed.
Traveling wave ratio = minimum amplitude on the traveling wave path / maximum amplitude on the traveling wave path

Therefore, one method is to solve the problem by automatically adjusting the phase difference "90 °" of the excitation signal in FIG. 8 which was conventionally set to a constant value by feedback control through phase detection. It can be considered as a means.

However, it is difficult to adopt zero cross detection, which is a general method for detecting a phase difference, in this work transfer device. This is because zero-cross detection has a problem of sampling speed, and it becomes difficult to detect the phase difference with high resolution in the ultrasonic region.

The present invention has been made by paying attention to such a problem, and is suitable for controlling a new vibration system, which can be suitably applied when it is necessary to perform phase control in a high frequency region such as ultrasonic transfer. The purpose is to realize an apparatus and a workpiece transfer apparatus.

An object of the present invention is to effectively solve these problems.

Therefore, the present invention has taken the following measures in order to solve such a problem.
That is, the vibration system control device according to the present invention has a phase difference detection unit that detects the phase difference between the two vibration systems and the vibration in order to drive the two vibration systems having different resonance frequencies through a common drive command. It includes a phase adjusting unit that changes the phase of one of the drive commands of the system, and the phase difference detecting unit includes a vibration detecting unit that detects vibration from each of the two vibration systems and the vibration detecting unit. A multiplication unit that multiplies the signals detected by the vibration detection unit, a filter unit that extracts the DC component from the multiplied signal according to the phase difference between the signals before multiplication, and the two vibration systems that extract the DC component. The phase adjusting unit is provided with a dividing unit that is normalized by dividing by the vibration amplitude of the above, so that the value representing the actual phase difference output from the dividing unit matches the value representing the preset target phase difference. It is characterized in that the phase of the drive command is adjusted.

In the case of zero-cross detection, it was difficult to detect the phase difference with high resolution due to the problem of sampling speed. However, in this way, the phase difference detection value can be extracted as a DC signal, so even if the frequency is high. The phase difference can be detected with high accuracy. Moreover, by normalizing the phase difference detection signal, the responsiveness of control does not depend on the amplitude, and the phase difference between the two vibration systems can be controlled stably and accurately even in the high frequency region. It will be possible.

In particular, the values representing the actual phase difference and the target phase difference are the cosine value or the sine value of the phase difference, and the deviation between the actual phase difference and the target phase difference becomes 0 based on the cosine value or the sine value. , It is preferable to shift the phase of the drive command in either the increasing or decreasing direction.

In this way, the target phase difference can be easily set, and the adjustment direction in the phase adjusting unit can be determined by comparison with an extremely simple actual phase difference.

Alternatively, the signals detected by the two vibration systems are both displacement signals, velocity signals, or acceleration signals, and the phase adjusting unit gives 0 as the cosine value or sine value of the target phase difference. It is preferable to adjust the phase of the drive command so that the cosine value or the sine value related to the actual phase difference becomes 0.

Displacement and velocity differ in 90 ° phase, and velocity and acceleration further differ in 90 ° phase, but the same signals are easy to handle. Then, when the cosine value or the sine value of the target phase difference is 0, the phase adjustment can be performed only by the DC component that appears.

When the vibrations of the two vibration systems are two standing wave vibrations for generating a traveling wave and transporting the work by vibrating with a phase difference of 90 °, the target is determined according to the traveling direction. It is desirable to switch the direction of phase shift for setting the cosine value of the actual phase difference to 0 with respect to the cosine value of the phase difference of 0, depending on whether it converges to + 90 ° or −90 °.

Assuming that there are first and second standing waves, the phase of the second standing wave with respect to the first standing wave is + 90 ° when the work transport direction is positive and -90 ° when the work transport direction is negative. become. When the target value is 90 °, cosφ swings to − when it exceeds 90 ° and swings to + when it falls below 90 °. On the other hand, when the target value is -90 °, it swings to + when it exceeds -90 °. If it falls below, it swings to-. Therefore, it is possible to perform control according to the transport direction only by switching the phase shift direction according to the traveling direction.

As a preferred application example of the present invention, a traveling wave for bending and vibrating the transporting portion is generated by synthesizing two standing waves having different phases and a transporting portion for transporting the workpiece in a mounted state. It is desirable that the traveling wave generating means for causing the traveling wave to be generated is provided, and the vibration system control device is applied to generate two standing waves of the traveling wave generating means.

With such a work transfer device, the phase difference between the two standing waves can be accurately brought close to 90 °, and highly efficient transfer with a high traveling wave ratio becomes possible.

According to the present invention described above, a new vibration system control device and a new vibration system control device that are extremely useful when applied to applications that require accurate phase control in a high frequency region, such as ultrasonic transfer. It becomes possible to provide a work transfer device.

The block diagram which shows the control device of the vibration system which concerns on one Embodiment of this invention. The block diagram which showed a part of FIG. 1 concretely. The graph which shows the relationship between the cosine value which shows the real phase difference and the phase difference in the same embodiment. The figure which shows the parts feeder as a work transfer apparatus which is an application example of the control apparatus which concerns on the same embodiment. The control block diagram for the bowl feeder which constitutes the part feeder. The control block diagram for the linear feeder which constitutes the part feeder. The block diagram corresponding to FIG. 2 which shows the modification of this invention. The principle diagram for demonstrating the conventional control apparatus which is contrasted with this invention. The figure which shows the relationship between 0 ° mode and 90 ° mode in the conventional control. A graph for explaining a defect in the conventional example.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the vibration system control device C according to the present embodiment. This control device C has first and second vibration systems 1 and 2, and has vibration units (1x and 2x) such that the resonance frequencies f1 and f2 of the vibration systems 1 and 2 are close to each other. As a vibration system in which the resonance frequencies f1 and f2 are close to each other in this way, for example, a traveling wave is generated by vibrating a plurality of locations having a spatial phase difference in a plurality of vibration modes under a temporal phase difference. An ultrasonic vibration system such as a parts feeder to be generated can be mentioned.

In this embodiment, a case of driving a transport unit having two standing wave modes (0 ° mode and 90 ° mode) in which the spatial phases are shifted by 90 ° is given as an example.

Specifically, the first and second vibration systems 1 and 2 are vibrated by the first vibrating device 11 that vibrates the 0 ° mode and the second vibrating device 21 that vibrates the 90 ° mode, respectively. ..

Periodic signals such as sine waves and square waves with variable frequencies generated by the drive command generator 3 of the transmitter etc. are sent to the first and second exciters 11 and 21 of the first and second amplifiers 12 and 22. It is amplified by and input. Regarding the second exciter 21, the phase of the periodic signal from the drive command generator 3 is shifted in the phase shifter 41 in order to give a relative phase difference based on the excitation in the first exciter 11. Then, what is amplified by the second amplifier 22 is input. The amount of this phase shift can be adjusted by an external signal.

That is, the periodic signal from the drive command generation unit 3 is input to the first amplifier 12 and is input to the second amplifier 22 with the phase shifted by the phase shifter 23.

Here, for stable workpiece transfer, it is desirable that the phase difference of vibration in each mode is 90 °. Therefore, it is necessary to change the phase of the drive command of one of the vibration systems so that the vibrations of the two vibration systems are detected and the phase difference becomes 90 °.

However, as described above, it is difficult to adopt zero-cross detection, which is a general method for detecting a phase difference, in an application such as this embodiment. This is because zero-cross detection has a problem of sampling speed, and it becomes difficult to detect the phase difference with high resolution in the ultrasonic region.

Therefore, this embodiment employs a configuration in which the phase difference is detected by a method other than zero cross.

Specifically, the phase adjusting unit 4 that changes the phase of the drive command input to one of the vibration systems, that is, the second vibration system 2, through the phase shifter 41, and the two vibration systems, that is, the first and second vibration systems. It is provided with a phase difference detecting unit 5 that detects the phase difference of 1 and 2 and outputs it as a direct current component.

The phase difference detection unit 5 inputs signals of the first and second vibration detectors 51 and 52 for detecting vibration waveforms in 0 ° mode and 90 ° mode, and the signals of the first and second vibration detectors 51 and 52. A phase difference detector 53 that outputs a signal corresponding to the phase difference thereof is included. In this embodiment, the first and second vibration detectors 51 and 52 detect either displacement signals, velocity signals, or acceleration signals.

Further, the phase adjusting unit 4 sets a target for the vibration phase difference of the first and second vibration systems 1 and 2, and outputs a signal corresponding to the target, and an output signal of the phase difference detector 53. The difference device 43, which is a comparison device that compares the output signals of the phase difference setting device 42, and the PI control unit 44, which is a control amount calculation unit that calculates the control amount so that the deviation in the difference device 43 becomes 0, and PI control. It is configured to include a phase shifter 41 that controls the phase shift amount by the output signal of the unit 44.

More specifically, the phase difference detector 53 is configured as shown in FIG. The phase difference detector 53 includes a multiplier 53a, which is a multiplication unit that multiplies the signals of the first vibration detector 51 and the second vibration detector 52, and a low-pass filter, which is a filter unit that extracts a DC component from the output signal of the multiplier 53a. The first and second amplitudes of the signals after passing through the 53b, the first and second amplitude detectors 53c and 53d that detect the amplitudes of the signals of the first and second vibration detectors 51 and 52, and the low pass filter 53b. The dividers 53e and 53f, which are division units for dividing by the detection signals of the detectors 53c and 53d, are provided, and the divided signal is fed back as the phase difference detection signal S1.

In this case, assuming that the phase difference between the 0 ° mode and the 90 ° mode is φ12, the signal of the phase difference detector 53 is a signal proportional to cos φ12. Therefore, when the phase difference between the 0 ° mode and the 90 ° mode is ± 90 ° (φ12 = ± 90 °), the signal value of the phase difference detector 53 is cos ± 90 °, that is, 0.

In order to set the phase difference between the 0 ° mode and the 90 ° mode to ± 90 ° (φ12 = ± 90 °), the set value of the phase difference setting device 42 is set to 0 as shown in FIG. In this case, it is not necessary to dare to provide the phase difference setting device 42.

The operation when configured in this way is as follows.
Let the signal of the first vibration detector 51 be v1cos (ωt + φ1) and the signal of the second vibration detector 52 be v2cos (ωt + φe + φ2). φe is the phase difference of the response to the command signal in 90 ° mode. Further, v1 and v2 are values proportional to the amplitudes of the 0 ° mode and the 90 ° mode. Here, if φe + φ2-φ1 = φ12, the signal of the second vibration detector 52 is v2cos (ωt + φ1 + φ12), and φ12 represents the phase difference of the vibration in the 90 ° mode with respect to the 0 ° mode. The signal of the first vibration detector 51 and the signal of the second vibration detector 52 are multiplied by the multiplier 53a and then passed through the low-pass filter 53b. The signal after multiplication is as follows.

v1cos (ωt + φ1) × v2cos (ωt + φ1 + φ12)
= v1 ・ v2 {cos ² (ωt + φ1) cos φ12-cos (ωt + φ1) sin (ωt + φ1) sin φ12}… (1)

When this signal is passed through the low-pass filter 53b, only the DC component is extracted and
(1/2) v1 ・ v2cos φ12… (2)
Will be.

Further, in the dividers 53e and 53f, division is performed (normalized) by the amplitude proportional signals (signals proportional to v1 and v2) detected by the first and second amplitude detectors 53c and 53d. The signal obtained thereby becomes a phase difference detection signal S1 proportional to cos φ12 without depending on the amplitude, and the phase difference detection signal S1 is fed back and controlled by the PI control unit 44.

Here, as shown in FIG. 3, when φ12 = 90 °, cos φ12 = 0, and in this vicinity, cos φ12 decreases monotonically with respect to the increase in φ12. Further, when φ12 = −90 °, cos φ12 = 0, and in this vicinity, cos φ12 increases monotonically with respect to the increase in φ12. φ12 (= φe + φ2-φ1) can be adjusted by the phase shift amount φe. Therefore, the phase difference φ12 between the vibrations in the 0 ° mode and the 90 ° mode can be maintained at + 90 ° or −90 ° by performing the following operations in the PI control unit 44.

In the control that needs to converge to + 90 °, φe is decreased when cosφ12 <0, and φe is increased when cosφ12> 0.
In the control that needs to converge to −90 °, φe is increased when cos φ12 <0, and φe is decreased when cos φ12> 0.

Since it is clear in advance whether to converge to + 90 ° or -90 ° depending on the application target, such control may cause a difference in characteristics between the 0 ° mode and the 90 ° mode and a change in the resonance frequency. Even so, the phase difference between the vibrations in the 0 ° mode and the 90 ° mode is maintained at ± 90 °, and stable traveling wave generation becomes possible.

FIG. 4 shows a parts feeder PF as a work transfer device as an example to which the vibration system control device C according to the present implementation system is applied. The parts feeder PF is appropriate by aligning and determining the direction of the bowl feeder Bf that causes the loaded work to climb along the spiral transport portion T1 and the work discharged from the bowl feeder Bf by the alignment transport portion t1. It is composed of a linear feeder Lf that allows only the work in the posture to pass and returns an inappropriate work to the bowl feeder Bf through the return transport unit t2.

Of these, as shown in FIG. 5, the bowl feeder Bf is the vibrating portion 1x of the first vibrating system 1 that vibrates in the 0 ° mode in the first region of the annular vibrating region on the bottom surface of the feeder body, and the third vibration region. By vibrating the vibrating part 2x of the second vibrating system that vibrates in the 90 ° mode in two regions through the first vibrating device 11 and the second vibrating device 12 using a piezoelectric element, the phase can be changed. A traveling wave generating means BZ for generating a traveling wave for flexing and vibrating the transport portion T1 by synthesizing different standing waves is configured. When the control device C is applied to the bowl feeder Bf, the first and second vibrators 11 and 21 of the traveling wave generating means BZ have the first and second amplifiers 12 shown in FIGS. 1 and 2. The periodic signal amplified by 22 may be input, and the vibrations of the first and second vibration systems 1 (1x) and 2 (2x) may be taken out through the first and second vibration detectors 51 and 52. .. In FIG. 5, other parts of the control device C (see FIGS. 1 and 2) are omitted, and the configuration and control method are the same as those in the above embodiment.

When driving such a parts feeder PF, it is customary to drive the parts feeder PF by assuming that the resonance frequencies of the vibration units 1x and 2x are almost the same. There was a possibility that the resonance frequency at a plurality of vibration points would change by several percent due to the heat generated by the piezoelectric element, the standing wave ratio would decrease, and the transfer efficiency would be significantly impaired. It becomes possible to solve the problem effectively.

On the other hand, as shown in FIG. 6, the linear feeder Lf of FIG. 4 is a vibrating portion of the first vibrating system 1 that is in the first region of the oval vibration region of the bottom surface of the feeder body and vibrates in the 0 ° mode. To vibrate 1x and the vibrating part 2x of the second vibrating system that vibrates in the 90 ° mode in the second region through the first vibrating device 11 and the second vibrating device 12 using a piezoelectric element. Therefore, a traveling wave generating means LZ for generating a traveling wave for flexing and vibrating the conveying portions t1 and t2 by synthesizing standing waves having different phases is configured. When the control device C is applied to the linear feeder Lf, the first and second vibrators 11 and 21 are used for the traveling wave generating means LZ, and the first and second amplifiers 12 shown in FIGS. 1 and 2 are used for the traveling wave generating means LZ. If the periodic signal amplified in 22 and 22 is input and the vibrations of the first and second vibration systems 1 (1x) and 2 (2x) are taken out through the first and second vibration detectors 51 and 52. Good. In FIG. 6, other parts of the control device C (see FIGS. 1 and 2) are omitted, and the configuration and control method are the same as those in the above embodiment.

Then, in the bowl feeder Bf and the linear feeder Lf, if the phase difference of the second vibration system is inverted by ± 90 ° with respect to the first vibration system 1, the transport direction becomes opposite, so such control is performed. This can be a countermeasure in the event of work clogging.

Then, as described with reference to FIG. 3, in the control for convergence to + 90 °, φe is reduced when cosφ12 <0, and φe is increased when cosφ12> 0, and −90 ° In the control of converging to, φe may be increased when cosφ12 <0, and φe may be decreased when cosφ12> 0.

As described above, the vibration system control device C according to the present embodiment has the above two vibration systems 1 and 2 having resonance frequencies different from those of f1 and f2, respectively, in order to drive them through a common drive command. It includes a phase difference detecting unit 5 for detecting the phase difference φ12 of the vibration systems 1 and 2, and a phase adjusting unit 4 for changing the phase of the drive command of the second vibration system 2. Specifically, the phase difference detection unit 5 includes a first vibration detector 51 and a second vibration detector 52, which are vibration detection units that detect vibrations from each of the first and second vibration systems 1 and 2, and both of these vibrations. A multiplier 53a, which is a multiplying unit that multiplies the signals detected by the detectors 51 and 52, and a low-pass filter 53b, which is a filter unit that extracts a DC component corresponding to the phase difference φ12 between the signals before crossing from the crossed signals. The phase adjusting unit 4 is provided with the dividers 53e and 53f, which are the dividers 53e and 53f, which normalize the extracted DC component by dividing it by the vibration amplitudes v1 and v2 of the two vibration systems 1 and 2. The phase shifter 41 adjusts the phase of the drive command to the second vibration system 2 so that the output value representing the actual phase difference matches the value representing the target phase difference set by the phase difference setter 42. It is composed of.

In the case of zero-cross detection, it was difficult to detect the phase difference with high resolution due to the problem of sampling speed. However, in this way, the phase difference detection value can be extracted as a DC signal, so even if the frequency is high. The phase difference can be detected with high accuracy. Moreover, by normalizing the extracted DC signal to obtain the phase difference detection signal S1, the responsiveness of control does not depend on the amplitude, and the phase difference φ12 of the two vibration systems 1 and 2 is in the high frequency region. However, stable and accurate control becomes possible.

In particular, in this embodiment, the values representing the actual phase difference and the target phase difference are the cosine value of the phase difference, that is, cosφ, and the deviation between the actual phase difference and the target phase difference becomes 0 based on the cosine value cosφ. The phase of the drive command is shifted in either the increasing or decreasing direction. Therefore, the target phase difference can be easily set, and the adjustment direction in the phase adjusting unit 4 can be determined by comparison with an extremely simple actual phase difference.

Further, in this embodiment, the signals detected by the first and second vibration systems 1 and 2 are both displacement signals, velocity signals, or acceleration signals, and the phase adjusting unit 4 has a target phase difference. 0 is given as the cosine value or the sine value, and the phase of the drive command is adjusted so that the cosine value or the sine value related to the actual phase difference becomes 0. That is, although the displacement and velocity have different 90 ° phases, and the velocity and acceleration have further different 90 ° phases, the same signals are easy to handle. Moreover, since the cosine value or the sine value of the target phase difference is set to 0, the phase adjustment can be performed only by the DC component that appears.

Specifically, the first and second vibration systems 1 and 2 in this embodiment vibrate with a phase difference of 90 ° to generate a traveling wave and convey the work. Therefore, depending on the traveling direction, whether the direction of phase shift for making the cosine value of the actual phase difference 0 with respect to the cosine value 0 of the target phase difference converges to + 90 ° or −90 °. I try to switch with. That is, the phase of the second standing wave with respect to the first standing wave is + 90 ° when the work transport direction is positive, and −90 ° when it is negative. When the target value is 90 °, cosφ swings to − when it exceeds 90 ° and swings to + when it falls below 90 °. On the other hand, when the target value is -90 °, it swings to + when it exceeds -90 °. If it falls below, it swings to-. Therefore, it is possible to perform control according to the transport direction only by switching the phase shift direction according to the traveling direction.

Then, in the parts feeder PF which is the work transfer device to which this embodiment is applied, two standing waves having different phases are combined with the transfer units T1, t1 and t2 which transfer the work in a mounted state. The traveling wave generating means BZ and LZ for generating the traveling wave for flexing and vibrating the transport units T1, t1 and t2 are provided, and the vibration system is used to generate two standing waves of the traveling wave generating means BZ and LZ. It is configured by applying the control device C of.

Therefore, the phase difference between the two standing waves can be accurately brought close to 90 °, and the device can be operated as a highly efficient transport device having a high traveling wave ratio.

Although one embodiment of the present invention has been described above, the specific configuration of each part is not limited to the above-described embodiment.

For example, in the above-described embodiment, the control amount calculation unit 44 uses PI control, but the present invention is not limited to this, and various control methods such as setting the deviation to 0 can be adopted.

Further, in the above embodiment, the vibration detectors 51 and 52 detect any of the vibration displacements, the vibration speeds, and the vibration accelerations, but one of the first and second vibration detectors vibrates. The displacement may be detected and the other may detect the vibration acceleration. In this case as well, control is performed so that the phase difference between the two detection signals is 90 °. Further, one of the first and second vibration detectors 51 and 52 may detect the vibration displacement and the other may detect the vibration velocity, one may detect the vibration velocity and the other may detect the vibration acceleration. May be good. In this case, control is performed so that the phase difference between the two detection signals is 0 ° (in-phase) or 180 ° (opposite phase). However, since the method of phase difference detection shown in FIG. 2 cannot be used, a configuration similar to this is adopted.

Furthermore, control for keeping the amplitude constant (constant amplitude control) may be performed at the same time by using the signals of the amplitude detectors 53c and 53d used for normalization. As a result, more stable driving becomes possible without providing a new detector.

Further, in the specific example shown in FIG. 2, the value of the phase difference setting device is set to 0, but the phase setting device 42 shown in FIG. 1 may be used to set an arbitrary value. As a result, the phase difference between the signals of the first and second vibration detectors 51 and 52 can be controlled to a value other than ± 90 °. For example, when the detection signal of the vibration detector is delayed, the phase difference can be controlled. It is possible to make adjustments such as correcting the deviation.

Further, in the specific example shown in FIG. 2, the signal after division (the signal proportional to cos φ12) is fed back as it is, but it is converted into the value of the phase difference φ12 itself (radian value, etc.) by calculation or mapping and fed back. May be good. In this way, extra processing of calculation or mapping is required, but the subsequent processing contents are easy to understand and easy.

Further, the above is the application of the present invention for controlling the phase difference between the two vibration systems to a desired value, but as shown in FIG. 7, the present invention is applied for the phase control of one vibration system. You can also do it.
For example, when it is desired to control the vibration system to be controlled to a predetermined phase difference with respect to the vibration signal extracted from a vibration system which is not the control target, or to a reference signal which is not caused by the vibration system given as a periodic signal from the outside. On the other hand, an application example is when the vibration system to be controlled is to be controlled to a predetermined phase difference.

Then, as a specific configuration for that purpose, in the vibration system control device shown in FIG. 7, when the vibration signal taken out from the above-mentioned vibration system or the reference signal given as a periodic signal from the outside is used as a "reference signal". , A phase difference detection unit that detects the phase difference between the reference signal acquired by the reference signal input unit 103 as a periodic signal from the outside and the actual vibration phase of the vibration system 101 in order to drive the vibration system 101 through a drive command. The 105 is provided with a phase adjusting unit 104 that changes the phase of the drive command with respect to the reference signal, and the phase difference detecting unit 105 is a vibration detecting unit 151 that detects vibration from the vibration system 101. A phase difference detector 153 that detects a phase difference from the signal related to the reference command and the signal detected by the vibration detection unit 105 of the vibration system 101 is provided. The phase difference detector 153 includes a multiplier 153a, which is a multiplication unit that multiplies the signal related to the reference command and a signal detected by the vibration detection unit 105 of the vibration system 101, and the signal before multiplication from the multiplied signal. The low-pass filter 153b, which is a filter unit for extracting the DC component corresponding to the phase difference of the above, and the dividing unit 153e, which divides the extracted DC component by the vibration amplitude of the vibration system 101, are provided, and the phase adjusting unit 104 is the dividing unit. The phase of the drive command is adjusted so that the value representing the actual phase difference output from the 153e matches the preset value representing the target phase difference.

In FIG. 7, the phase shifter 141 corresponds to the phase shifter 41 of the embodiment, the amplifier 112 corresponds to the first amplifier 12 of the embodiment, and the exciter 111 corresponds to the exciter 11 of the embodiment. Equivalent to. Further, the amplitude detector 153d corresponds to the amplitude detector 53d of the embodiment, the phase difference setting device 142 corresponds to the phase difference setting device 42 of the embodiment, and the differential device 143 corresponds to the differential device 43 of the embodiment. The PI control unit 144, which is a control amount calculation unit, corresponds to the PI control unit 44 of the embodiment.

In this way, the phase of one vibration system is controlled to the target phase based on a reference signal such as a vibration signal of a vibration system that is not another control target or a periodic signal that is not caused by the control system. However, by applying according to the above, appropriate phase difference control can be realized even in a high frequency region.

Other configurations can be modified in various ways without departing from the spirit of the present invention.

1 ... 1st vibration system 2 ... 2nd vibration system 4 ... Phase adjustment unit 5 ... Phase difference detection unit 41 ... Phase shifter 42 ... Phase difference setting device 43 ... Difference device 51, 52 ... Vibration detection unit 53 ... Phase difference detection Instrument 53a ... Multiplying unit (multiplier)
53b ... Filter unit (low-pass filter)
53e, 53f ... Divider (divider)
101 ... Vibration system 104 ... Phase adjustment unit 105 ... Phase difference detection unit 151 ... Vibration detection unit 153 ... Phase difference detector 153a ... Multiplier unit (multiplier)
153b ... Filter unit (low-pass filter)
153e ... Divider (divider)
BZ, LZ ... Traveling wave generating means C ... Vibration system control device f1, f2 ... Resonance frequency PF ... Work transfer device (parts feeder)
T1, t1, t2 ... Transport section

Claims (5)

In order to drive two vibration systems having different resonance frequencies through a common drive command, the phase difference detection unit that detects the phase difference between the two vibration systems and the phase of one of the drive commands of the vibration system are changed. It is provided with a phase adjusting unit and has a phase adjusting unit.
The phase difference detection unit includes a vibration detection unit that detects vibration from each of the two vibration systems, a multiplication unit that multiplies the signals detected by the vibration detection unit, and a signal before multiplication from the multiplied signal. The phase adjustment unit includes a filter unit that extracts a DC component according to the phase difference between the two, and a division unit that divides the extracted DC component by the vibration amplitudes of the two vibration systems to normalize the frequency adjustment unit. A vibration system control device, characterized in that the phase of one of the drive commands is adjusted so that a value representing the actual phase difference output from is matched with a preset value representing the target phase difference. The values representing the real phase difference and the target phase difference are cosine values or sine values of the phase difference, and the deviation between the real phase difference and the target phase difference becomes 0 based on the cosine value or the sine value. The vibration system control device according to claim 1, wherein the phase of the drive command is shifted in any direction of increase or decrease. The signals detected by the two vibration systems are both displacement signals, velocity signals, or acceleration signals, and the phase adjusting unit gives 0 as the cosine value or sine value of the target phase difference, and the actual position is set. The vibration system control device according to claim 1 or 2, wherein the phase of the drive command is adjusted so that the cosine value or the sine value related to the phase difference becomes 0. The vibrations of the two vibration systems are two standing wave vibrations for generating a traveling wave by vibrating with a phase difference of 90 ° to convey the work, and the target phase difference is increased according to the traveling direction. The vibration system control device according to claim 3, wherein the direction of phase shift for making the cosine value of the actual phase difference 0 with respect to the cosine value 0 is switched depending on whether the cosine value is converged to + 90 ° or −90 °. .. A traveling wave generating means for generating a traveling wave for flexing and vibrating the transporting portion by synthesizing two standing waves having different phases is provided. A work transfer device, wherein the vibration system control device according to any one of claims 1 to 4 is applied to generate two standing waves of the traveling wave generating means.

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