JP3711681B2 - Automatic piano - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic piano suitable for reproducing performance information performed using a loud petal.
[0002]
[Prior art]
In an automatic piano, when a performer presses a key, an action mechanism is activated in conjunction with this, and the damper is released from the string and the hammer is rotated to strike a string. When the key is released, the damper touches the string and the sound is muted. As described above, a musical tone is usually generated by a series of operations of key pressing → stringing → key release → mute. For this reason, performance information is generated and recorded based on each of the above operations during recording, and the key operation is controlled based on the read performance information during reproduction. In the key control in this case, the solenoid is excited and the key is driven based on the performance information, and the hammer rotates in response to the string.
[0003]
Some automatic pianos include a loud pedal. The loud pedal is linked to a damper via a piano mechanism, and when the performer depresses the loud pedal, the damper is separated from the strings all at once. Thereby, even after the key is completely released, the sound can be reverberated without being muted. Also, the way the sound resonates differs depending on whether the timing of depressing the loud pedal is before or after the sound generation or at the same time. Therefore, the performer often uses the loud pedal to express the interpretation of the work. For this reason, some automatic pianos attempt to reproduce the actual performance by recording information related to the loud pedal as well as information related to the operation of the key as performance information and playing it back.
[0004]
In an automatic piano reproduction system, position data indicating the key position is calculated for each unit time based on performance information, and the key position is controlled using this position data as a target value. As a key control method, a feedback control method is often performed in which the key position is detected by a sensor, the key position is compared with a target value, and control is performed so that both match.
[0005]
By the way, since the key is interlocked with the action mechanism, the action mechanism acts as a load on the key. Further, since the loud pedal is interlocked with a damper that is a part of the action mechanism, the load on the key varies depending on the degree of depression of the loud pedal. Therefore, when the key is controlled during reproduction, the load fluctuation caused by the loud pedal acts as a disturbance. In this case, in the feedback control, the influence of disturbance can be reduced by increasing the servo gain. However, increasing the servo gain has the disadvantage that the phase margin decreases and the servo system becomes unstable. Therefore, the servo gain is determined based on a balance between disturbance suppression and servo system stability. For this reason, the servo gain cannot be sufficiently increased so that the key position does not fluctuate due to fluctuations in the load of the loud pedal.
[0006]
In order to improve this point, the conventional automatic piano refers to the drive data table when generating drive data for driving the solenoid. Two types of drive data tables corresponding to the state in which the loud pedal is depressed and the original state are prepared. When a drive command value is input, the table is selected according to the state of the loud pedal, and corrected drive data is output. It has come to be.
[0007]
[Problems to be solved by the invention]
By the way, the state of the loud pedal in the actual performance includes not only the stepped-on state and the original state but also an intermediate state, and the load applied to the key varies depending on the degree of the stepping. Accordingly, there is a problem that the key operation cannot be accurately reproduced by canceling the load in the intermediate state only by providing two types of drive data tables.
[0008]
In this case, if the drive data table is increased to cope with the intermediate state, the memory capacity increases. For example, if the depression state of the loud pedal is represented by 7 bits, 128 drive data tables are required. On the other hand, if the intermediate state is calculated by interpolation processing in order to reduce the memory capacity, a special calculation means is required for the interpolation processing, and an error occurs and the key cannot be driven accurately. There is.
[0009]
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to accurately reproduce a key operation by canceling a load variation caused by a loud pedal while reducing a memory capacity.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problem, in the invention according to claim 1, the state of the key is indicated in an automatic piano that performs automatic performance based on performance information that indicates the state of the key and the state of the loud pedal. Data generating means for generating position data of the key based on performance information, servo driving the key so that the position of the key is a position indicated by the position data, and using the servo system characteristics as drive parameters Based on the detection result of the state detecting means, the state detecting means for detecting the state of the loud pedal, the storage means for storing the correction data for correcting the driving parameter in association with the state of the loud pedal, and the detection result of the state detecting means And correction means for reading the correction data from the storage means and correcting the drive parameter based on the correction data. And butterflies.
[0011]
According to the invention of claim 2, in an automatic piano that performs automatic performance based on performance information that indicates the state of the key and the state of the loud pedal, on the basis of the performance information that indicates the state of the key. Data generating means for generating position data of the key, and driving means for servo-driving the key so that the position of the key becomes a position indicated by the position data, and setting characteristics of the servo system using drive parameters; Storage means for storing the correction data for correcting the drive parameter in association with the state of the loud pedal, and reading the correction data from the storage means based on performance information indicating the state of the loud pedal, and based on the correction data Correction means for correcting the drive parameter.
[0012]
According to a third aspect of the present invention, the state detection means detects the position of the loud pedal, and the storage means stores the correction data in association with the position of the loud pedal. To do.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
1. Overall Configuration of Embodiment Hereinafter, the configuration of the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an automatic piano according to an embodiment of the present invention.
In FIG. 1, 1 is a key, and 3 is a hammer action mechanism that transmits the movement of the key 1 to the hammer 2. 4 is a string that is struck by the hammer 2, 28 is a key solenoid that drives the key 1, and the position of the plunger is detected by a key solenoid position sensor 29 that is formed integrally therewith. Yes. In this case, when the plunger of the key solenoid 28 protrudes, the key 1 rotates about the balance pin P and falls to the performer side (hereinafter, this state is referred to as a key-pressed state). The action mechanism 3 operates, the damper 6 moves away from the string 4, and the hammer 2 rotates to strike the string. On the other hand, when the performer plays, pressing the key 1 with a finger causes the same operation as described above to be performed. Reference numeral 100 denotes a damper mechanism that transmits the movement of the loud pedal 101 to the damper 6. In this case, when the performer depresses the loud pedal 101, the damper 6 is pushed upward, and the damper 6 moves away from the string 4. On the other hand, when the performer removes his / her foot from the loud pedal 101 and returns to the original state from the state where the loud pedal 101 is depressed, the damper 6 contacts the string 4 as shown in the figure.
[0014]
In the figure, SE1 and SE2 are sensors for measuring the string striking speed, and the performance recording unit 30 measures the time for which the hammer 2 passes between these sensors SE1 and SE2, thereby providing a hammer. 2, i.e., the stringing speed (sounding speed) is measured, and the time when the hammer 2 passes the sensor SE <b> 1 is detected as the stringing time (sounding time).
[0015]
Next, 7 is a plate-like shutter attached to the lower surface of the key 1. Reference numeral 8 denotes a key sensor constituted by two sets of photosensors SF2 and SF3 provided at a predetermined distance in the vertical direction. When the key 1 starts to be depressed, the upper photosensor SF2 is first shielded from light, and then the lower side. The photosensor SF3 is shielded from light. When the key is released, the lower photo sensor SF3 is in a light receiving state, and then the upper photo sensor SF2 is in a light receiving state.
[0016]
The output signal of the key sensor 8 is supplied to the performance recording unit 30. At the time of key depression, the performance recording unit 30 measures the time from when the upper photo sensor SF2 is in the light shielding state to when the lower photo sensor SF3 is in the light shielding state, and detects the key depression speed therefrom. . Further, the performance recording unit 30 detects the time when the lower photo sensor SF2 is in the light-shielded state as the key pressing time.
[0017]
On the other hand, when the key is released, the performance recording unit 30 measures the time from when the lower photo sensor SF3 is in the light receiving state until the upper photo sensor SF2 is in the light receiving state, and from this, the key release speed is determined. To detect. The performance recording unit 30 detects the time when the upper photo sensor SF2 is in the light receiving state as the key release time.
[0018]
Next, 23 is a loud pedal solenoid that drives the loud pedal 101 during reproduction. Reference numeral 24 denotes a loud pedal position sensor which detects the position of the loud pedal 101. The output signal of the loud pedal position sensor 24 is supplied to the performance recording unit 30.
[0019]
The post-recording processing unit 31 normalizes the various types of information supplied from the performance recording unit 30, converts the information into a predetermined data format, and supplies the information to an external recording medium as performance information. Here, the normalization process is a process for absorbing individual differences between pianos. In other words, the position of the loud pedal, stringing time / stringing speed, key pressing time / key pressing speed, key releasing time / key releasing speed, etc. are specific to the position of the sensor in each piano, structural differences, or mechanical errors. Therefore, the standard piano is assumed to be converted into a string hitting time, string hitting speed, and the like.
[0020]
Reference numeral 20 denotes a reproduction system, which is key position data KD (t, X) and loud pedal 101 position data RD every unit time t based on performance data ED supplied from a recording medium or an external real-time communication device. (T, X) is created, and the key 1 and the loud pedal 101 are driven based on these.
[0021]
2. FIG. 2 is a block diagram of a playback system for an automatic piano according to this embodiment. FIG. 2 also shows the peripheral circuit in addition to the reproducing system 20.
In the figure, 21 is a control unit that creates key trajectory data based on the performance data ED, and creates key position data KD (t, X) from the key trajectory data. Further, the control unit 21 creates the position data RD (t, X) of the loud pedal 101 based on the performance data ED.
[0022]
Reference numeral 22 denotes a loud pedal drive unit that generates a drive current for driving the loud pedal solenoid 23 based on the position data RD (t, X) of the loud pedal 101. When the drive current is supplied to the loud pedal solenoid 23, the solenoid coil is excited and the loud pedal 101 is driven. The position of the loud pedal 101 is detected by the loud pedal position sensor 24. This detection signal is supplied to the loud pedal drive unit 22 as a feedback signal. The loud pedal drive unit 22 compares the position data RD and the feedback signal, and drives the loud pedal solenoid 23 so that they match.
[0023]
Reference numeral 25 denotes a drive parameter correction unit, which includes a correction table that stores correction data HD in association with a loud pedal position. Based on the output signal of the loud pedal position sensor 24, the drive parameter correction unit 25 predicts a change in the damper load applied to the key 1 and generates correction data HD for canceling the fluctuation. A drive parameter that is a parameter for controlling the key 1 is corrected by the correction data HD.
[0024]
The drive parameters include key position data KD as a target value, servo gain, or fixed force data that gives an offset. In this example, key position data KD (target value) is the target of correction. . The value of the correction data HD is a value measured by experiments so that, when added to the target value, fluctuations in the damper load are canceled and an accurate stringing result is obtained.
[0025]
In this case, although the correction table is constituted by a memory, correction data HD is stored in association with the position of the loud pedal 101. For this reason, the correction data HD can be stored not only in the state in which the loud pedal 101 is depressed or in the original state, but also in an intermediate state between them. The correction data HD is data for correcting the drive parameter and does not indicate the drive command value itself. Therefore, according to this example, it is not necessary to prepare a drive data table according to the position of the loud pedal 101, so that the memory capacity can be greatly reduced.
[0026]
Next, reference numeral 26 denotes a drive parameter changing unit that changes the drive parameter based on the correction data HD. Specifically, the corrected position data KD ′ is generated by adding the correction data HD to the position data KD. The corrected position data KD ′ takes into account the load variation of the damper.
[0027]
Next, 27 is a key drive unit, which generates a drive current based on the corrected position data KD ′. When the key solenoid 28 is driven by this drive current, the key position is detected by the key solenoid position sensor 29, and this is fed back to the key drive unit 27 as a feedback signal.
[0028]
3. Next, the key driving unit 27 will be described. FIG. 3 is a circuit diagram of the key driving unit 27. In the figure, the subtracter 271 is supplied with the corrected position data KD ′ from the drive parameter changing unit 26 as a target value to the positive input terminal, and is also supplied with the actually measured position data JD of the key 1 from the key solenoid position sensor 29. Is done. The adder 271 generates error data by subtracting the measured position data JD from the corrected position data KD ′.
[0029]
Thereafter, when error data is supplied to the amplifier 272, the amplifier 272 amplifies and outputs the error data. The servo gain is determined by this amplification degree. In this example, feedback control is performed using the corrected position data KD ′ taking into account the load variation of the damper as a target value, so that it is not necessary to set the servo gain too high, and the servo system can be stabilized.
[0030]
When the output data of the amplifier 272 is supplied to one input terminal of the adder 273, the adder 273 adds the fixed force data supplied to the other input terminal and the output data to generate drive data. To do. The drive data is converted into a drive current via a drive current generation circuit (not shown), and the key solenoid 28 is driven by this drive current.
[0031]
4). Summary According to the above-described embodiment, the correction data HD corresponding to the position of the loud pedal 101 is stored in the correction table provided in the drive parameter correction unit 25 in advance, and the position of the loud pedal 101 detected by the loud pedal position sensor 24 is stored. The correction data HD is generated based on this, and the target value as the drive parameter is corrected using this. For this reason, the load fluctuation of the damper applied to the key 1 can be predicted according to the degree to which the loud pedal 101 is depressed, and this can be canceled, so that the operation of the key 1 can be accurately reproduced. As a result, even when the performer uses the loud pedal 101 to express the subtle nuances of the music, it can reproduce the actual performance.
[0032]
Further, according to the above-described embodiment, the correction data table only needs to store the correction data HD for correcting the drive parameter in association with the state of the loud pedal 101, so that the memory capacity is greatly reduced. be able to.
[0033]
Further, since the loud pedal position sensor 25 for detecting the state of the loud pedal 101 is also used as a sensor for feedback control of the loud pedal 101, it is not necessary to provide a special sensor for generating the correction data HD.
[0034]
5. Although the embodiments according to the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications described below are possible.
(1) In the above-described embodiment, the position of the loud pedal 101 is measured by the loud pedal position sensor 24. However, the loud pedal 101 at the time of reproduction is controlled based on the position information of the loud pedal 101 included in the performance data ED. Therefore, the drive parameter correction unit 25 may generate correction data HD based on the position information. Further, the drive parameter correction unit 25 may generate the correction data HD based on the position data RD of the loud pedal 101 generated by the control unit 21.
[0035]
(2) In the above-described embodiment, the correction data HD is generated so as to cancel the load fluctuation of the damper 6 based on the position of the loud pedal 101. However, the present invention is not limited to this, and the loud pedal 101 is not limited thereto. The drive parameter may be changed based on the state. For example, the correction data HD may be generated based on the speed or acceleration of the loud pedal 101. Further, the correction data HD may be generated based on a combination of the position, speed or acceleration of the loud pedal 101 as appropriate. In this case, a speed sensor and an acceleration sensor may be provided as means for detecting the speed and acceleration. However, the position data output from the loud pedal position sensor 24 is differentiated to obtain speed data, and the speed data is further differentiated. Thus, acceleration data may be obtained.
[0036]
Incidentally, the key drive unit 27 drives the key 1 based on error data that is the difference between the corrected position data KD ′ and the measured position data JD, and the drive mechanism is mechanically configured. For this reason, there is a time delay from when the drive parameter is changed to when the key 1 is actually driven. However, due to this time delay, the trajectory of the key 1 may not be accurately reproduced.
[0037]
For example, if the loud pedal 101 is suddenly returned to the original state, the damper 6 contacts the string 4 in a short time, and the load applied to the key 1 fluctuates rapidly. Here, it is assumed that the time delay of the key drive is Δt, and the damper 6 is connected at time T. In this case, when the correction data HD is generated based only on the position data of the loud pedal 101, the correction data HD is generated reflecting the fact that the loud pedal 101 returns to the original state at time T and the damper 6 is connected at this time. Is done. However, the key 1 is actually driven based on the correction data HD generated at time T at time T + Δt. For this reason, when the control is performed based only on the position data, it may not be possible to follow the load fluctuation.
[0038]
On the other hand, when the correction data HD is generated based on the position data and the speed data, the position data after Δt time is predicted from the position data and the speed data, and the correction data HD is generated based on the predicted position data. Can do. If the position data value is P, the velocity data value is V, and the predicted position data value is P ′, then P ′ can be calculated by the following equation.
P ′ = P + V · Δt
Furthermore, if the acceleration data value is A, P ′ can be calculated by the following equation.
P ′ = P + V · Δt + 1/2 · A · Δt ²
Thus, by using velocity data and acceleration data in addition to position data, it is possible to more accurately cancel load fluctuations and accurately reproduce key operations.
[0039]
(3) In the above-described embodiment, the correction data HD is actually measured by experiment. However, the present invention is not limited to this, and may be correction data HD obtained by self-learning. . In this case, the correction data HD may be updated at the time of factory shipment or maintenance, or may be updated at the time of performance. The correction data HD to be updated may be generated by the drive parameter correction unit 25 so that the error data output from the adder 271 of the key drive unit 27 is reduced.
Further, the correction data HD is obtained by measuring the difference in the stringing result by the same drive instruction value between the state where the loud pedal 101 is depressed (when the damper is loaded) and the state where the loud pedal 101 is in the original state (when the damper is not loaded). From the above, the correction data HD may be generated. Further, the difference in the string striking result may be measured not in the two states but also in the intermediate state, and the correction data HD may be generated based on these. Further, it may be an interpolated value on a characteristic curve obtained by experiment.
[0040]
(4) In the above-described embodiment, the drive parameter to be corrected has been described by taking the target value as an example. However, the present invention is not limited to this and may be a servo gain or a fixed force. In short, any parameter may be used as long as it is used in the servo system for driving the key. For example, when the servo gain is to be corrected, the gain of the amplifier 272 shown in FIG. 3 may be adjusted based on the correction data HD. When the fixing force is to be corrected, the fixing force data shown in FIG. 3 may be adjusted based on the correction data HD. Further, a target value, a servo gain, or a combination of a fixing force may be appropriately corrected. In the above-described embodiment, the driving of the key 1 is performed based on the position of the key 1 detected by the key solenoid position sensor 29. However, instead of the key solenoid position sensor 29, the key 1 is used. , And the key 1 may be driven based on the detected speed.
[0041]
【The invention's effect】
As described above, according to the invention specific matter according to the present invention, it is possible to predict the load fluctuation applied to the key in accordance with the state of the loud pedal and cancel it, so that the operation of the key can be accurately reproduced. . In addition, since the drive parameter is an object to be corrected, the storage capacity of the storage unit can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram of an automatic piano according to an embodiment of the present invention.
FIG. 2 is a block diagram of a playback system of the automatic piano according to the embodiment.
FIG. 3 is a circuit diagram of a key drive unit of the automatic piano according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Key, ED ... Performance information, 21 ... Control part (data production | generation means), 24 ... Loud pedal position sensor (state detection means), 25 ... Drive parameter correction | amendment part (memory | storage means, correction | amendment means), 26 ... Drive parameter change part (Correction means), 27... Key drive unit (drive means), 101...

Claims (3)

In an automatic piano that performs automatically based on performance information that indicates the state of the keys and the state of the loud pedal,
Data generating means for generating position data of the key based on performance information indicating the state of the key;
Drive means for servo-driving the key such that the position of the key is a position indicated by the position data, and setting the characteristics of the servo system using drive parameters;
State detecting means for detecting the state of the loud pedal;
Storage means for storing correction data for correcting the drive parameter in association with the state of the loud pedal;
An automatic piano comprising: correction means for reading the correction data from the storage means based on the detection result of the state detection means and correcting the drive parameter based on the correction data. In an automatic piano that performs automatically based on performance information that indicates the state of the keys and the state of the loud pedal,
Data generating means for generating position data of the key based on performance information indicating the state of the key;
Drive means for servo-driving the key such that the position of the key is a position indicated by the position data, and setting the characteristics of the servo system using drive parameters;
Storage means for storing correction data for correcting the drive parameter in association with the state of the loud pedal;
An automatic piano comprising: correction means for reading the correction data from the storage means based on performance information indicating the state of the loud pedal, and correcting the drive parameter based on the correction data. The automatic piano according to claim 1, wherein the state detection unit detects a position of the loud pedal, and the storage unit stores the correction data in association with the position of the loud pedal.

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