JP2646840B2 - Keyboard instrument performance detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a playing state of a keyboard instrument, for example, a reflection type light for outputting a signal having an extreme value with respect to a change in a distance from an object to be measured. Using a sensor, the reflection type optical sensor is disposed at a position where the extreme value is output before striking the hammer, and from the time when the first output value is output to the time when the second output value is output after the extreme value is output. By calculating the stringing speed based on the elapsed time, it is possible to easily mount and adjust the sensor, and to accurately detect the actual stringing speed by a hammer in an automatic piano.

<Prior Art> In an automatic piano, the performance can be recorded and reproduced automatically. Specifically, the recording of this performance is to detect and record the pressed key and the string striking speed by the hammer corresponding to the key by the sensor. By detecting the string striking speed, the timbre and volume are determined.

As an apparatus for detecting the stringing speed of a conventional automatic piano, for example, an apparatus having a configuration as shown in FIG. 7 has been known.

In this detection device, as shown in FIG. 7, a hammer 72 for striking a string 71 is provided with a hammer shutter 74 made of a plate material at an intermediate portion of the hammer shank 73.

The transmitted light type optical sensors 75A and 75B are disposed on both sides of a plane including the rotation locus of the hammer shutter 74 by opposing the light emitter and the light receiver, respectively. These optical sensors 75A and 75B are arranged close to each other. For example, these two optical sensors 75A and 75B are fixed to the fixing member 76 at predetermined intervals along the rotation locus of the hammer shutter 74.

That is, in the stringing operation of the hammer 72, the rotating hammer shutter 74 can block the respective optical paths of the optical sensors 75A and 75B.

Therefore, the hammer shutter 74 rotates at a predetermined speed in accordance with the stringing operation of the hammer 72, and sequentially blocks the optical paths of the two transmitted light type optical sensors 75A and 75B. In this apparatus, the time difference between the interruption light times of the optical sensors 75A and 75B is measured, and based on the time difference, the stringing speed of the hammer 71 is calculated and recorded.

Therefore, in order to accurately detect the actual stringing speed by the hammer 72, not the rotational speed of the hammer shank 73 during the stringing process, these optical sensors 75A and 75B are used to detect the actual stringing by the hammer 72. It had to be mounted as close as possible to the location.

In order to improve the detection accuracy, each optical sensor 75
In A and 75B, it is necessary to accurately perform the positioning between the light emitter and the light receiver, the mechanical positioning between each optical sensor 75A, 75B and the hammer shutter 74, and the setting of the interval between each optical sensor 75A, 75B. there were.

<Problems to be Solved by the Invention> However, in such a conventional stringing speed detecting apparatus for an automatic piano, all of the paired optical sensors 75A and 75B corresponding to 88 keys have these intervals. It was difficult to attach a fixed distance. If there is a variation in the installation interval, an accurate striking speed cannot be obtained even if the time difference is measured.

Also, with respect to the correction of the distance between the sensors and the correction of the sensor mounting position due to individual differences of the hammers, it is difficult to perform operations such as fixing the hammer shutter to the hammer shank and positioning the hammer shutter with respect to the sensor. For example, in order to attach a hammer shutter to a hammer shank, high-precision processing is required for the hammer shank, which has led to an increase in the number of assembling and adjusting steps.

Further, in such a conventional detection device, it is impossible to dispose an optical sensor close to the striking point. This is because a mounting space for adjusting the optical sensor for the individual difference correction or the like cannot be secured. As a result, the conventional device merely detects, for example, the average rotation speed of the hammer, and cannot detect the actual stringing speed with high accuracy. This is because the actual striking point differs depending on the striking mechanism of each string, but the conventional sensor cannot be mounted close to the striking point as described above.

In other words, despite the fact that the sensors are required to be positioned with high accuracy, the stringing speed detected by each sensor may be of low accuracy due to individual differences between the sensors and the like. There was room for it.

In other words, when striking with a hammer, microscopically, it is difficult to mechanically specify the exact striking position by striking the string into the hammer felt by striking or bending the string by striking force. Because it is extremely difficult.

Therefore, in order to eliminate these drawbacks, a sensor capable of following the rotation of a stringing mechanism such as a hammer, that is, a sensor that obtains an output corresponding to a change in distance from a stringing mechanism component (for example, a reflection type Optical sensor).

In this case, the optical sensor is configured to output a signal whose output value changes in response to a change in the distance from the string striking mechanism component. Then, based on the sensor output, a first output value and a second output value are obtained for two measurement points having different distances between the constituent member and the measurement point, and a rotation time therebetween is measured. The hammering speed of the hammer is obtained based on the distance between these two measurement points and the measurement time.

However, in this optical sensor, it is conceivable that the output characteristics of each optical sensor with respect to a change in distance vary.
This is because the output characteristics of the optical sensors are different, the reflectivity of the light reflecting surfaces of the constituent members is different, and there are individual differences in the mounting positions of the optical sensors.

Therefore, it is necessary to correct the variation in the string hit speed detection by each optical sensor.

Therefore, an object of the present invention is to eliminate the work of attaching the hammer shutter to the hammer shank, and to perform complicated work such as adjustment work for correcting individual differences of the hammer, etc. An object of the present invention is to provide an apparatus for detecting a playing state of a musical instrument.

Another object of the present invention is to provide a performance detecting device for a keyboard instrument, which is capable of detecting a speed immediately before striking a string and has improved accuracy in detecting a striking speed.

Further, another object of the present invention is to normalize the output of each sensor (each of which has a different peak value),
For example, by performing detection at a fixed ratio of the output value to the peak output of the sensor, all sensors can measure in a fixed measurement section (fixed distance), and the detection output value (measurement time → stroke) due to individual differences An object of the present invention is to provide an apparatus for detecting a playing state of a keyboard instrument, which eliminates variations in string speed.

Further, according to the present invention, a performance state detecting device capable of setting a measurement section immediately before an actual striking point very close to a string, and capable of measuring a striking speed substantially matching the actual striking speed. Its purpose is to provide.

<Means for Solving the Problems> The present invention is provided so as to be close to and opposed to a component of a string striking mechanism of a keyboard musical instrument which is rotated by a key depression operation, and to change a distance between the component and the component. And detecting means for outputting a signal that changes with an extreme value, and detecting the extreme value in an output signal from the detecting means,
Output value calculating means for calculating a first output value and a second output value output after the detection of the extreme value based on the extreme value;
A time measuring means for measuring a time during which the output from the detecting means changes from the first output value to the second output value; and a striking mechanism by the string striking mechanism based on the measured time and the distance between the two measuring points. A playing state detecting device for a keyboard instrument, comprising: a striking speed calculating means for calculating a string speed.

<Operation> The present invention calculates the distance between two measurement points based on the first output value and the second output value of the output signal from the detection means. Then, the time at which the stringing mechanism component passes through these two measurement points is detected, and the stringing speed is calculated from the measured values of the distance and the time. In this case, the first output value and the second output value, which are the outputs from the detecting means, are normalized by their extreme values. As a result, there is no variation in the calculation result of the detection device for each string.
All the calculated stringing speeds are accurate.

For example, the string striking mechanism is turned and struck by a key press,
The output of the detecting means changes in accordance with the rotation of the string striking mechanism. The peak value (extreme value) of the output is detected, and the output value calculation means calculates the first output value and the second output value based on the peak value. The first output value and the second output value define two measurement points.

Then, when the string striking mechanism is rotated again by depressing a key, the elapsed time is measured by the time measuring means based on the first output value and the second output value. For example, after the peak value has passed, the first
When an output value is detected, a timer is started, and when the second output value is detected, the timer is stopped. String striking speed calculating means calculates a string striking speed based on the elapsed time and the distance between the two measurement points.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block circuit diagram showing an apparatus for detecting a playing state of an automatic piano (string striking speed detecting apparatus) according to a first embodiment of the present invention.

FIG. 2 is a side view showing a string striking mechanism of the automatic piano according to the first embodiment.

First, as shown in FIG. 1, the keying speed detecting device has a reflection type optical sensor 11. The optical sensor 11 irradiates a member (described later) constituting the string striking mechanism with light, and outputs a current Ic that changes depending on the intensity of the reflected light.

The optical sensor 11 is set such that the output current Ic has a peak value IcMax during the string striking process by the string striking mechanism. For example, the distance from the stringing mechanism component and the focal length of the optical sensor 11 are set to appropriate values.

The output of the optical sensor 11 is a peak value IcMa of the output current Ic.
It is input to an IcMax detection and holding circuit 12 that detects and holds x.

The peak value IcMax, which is the output of the detection and holding circuit 12, is
The arithmetic processing is performed in the arithmetic circuit 13 and the first output value of 0.
9IcMax and 0.8IcMax, which is the second output value, are calculated. Two measurement points will be set.

The first output value (0.9IcMax) is output to the holding circuit 14, and the second output value (0.8IcMax) is output to the holding circuit 15 and held.

The output from the optical sensor 11 (which changes over time) is input to comparison circuits 18 and 19, respectively. These comparison circuits 18 and 19 respectively output the first output value (0.
9IcMax) and the second output value (0.8IcMax) are compared with the output Ic from the optical sensor 11.

The determination circuit 20 determines the result of the comparison by the comparison circuit 18 and starts the timer 21 when the output Ic of the optical sensor 11 exceeds the peak value (IcMax) and becomes lower than the first output value (0.9IcMax). Outputs trigger signal.

Further, the judgment circuit 22 changes the output Ic of the optical sensor 11,
As a result of the comparison by the comparison circuit 19, when the output Ic becomes smaller than the second output value 0.8IcMax after the peak value is output, a stop signal for stopping the timer 21 is output.

The timer 21 measures the time from the start to the stop based on the number of pulses, and outputs a timer signal Δt indicating the elapsed time between the two measurement points (rotation time of the string striking mechanism).

Then, the timer signal Δt is converted by the MIDI velocity table 23 to obtain the string striking strength V by the string striking mechanism.

Here, as shown in FIG. 2, an action (string striking mechanism) 25 for striking a string 24 stretched in the vertical direction is provided for each of the 88 keys.

 The action 25 includes the following members.

That is, a hammer 26 that strikes the string 24, a hammer shank 27 connected to the hammer 26, a bat 28 fixed to the base end of the hammer shank 27, and a hammer shank 27 and a bat 28 And a butt flange 29 that swingably supports the hammer shank 27, a hammer rail 30 that defines the distance of the hammer shank 27 from the string 24, and the like.

The damper 31 is disposed between the string 24 and the action 25 and close to the string 24. Although the damper 31 is linked to the action 25, the vibration of the string 24 can be maintained by depressing the damper pedal to separate from the string 24.

Here, reference numeral 32 denotes a center rail, which fixes and supports the butt flange 29 and the like.

A horizontal bracket is provided at the upper end of this center rail 32.
33 extends in a direction away from the string 24. A rear end 33A of the bracket 33 separated from the string 24 is bent upward, and a board 34 holding the above circuits 12 to 23 is horizontally fixed to the upper end of the bent side 33A. I have.

On this substrate 34, a reflection type optical sensor 35 (11) is provided.
The reflection type optical sensor 35 includes a light projection unit 35A capable of irradiating light downward, a light receiving unit 35B capable of receiving the reflected light,
Are integrated.

The optical sensor 35 is disposed so as to be able to face a catcher 36 projecting rearward of the bat 28.
That is, at the time of striking by the hammer 26, the front end 36A of the catcher 36 rotates from the position shown by the broken line to the position shown by the solid line in FIG.
With a predetermined interval. The catcher 36 is one of the components of the stringing mechanism 25.
35 will be provided.

In the drawing, 37 is a jack, and 38 is a wippen.

The light sensor 35 irradiates light downward from a light projecting unit 35A having a light emitting element (eg, an LED), a light emitting lens, and the like, and reflects the light reflected by the reflecting surface on a light receiving element (photodiode), Light is received by a light receiving unit 35B including a light receiving lens and the like. The output current Ic of the optical sensor 35 changes according to the amount (intensity) of the reflected light received by the light receiving unit 35B.

In the stringing stroke by the action 25, the catcher 36 rotates integrally with the bat 28, the hammer 26, and the like, and the distance d between the opening 36A of the catcher 36 and the optical sensor 35 changes. The amount of light received by the light receiving unit 35B of the optical sensor 35 changes in accordance with the change in the distance.

Here, the output Ic of the optical sensor 35 with respect to the change of the distance d changes as shown in FIG.

As shown in this graph, the output is smaller as the tip 36A of the catcher 36 is farther from the optical sensor 35 at the position (d ₁ ), and the tip 36A is transmitted to the optical sensor 35 from this far position. Its power increases as it approaches (d ₁
→ d ₀ ). Then, take the butt end surface 36A is at the predetermined distance d _0, the output of the optical sensor 35 is a peak value (extremal) Icmax. Further, when the tip surface 36A approaches (d ₀ → d ₃ → d ₄ → d ₂ ), the output thereof becomes smaller than the peak value IcMax. The fixed distance d ₀ is the light emitting portion 35A, the light emission lens of the light receiving portion 35B, and is set by such directional characteristics of the light-receiving lens. In particular, since data after peak value detection is used in sensor output, it is preferable to use an optical sensor 35 having a considerably long focal length. Using an optical sensor with a long focal length increases the reliability of the output data.

Therefore, the optical sensor 35 is positioned at a distance (d _{1 to} d ₁₎ to the front end 36A of the catcher 36 such that the output Ic is within a certain range that changes with the peak value IcMax.
₂ ) is set. In other words, are disposed an optical sensor 35 to a position where the peak value IcMax rotatable range (d ₁ ~d ₂₎ sensor output signal in the catcher 36 at the string-striking stroke is output. Incidentally, the distance d ₃ in the first output value 0.9IcMax, the distance d ₄ in the second output value 0.8IcMax, respectively output. Therefore, the position of the tip 36A where the first output value was output and the second
The distance between two measurement points between the position where the output value was output and the position where the output value was output is Δd
= A d ₃ -d _4.

FIG. 4 is a graph showing a change in the output signal Ic of the optical sensor 35 during the string striking process.

In this stringing stroke, as shown in FIG.
The distance between the reflecting surface 36A is, d _1, d ₀ (peak value output), d ₃ (first output value output), d ₄ (second output value output), d ₂
(String striking point), d ₄ , d ₃ , d ₀ , d ₁ .

That is, in the stringing stroke in which the hammer 26 rotates so as to approach the string 24 by pressing a key, the catcher 36 also rotates integrally with the hammer 26, and the tip 36A of the catcher 36
Approach 5. In accordance with this approach, it is at a certain time t ₁ IcM
The output of ax (peak value) is obtained. The time of output of the peak value and t _1, between the case of the sensor-catcher distance is d _0.

Then, by the rotation of the further approaching direction of the catcher 36, at time t ₂ 90% of the output of Icmax (first output value)
Is obtained (the distance between the sensor and the catcher is d ₃ ).

Further then, at time t ₃ 80% of the output of Icmax (second output value) is obtained (between the sensor-catcher distance
d ₄ ).

Then, at time t _4, to form a string striking point the hammer 26 strikes the string 24 (between the sensor-catcher distance
d ₂ ), the action 25 including the hammer 26 will rebound. That is, the output of the sensor 35 around the Datsuruten t ₄ varies symmetrical. Therefore, when the first output value is output
t ₂ and the elapsed time between the output time t ₃ of the second output value, Delta] t =
It is represented by t ₃ −t ₂ .

FIG. 5 conceptually shows a change in the distance d between the tip 36A of the catcher 36 and the optical sensor 35.

As shown in this figure, the butt end surface 36A at the time of hitting of the string is at a distance d ₂ which is closest to the light sensor 35. Further, when outputting the peak value, these are separated by a distance d _0. Further, when outputting the first output value 0.9IcMax and the second output value 0.8IcMax, the distance between the butt end surface 36A and the light sensor 35 are separated by d _3, d _4, respectively.

Therefore, in this automatic piano, at the time of the first automatic striking (automatic keying by driving an actuator such as a solenoid), as described above, the maximum value (peak value) of the sensor output of each optical sensor 11 (35) is obtained. The value IcMax) is stored in the detection holding circuit 12, and the first output value (0.9IcMax) which is 90% of this maximum value and the second output value (0.8
IcMax) is calculated by the arithmetic circuit 13.

The first output value and the second output value are respectively stored in a holding circuit.
It is output to 14 and 15 and held.

Then, each output of the holding circuits 14 and 15 is compared with a comparison circuit 18,
19 is entered as the reference value.

Next, at the time of performance recording, the action 25 is rotated by key depression, and the optical sensor 35 outputs a signal shown in FIG. 4 or a signal having a similar curve.

Based on the change in the output Ic, that is, the determination circuit 2 first determines whether or not the sensor output signal Ic has reached the peak value IcMax.
The comparison circuit 18 compares whether or not the sensor output has decreased to the first output value.
20 outputs a timer start signal to the timer 21 when the sensor output Ic matches the first output value. As a result, the timer 21 starts counting from the matched time t _2.

Next, when the sensor output reaches the second output value, the determination circuit
22 outputs a stop signal to the timer 21. As a result, the timer 21 ends the timing.

The measured time Δt is output from the timer 21 and converted by the MIDI speed table 23 to obtain the string striking strength V.

If the output of the optical sensor 11 passes through the peak value and does not reach the string output value, it is assumed that the string has not been struck.

Further, the waveform of the sensor output Ic may differ due to a variation in the mounting position in each optical sensor 35, a variation in the light reflectance of the front end 36A of the catcher 36, and the like.

However, from time t2 when the catcher 36 passes the first measurement point of 90% output normalized to the peak value IcMax of the output of each sensor 35, the _second value of 80% output to the peak value is obtained.
The elapsed time Δt between until time t ₃ when passing through the measurement point, is measured in this embodiment. As a result, it is possible to accurately detect a striking speed approximate to the actual striking point by the hammer 26.

FIG. 6 shows another example of the setting of the first output value and the second output value in this embodiment.

As shown in this figure, two measurement points A and B may be calculated as α% and β% of the peak value IcMax of the sensor output.
The time Δt during which the catcher is displaced between these two measurement points is
The measurement is performed using the first output value αIcMax and the second output value βIcMax.

As described above, after the peak value is output, the first output value and the second output value are appropriately calculated and set, whereby the turning speed of the hammer 26 immediately before the actual string striking can be detected with high accuracy.

In the above embodiment, the operation and storage of various output values can be performed by a well-known logic operation circuit such as a microprocessor.

In the first embodiment, an example using a light reflection type sensor has been described. However, for example, as shown in FIG. 3, if the sensor outputs a signal that changes with a change in distance, an ultrasonic sensor, The present invention can be realized by a magnetic sensor or the like.

<Embodiment> As described above, the playing state detecting device for a keyboard instrument according to the present invention eliminates the work of attaching the hammer shutter to the hammer shank, and therefore, the positioning work of the hammer shutter and the high-precision processing of the hammer shank. Work becomes unnecessary, and the assembly and adjustment man-hours are reduced.

Further, the timing of detection by the optical sensor can be set close to immediately before the stringing point, and the stringing speed can be detected with high accuracy. In this case, there is no need to mount all the optical sensors of the 88 keys close to the striking point, and even when correcting individual differences with a hammer, complicated work such as adjustment is unnecessary. It will be easier.

In addition, since the sensor output is standardized (normalized) and the distance and time are measured based on the standardized output (can be set arbitrarily), it is possible to eliminate the dispersion of the measurement values of each sensor (detection means). Was.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a keyboard musical instrument performance state detecting apparatus according to a first embodiment of the present invention, FIG. 2 is a side view showing a string striking mechanism according to the first embodiment, and FIG. FIG. 4 is a graph showing the relationship between the output of the optical sensor according to the first embodiment and the distance between the reflection surface, FIG. 4 is a graph showing the output characteristics of the optical sensor according to the first embodiment, and FIG. FIG. 6 is a conceptual diagram showing a change in distance between the optical sensor and the catcher tip surface according to the embodiment; FIG. 6 is a graph showing output characteristics of the optical sensor for explaining setting change of an output value according to the first embodiment; FIG. 1 is a side view showing a conventional string velocity detecting device. 11: Optical sensor (detection means), 13: Arithmetic circuit (output value calculation means), 21: Timer (time measurement means), 23: MIDI velocity table, 24: String, 25: Action (string striking) Mechanism), 35: Optical sensor, 36: Catcher (component), 36A: Kiguchi surface (light reflecting surface).

Claims (1)

(57) [Claims] 1. A striking mechanism for a keyboard instrument which is rotated by a key-depression operation, is disposed in close proximity to a component of a striking mechanism, and copes with a change in the distance between the component and an extreme value. Detecting means for outputting a signal having a change, detecting an extreme value in an output signal from the detecting means, and outputting a first output value and a second output value output after the detection of the extreme value. Output value calculation means for calculating based on the extreme value; time measurement means for measuring a time during which the output from the detection means changes from the first output value to the second output value; A string striking speed calculating means for calculating a string striking speed by the string striking mechanism based on the point-to-point distance;