JP4848809B2 - Keyboard instrument - Google Patents

Description

  The present invention relates to a keyboard instrument.

Various electronic pianos have been proposed in which a plunger and a solenoid are provided on the back side of a keyboard, and automatic performance is performed by controlling the waveform of an AC drive signal supplied to the solenoid. This type of electronic piano is equipped with a sound source that converts the amount of key displacement into sound and outputs it. When the plunger pushes the key upward by supplying an AC drive signal to the solenoid, the displacement The sound of velocity according to the amount is output from the sound source.
By the way, the electromagnetic characteristics of the solenoid fluctuate depending on the installation environment and aging, so that the fluctuation is absorbed and the relationship between the key displacement and the waveform control of the AC drive signal supplied to the solenoid is always kept good. It is essential to incorporate the mechanism into an electronic piano. On the other hand, the automatic performance device described in Patent Document 1 is provided with a speed sensor in the vicinity of the plunger, and the detected value of the speed sensor is fed back to the AC drive signal supplied to the solenoid, thereby maintaining a good relationship between the two. . The electromagnetic actuator displacement device described in Patent Document 2 superimposes a carrier for position detection on an AC drive signal for driving a solenoid, and feeds back a detection result of the superimposed carrier.
JP-A-10-301561 JP-A-7-288895

However, according to the technique described in Patent Document 1, there is a problem that the speed sensor provided in the vicinity of the plunger increases the cost of the electronic piano itself. Further, the technique described in Patent Document 2 has a problem that the control logic has to be complicated because the carrier is superimposed on the drive signal of the solenoid.
The present invention has been devised under such a background, and an object of the present invention is to provide a mechanism capable of precisely executing an automatic performance of an electronic piano by relatively simple control.

A keyboard instrument according to a preferred aspect of the present invention includes a key that can be displaced vertically between a rest position and an end position, a solenoid that has a plunger that is driven by applying a force to the key, and a key that is used to drive the key. A storage means storing a pair of target speed information indicating a target speed and a signal control parameter indicating a duty ratio of an AC drive signal to be supplied to the solenoid; an instruction means for instructing key driving; and the instruction means When a key drive is instructed, a signal supply means for supplying an alternating current drive signal having a duty ratio indicated by a signal control parameter forming one of the pair stored in the storage means to the solenoid, and the alternating current drive signal are supplied. The actual speed of the key is calculated based on the change in inductance of the solenoid calculated from the state of the current flowing through the solenoid during A degree calculating means, the determined actual speed deviation to the target speed indicated by the target speed information actual speed calculation means has calculated that form the other pair, calibration means for calibrating according to the target speed information to the difference determined the And the actual speed calculation means starts to change the inductance of the solenoid as the key applied to the plunger of the solenoid that is supplied with the AC drive signal is displaced from the rest position toward the end position. key has reached the end position from the measured length of time until the change is stopped, it calculates the actual speed of the displacement of the key based on the time length measured.

  The storage means stores another pair consisting of holding state information indicating a holding state in which the key is driven to the rest position and stayed at the position and a signal control parameter, and the signal supply means After the change of the inductance of the solenoid stops when the key applied to the plunger of the solenoid that has been supplied with the AC drive signal reaches the end position, the duty ratio of the supplied AC drive signal is incremented by a predetermined amount. When the duty ratio of the AC drive signal supplied to the solenoid by the signal supply means decreases, the calibration means moves the key applied to the plunger from the end position toward the rest position. The duty ratio when the inductance of the solenoid starts to change again and the storage means A deviation of the signal control parameters are the duty ratio shown forming the holding state information paired, the signal control parameters may be calibrated in accordance with the difference determined the.

Also, an input means for inputting performance information, and after the calibration means calibrates the target speed information , the performance information input via the input means is converted according to a predetermined algorithm to thereby maintain the target speed information and the holding state. Performance information reproduction pre-processing means for obtaining a sequence of information arranged, and the signal supply means stores each signal control parameter stored in the storage means in association with each of target speed information and holding state information. You may make it supply the alternating current drive signal of the duty ratio shown to the said solenoid according to the procedure which the said acquired sequence shows.

  You may further provide the behavior detection means which detects the behavior of the key driven with the said plunger, and the sound source which produces | generates a musical tone signal according to the behavior of the key which the said behavior detection means detected.

  The upper end of the plunger is connected to a predetermined position on the lower surface of the key, and the solenoid applies an upward force to the predetermined position by pushing up the plunger under the action of an AC drive signal supplied to itself. You may make it add.

  According to the present invention, automatic performance of an electronic piano can be precisely executed by relatively simple control.

(First embodiment)
A first embodiment of the present invention will be described.
The keyboard instrument according to the present embodiment has a mode (hereinafter referred to as “performance information recording mode”) in which the operation content of the key by the user is converted into performance information in accordance with the MIDI (Musical Instruments Digital Interface) standard and recorded. A different behavior is performed in each of the two modes of driving the key based on the recorded performance information and reproducing the operation content (hereinafter referred to as “performance information playback mode”).

  FIG. 1 is a block diagram showing a schematic hardware configuration of a keyboard instrument. As shown in the figure, the keyboard instrument 1 includes a CPU 11, a RAM 12 that provides a work area to the CPU 11, a ROM 13 that stores an IPL (Initial Program Loader) and other various programs, a key sensor 14, a key 15, a plunger 16, A solenoid 17, a sound source 18, a PWM (Pulse Width Modulation) signal supply unit 19, a sensor amplifier unit 20, a flexible disk drive (hereinafter referred to as “FDD 21”) 21, and a parameter memory 22 are provided. The 88 keys 15 shown in the figure are arranged in a horizontal row, and the key sensor 14, the plunger 16, and the solenoid 17 are provided in each of the 88 keys 15. Further, each set including the key 15, the plunger 16, and the solenoid 17 operates individually as a key pressing mechanism.

  FIG. 2 is a diagram illustrating the configuration of the key pressing mechanism. As shown in the figure, the substantially central portion of the lower surface of the key 15 is supported by the balance pin 23 so as to be swingable in the vertical direction. A part on the front side of the upper surface of the key 15 (hereinafter, this part is referred to as “finger contact part”) to be brought into contact with the user's finger by swinging about the balance pin 23 is a rest position and an end. It can be displaced vertically between positions. A key sensor 14 for detecting the behavior of the key 15 is provided at a position just opposite to the finger contact portion under the key 15, and a solenoid 17 for applying a driving force to the key 15 on the rear side of the balance pin 23. Is provided.

  The key sensor 14 includes a sensor box 14a that houses a shutter 15a erected on the back surface of the key 15, and two sets of photosensors that are provided at a predetermined distance in the vertical direction. The photo sensor detects a downward displacement amount of the finger contact portion from the light shielding amount of the photo sensor caused by the entrance of the shutter 15a into the sensor box 14a, and outputs a displacement amount signal that is an analog signal indicating the detected displacement amount. The sound is supplied to the sound source 18 shown in FIG.

  The solenoid 17 has a plunger 16 accommodated in a bobbin in which a coil is wound. The solenoid 17 is supplied with a rectangular wave AC drive signal having a frequency of about 1 kHz from the PWM signal supply unit 19 and pushes the plunger 16 upward. When the plunger 16 is pushed up, the connection portion between the upper end of the plunger 16 and the back surface of the key 15 is lifted upward, while the finger contact portion side with the balance pin 23 sandwiched is displaced downward. When the displacement signal obtained by quantifying the downward displacement amount of the finger contact portion by the key sensor 14 is supplied to the sound source 18, the sound source 18 has a volume corresponding to the displacement amount indicated by the displacement amount signal. The music signal is synthesized and output. The sound source 18 has a built-in table in which 88 sets of key pressing mechanisms are associated with key codes of pitches assigned to them, and this table is referred to based on the identifier of the key pressing mechanism. By doing this, the pitch of the tone signal to be output is specified.

  FIG. 3 is an equivalent circuit diagram showing an electrical configuration of the solenoid 17 and the PWM signal supply unit 19. As shown in the figure, a MOS (Metal Oxide Semiconductor) type FET (Field-Effect Transistor) 24 serving as a switching element is connected in series to the solenoid 17. Switching of the FET 24 is performed from a PWM signal supply unit 19 to a driver 25. It is determined by the duty ratio of the AC drive signal supplied via. That is, the current flowing into the solenoid 17 increases in proportion to the duty ratio of the AC drive signal, and the driving force also increases. On the other hand, the sensor amplifier unit 20 detects a voltage value applied to a resistor r connected in series with the solenoid 17. As will be described later in detail, the actual speed of the key 15 is calculated based on the amount of change in inductance of the solenoid 17 calculated from the voltage value applied to the resistor r.

  In FIG. 1, an FDD 21 controls writing and reading of data to and from a flexible disk. In the performance information recording mode, performance information generated based on the operation content of the key 15 is written to the flexible disk, while in the performance information reproduction mode, the key 15 is based on the performance information read from the flexible disk. The operation content is reproduced by driving. As described at the beginning, the performance information is data describing the operation contents of the key 15 by the user in accordance with the MIDI standard, and more specifically, a series of MIDI events are associated with a delta time indicating the execution timing. Sequence data described in chronological order. MIDI events described as performance information include note-on for instructing sound generation and note-off for instructing mute. The note-on MIDI event includes a parameter indicating a key code and a parameter indicating velocity.

In the parameter memory 22, each signal control parameter that specifies the duty ratio of the AC drive signal is associated with an individual index.
FIG. 4 is a data structure diagram of the parameter memory 22. As shown in the figure, in the parameter memory 22, a plurality of records each having two fields of "index" and "parameter" are collected. In the “parameter” field of each record excluding the lowest record in the parameter memory 22, a signal representing the duty ratio between the maximum value of 100% and the minimum value of 1% in increments of 1%. The control parameters are stored, and further, the index paired with each of the signal control parameters drives each key 15 based on the performance information in the performance information reproduction mode such as V100, V99, V98. The data represents the target speed at the time. The value of each target speed serving as an index is determined by the manufacturer through actual measurement using a master experimental machine or the like, and the default value of the target speed of the key 15 that is generally obtained by supplying an AC drive signal of each duty ratio to the solenoid 17. Is stored in advance in the parameter memory 22.

  In addition, the index of the lowest record in the parameter memory 22 is not the target speed but “held”. The “holding state” index indicates a record in which the duty ratio necessary for driving the key 15 to the end position and staying at the end position in the performance information reproduction mode is stored. The contents of “M%”, which is the value of the signal control parameter stored in the “parameter” field of this record, are also determined by the manufacturer through actual measurement, and are necessary for the key 15 to remain at the end position. The default value of the duty ratio is stored in advance in the parameter memory 22.

Next, the operation of this embodiment will be described.
The operation of the present embodiment includes a calibration process, a performance information recording mode process, and a performance information reproduction mode process. When the power of the keyboard instrument 1 is turned on, a calibration process is first executed. After the execution of the process, a performance information recording mode process or a performance information reproduction mode process is executed according to the user's mode selection.

  FIG. 5 is a flowchart showing the calibration process. As described above, in the parameter memory 22 of the keyboard instrument 1, the correspondence between the target speed of the key 15 and the index indicating the state where the key 15 is held at the rest position and the signal control parameter is under actual measurement by the manufacturer. It is set in advance. However, since the electromagnetic characteristics of the solenoid 17 of the keyboard instrument 1 fluctuate depending on the installation environment and aging, the contents of the parameter memory 22 are optimized by performing a series of processes shown in the figure every time the power is turned on. Turn into.

When the power is turned on, the CPU 11 of the keyboard instrument 1 identifies one of the records in the parameter memory 22 as a reference target (S100). The identification of records in this step is performed in ascending order.
The CPU 11 supplies an AC drive signal having a duty ratio indicated by the signal control parameter stored in the “parameter” field of the record identified in step 100 from the PWM signal supply unit 19 to the solenoid 17, and then the sensor amplifier unit 20. Measure the length of time from when the voltage value applied to the resistor r starts to change until the change stops, and differentiate the distance between the rest position and the end position of the key 15 by the time length, thereby The actual speed is calculated (S110).

Here, the causal relationship between the change in the voltage value when the AC drive signal is supplied to the solenoid 17 in this step and the actual speed of the key 15 will be described.
When an alternating current drive signal is supplied to the solenoid 17, the plunger 16 pushes up the connecting portion between itself and the key 15 in response to the exciting action, so that the connecting portion between the plunger 16 and the key 15 is also displaced upward. As described above. When the position of the plunger 16 in the bobbin does not change, the inductance of the solenoid 17 does not change. When the position of the plunger 16 changes, the inductance of the solenoid 17 changes accordingly. This can be understood more easily by referring to the measurement results of FIG.
FIG. 6 shows a change in inductance when the position of the plunger 16 is changed in a state where an AC drive signal having a frequency of 20 kHz is supplied to the solenoid 17, and a state where the plunger 16 is supplied in a state where an AC drive signal having a frequency of 1 kHz is supplied to the solenoid 17. It is a plot of the change in inductance when the position is changed. Referring to the figure, the inductance also changes in accordance with the change in the position of the plunger 16 accommodated in the bobbin of the solenoid 17, and the change in the inductance becomes clearer when an AC drive signal having a frequency of 1 kHz is adopted. You can see it.

よって、抵抗ｒの電圧値Ｖが変化し始めた時、つまり、ソレノイド１７のインダクタンスが変化し始めた時に鍵１５がレスト位置からエンド位置に向かって変位を始め、その変化が止まった時にエンド位置に到達したと考えることができる。この因果関係から、インダクタンスの変化の開始から終了までの両位置の間の距離をその時間長で微分して得た値を鍵１５の変位の実速度とみなすことができるのである。 Further, when the voltage value of the resistor r connected in series to the solenoid 17 is V, the inductance of the coil of the solenoid 17 is L, the winding resistance of the coil itself is R, and the frequency of the AC drive signal is ω, The voltage value V and the inductance L have a correlation as shown in the following equation.

Therefore, when the voltage value V of the resistor r starts to change, that is, when the inductance of the solenoid 17 starts to change, the key 15 starts to move from the rest position toward the end position, and when the change stops, the end position Can be considered to have reached. From this causal relationship, the value obtained by differentiating the distance between the two positions from the start to the end of the inductance change by the time length can be regarded as the actual speed of the displacement of the key 15.

In FIG. 5, the CPU 11 determines whether or not the target speed represented by the data stored in the “index” field of the record identified in step 100 matches the actual speed obtained in step 110 (S120).
The CPU 11 that has determined that the target speed and the actual speed do not match in step 120 replaces the stored contents of the “index” field of the record identified in step 100 with data representing the actual speed obtained in step 110 (S130). On the other hand, the CPU 11 that has determined that the target speed matches the actual speed proceeds to the next step without executing this step.
Subsequently, the CPU 11 advances one record to be referred to (S140). Thereafter, it is determined whether or not “holding state” data is stored in the “index” field of the new record to be referred to (S150).

If the CPU 11 determines in step 150 that the “holding state” data is not stored, the CPU 11 returns to step 110 and executes the subsequent processing.
On the other hand, the CPU 11 that has determined that the “holding state” data is stored in step 150 supplies an alternating current drive signal with a duty ratio of 100% to the solenoid 17 until the voltage value V of the resistor r does not change. The duty ratio is decreased by a predetermined amount, and a signal control parameter indicating the duty ratio when the voltage value starts to change again is stored in the parameter memory 22 as a value of “M%” (S160). As is well known, after the key 15 reaches the end position, it is possible to keep the key 15 in that position without continuing to flow the same current to the solenoid 17 as before. Therefore, in this step, the duty ratio necessary for flowing the minimum current through the solenoid 17 that can keep the key 15 that has reached the end position in that position is measured.
This completes the calibration process.

FIG. 7 is a flowchart showing the performance information recording mode process.
When the execution of the performance information recording mode is instructed, the CPU 11 supplies an AC drive signal with a duty ratio of 5% from the PWM signal supply unit 19 to the solenoid 17 (S200). Due to the supply of this AC drive signal, the solenoid 17 is weakly excited so as not to drive the key 15. Therefore, when the finger pressing part of the key 15 is pressed downward by the finger and the connecting part of the key 15 and the plunger 16 is displaced upward, the displacement amount appears as a change in inductance of the solenoid 17.

After executing Step 200, the CPU 11 searches whether or not the voltage value of the resistor r connected in series to the solenoid 17 of any key 15 has changed (S210).
When the voltage value of the resistor r connected in series to the solenoid 17 of any one of the keys 15 changes, the relative time length from the start of the performance information recording mode to the start of the change is converted to a delta. Time is acquired (S220).
Next, the CPU 11 specifies the key code assigned to the key pressing mechanism including the solenoid 17 connected to the resistor r whose voltage value has changed (S230).

The CPU 11 calculates the actual speed of the key 15 from the time length from when the voltage value applied to the resistor r starts to change until the change stops, and acquires the velocity by converting the calculated actual speed (S240). The conversion in this step may be performed by referring to a table in which the velocity value and the actual speed are associated in advance.
The CPU 11 buffers the note-on MIDI event including the key code acquired in step 230 and the parameter indicating the velocity acquired in step 240 in a predetermined area of the RAM 12 in association with the delta time acquired in step 220 (S250).

Further, the CPU 11 stops changing the voltage value applied to the resistor r when the key 15 reaches the end position, and then the connecting portion between the key 15 and the plunger 16 is again displaced downward to change the voltage value. The delta time is acquired by converting the relative time length from when the key 15 reaches the end position until the change stops again after starting to start (S260).
Then, the CPU 11 buffers the note-off MIDI event in a predetermined area of the RAM 12 in association with the delta time acquired in step 260 (S270).

  The series of processes described above is executed each time a change in the voltage value of the resistor r is detected by the key 15 being displaced by a user operation. When the end of the performance is instructed, performance information obtained by arranging a series of MIDI events buffered in the RAM 12 through the processing so far in order of time series indicated by the delta time is stored in the flexible disk (S280).

FIG. 8 is a flowchart showing the performance information reproduction mode process.
When the execution of the performance information playback mode is instructed, the CPU 11 reads the performance information stored on the flexible disk into the RAM 12 (S300).
The CPU 11 refers to the performance information in the RAM 12 while measuring the delta time, and specifies the MIDI event associated with the current delta time (S310).

The CPU 11 specifying the MIDI event determines whether the MIDI event is note-on or note-off (S320).
The CPU 11 that has determined that the MIDI event is note-on in step 320 identifies the key code and velocity indicated by the parameter included in the MIDI event (S330).

Subsequently, the CPU 11 converts the velocity specified in step 330 to acquire the target speed (S340). The conversion in this step may be performed by referring to a table in which the velocity value and the target speed are associated in advance.
The CPU 11 calculates a predicted time length required for the displacement from the rest position to the end position when the key 15 is driven at the target speed obtained by the conversion in step 340 (S350). The predicted time length is obtained as a quotient of the distance between the rest position and the end position and the target speed.

  Further, the CPU 11 uses the target speed acquired in step 340 as an index, and the key pressing mechanism to which the key code specified in step 330 is assigned the AC drive signal having the duty ratio indicated by the signal control parameter stored in the parameter memory 22. Is supplied from the PWM signal supply unit 19 to the solenoid 17 (S360). Thereby, the key 15 can be displaced from the rest position toward the end position, and a sound having a volume corresponding to the amount of displacement can be output from the sound source 18.

  When the estimated time length calculated in step 350 has elapsed, the CPU 11 that has started supplying the AC drive signal in step 360 has a duty ratio indicated by the signal control parameter stored in the parameter memory 22 with “holding state” as an index. The AC drive signal is supplied from the PWM signal supply unit 19 to the solenoid 17 of the key 15 to which the key code specified in step 330 is assigned (S370). As a result, the key 15 that should have reached the end position can be kept at that position.

CPU11 which judged that the MIDI event is note-off in step 320 stops supply of the alternating current drive signal from the PWM signal supply part 19 to the solenoid 17 (S380). Thereby, the excitation of the solenoid 17 is canceled and the key 15 can be returned to the rest position.
The series of processes described above are sequentially executed with reference to all MIDI events stored as performance information in the RAM 12.

  As described above, the keyboard instrument 1 according to the present embodiment first performs the calibration process when the power source is activated. In this calibration process, an AC drive signal having a duty ratio indicated by each signal control parameter stored in the parameter memory 22 is sequentially supplied to the solenoid 17 to drive the key 15 from the rest position toward the end position. Then, the actual speed of the key 15 is calculated based on the amount of change in the inductance of the solenoid 17 into which current has flowed. When the calculated actual speed does not match the target speed that is the index of the signal control parameter, the target speed in the index is replaced with the actual speed. Therefore, the performance information recording mode and performance information reproduction mode services are provided while absorbing the electromagnetic characteristics of the solenoids 17 that vary depending on the installation environment and aging, etc., and keeping the response sensitivity of the solenoids 17 always good. be able to.

(Second Embodiment)
A second embodiment of the present invention will be described.
In the above-described embodiment, the contents of the target speed that is an index of each signal control parameter in the parameter memory 22 are updated according to the actual speed when the AC drive signal having the duty ratio indicated by each is supplied to the solenoid 17. After that, both the performance information recording mode and the performance information reproduction mode are executed without changing the content of the parameter memory 22 itself. This is because, in the case of the keyboard instrument 1 equipped with the sound source 18, the portion where the musical sound is played does not receive a physical action from the key pressing mechanism, and therefore the driving of the key 15 may be controlled by an open loop without feedback. Because there is no.
On the other hand, the keyboard instrument 1 according to the present embodiment subsequently calculates the deviation between the actual speed and the target speed of the key 15 calculated based on the amount of change in the inductance of the solenoid 17 supplied with the AC drive signal having a certain duty ratio. The drive of the key 15 is controlled by a closed loop that feeds back to the supplied AC drive signal.
The schematic hardware configuration of the keyboard instrument 1 according to the present embodiment is the same as that shown in FIG.

Next, the operation of this embodiment will be described.
As in the first embodiment, the operation of the present embodiment includes a calibration process, a performance information recording mode process, and a performance information playback mode process. Among these three processes, the contents of the performance information playback mode process are the first. Different from the embodiment.

FIG. 9 is a flowchart showing the performance information playback mode process.
In the figure, the contents after step 340 are different from those in FIG.
The contents of each process will be described. The CPU 11 that has converted the velocity in step 340 and obtained the target speed immediately proceeds to step 360, and the signal control parameter stored in the parameter memory 22 indicates the target speed as an index. The AC drive signal having the duty ratio is supplied to the solenoid 17 of the key pressing mechanism to which the key code specified in step 330 is assigned. By supplying this AC drive signal, the key 15 is displaced from the rest position toward the end position, and the inductance of the solenoid 17 changes, and the change in the inductance is detected in the form of a change in the voltage value of the resistance r of the sensor amplifier unit 20. Is done.

The CPU 11 waits without detecting the inductance for a predetermined time length (for example, 5 msec) until the key 15 starts to be displaced from the rest position by the supply of the AC drive signal after the supply of the AC drive signal is started. (S361).
After passing through a wait for a predetermined time length, the CPU 11 measures the amount of change in the voltage value of the resistance r of the sensor amplifier unit 20 during a predetermined sampling period (for example, 1 msec) (S362).

The CPU 11 calculates the actual speed of the key 15 based on the change amount of the voltage value measured in step 362 (S363).
The CPU 11 determines whether or not the actual speed obtained in step 363 is 0 (S364).
The CPU 11 having determined that the actual speed is 0 in step 364 returns to step 310 in FIG. 8 and executes the subsequent processing.
The CPU 11 having determined that the actual speed is not 0 in step 364 determines whether the actual speed is equal to the target speed, smaller than the target speed, or larger (S365).

The CPU 11 that has determined that the actual speed is equal to the target speed in step 365 returns to step 362 and measures the amount of change in the voltage value in the next sampling period.
The CPU 11 having determined that the actual speed is lower than the target speed in step 365 increases the duty ratio of the AC drive signal supplied to the solenoid 17 (S366), and then returns to step 362.
The CPU 11 having determined that the actual speed is larger than the target speed in step 365 reduces the duty ratio of the AC drive signal supplied to the solenoid 17 (S367), and then returns to step 362.
Similarly to FIG. 8, when it is determined in step 320 that the MIDI event is note-off, the process proceeds to step 380 and the supply of the AC drive signal from the PWM signal supply unit 19 to the solenoid 17 is stopped.

  As described above, the keyboard instrument 1 according to the present embodiment calculates the deviation between the actual speed of the key 15 and the target speed calculated based on the amount of change in the inductance of the solenoid 17 supplied with the AC drive signal having a certain duty ratio. It feeds back to the AC drive signal supplied thereafter. Therefore, the driving of the key 15 at the target speed can be further stabilized.

(Other embodiments)
The present invention can be modified in various ways.
In the performance information recording mode process of the above embodiment, an AC drive signal with a duty ratio of 5% is supplied to the solenoid 17 in order to calculate the amount of displacement of the key 15 from the amount of change in the inductance of the solenoid 17. However, if the value does not lead to driving the key 15, an AC drive signal having a duty ratio larger than 5% may be supplied, or an AC drive signal having a small duty ratio may be supplied. .
In the above embodiment, the PWM signal supply unit 19 supplies an alternating current drive signal having a frequency of about 1 kHz to the solenoid 17, but if the frequency is within the band of 100 to 5 kHz, the frequency is made smaller than 1 kHz. It may be larger or larger.
In the above embodiment, the signal memory parameters are stored in the parameter memory 22 with the respective target speeds and holding states as indices, and an AC drive signal having a duty ratio indicated by a signal control parameter corresponding to a certain target speed is transmitted to the solenoid 17. When the key 15 reaches the end position, an AC drive signal having a duty ratio indicated by the signal control parameter corresponding to the holding state is supplied to keep the key 15 at the end position. It was. On the other hand, when the key 15 reaches a position intermediate between the rest position and the end position, an AC drive signal having a duty ratio represented by the signal control parameter corresponding to the holding state is supplied, so that the key 15 is ended. You may make it remain in the middle position instead of a position.
In this modification, for example, after calculating the predicted time length at which the key 15 is displaced from the rest position to the end position at a certain target speed, the signal control parameter corresponding to the holding state at a predetermined timing before the predicted time length elapses. An AC drive signal having a duty ratio indicated by is supplied. According to this modification, the key 15 is not pushed down from the rest position to the end position, but can be held at a position slightly pushed down from the rest position. Therefore, by performing such control based on performance information prepared as teaching materials in advance, a performance support device is realized in which the key 15 of the musical tone to be output next is pushed down a little and the pressing is sequentially promoted. You can also

It is a hardware schematic block diagram of a keyboard musical instrument. It is a block diagram of a key pressing mechanism. It is an equivalent circuit diagram of a solenoid and a PWM signal supply unit. It is a data structure figure of the memory for parameters. It is a flowchart which shows a calibration process. It is a figure which shows the relationship between an inductance and a position. It is a flowchart which shows a performance information recording mode process. It is a flowchart which shows a performance information reproduction | regeneration mode process (1st Embodiment). It is a flowchart which shows a performance information reproduction | regeneration mode process (2nd Embodiment).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Keyboard instrument, 11 ... CPU, 12 ... RAM, 13 ... ROM, 14 ... Key sensor, 15 ... Key, 16 ... Plunger, 17 ... Solenoid, 18 ... Sound source, 19 ... PWM signal supply part, 19 ... PWM signal supply part 20 ... sensor amplifier unit, 21 ... FDD, 22 ... parameter memory, 23 ... balance pin, 24 ... MOS FET, 25 ... driver

Claims (5)

A key that can be displaced vertically between the rest position and the end position;
A solenoid having a plunger that is driven by applying a force to the key;
Storage means for storing a pair of target speed information indicating a target speed when driving the key and a signal control parameter indicating a duty ratio of an AC drive signal to be supplied to the solenoid;
Instruction means for instructing driving of the key;
A signal supply means for supplying an alternating current drive signal having a duty ratio indicated by a signal control parameter forming one of the pair stored in the storage means to the solenoid when the instruction means instructs to drive the key;
An actual speed calculating means for calculating an actual speed of the key based on a change in inductance of the solenoid calculated from a state of a current flowing through the solenoid while the AC drive signal is supplied;
A calibration means for obtaining a deviation between the target speed indicated by the target speed information forming the other of the pair and the actual speed calculated by the actual speed calculation means, and calibrating the target speed information according to the obtained deviation ;
The actual speed calculation means includes
The key that is applied to the plunger of the solenoid that is supplied with the AC drive signal is displaced from the rest position toward the end position, so that the inductance of the solenoid starts to change, and then the key reaches the end position and changes. A keyboard instrument that measures the length of time until it stops and calculates the actual speed of key displacement based on the measured length of time . In the keyboard musical instrument as set forth in 請 Motomeko 1,
The storage means
Storing another pair of holding state information and a signal control parameter indicating the holding state in which the key is driven to the rest position and stayed at that position;
The signal supply means includes
Decrease the duty ratio of the supplied AC drive signal by a predetermined amount after the change in the inductance of the solenoid stops when the key applied to the plunger of the solenoid supplied with the AC drive signal reaches the end position. Go and
The calibration means includes
When the duty ratio of the AC drive signal supplied to the solenoid by the signal supply means becomes small, the inductance of the solenoid changes again as the key applied to the plunger is displaced from the end position toward the rest position. A keyboard instrument that obtains a deviation of a duty ratio indicated by a signal control parameter that forms a pair with the holding ratio information in the storage means when the duty ratio is started, and calibrates the signal control parameter according to the obtained deviation. In the keyboard musical instrument as set forth in 請 Motomeko 1 or 2,
Input means for inputting performance information;
After the calibration means calibrates the target speed information , performance information reproduction for obtaining a sequence in which target speed information and holding state information are arranged by converting performance information input through the input means according to a predetermined algorithm A pre-processing means, and
The signal supply means includes
A keyboard instrument that supplies an AC drive signal having a duty ratio indicated by each signal control parameter stored in the storage means in association with each of target speed information and holding state information to the solenoid according to a procedure indicated by the acquired sequence. In the keyboard instrument according to 請 Motomeko 1 to 3,
Behavior detecting means for detecting the behavior of a key driven by the plunger;
A keyboard instrument further comprising: a sound source that generates a musical sound signal according to the behavior of the key detected by the behavior detecting means. In the keyboard instrument according to 請 Motomeko 1 to 4,
The upper end of the plunger is connected to a predetermined position on the lower surface of the key,
The solenoid is
A keyboard instrument that applies an upward force to the predetermined position by pushing up the plunger under the action of an AC drive signal supplied to itself.

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