JPH0231394B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to an automatic piano performance device, and more particularly to a method for driving a pedal solenoid for automatically operating a damper pedal, soft pedal, etc.

FIG. 1 is a waveform diagram showing an example of a drive signal for a pedal solenoid. In this diagram, symbol A is touch data for driving the plunger of the solenoid (projecting state), and B is touch data for holding the plunger in a driving state. This is retained data for the purpose of In this case, the touch data A is data whose level and time width are constant, and the held data B is data whose level is constant and whose time width is determined according to the pedal-on time. Although FIG. 1 shows an analog waveform, in reality, the solenoid is often driven by a pulse signal having a duty ratio corresponding to each level.

By the way, in the conventional pedal solenoid drive method, the drive signal shown in FIG. 1 was simply applied to the solenoid, so the pedal quickly returned to its original position when the drive signal was turned off. Therefore, there was a problem that large mechanical noise was generated.

Therefore, the present invention provides a pedal solenoid driving method that can prevent mechanical noise generated when the pedal returns to its original position. In a method for driving a pedal solenoid for automatically operating a pedal of a player piano, the present invention provides a holding power required to maintain the pedal in a depressed state after a drive signal that causes the pedal to be in a depressed state is released. The present invention is characterized in that brake power is supplied to the pedal solenoid, which increases stepwise over time within a range smaller than the above.

An embodiment of the method according to the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing the configuration of a drive circuit for driving a damper pedal of a piano. In this figure, reference numeral 1 is a pedal-on signal output circuit that outputs a pedal-on signal PON (see Figure 3 A) indicating the timing to drive the damper pedal 2, and the output pedal-on signal
PON is supplied to the solenoid drive circuit 3. The solenoid drive circuit 3 creates a signal S shown in FIG. In this signal S,
Symbols A and B are the touch data and hold data described above, respectively, and the solenoid drive signal K is formed by these data A and B. Signals E and F output following this solenoid drive signal K are a first brake signal and a second brake signal, respectively. These brake signals E and F are both signals for preventing mechanical noise generated when the pedal 2 returns to its original position, and the level data D ₃ and D ₄ and time data in these signals E and F _T3 , _T4
are each constant values. Then, each data in the signal S mentioned above, that is, the level data D ₁ in the touch data A, the time data T ₁ , the level data D ₂ in the held data B, and each data D ₃ , D ₄ , T ₃ in the signals E and F , T ₄ are each stored in advance in the memory 4.

When the pedal-on signal PON is output from the pedal-on signal output circuit 1 and supplied to the solenoid drive circuit 3, the solenoid drive circuit 3
First, level data D ₁ and time data T ₁ are read from the memory 4, a pulse signal having a duty ratio corresponding to the level data D ₁ is created, and is outputted to the solenoid 5 as a signal S at the time of the time data T ₁ . As a result, the plunger 5a of the solenoid 5 is driven, and therefore the damper pedal 2
is driven. Next, the solenoid drive circuit 3 reads the level data _D2 from the memory 4, creates a pulse signal having a duty ratio corresponding to this level data _D2 , and outputs it as a signal S to the solenoid 5. Then, when the pedal-on signal PON is turned off, the signal S is turned off. As a result, the pedal 2 begins to return to its original position. next,
Reads the level data _D3 and time data _T3 from the memory 4, creates a pulse signal having a duty ratio corresponding to the level data _D3 , and outputs it as a signal S at the time of the time data _T3 (first brake signal E). Next, the level data D ₄ and the time data T ₄ are read from the memory 4, a pulse signal having a duty ratio corresponding to the level data D ₄ is created, and the pulse signal is output as the signal S at the time of the time data T ₄ (second Brake signal F). 1st brake signal E
This prevents mechanical noise when the piano damper collides with the strings, and also prevents the second brake signal F.
This prevents mechanical noise when the damper pedal 2 returns to its original position. In addition, level data
The values of D ₃ , D ₄ and time data T ₃ , T ₄ are each determined based on experimental results.

Thus, in the embodiment shown in FIG.
After the solenoid drive signal K is turned off, brake signals E and F that change in two steps are sequentially applied to the solenoid 5, thereby preventing mechanical noise when the pedal 2 returns. By the way, when a pedal is driven by a solenoid, the most ideal thing is to be able to drive the pedal in the same manner as when a human (piano player) operates the pedal with his or her feet. To achieve this, the above-mentioned brake signal may be made more multistage as shown in FIG. 4, for example, so that it can be brought closer to the human operating state.

As explained above, according to the present invention, after releasing the drive signal that causes the pedal to be in the depressed state, the power is increased as time elapses within a range smaller than the holding power required to maintain the pedal in the depressed state. Since the brake power that increases in stages is supplied to the pedal solenoid, mechanical noise that occurs when the pedal returns to its original position can be prevented, and the movement of the pedal when it returns to its original position can be prevented. The advantage is that it can more closely approximate human operating conditions.

[Brief explanation of drawings]

Figure 1 is a waveform diagram showing an example of the drive signal applied to the pedal solenoid that automatically operates the pedal.
The figure is a block diagram showing the configuration of one embodiment of the present invention, and FIGS. 3A and 3B are waveform diagrams showing the waveforms of the pedal-on signal PON and signal S in the same embodiment,
FIG. 4 is a waveform diagram showing another example of the brake signal. 2... Damper pedal, 3... Solenoid drive circuit, 4... Memory, 5... Pedal solenoid.

Claims (1)

[Claims] 1. In a method for driving a pedal solenoid for automatically operating a pedal of a player piano, the holding necessary to maintain the pedal in the depressed state after releasing the drive signal that causes the pedal to be in the depressed state is provided. A method for driving a pedal solenoid, characterized in that the pedal solenoid is supplied with brake power that increases stepwise over time within a range smaller than the electric power.