Self-calibrating transducer system and musical instrument equipped with the same

• US 7,411,124 B2
• Filed: 12/02/2005
• Issued: 08/12/2008
• Est. Priority Date: 01/24/2005
• Status: Active Grant

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Muramatsu, Shigeru
• Primary Examiner(s): Warren; David S.
• Application Number:
  US11/293,573
• Publication Number:
  US 20060162534A1
• Time in Patent Office: 984 Days
• Field of Search: 846/15, 846/53, 318/400.4, 318/400.08
• US Class Current: 84/615
• CPC Class Codes: G01D 18/006 Intermittent recalibration
• CPC Class Codes: G01D 18/008 with calibration coefficients stored in memory
• CPC Class Codes: G10F 1/02 Pianofortes with keyboard

Abstract

A self-calibrating key sensor system is constituted by an optical modulator, optical position transducers, a data accumulator and a data analyzer, and the optical modulator has a gray scale section to produce a key position signal varied together with the keystroke and an absolute data section to produce a calibration signal representative of a strictly adjusted distance between transparent areas of the absolute data section; the data accumulator accumulates discrete values of the calibration signal and discrete values of the key position signal together with the sampling time, and the data analyzer determines the gradient of the key position signal on the basis of peaks of the calibration signal produced at both ends of the strictly adjusted distance so as to estimate the true distance between the rest and end positions.

Claims

1. A self-calibrating transducer system for converting a physical quantity expressing motion of a manipulator on a trajectory to a data signals, comprising:

a first signal generator producing said data signal, a magnitude of which is representative of said physical quantity on said trajectory;

a second signal generator producing a calibration signal, a magnitude of which is representative of a predetermined value of said physical quantity at unique points on said trajectory;

a data accumulator connected to said first signal generator and said second signal generator, and accumulating a series of values of said magnitude of said data signal on said trajectory, another series of values of said magnitude of said calibration signal and pieces of tag data making the values of said magnitude of said data signal correlated with the values of said magnitude of said calibration signal;

a data analyzer connected to said data accumulator, estimating a value of said physical quantity of said data signal at a certain point on said trajectory on the basis of said predetermined value of said physical quantity and a value of said magnitude of said data signal at said certain point, and determining a relation between said physical quantity and said magnitude of said data signal along said trajectory so as to memorize said relation therein; and

a determiner connected to said data analyzer and said first signal generator, and responsive to said data signal so as uniquely to make values of said magnitude of said data signal correspond to values of physical quantity of said manipulator at any point on said trajectory with reference to said relation memorized in said data analyzer.

2. The self-calibrating transducer system as set forth in claim 1, in which said first signal generator includes

a generator radiating a flux across said trajectory,

a modulator connected to said manipulator so as to modulate said flux, and

a converter converting the modulated flux to said data signal.

3. The self-calibrating transducer system as set forth in claim 2, in which said generator includes

a light emitting element producing detecting light from electric power,

a light radiating port for radiating said detecting light as a light beam serving as said flux, and

an optical fiber connected between said light emitting element and said light radiating port.

4. The self-calibrating transducer system as set forth in claim 3, in which said light radiating port further radiates said detecting light as another light beam toward another modulator attached to another manipulator so that said manipulator shares said light radiating port with said another manipulator.

5. The self-calibrating transducer system as set forth in claim 2, in which said modulator has a gray scale so as to modulate said flux.

6. The self-calibrating transducer system as set forth in claim 2, in which a surface of said manipulator serves as said modulator.

7. The self-calibrating transducer system as set forth in claim 2, in which said converter includes

a light receiving port receiving a modulated light beam as said flux passing through said modulator

a light detecting element converting said modulated light beam to photo current serving as said data signal, and

an optical fiber connected between said light receiving port and said light detecting element.

8. The self-calibrating transducer system as set forth in claim 7, in which said light receiving port further receiving another modulated light beam modulated through another modulator attached to another manipulator so that said manipulator shares said light receiving port with said another manipulator.

9. The self-calibrating transducer system as set forth in claim 1, in which said second signal generator includes

a generator radiating a flux across said trajectory,

a modulator connected to said manipulator so as to modulate said flux, and

a converter converting the modulated flux to said data signal.

10. The self-calibrating transducer system as set forth in claim 9, in which said generator includes

a light emitting element producing detecting light from electric power,

a light radiating port for radiating said detecting light as a light beam serving as said flux, and

an optical fiber connected between said light emitting element and said light radiating port.

11. The self-calibrating transducer system as set forth in claim 10, in which said light radiating port further radiates said detecting light as another light beam toward another modulator attached to another manipulator so that said manipulator shares said light radiating port with said another manipulator.

12. The self-calibrating transducer system as set forth in claim 9, in which said modulator is formed with said unique points different in transparency from a remaining portion so that said flux is at least once modulated at each of said unique points.

13. The self-calibrating transducer system as set forth in claim 12, in which said unique points are implemented by a boundary between a transparent portion and said remaining portion and another boundary between another transparent portion and said remaining portion.

14. The self-calibrating transducer system as set forth in claim 13, in which said boundary is spaced from said another boundary by a predetermined distance so that said relation expresses said magnitude of said data signal varied together with a current position of said manipulator on said trajectory.

15. The self-calibrating transducer system as set forth in claim 1, in which said physical quantity is a distance between a current position of said manipulator and an origin on said trajectory.

16. The self-calibrating transducer system as set forth in claim 15, in which said data analyzer determines an increment of said magnitude of said data signal at a unit value of said distance, and estimates a value of said distance at said certain point on said trajectory as said value of said physical quantity.

17. The self-calibrating transducer system as set forth in claim 9, in which said converter includes

a light receiving port receiving a modulated light beam as said flux passing through said modulator,

a light detecting element converting said modulated light beam to photo current serving as said data signal, and

an optical fiber connected between said light receiving port and said light detecting element.

18. The self-calibrating transducer system as set forth in claim 17, in which said light receiving port further receiving another modulated light beam modulated through another modulator attached to another manipulator so that said manipulator shares said light receiving port with said another manipulator.

19. A musical instrument for producing tones, comprising:

plural manipulators respectively assigned attributes of tones, and independently moved along trajectories, respectively;

a tone generating system associated with said plural manipulators, and producing said tones having the designated attributes; and

a self-calibrating transducer system monitoring said plural manipulators for converting a physical quantity expressing motion of each manipulator on the trajectory to a data signal, and including

a first signal generator producing said data signal, a magnitude of which is representative of said physical quantity on said trajectory,

a second signal generator producing a calibration signal, a magnitude of which is representative of a predetermined value of said physical quantity at unique points on said trajectory,

a data accumulator connected to said first signal generator and said second signal generator and accumulating a series of values of said magnitude of said data signal on said trajectory, another series of values of said magnitude of said calibration signal and pieces of tag data making the values of said magnitude of said data signal correlated with the values of said magnitude of said calibration signal,

a data analyzer connected to said data accumulator, estimating a value of said physical quantity of said data signal at a certain point on said trajectory on the basis of said predetermined value of said physical quantity and a value of said magnitude of said data signal at said certain point and determining a relation between said physical quantity and said magnitude of said data signal along said trajectory so as to memorize said relation therein, and

a determiner connected to said data analyzer and said first signal generator and responsive to said data signal so as uniquely to make values of said magnitude of said data signal correspond to values of physical quantity of said manipulator at any point on said trajectory with reference to said relation memorized in said data analyzer.

20. The musical instrument as set forth in claim 19, in which keys and a combination of action units, hammers, strings and key actuators serve as said plural manipulators and said tone generating system so that said musical instrument is fabricated on the basis of an acoustic piano.