Detector for force, acceleration or magnetism with respect to components in multi-dimensional directions

• US 5,343,765 A
• Filed: 10/13/1992
• Issued: 09/06/1994
• Est. Priority Date: 10/25/1991
• Status: Expired due to Fees

• Current Assignee: Kazuhiro Okada
• Original Assignee: Kazuhiro Okada
• Inventors: Okada, Kazuhiro
• Primary Examiner(s): RAEVIS, ROBERT R
• Application Number:
  US07/960,545
• Time in Patent Office: 693 Days
• Field of Search: 73/862.043, 73/862.044, 73/794, 73/862.042, 73/767, 310/338
• US Class Current: 73/862.043
• CPC Class Codes: G01L 5/165 using variations in capacitance
• CPC Class Codes: G01L 5/167 using piezoelectric means
• CPC Class Codes: G01P 15/0922 of the bending or flexing mode type
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/084 the mass being suspended at more than one of its sides, e.g. membrane-type suspension, so as to permit multi-axis movement of the mass
• CPC Class Codes: G01R 33/038 using permanent magnets, e.g. balances, torsion devices

Abstract

On the upper surface of a flexible substrate, four displacement electrodes are arranged. A fixed substrate is arranged thereabove, and fixed electrodes opposite to the displacement elctrodes are respectively arranged on the fixed substrate. These displacement electrodes and the fixed electrodes form capacitance elements C1 to C4, respectively. A columnar working body is fixed on the lower surface of the flexible substrate. A bending is produced in the flexible substrate on the basis of an acceleration exerted thereon. As a result, capacitance values of the respective capacitance elements C1 to C4 vary. The capacitance values of the capacitance elements C1 to C4 are converted to respective voltage values V1 to V4. A component in the X-axis direction is obtained as Vx=(V1+V4)-(V2+V3), a component in the Y-axis direction is obtained as Vy=(V1+V2)-(V3+V4), and a component in the Z-axis direction is obtained as Vz=V1+V2+V3+V4.

Claims

1. A force detector for detecting components in multi-dimensional directions of force in an XYZ three-dimensional coordinate system, comprising:

eight sets of detection elements constituted by piezoelectric elements in a plate form, upper electrodes formed on upper surfaces of said piezoelectric elements, and lower electrodes formed on lower surfaces of said piezoelectric elements, and

a substrate having flexibility wherein the origin is defined at a point within the substrate, an X-axis is defined so that it passes through the origin and extends in a direction parallel to the substrate surface, a Y-axis is defined so that it is perpendicular to the X-axis at the origin and extends in a direction parallel to the substrate surface, and a Z-axis is defined so that it passes through the origin and extends in a direction perpendicular to the substrate surface,

wherein said eight sets of detection elements are such that the first detection element is arranged on the substrate in a central area corresponding to the first quadrant of the XY plane, the second detection element is arranged on the substrate in a central area corresponding to the second quadrant of the XY plane, the third detection element is arranged on the substrate in a central area corresponding to the third quadrant of the XY plane, the fourth detection element is arranged on the substrate in a central area corresponding to the fourth quadrant of the XY plane, the fifth detection element is arranged on the substrate in a peripheral area corresponding to the first quadrant of the XY plane, the sixth detection element is arranged on the substrate in a peripheral area corresponding to the second quadrant of the XY plane, the seventh detection element is arranged on the substrate in a peripheral area corresponding to the third quadrant of the XY plane, and the eight detection element is arranged on the substrate in a peripheral area corresponding to the fourth quadrant of the XY plane, one electrode of said respective detection elements being fixed to the substrate,

wherein either of peripheral portion of said substrate or a central portion in a vicinity of the origin thereof is fixed to a detector casing,

wherein there is a working point having a function to transmit a force produced on the basis of a physical action exerted from an external point to the peripheral portion or the central portion of said substrate, and

wherein potentials of one electrode with respect to the other electrodes fixed on the substrate are obtained in the respective detection elements,

the detector detecting a force component in the x-axis direction produced at said working point by detecting a difference between a sum of respective potentials of said first, fourth, sixth and seventh detection elements and a sum of respective potentials of said second, third, fifth and eighth detection elements, and

the detector detecting a force component in the Y-axis direction produced at said working point by detecting a difference between a sum of respective potentials at said first, second, seventh, and eight detection elements and a sum of respective potentials of said third, fourth, fifth and sixth, detection elements.

2. A force detector as set forth in claim 1, wherein the detector detecting a force component in the Z-axis direction produced at said working point by detecting a difference between a sum of respective potentials at said first and third detection elements and a sum of respective potentials of said fifth and seventh detection elements.

3. A force detector as set forth in claim 1, wherein the detector detecting a force component in the Z-axis direction produced at said working point for detecting a difference between a sum of respective potentials at said first, second, third and fourth detection elements and a sum of respective potentials at said fifth, sixth, seventh and eighth detection elements.

4. A force detector for detecting components in multi-dimensional directions of force in an XYZ three-dimensional coordinate system, comprising:

eight sets of detection elements each of the elements comprising a piezoelectric element in a plate form and a first electrode formed on a first surface of said piezoelectric elements, and

a substrate having flexibility which comprises eight second electrodes formed on a surface thereof, each of said eight sets of detection elements being arranged on each of said eight second electrodes, respectively, in such a manner that a second surface of each piezoelectric element of each detection is fixed to each second electrode,

wherein the origin is defined at a point within said substrate, an X-axis is defined so that it passes through the original and extends in a direction parallel to the substrate surface, a Y-axis is defined so that it is perpendicular to the X-axis at the origin and extends in a direction parallel to the substrate surface, and a Z-axis is defined so that it passes through the origin and extends in a direction perpendicular to the substrate surface,

wherein said eight sets of detection elements are such that the first detection element is arranged on the substrate in a central area corresponding to the first quadrant of the XY plane, the second detection element is arranged on the substrate in a central area corresponding to the second quadrant of the XY plane, the third detection element is arranged on the substrate in a central area corresponding to the third quadrant of the XY plane, the fourth detection element is arranged on the substrate in a central area corresponding to the fourth quadrant of the XY plane, the fifth detection element is arranged on the substrate in a peripheral area corresponding to the first quadrant of the XY plane, the sixth detection element is arranged on the substrate in a peripheral area corresponding to the second quadrant of the XY plane, the seventh detection element is arranged on the substrate in a peripheral area corresponding to the third quadrant on the XY plane, and the eight detection element is arranged on the substrate in a peripheral area corresponding to the forth quadrant of the XY plane, one electrode of said respective detection elements being fixed to the substrate,

wherein either a peripheral portion of said substrate or a central portion in a vicinity of the origin thereof is fixed to a detector casing,

wherein there is a working point having a function to transmit a force produced on the basis of a physical action exerted from an external point to the peripheral portion or the central portion of said substrate, and

wherein potentials of one electrode with respect to the other electrodes fixed on the substrate are obtained in the respective detection elements.

the detector detecting a force component in the X-axis direction produced at said working point by detecting a difference between a sum of respective potentials of said first, fourth, sixth and seventh detection elements and a sum of respective potentials of said second, third, fifth and eighth detection elements, and

the detector detecting a force component in the Y-axis direction produced at said working point by detecting a difference between a sum of respective potentials at said first, second, seventh, and eighth detection elements and a sum of respective potentials of said third, fourth, fifth and sixth detection elements.

5. A force detector as set forth in claim 4, wherein the detector detecting a force component in the Z-axis direction produced at said working point by detecting a difference between a sum of respective potentials at said first and third detection elements and a sum of respective potentials of said fifth and seventh detection elements.

6. A force detector as set forth in claim 4, wherein the detector detecting a force component in the z-axis direction produced at said working point by detecting a difference between a sum of respective potentials at said first, second, third and fourth detection elements and a sum of respective potentials at said fifth, sixth, seventh and eighth detection elements.