Apparatus for remotely determining the angular orientation, speed and/or direction of rotary objects

• US 4,779,094 A
• Filed: 11/21/1986
• Issued: 10/18/1988
• Est. Priority Date: 11/23/1985
• Status: Expired due to Fees

• Current Assignee: Chae T. Lim, Dong W. Choi, Doo S. Lee, Hyoung J. Lee
• Original Assignee: Chae T. Lim, Dong W. Choi, Doo S. Lee, Hyoung J. Lee
• Inventors: Lee, Hyoung J., Lee, Doo S., Choi, Dong W., Lim, Chae T.
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): OBERLEY, ALVIN E
• Application Number:
  US06/933,178
• Time in Patent Office: 697 Days
• Field of Search: 340/870.37, 340/347 P, 340/365 S, 324/61 R, 250/231 SE
• US Class Current: 340/870.37
• CPC Class Codes: G01D 5/2415 adapted for encoders
• CPC Class Codes: G01P 13/045 with speed indication
• CPC Class Codes: H03M 1/28 with non-weighted coding

Abstract

A circular array of equally spaced, identical stationary electrodes are arranged about the center of the array and a rotary electrode is substantially arranged on a surface of the rotary member to be monitored in such a manner that M among N stationary electrodes have a maximum capacitance by being in confronting relationship to the rotary electrode according to the angular position of the rotary member, a maximum capacitance is in proportion to θ which is the azimuthal angle of the radius as measured from the initial end of the stationary electrode. The angular position of rotary member is identified from the stationary electrodes which are in confronting relationship to rotary electrode and are identified by measuring the output signal owing to a maximum capacitance while scanning the stationary electrodes.

Claims

1. A capacitively reading apparatus for remotely reading the angular position, speed and/or direction of rotation of a rotary member as it rotates about an axis of rotation and defines a circumferential path comprising:

a. means for arranging a rotary electrode on a surface of said rotary member to be monitored;

b. means for arranging an array of stationary electrodes on a surface of a stationary member whose surface is positioned in a confronting relationship to said circumferential path so that capacitance is defined between each of said stationary electrodes and said rotary electrode, a plurality of said stationary electrodes being in a confronting relationship to said rotary electrode according to the angular position of said rotary electrode, have dominant capacitance;

c. means for being connected to said electrodes to apply an input signal to said capacitance and measure an output signal which is in position to said capacitance;

d. means for generating codes, each of which is corresponding to each angular position of said rotary member, while applying said input signal to said capacitance and measuring the output signal owing to said capacitance;

e. means for latching the codes corresponding to the angular position of said rotary electrode by a maximum output signal owing to said dominant capacitance; and

f. means for transmitting said codes to one of a local facility for display and a central facility at a distance for further process, wherein said applying means includes means for insuring said output signal obtained during one of said codes consists of several periods, further comprising means for selecting the central periods of said output signal.

2. A capacitively reading apparatus for remotely reading the angular position, speed and/or direction of rotation of a rotary member as it rotates about an axis of rotation and defines a circumferential path comprising:

a. means for arranging a rotary electrode on a surface of said rotary member to be monitored;

b. means for arranging an array of stationary electrodes on a surface of a stationary member whose surface is positioned in a confronting relationship to said circumferential path so that capacitance is defined between each of said stationary electrodes and said rotary electrode, and a plurality of said stationary electrodes, being in a confronting relationship to said rotary electrode according to the angular position of said rotary electrode, have dominant capacitance;

c. means for being connected to said electrodes to apply an input signal to said capacitance and measure an output signal which is in position to said capacitance;

d. means for generating codes, each of which is corresponding to each angular position to said rotary member, while applying said input signal to said capacitance and measuring the output signal owing to said capacitance;

e. means for latching the codes corresponding to the angular position of said rotary electrode by a maximum output signal owing to said dominant capacitance; and

f. means for transmitting said codes to one of a local facility for display and a central facility at a distant for further process, wherein said transmitting means is achieved by modulating a carrier, which is the input waveform of a counter which is used to scan said stationary electrodes, with a modulation signal which is said maximum output signal.

3. An apparatus according to claim 2, wherein said carrier is converted into a sinusoidal waveform by a filtering function and said modulation signal is converted into a sinusoidal waveform by filtering function.

4. An apparatus according to claim 2, wherein said sinusoidal waveforms are obtained by integrating functions.

5. A capacitively sensing device for remotely monitoring the angular position, speed and/or direction of rotation of a rotary member as it rotates about an axis of rotation and defines a circumferential path comprising:

an array of N identical stationary electrodes substantially arranged on equally divided N areas on a surface of a stationary member which is positioned in parallel to said circumferential path where N is an integer;

a rotary electrode substantially arranged on a surface of the rotary member in such a manner that said rotary electrode is unsymmetrical about an axis of rotation and is in confronting relationship to M stationary electrodes among said N stationary electrodes, where M is an integer greater than one and less than N;

means for applying one analog input signal simultaneously to M capacitors defined between said M stationary electrodes and said rotary electrode, where each capacitor has a maximum capacitance defined by the area of a stationary electrode; and

means for measuring an output signal whose magnitude is in proportion to said maximum capacitance;

wherein said applying means comprises means for connecting said input signal simultaneously to K stationary electrodes among said M stationary electrodes where K is an integer less than M; and

said measuring means comprises means for connecting an amplifier simultaneously to the remaining M-K stationary electrodes among said M stationary electrodes in such a manner that said amplifier provides a maximum analog output signal which is responsive to the sum of capacitively induced signals in said M-K stationary electrodes.

6. A sensing device according to claim 5, wherein N is 10;

M is 2;

said input signal is connected to one of said 2 stationary electrodes which are in confronting relationship to said rotary electrode; and

said amplifier is connected to the other of said 2 stationary electrodes.

7. A sensing device according to claim 6, wherein each of alternate 5 stationary electrodes (A, B, C, D, E) among said 10 stationary electrodes is connected to the third stationary electrode from that stationary electrode, respectively, in the same direction;

said rotary electrode is in confronting relationship to 2 stationary electrodes which are next to each other;

said input signal is connected to one of said 2 stationary electrodes through one of said 5 stationary electrodes (A, B, C, D, E); and

said amplifier is connected to the other stationary electrode of said 2 stationary electrodes through one of the remaining 4 stationary electrodes except the one connected to said input signal among said 5 stationary electrodes (A, B, C, D, E).

8. A capacitively reading apparatus for remotely monitoring the angular position, speed and/or direction of rotation of a rotary member as it rotates abut an axis of rotation and defines a circumferential path comprising:

an array of N identical stationary electrodes substantially arranged on equally divided N areas on a surface of a stationary member which is positioned in parallel to said circumferential path, where N is an integer;

a rotary electrode substantially arranged on a surface of the rotary member in such a manner that said rotary electrode is unsymmetrical about an axis of rotation and is in confronting relationship to M stationary electrodes among said N stationary electrodes, where M is an integer less than N;

means for applying an analog input signal of P cycles simultaneously to K stationary electrodes among said M stationary electrodes, where P and K are integers and K is less than M;

means for connecting an analog amplifier simultaneously to the remaining M-K stationary electrodes among said M stationary electrodes so as to provide a maximum analog output signal which is responsive to the sum of capacitively induced signal in said M-K stationary electrodes;

means for converting the analog output signal obtained from said amplifier into a digital signal;

means for counting the number of one among said M stationary electrodes which are connected between said input signal and said output signal; and

means for latching said number by said digital signal.

9. An apparatus according to claim 8, wherein N is 10;

M is 2;

said means for applying said analog input signal comprises a means for connecting one of said 2 stationary electrodes, which are in confronting relationship to said rotary electrode, to said input signal; and

said means for connecting to said amplifier comprises a means for connecting the other stationary electrode of said 2 stationary electrodes to said amplifier.

10. An apparatus according to claim 9, wherein each of alternate 5 stationary electrodes (A, B, C, D, E) among said 10 stationary electrodes is connected to the third stationary electrode from that stationary electrode, respectively, in the same direction;

said rotary electrode is in confronting relationship to 2 stationary electrodes which are next to each other;

said means for applying an input signal comprises a means for connecting one of said 2 stationary electrodes which are in confronting relationship to said rotary electrode to said input signal through one of said 5 stationary electrodes (A, B, C, D, E); and

said means for connecting said amplifier comprises a means for connecting the other stationary electrode of said 2 stationary electrodes to said amplifier through one of the remaining 4 stationary electrodes except the one connected to said input signal among said 5 stationary electrodes (A, B, C, D, E).

14. An apparatus according to one of claims 8-13, wherein said means for converting said analog output signal into a digital signal includes means for selecting the central few cycles among said P cycles of said analog output signal and converting said few cycles into a digital signal.

11. A capacitively reading apparatus for remotely monitoring the angular position, speed and/or direction of rotation of a rotary member as it rotates about an axis of rotation and defines a circumferential path comprising:

an array of N identical stationary electrodes substantially arranged on equally divided N areas on a surface of a stationary member which is positioned in parallel to said circumferential path where N is an integer;

a rotary electrode substantially arranged on a surface of the rotary member in such a manner that said rotary electrode is unsymmetrical about an axis of rotation and is in confronting relationship to M stationary electrodes among said N stationary electrodes where M is an integer less than N;

means for applying an analog input signal of P cycles simultaneously to K stationary electrodes among said M stationary electrodes where P and K are integers and K is less than M;

means for connecting an analog amplifier simultaneously to the remaining M-K stationary electrodes among said M stationary electrodes so as to provide a maximum analog output signal which is responsive to the sum of capacitively induced signal in said M-K stationary electrodes;

means for converting said analog output signal into a digital signal;

means for generating a carrier signal from said input signal;

means for generating a modulation signal from said digital signal; and

means for modulating said carrier signal with said modulation signal.

12. An apparatus according to claim 11, wherein:

N is 10;

M is 2;

said means for applying an input signal comprises a means for connecting one of said 2 stationary electrodes, which are in confronting relationship to said rotary electrode, to said input signal; and

said means for connecting said amplifier comprises a means for connecting the other of said 2 stationary electrodes to said amplifier.

13. An apparatus according to claim 12, wherein each of alternate 5 stationary electrodes (A, B, C, D, E) among said 10 stationary electrodes is connected to the third stationary electrode from that stationary electrode, respectively, in the same direction;

said rotary electrode is in confronting relationship to 2 stationary electrodes which are next to each other;

said means for applying an input signal comprises a means for connecting one of said 2 stationary electrodes which are in confronting relationship to said rotary electrode to said input signal through one of said 5 stationary electrodes; and

said means for connecting said amplifier comprises a means for connecting the other stationary electrode of said 2 stationary electrodes to said amplifier through one of the remaining 4 stationary electrodes except the one connected to said input signal among said 5 stationary electrodes (A, B, C, D, E).