METHOD AND APPARATUS FOR AUTOMATICALLY BALANCING DEFLECTION SENSORS ON ROTATING EQUIPMENT

• US 3,681,978 A
• Filed: 02/23/1971
• Issued: 08/08/1972
• Est. Priority Date: 02/23/1971
• Status: Expired due to Term

• Current Assignee: Edgar J. Watson, Richard A. Mathias
• Original Assignee: Edgar J. Watson, Richard A. Mathias
• Inventors: Mathias, Richard A., Watson, Edgar J.
• Primary Examiner(s): Gill, James J.
• Application Number:
  US05/118,063
• Time in Patent Office: 532 Days
• Field of Search: 73/71.4,67 324/61R
• US Class Current: 73/660
• CPC Class Codes: G01B 7/16 for measuring the deformation in a solid, e.g. by resistance strain gauge
• CPC Class Codes: G01B 7/312 for measuring eccentricity, i.e. lateral shift between two parallel axes
• CPC Class Codes: G01M 1/22 and converting vibrations due to imbalance into electric variables
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/37391 Null, initial load, no load torque detection or other parameter at no load
• CPC Class Codes: G05B 2219/49177 Runout, eccentricity, unbalance of tool or workpiece

Abstract

A method and apparatus for automatically balancing a periodic deflection signal being produced by deflection sensors which are applied to a rotating body. A device is provided for dividing each period of the deflection signal into a number of timing periods. During each timing period, while the body is idling, a digital signal representing the deflection signal is generated and input into storage. During successive corresponding periods of the deflection signal, when an external load is applied to the body, the digital signal is retrieved from storage and converted into an analogue noise signal. The noise signal is subtracted from the deflection signal thus balancing the sensors and producing a corrected deflection signal representing a very accurate indication of deflection of the body as a result of the external load.

Claims

1. An apparatus for balancing deflection transducers responsive to a rotating body, said transducers producing a periodic analogue deflection signal representing inherent periodic eccentricities when the body is idling, the apparatus comprising:

a. means for cyclically generating sampling signals defining a number of timing periods;

b. means responsive to the deflection signal and the sampling signals for converting the deflection signal during each timing period into a corresponding digital signal;

c. means responsive to the sampling signals and the digital signal for storing the digital signal during each timing period;

d. means connected to the storing means for converting a stored digital signal into an analogue idling noise signal; and

e. means responsive to the deflection signal aNd the idling noise signal for modifying the deflection signal as a function of the noise signal to produce a corrected deflection signal having a magnitude of approximately zero while the rotating body is idling.

2. An apparatus for balancing deflection transducers responsive to a rotating body, said transducers producing a periodic analogue deflection signal representing inherent periodic eccentricities when the body is idling, the apparatus comprising:

a. means responsive to the rotating body for generating sampling signals representing a number of timing periods over each period of the eccentricity;

b. means responsive to the deflection signal and the sampling signals for converting the deflection signal during each timing period into a corresponding digital signal;

c. means responsive to the sampling signals and the digital signal for storing the digital signal during each timing period;

d. means connected to the storing means for converting a stored digital signal into an analogue idling noise signal; and

e. means responsive to the deflection signal and the idling noise signal for modifying the deflection signal as a function of the noise signal to produce a corrected deflection signal having a magnitude of approximately zero while the rotating body is idling.

3. An apparatus for balancing deflection sensors responsive to a rotating body, said sensors producing a periodic analogue deflection signal representing a sensor unbalance when the body is not under the influence of an external load, the apparatus comprising:

a. means responsive to the rotating body for generating sampling signals defining a predetermined number of timing periods during each period of the analogue deflection signal;

b. means responsive to the analogue deflection signal and the sampling signals for converting the sign and magnitude of the analogue deflection signal during each timing period to a corresponding digital signal;

c. means responsive to the sampling signals and the digital signal for storing the digital signal during each timing period;

d. means responsive to the sampling signals and the storing means for sequentially producing each of the stored digital signals as an output during successive corresponding timing periods;

e. means responsive to the output of the producing means for converting each digital signal into an analogue idling noise signal representing inherent deflections of the idling rotating body; and

f. means responsive to the analogue deflection signal and the analogue idling noise signal for changing said deflection signal as a function of the sign and magnitude of the idling noise signal to produce a corrected deflection signal defining a balanced condition of the sensors.

4. An apparatus for balancing deflections sensors responsive to a rotating body and producing a periodic analogue deflection signal, the apparatus comprising:

a. means responsive to the rotating body for generating sampling signals defining a predetermined number of timing periods during each period of the analogue deflection signal;

b. means responsive to the rotating body for producing a control signal when the rotating body is idling;

c. means responsive to the control signal, the analogue deflection signal and the sampling signals for converting the sign and magnitude of the analogue deflection signal into a corresponding digital signal during each timing period while the rotating body is idling;

d. means responsive to the sampling signals and the digital signal for storing the digital signal during each timing period;

e. means responsive to the sampling signals and the storing means for sequentially producing each of the stored digital signals as an output during successive corresponding timing periods;

f. means responsive to the output of the producing means for converting each digital signal into an analogue idling noise signal representing inherent deflections of the idling rotating body; and

g. means responsive to the analogue deflection signal and the analogue idling noise signal for changing said deflection signal as a function of the sign and magnitude of the idling noise signal to produce a corrected deflection signal defining a balanced condition of the sensors.

5. An apparatus for balancing deflection sensors responsive to a rotating body, said sensors producing a periodic analogue deflection signal representing a sensor unbalance when the body is not under the influence of an external load, the apparatus comprising:

a. means responsive to the rotating body for generating sampling signals defining a predetermined number of timing periods during each period of the analogue deflection signal;

b. means responsive to the sampling signals for generating a number of timing signals during each timing period;

c. a digital store responsive to the timing signals and including a number of storage elements and an addressing circuit for addressing a unique storage element containing a previously stored signal;

d. a buffer store connected to the digital store and responsive to the timing signals for storing the previously stored signal in the addressed storage element;

e. means responsive to the timing signals and the analogue signal and having an output connected to the digital store for converting the analogue signal into a corresponding digital signal and transferring said digital signal into the addressed storage element;

f. means connected to the buffer store for converting each digital signal into an analogue idling noise signal representing inherent deflections of the idling rotating body; and

g. means responsive to the analogue deflection signal and the analogue idling noise signal for changing said deflection signal as a function of the sign and magnitude of the idling noise signal to produce a corrected deflection signal defining a balanced condition of the sensors.

6. An apparatus for balancing a deflection transducer circuit responsive to a rotating body and producing a periodic analogue deflection signal, the apparatus comprising:

a. a position encoder coupled to the rotating body for producing a number of sampling signals representing a number of timing periods during each period of the analogue deflection signal;

b. a timing signal generator connected to the position encoder for producing a number of timing signals during each of the timing periods;

c. means responsive to the rotating body for producing a first control signal when the rotating body is idling and a second control signal when the rotating body is under the influence of an external load;

d. an addressing circuit connected to the timing signal generator for producing an addressing signal in response to a first timing signal;

e. a digital store connected to the timing signal generator and the addressing circuit and containing a plurality of storage elements each containing a previously stored digital signal, one of said elements being uniquely selected by the addressing signal and being cleared to zero in response to a third timing signal and the first control signal;

f. a buffer store connected to the timing signal generator and the digital store for storing the previously stored digital signal in response to a second timing signal and maintaining said signal as an output for the duration of the g. an analogue to digital converter having inputs responsive to the control signals, the analogue deflection signal and the timing signals and an output connected to the digital store for converting the analogue deflection signal into a corresponding digital signal in response to the second timing signal and the first control signal and transferred said digital signal to the uniquely selected storage element, said converter being inhibited in response to the second control signal;

h. a digital to analogue converter connected to the buffer store for converting the previously stored digital signal into an analogue idling noisE signal; and

i. an amplifier circuit connected to the digital to analogue converter and the transducer circuit for subtracting during each timing period the idling noise signal from the analogue deflection signal to produce a corrected deflection signal.

7. A method for balancing deflection sensors responsive to a rotating body to compensate for deflections inherent in an idling rotating of said body, said sensors producing a periodic analogue deflection signal, the method comprising the steps of:

a. generating a number of sampling signals representing timing periods during each period of the analogue deflection signal;

b. converting the magnitude of the analogue deflection signal into a corresponding digital signal during each timing period generated during an idling rotation of said body;

c. storing each of the digital signals;

d. converting each digital signal into a corresponding analogue idling noise signal; and

e. modifying the analogue deflection signal as a function of the idling noise signal to produce a corrected deflection signal having a magnitude of approximately zero when the rotating body is idling.

8. A method for balancing deflection sensors responsive to a rotating body by compensating a periodic analogue deflection signal from said sensors by a signal representing inherent deflections during an idling rotating of said body, the method comprising the steps of:

a. generating a number of sampling signals representing timing periods in response to each period of the deflection signal;

b. producing a number of timing signals in response to each of the sampling signals;

c. converting during an idling rotating of said body the sign and magnitude of the analogue deflection signal into a representative digital signal in response to one timing signal;

d. storing the digital signal in a digital store in response to another timing signal;

e. transferring the digital signal from said digital store to a buffer store in response to a successive corresponding sampling signal;

f. converting the digital signal into an analogue idling noise signal; and

g. subtracting during each timing period the idling noise signal from the analogue deflection signal to produce a corrected deflection representing an output of balanced deflection sensors.

9. A method for balancing deflection sensors responsive to a rotating body, said sensors producing a periodic analogue deflection signal representing inherent deflections of the body when no external load is applied thereto, the method comprising the steps of:

a. generating a plurality of sampling signals representing timing periods during each period of the analogue deflection signal;

b. addressing in response to each sampling signal a unique storage element in a digital store, said element containing a previously stored digital signal therein;

c. transferring the previously stored digital signal from the unique storage element to a buffer store;

d. converting the digital signal in the buffer store into an analogue idling noise signal;

e. subtracting the idling noise signal from the analogue deflection signal to produce a corrected deflection signal defining a balanced state of the deflection sensors;

f. clearing the unique storage element to zero;

g. converting during each timing period the analogue deflection signal into a new digital signal; and

h. storing the new digital signal in the unique storage element in the digital store.

10. A method for balancing deflection sensors responsive to a rotating body by compensating a periodic analogue deflection signal from said sensors by a signal representing inherent deflections during an idling rotating of said body, the method comprising the steps of:

a. generating a plurality of sampling signals representing timing periods during each period of the analogue deflection signal;

b. generating a number of timing signals in response to each of the sampling signals;

c. addressing in response to a first timing signal a unique storage element in a digital store, said element containing a previously stored digital signal;

d. transferring the previously stored digital signal from the unique storage element into a buffer store in response to a second timing signal;

e. generating a control signal in response to an idling rotation of said body;

f. clearing the unique storage element to zero in response to a third timing signal and the control signal;

g. converting the analogue deflection signal into a new digital signal in response to the second timing signal and the control signal;

h. storing the new digital signal in the unique storage element in the digital store;

i. converting the previously stored digital signal in the buffer store into an analogue idling noise signal; and

j. subtracting the analogue idling noise signal from the analogue deflection signal to produce a corrected deflection signal defining a balanced condition of the deflection sensors.