US5073746A
Expired / Lapsed
US
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Speed control method for servomotors
Assignee: Fanuc Corp
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Filing: 1989-12-05
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Granted: 1991-12-17
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Expires: 2009-12-05
Abstract
Abstract A speed control method for a servomotor, capable of smoothly rotating the servomotor without causing pulsating rotation even when the servomotor rotates at low speeds. On the basis of the numbers of feedback pulses (P2k(m-1)-k+1, . . . , P2km) detected and stored at intervals of a period (TS/2k) equal to a value obtained by dividing an estimated speed calculation period (TS) by an integer multiple of 2, the number (A) of feedback pulses in each estimated speed calculation period and the number (B) of pulses in a time period from a midpoint ((m-1)TS-TS/2) of an estimated speed calculation period immediately before each estimated speed calculation period to a midpoint (mTS-TS/2) of each estimated speed calculation period are calculated, and an estimated speed indicative of an actual rotation speed of the servomotor is further calculated on the basis of the thus calculated numbers (A, B) of pulses.
Inventors
- 👤 Keiji Sakamoto
- 👤 Yasusuke Iwashita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:12
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/48; G01P3/481; G01P3/489; H; H02; H02P; H02P23/00; H02P23/16
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
159 words
A speed control method for a servomotor, comprising the steps of: (a) detecting feedback pulses at first intervals of a detection period equal to a value obtained by dividing an estimated speed calculation period by an integer multiple of 2; (b) storing a first number of the feedback pulses detected in each of the first intervals of the detection period; (c) calculating a first value indicative of a second number of feedback pulses detected and stored in a second interval corresponding to the estimated speed calculation period; (d) calculating a second value indicative of a third number of feedback pulses detected in a third interval from a midpoint of an estimated speed calculation period immediately before the estimated speed calculation period corresponding to the second interval to a midpoint of the estimated speed calculation period; and (e) calculating an estimated speed indicative of an actual rotation speed of the servomotor based upon the first value and the second value.
Claim 2
Dependent Claim
159 words
A speed control method for a servomotor, comprising the steps of: (a) detecting feedback pulses at first intervals of a detection period equal to a value obtained by dividing an estimated speed calculation period by an integer multiple of 2; (b) storing a first number of the feedback pulses detected in each of the first intervals of the detection period; (c) calculating a first value indicative of a second number of feedback pulses detected and stored in a second interval corresponding to the estimated speed calculation period; (d) calculating a second value indicative of a third number of feedback pulses detected in a third interval from a midpoint of an estimated speed calculation period immediately before the estimated speed calculation period corresponding to the second interval to a midpoint of the estimated speed calculation period; and (e) calculating an estimated speed indicative of an actual rotation speed of the servomotor based upon the first value and the second value.
Claim 3
Dependent Claim
53 words
A speed control method according to claim 1, wherein said calculating in step (e) produces the estimated speed by summing the first and second values and dividing by two to produce an average value of the first value and the second value and dividing the average value by the estimated speed calculation period.
Claim 4
Dependent Claim
173 words
A speed control method for a servomotor, comprising the steps of: (a) detecting feedback pulses during each of a plurality of detection periods, each detection period having a length equal to a value obtained by dividing an estimated speed calculation period by an integer multiple of 2; (b) storing a first number of the feedback pulses detected in each of the detection periods; (c) calculating a first value indicative of a second number of the feedback pulses detected and stored in each of consecutive intervals of the estimated speed calculation period; (d) calculating a plurality of second values indicative of third numbers of feedback pulses detected in overlapping intervals, each starting with one of the detection periods and ending with a corresponding detection period to have a length equal to the estimated speed calculation period while overlapping a pair of the consecutive intervals; and (e) calculating an estimated speed indicative of an actual rotation speed of the servomotor based upon the first value and the second values for each of the consecutive intervals.
Claim 5
Dependent Claim
173 words
A speed control method for a servomotor, comprising the steps of: (a) detecting feedback pulses during each of a plurality of detection periods, each detection period having a length equal to a value obtained by dividing an estimated speed calculation period by an integer multiple of 2; (b) storing a first number of the feedback pulses detected in each of the detection periods; (c) calculating a first value indicative of a second number of the feedback pulses detected and stored in each of consecutive intervals of the estimated speed calculation period; (d) calculating a plurality of second values indicative of third numbers of feedback pulses detected in overlapping intervals, each starting with one of the detection periods and ending with a corresponding detection period to have a length equal to the estimated speed calculation period while overlapping a pair of the consecutive intervals; and (e) calculating an estimated speed indicative of an actual rotation speed of the servomotor based upon the first value and the second values for each of the consecutive intervals.
Claim 6
Dependent Claim
35 words
A speed control method according to claim 3, wherein said calculating in step (e) produces the estimated speed from an average of the first value and second values divided by the estimated speed calculation period.
Claim 7
Independent Claim
113 words
An apparatus for determining an estimated speed of a motor, comprising: a detector to produce a pulse count representative of an amount of movement during each of a plurality of detection periods, and an estimated speed calculator to calculate the estimated speed of the motor during each of a plurality of consecutive intervals, each having a length equal to a speed calculation period and including an integral number of multiple detection periods, the estimated speed being calculated using a sum of the pulse count in the detection periods included in one of the consecutive intervals and in at least one preceding and overlapping interval having a length equal to the speed calculation period.
Claim 8
Independent Claim
113 words
An apparatus for determining an estimated speed of a motor, comprising: a detector to produce a pulse count representative of an amount of movement during each of a plurality of detection periods, and an estimated speed calculator to calculate the estimated speed of the motor during each of a plurality of consecutive intervals, each having a length equal to a speed calculation period and including an integral number of multiple detection periods, the estimated speed being calculated using a sum of the pulse count in the detection periods included in one of the consecutive intervals and in at least one preceding and overlapping interval having a length equal to the speed calculation period.
Claim 9
Independent Claim
179 words
A method for determining an estimated speed of a motor, comprising the steps of: (a) producing a pulse count representative of an amount of movement of the motor during each of a plurality of detection periods; (b) summing the pulse count produced in step (a) for each of a plurality of consecutive intervals, each having a length equal to a speed calculation period including an integral number of multiple detection periods, to produce a current interval sum for each consecutive interval; (c) summing the pulse count produced in step (a) for each of at least one preceding interval overlapping a corresponding one of the consecutive intervals to produce an overlapping interval sum for a number of the preceding intervals; and (d) producing the estimated speed corresponding to each of the consecutive intervals by adding the current interval sum to the overlapping interval sum for each of the preceding intervals corresponding thereto, to produce a result and dividing the result by the speed calculation period times one plus the number of preceding intervals used to produce the overlapping interval sum.
Claim 10
Independent Claim
179 words
A method for determining an estimated speed of a motor, comprising the steps of: (a) producing a pulse count representative of an amount of movement of the motor during each of a plurality of detection periods; (b) summing the pulse count produced in step (a) for each of a plurality of consecutive intervals, each having a length equal to a speed calculation period including an integral number of multiple detection periods, to produce a current interval sum for each consecutive interval; (c) summing the pulse count produced in step (a) for each of at least one preceding interval overlapping a corresponding one of the consecutive intervals to produce an overlapping interval sum for a number of the preceding intervals; and (d) producing the estimated speed corresponding to each of the consecutive intervals by adding the current interval sum to the overlapping interval sum for each of the preceding intervals corresponding thereto, to produce a result and dividing the result by the speed calculation period times one plus the number of preceding intervals used to produce the overlapping interval sum.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-16 | 1995-06-17 | 1995-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-16 | 1999-06-17 | 1999-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-16 | 2003-06-17 | 2003-12-17 | $7700.00 | Window Closed / Lapsed |