US5132599A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Velocity control apparatus
Assignee: Fanuc Corp
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Filing: 1989-01-27
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Granted: 1992-07-21
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Expires: 2009-01-27
Abstract
Abstract A velocity control apparatus in which velocity of a servomotor (12) is controlled by PWM-control of an inverter is so adapted that the gain (K') of an amplifier section (11) in a current loop is held constant by detecting the power supply voltage of the inverter.
Inventors
- 👤 Shinichi Kono
- 👤 Hironobu Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:49
CPC Classifications
H; H02; H02P; H02P27/00; H02P27/04; H02P27/06; H02P27/08; G; G05; G05B; G05B11/00; G05B11/01; G05B11/26; G05B11/28; H02M; H02M5/00; H02M5/40; H02M5/42; H02M5/44; H02M5/453; H02M5/458
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
136 words
A velocity control apparatus for controlling drive current of a servomotor by a PWM-controlled inverter circuit, said PWM-controlled inverter circuit being operatively connected to a power supply, said velocity control apparatus comprising: voltage detecting means for detecting an output voltage value of the power supply; gain control means for holding constant a current loop gain based on the output voltage value detected by said voltage detecting means; means for receiving a command current value; and PWM-control means for PWM-controlling the PWM-controlled inverter circuit, said PWM-control means includes at least constant computing means for computing a current loop constant inversely proportional to the output voltage value of the power supply, and signal generating means for forming a PWM-control signal from the current loop constant and the command current value so that the current loop gain remains constant.
Claim 2
Dependent Claim
136 words
A velocity control apparatus for controlling drive current of a servomotor by a PWM-controlled inverter circuit, said PWM-controlled inverter circuit being operatively connected to a power supply, said velocity control apparatus comprising: voltage detecting means for detecting an output voltage value of the power supply; gain control means for holding constant a current loop gain based on the output voltage value detected by said voltage detecting means; means for receiving a command current value; and PWM-control means for PWM-controlling the PWM-controlled inverter circuit, said PWM-control means includes at least constant computing means for computing a current loop constant inversely proportional to the output voltage value of the power supply, and signal generating means for forming a PWM-control signal from the current loop constant and the command current value so that the current loop gain remains constant.
Claim 3
Dependent Claim
59 words
A velocity control apparatus as recited in claim 1, wherein said apparatus further comprises: a servomotor; command means for forming a current command a velocity command for the servomotor; and arithmetic means for computing a PWM command voltage based on a differential signal between the current command from said command means and a current feedback signal from the servomotor.
Claim 4
Dependent Claim
66 words
A velocity control apparatus as recited in claim 2, wherein said velocity control apparatus further comprises a control unit including at least means for executing computations of a constant in the PWM control means within one sampling period of the current feedback signal from the servomotor; means for executing computing the PWM command voltage; and means for deciding and outputting the drive current to the servomotor.
Claim 5
Independent Claim
98 words
A method for controlling a motor current to a servomotor in accordance with a command current, said method comprising the steps of: (a) detecting an actual motor current of the servomotor; (b) calculating an error current as the difference between the command current and the actual motor current; (c) detecting a power supply voltage; (d) calculating a current loop constant to be inversely proportional to the power supply voltage; (e) calculating a PWM control signal based on the error current and the current loop constant; and (f) controlling the motor current in accordance with the PWM control signal.
Claim 6
Independent Claim
98 words
A method for controlling a motor current to a servomotor in accordance with a command current, said method comprising the steps of: (a) detecting an actual motor current of the servomotor; (b) calculating an error current as the difference between the command current and the actual motor current; (c) detecting a power supply voltage; (d) calculating a current loop constant to be inversely proportional to the power supply voltage; (e) calculating a PWM control signal based on the error current and the current loop constant; and (f) controlling the motor current in accordance with the PWM control signal.
Claim 7
Dependent Claim
22 words
A method as recited in claim 4, wherein a current loop gain is constant irrespective of changes to the power supply voltage.
Claim 8
Dependent Claim
27 words
A method as recited in claim 4, wherein said method further comprises step (g) controlling the servomotor in accordance with the motor current produced in step (e).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-21 | 1996-01-20 | 1996-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-21 | 2000-01-20 | 2000-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-21 | 2004-01-20 | 2004-07-21 | $7700.00 | Window Closed / Lapsed |