US4388570A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digitally controlled pulse width modulated motor speed control for servo positioning systems
Assignee: Babcock and Wilcox Co
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Filing: 1981-03-16
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Granted: 1983-06-14
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Expires: 2001-03-16
Abstract
Abstract A digitally controlled pulse width modulated control system for a servo device is disclosed wherein the control transistors (46, 48, 50, 52) can be operated directly from the incoming voltage source. The system converts the input or feedback signal into digital form that is applied to a downward counter arrangement (16, 18) which, after a pre-set period of time, allows logic circuitry (20) to selectively apply conduction pulses to the transistors (46, 48, 50, 52). Such selective conduction allows the transistors (46, 48, 50, 52) to regulate the direction of rotation of a motor (58) and the "width" or portion of the incoming waveform applied thereto via the transistors (46, 48, 50, 52).
Inventors
- 👤 Neal V. Sangree
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:07
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/03; H02P7/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
173 words
A pulse width modulated control system for positioning a servo device in response to an analog feedback signal indicative of the actual position of the servo device comprising: means for converting said analog feedback signal into a digital signal; having a first and second total number of predetermined bits; first counter means for receiving said digital signal of predetermined bits of said first total from said converting means and counting downward through said first total of predetermined bits and establishing a first control signal thereafter; second counter means for receiving said digital signal of predetermined bits of said second total number less than said first total and counting downward through said predetermined bits of said second total and establishing a second control signal thereafter; means for supplying power to said servo device; means for controlling the transmission of power from said power supplying means to said servo device; and circuit means responsive to said first and second control signals for selectively actuating said controlling means to regulate the operation of said servo device.
Claim 2
Dependent Claim
173 words
A pulse width modulated control system for positioning a servo device in response to an analog feedback signal indicative of the actual position of the servo device comprising: means for converting said analog feedback signal into a digital signal; having a first and second total number of predetermined bits; first counter means for receiving said digital signal of predetermined bits of said first total from said converting means and counting downward through said first total of predetermined bits and establishing a first control signal thereafter; second counter means for receiving said digital signal of predetermined bits of said second total number less than said first total and counting downward through said predetermined bits of said second total and establishing a second control signal thereafter; means for supplying power to said servo device; means for controlling the transmission of power from said power supplying means to said servo device; and circuit means responsive to said first and second control signals for selectively actuating said controlling means to regulate the operation of said servo device.
Claim 3
Dependent Claim
207 words
A pulse width modulated control system for a servo device comprising means for converting an analog input signal into a digital signal, means for receiving said digital signal and counting downward therefrom, means for retarding said receiving means from producing an output signal until a pre-determined count has been reached, said retarding means being a counting device having an adjustable output permitting the varying of said pre-determined count to regulate said output signal produced by said receiving means, means for supplying power to said servo device, means for controlling the transmission of power from said power supplying means to said servo device, said controlling means being electrically connected between said power supplying means and said servo device and being selectively actuatable for a variable period of time, means for synchronizing the operation of said converting means with said power suppying means, circuit means responsive to said output signal produced by said receiving means and selectively actuating said controlling means to regulate the speed and direction of rotation of said servo device, and means to insure that said output signal is of sufficient duration so that said controlling means is selectively actuated for a minimum period of time so as to overcome the inertia of said servo device.
Claim 4
Dependent Claim
207 words
A pulse width modulated control system for a servo device comprising means for converting an analog input signal into a digital signal, means for receiving said digital signal and counting downward therefrom, means for retarding said receiving means from producing an output signal until a pre-determined count has been reached, said retarding means being a counting device having an adjustable output permitting the varying of said pre-determined count to regulate said output signal produced by said receiving means, means for supplying power to said servo device, means for controlling the transmission of power from said power supplying means to said servo device, said controlling means being electrically connected between said power supplying means and said servo device and being selectively actuatable for a variable period of time, means for synchronizing the operation of said converting means with said power suppying means, circuit means responsive to said output signal produced by said receiving means and selectively actuating said controlling means to regulate the speed and direction of rotation of said servo device, and means to insure that said output signal is of sufficient duration so that said controlling means is selectively actuated for a minimum period of time so as to overcome the inertia of said servo device.
Claim 5
Dependent Claim
39 words
A control system as defined in claim 1 wherein said second counter means includes a dead band adjustment to permit varying the count of said second counter means to thereby allow said circuit means to regulate said servo device.
Claim 6
Dependent Claim
28 words
A control system as defined in claim 3 further including a zero crossing detector circuit for synchronizing the operation of said converting means with said power supplying means.
Claim 7
Dependent Claim
35 words
The control system as defined in claim 3 wherein said controlling means is selectively actuatable for a variable period of time permitting the speed and direction of rotation of said servo device to be controlled.
Claim 8
Dependent Claim
31 words
The control system as defined in claim 1 further including means for adjusting the time period required by said receiving means and said retarding means to complete their respective downward count.
Claim 9
Dependent Claim
31 words
The control system as defined in claim 6 further including means for adjusting the time period required by said converting means to convert said analog input signal into a digital signal.
Claim 10
Dependent Claim
45 words
The control system as defined in claim 1 further including means to insure that said output signal is of sufficient duration so that said controlling means is selectively actuated for a minimum period of time so as to overcome the inertia of said servo device.
References Cited (Backward Citations)
US4263557A
Cited
US4201936A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-06-13 | 1986-12-13 | 1987-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-13 | 1990-12-13 | 1991-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-13 | 1994-12-13 | 1995-06-14 | $7700.00 | Window Closed / Lapsed |