Patent US3665282A successfully refreshed from Google Patents.
US3665282A
Expired / Lapsed
US
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Scan control system
Assignee: Raytheon Co
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Filing: 1969-07-24
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Granted: 1972-05-23
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Expires: 1989-07-24
Abstract
Abstract A system for accurately reciprocally driving a structural element, such as a flat reflector. The system includes a torque motor for driving the reflector, a position pick-off device for monitoring the position of the reflector, and an electronic unit comprising feedback paths coupling the pick-off device to the torque motor. The electronic unit includes a negative feedback positioning loop enclosed within an outer positive feedback hysteresis loop. The positioning loop comprises a type II (double integration) loop which yields a zero position error for a constant scan rate (angular velocity) input. The outer positive feedback loop functions to produce a precise triangular waveform (scan rate input) whose turn around points are precisely maintained in order to prevent drift of the scan angle center point position. The system enables different scan angles (e.g., wide and narrow) to be selected by varying scan frequency while maintaining scan rate constant.
Inventors
- 👤 Bernard J Skehan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:57
CPC Classifications
G; G05; G05D; G05D3/00; G05D3/12; G05D3/14
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
125 words
A system for reciprocally driving a member at a constant rate through a precisely defined scan angle, said system comprising: a motor having a drive shaft coupled to said member; type II feedback loop means, including said motor and a summing junction, for driving said member as a function of the difference of two signals applied to said summing junction, said type II feedback loop means, including means for performing a double integration of said difference signal; means for coupling a feedback signal to said summing junction indicative of the actual angular position of said motor drive shaft; hysteresis loop means responsive to said feedback signal for producing a reference signal of triangular waveform; and means for applying said reference signal to said summing junction.
Claim 2
Independent Claim
125 words
A system for reciprocally driving a member at a constant rate through a precisely defined scan angle, said system comprising: a motor having a drive shaft coupled to said member; type II feedback loop means, including said motor and a summing junction, for driving said member as a function of the difference of two signals applied to said summing junction, said type II feedback loop means, including means for performing a double integration of said difference signal; means for coupling a feedback signal to said summing junction indicative of the actual angular position of said motor drive shaft; hysteresis loop means responsive to said feedback signal for producing a reference signal of triangular waveform; and means for applying said reference signal to said summing junction.
Claim 3
Dependent Claim
61 words
The system of claim 1 wherein said means for coupling a feedback signal to said summing junction includes a position pick-off means providing a high frequency output signal having an envelope whose amplitude is proportional to the actual angular position of said motor drive shaft; and means responsive to said position pick-off means for producing a signal corresponding to said envelope.
Claim 4
Dependent Claim
104 words
The system of claim 2 wherein said hysterisis loop means includes a logic means responsive to said signal produced by said pick-off means, for developing time duration signals of either first or second levels indicative of the duration said motor drive shaft is to either side of the center point of said scan angle; and integrator means responsive to said logic means for producing said reference signal comprised of linearly increasing segments during intervals said signal produced by said logic means is at a first level and linearly decreasing segments during intervals said signal produced by said logIc means is at a second level.
Claim 5
Dependent Claim
34 words
The system of claim 3 including oscillator means providing an AC excitation signal to said pick-off means; and means responsive to deviations in the amplitude of said excitation signal for controlling said integrator means.
Claim 6
Dependent Claim
56 words
The system of claim 1 wherein said means for coupling a feedback signal comprises a microsyn signal generator providing a high frequency output signal having an envelope whose amplitude is proportional to the actual angular position of said motor drive shaft; and means responsive to said output signal for producing a signal corresponding to said envelope.
Claim 7
Dependent Claim
98 words
The system of claim 5 wherein said hysteresis loop means includes a logic means responsive to said envelope signal, for developing time duration signals of either first or second levels indicative of the duration said member is to either side of the center point of said scan angle; and integrator means responsive to said logic means for producing said reference signal comprised of linearly increasing segments during intervals said signal produced by said logic means is at a first level and linearly decreasing segments during intervals said signal produced by said logic means is at a second level.
Claim 8
Dependent Claim
35 words
The system of claim 6 including oscillator means providing an AC excitation signal to said microsyn signal generator; and means responsive to deviations in the amplitude of said excitation signal for controlling said integrator means.
Claim 9
Independent Claim
172 words
A system for reciprocally driving a reflector at a constant rate through a precisely defined scan angle, said system comprising: a motor having a drive shaft and exhibiting a constant acceleration output in response to a constant current input; a pick-off device for producing a signal whose amplitude is related to the actual position of said motor drive shaft; logic means responsive to said signal produced by said pick-off device for developing time duration signals of either first or second levels indicative of the duration said motor drive shaft is to either side of the center point of said scan angle; integrator means responsive to said logic means for producing a reference signal comprised of linearly increasing segments during intervals said signal produced by said logic means is at a first level and linearly decreasing segments during intervals said signal produced by said logic means is at a second level; and means responsive to the difference between said signals produced by said pick-off device and said integrator means for driving said motor.
Claim 10
Independent Claim
172 words
A system for reciprocally driving a reflector at a constant rate through a precisely defined scan angle, said system comprising: a motor having a drive shaft and exhibiting a constant acceleration output in response to a constant current input; a pick-off device for producing a signal whose amplitude is related to the actual position of said motor drive shaft; logic means responsive to said signal produced by said pick-off device for developing time duration signals of either first or second levels indicative of the duration said motor drive shaft is to either side of the center point of said scan angle; integrator means responsive to said logic means for producing a reference signal comprised of linearly increasing segments during intervals said signal produced by said logic means is at a first level and linearly decreasing segments during intervals said signal produced by said logic means is at a second level; and means responsive to the difference between said signals produced by said pick-off device and said integrator means for driving said motor.
Claim 11
Dependent Claim
79 words
The system of claim 8 wherein said logic means includes first and second differential amplifiers each having positive and negative input terminals; means applying a positive threshold signal to said negative input terminal of said first differential amplifier; means applying a negative threshold signal to said positive input terminal of said second differential amplifier; and means applying said signal produced by said pick-off device to said positive and negative input terminals respectively of said first and second differential amplifiers.
Claim 12
Dependent Claim
59 words
The system of claim 9 including a flip-flop; means coupling said first and second differential amplifiers to said flip-flop for switching said flip-flop when said signal produced by said pick-off device increases to the level of said first threshold signal or decreases to the level of said second threshold signal; and means coupling said flip-flop to said integrator means.
Claim 13
Dependent Claim
26 words
The system of claim 8 wherein said logic means includes means for comparing said signal produced by said pick-off device with first and second threshold levels.
Claim 14
Dependent Claim
43 words
The system of Claim 11 including first and second attenuation paths; a scan angle command means; and means responsive to said scan angle command means for selectively coupling either said first or second attenuation paths between said pick-off device and said logic means.
Claim 15
Dependent Claim
25 words
The system of claim 1 wherein said motor is a torque motor characterized by a constant acceleration output in response to a constant current input.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |