Patent US3906641A successfully refreshed from Google Patents.
US3906641A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Autopilot employing improved hall-effect direction sensor
Assignee: METAL MARINE PILOT Inc
•
Filing: 1971-09-27
•
Granted: 1975-09-23
•
Expires: 1991-09-27
Abstract
Abstract An improved marine compass employs a Hall-effect device which provides an output signal related to the relative rotation of the compass card therein. When the Hall-effect device is mounted on a course dial whose position with respect to the compass'' lubber line indicates a desired course, the output signal may be used as an input to an autopilot system. The system includes a DC constant current supply for the Hall-effect device, and an integrated circuit operational amplifier for amplifying said output signal to provide an angle signal having a usable level. A differentiator including a second IC operational amplifier provides a rate signal from the angle signal. A rudder signal is provided by a rudder position sensor employing a second Halleffect device and a third IC operational amplifier. The angle and rate signals are combined and supplied with the rudder signal to a variable-threshold differential amplifier which in turn provides a control signal to a steering servomotor to modify the rudder position so as to return the vessel to its desired course. To allow high rates of rudder positioning without overshoot, a null damper circuit varies the threshold of the differential amplifier to pulse modulate the control signal at small values thereof. By replacing the marine compass with a manual control employing a Hall-effect device, the system operates as a remote steering system.
Inventors
- 👤 Robert M Freeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:36
CPC Classifications
G; G01; G01C; G01C17/00; G01C17/02; G01C17/28; G05; G05D; G05D3/00; G05D3/12; G05D3/14
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
360 words
A direction sensor for providing a DC output voltage whose magnitude is proportional to the sine of the relative angular deviation between the orientation of a first member and that of a second member, and whose polarity is dependent on the direction of such deviation, comprising: a. a Hall-effect device affixed to the first member, said device comprising an essentially planar wafer of material exhibiting the Hall-effect, and having first and second pairs of opposing edge surfaces, a pair of current terminals on said first pair of opposing edge surfaces and a pair of voltage terminals on said second pair of opposing edge surfaces, said pair of voltage terminals and said pair of current terminals thereby defining an null plane; b. a source of constant DC current coupled to said pair of current terminals; c. a permanent magnet producing a magnetic field; d. means supporting said permanent magnet in proximity to said Hall-effect device so that said Hall-effect device is located in said magnetic field and so that said permanent magnet is rotatable with the second member; e. means for coupling one of said pair of current terminals to one of said pair of voltage terminals to provide equal voltage drops between said one current terminal and each of said pair of voltage terminals when no magnetic field is present; f. a linear operational amplifier of the integrated circuit type having a pair of fist inputs consisting of an inverting and a non-inverting input, a pair of second inputs for supply voltage, a pair of third inputs for offset compensation, and an output; g. means coupling said first inputs to said pair of voltage terminals; h. a source of a DC supply voltage having first and second terminals; i. means coupling said first and second terminals to said second inputs; j. a source of DC reference potential; k. means coupling said DC reference potential to one of said first inputs; l. adjustable resistive means connected one of said second inputs to both of said third inputs to allow adjustment of the potential appearing on said output to equal said reference potential when the first and the second members are aligned.
Claim 2
Dependent Claim
360 words
A direction sensor for providing a DC output voltage whose magnitude is proportional to the sine of the relative angular deviation between the orientation of a first member and that of a second member, and whose polarity is dependent on the direction of such deviation, comprising: a. a Hall-effect device affixed to the first member, said device comprising an essentially planar wafer of material exhibiting the Hall-effect, and having first and second pairs of opposing edge surfaces, a pair of current terminals on said first pair of opposing edge surfaces and a pair of voltage terminals on said second pair of opposing edge surfaces, said pair of voltage terminals and said pair of current terminals thereby defining an null plane; b. a source of constant DC current coupled to said pair of current terminals; c. a permanent magnet producing a magnetic field; d. means supporting said permanent magnet in proximity to said Hall-effect device so that said Hall-effect device is located in said magnetic field and so that said permanent magnet is rotatable with the second member; e. means for coupling one of said pair of current terminals to one of said pair of voltage terminals to provide equal voltage drops between said one current terminal and each of said pair of voltage terminals when no magnetic field is present; f. a linear operational amplifier of the integrated circuit type having a pair of fist inputs consisting of an inverting and a non-inverting input, a pair of second inputs for supply voltage, a pair of third inputs for offset compensation, and an output; g. means coupling said first inputs to said pair of voltage terminals; h. a source of a DC supply voltage having first and second terminals; i. means coupling said first and second terminals to said second inputs; j. a source of DC reference potential; k. means coupling said DC reference potential to one of said first inputs; l. adjustable resistive means connected one of said second inputs to both of said third inputs to allow adjustment of the potential appearing on said output to equal said reference potential when the first and the second members are aligned.
Claim 3
Dependent Claim
18 words
A direction sensor as recited in claim 1, wherein said material of said Hall-effect device is indium arsenide.
Claim 4
Dependent Claim
25 words
A direction sensor as recited in claim 2, wherein said source of constant current maintains the current through said Hall-effect device at approximately 150 milliamps.
Claim 5
Dependent Claim
24 words
A direction sensor as recited in claim 1, wherein said material of said Hall-effect device provides an electronic mobility in excess of 12,000 cm2/V/sec.
Claim 6
Dependent Claim
52 words
A direction sensor as recited in claim 1, wherein said pair of current terminals and said pair of voltage terminals are positioned on said Hall-effect device such that a line drawn between said pair of current terminals intersects a line drawn between said pair of voltage terminals at essentially a right angle.
Claim 7
Dependent Claim
97 words
A direction sensor as recited in claim 1, wherein said source of constant DC current comprises a DC voltage source having positive and negative terminals, resistive means coupling one of said positive and negative terminals to one of said pair of current terminals of said Hall-effect device, means connecting the other of said positive and negative terminals to the other of said pair of current terminals, and a silicon diode connected across said current terminals and in close proximity to said current terminals, said silicon diode being biased in the forward direction by said DC voltage source.
Claim 8
Dependent Claim
61 words
A direction sensor as recited in claim 1, wherein the second member Comprises the earth, said direction sensor further comprising a compass card, a housing including first means supporting said compass card for relative rotation therewith, means mounting said permanent magnet on said compass card, and wherein the first member comprises a course dial supporting said Hall-effect device from said housing.
Claim 9
Dependent Claim
20 words
A direction sensor as recited in claim 7, wherein said course dial is relatively rotatable with respect to said housing.
Claim 10
Dependent Claim
58 words
A direction sensor as recited in claim 1, wherein the first member comprises a housing, and the second member comprises a control surface, said direction sensor further comprising means supporting said Hall-effect device from said housing, shaft means rotatably journaled in said housing for receiving said permanent magnet, and means coupling said control surface to said shaft means.
Claim 11
Dependent Claim
31 words
A direction sensor as recited in claim 1, wherein said means for coupling one of said pair of current terminals to one of said pair of voltage terminals comprises a resistor.
Claim 12
Dependent Claim
36 words
A direction sensor as recited in claim 1, wherein said DC reference potential has a magnitude midway between the magnitudes of the potentials on said first and second terminals of said source of DC supply voltage.
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) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |