Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2002-04-04
2004-09-14
Mullins, Burton (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C324S163000, C702S145000
Reexamination Certificate
active
06791217
ABSTRACT:
TECHNICAL FIELD
The invention relates to a tachometer apparatus and methodology for determining the velocity of a motor as applied to a vehicle steering system.
BACKGROUND OF THE INVENTION
Speed sensors, or detectors of various types are well known in the art. In recent years the application of speed detection to motor control functions has stimulated demands on the sophistication of those sensors. Rotational speed sensors are commonly configured in the same manner as an electric machine, for example, a coil is placed in proximity to rotating magnets whereby the magnetic field induces a voltage on the passing coil in accordance with Faraday's Law. The rotating permanent magnets induce a voltage on the coil and ultimately a voltage whose frequency and magnitude are proportional to the rotational speed of the passing magnets.
Many of the tachometers that are currently available in the art exhibit a trade off between capabilities and cost. Those with sufficient resolution and accuracy are often very expensive and perhaps cost prohibitive for mass production applications. Those that are inexpensive enough to be considered for such applications are commonly inaccurate or provide insufficient resolution or bandwidth for the application.
Thus, there is a need, in the art for a low cost robust tachometer that provides sufficient accuracy and resolution for motor control applications and yet is inexpensive enough to be cost effective in mass production.
SUMMARY OF THE INVENTION
The above-identified drawbacks of the prior art are alleviated by the method described in the invention.
A method and apparatus for determining the velocity of a rotating device is described herein. The apparatus includes a set of sense magnets affixed to a rotating shaft of a rotating device and a circuit assembly, which interact to form an air core electric machine. The circuit assembly includes a circuit interconnection having a plurality of sense coils and sensors affixed thereto. The circuit assembly is adapted to be in proximity to the set of sense magnets on the rotating part.
A controller is coupled to the circuit assembly, where the controller is adapted to execute an adaptive algorithm that determines the velocity of the rotating device. The algorithm is a method of combining a derived velocity with a velocity from the tachometer. The algorithm includes a plurality of functions including: receiving a position signal related to the rotational position of the shaft; determining a derived velocity from the position signal; generating a plurality of tachometer velocity signals; determining a compensated velocity in response to the plurality tachometer velocity signals; and blending the compensated velocity with derived velocity to generate a blended velocity output.
REFERENCES:
patent: 3731533 (1973-05-01), Geery
patent: 4008378 (1977-02-01), Nance et al.
patent: 4305025 (1981-12-01), Arnold
patent: 4396884 (1983-08-01), Toalson
patent: 4437061 (1984-03-01), Shinozaki et al.
patent: 4512367 (1985-04-01), Abe et al.
patent: 4562399 (1985-12-01), Fisher
patent: 4710683 (1987-12-01), Bahn et al.
patent: RE32857 (1989-02-01), Luneau
patent: 4803425 (1989-02-01), Swanberg
patent: 4836319 (1989-06-01), Haseda et al.
patent: 4838074 (1989-06-01), Morishita et al.
patent: 4853604 (1989-08-01), McMullin et al.
patent: 4868497 (1989-09-01), Wallrafen
patent: 4897603 (1990-01-01), Bieber et al.
patent: 4901015 (1990-02-01), Pospischil et al.
patent: 4922197 (1990-05-01), Juds et al.
patent: 4924161 (1990-05-01), Ueki et al.
patent: 4924696 (1990-05-01), Schroeder et al.
patent: 4955228 (1990-09-01), Hirose et al.
patent: 4961017 (1990-10-01), Kakinoki et al.
patent: 4983915 (1991-01-01), Rossi
patent: 5027648 (1991-07-01), Filleau
patent: 5029466 (1991-07-01), Nishihara et al.
patent: 5045784 (1991-09-01), Pizzarello et al.
patent: 5062064 (1991-10-01), Sagues et al.
patent: 5088319 (1992-02-01), Hirose et al.
patent: 5218279 (1993-06-01), Takahashi et al.
patent: 5223760 (1993-06-01), Peck et al.
patent: 5260650 (1993-11-01), Schwesig et al.
patent: 5293125 (1994-03-01), Griffen et al.
patent: 5298841 (1994-03-01), Katayama et al.
patent: 5309758 (1994-05-01), Kubota et al.
patent: 5329195 (1994-07-01), Horber et al.
patent: 5406267 (1995-04-01), Curtis
patent: 5408153 (1995-04-01), Imai et al.
patent: 5422570 (1995-06-01), Moreira
patent: 5498072 (1996-03-01), Shimizu
patent: 5503421 (1996-04-01), DeLisser et al.
patent: 5541488 (1996-07-01), Bansal et al.
patent: 5717268 (1998-02-01), Carrier et al.
patent: 5736852 (1998-04-01), Pattantyus
patent: 5828973 (1998-10-01), Takeuchi et al.
patent: 5902342 (1999-05-01), Mishra
patent: 6002234 (1999-12-01), Ohm et al.
patent: 6051951 (2000-04-01), Arai et al.
patent: 6101879 (2000-08-01), Shirai et al.
patent: 6155106 (2000-12-01), Sano
patent: 6230110 (2001-05-01), Iwazaki
patent: 6244372 (2001-06-01), Sakamaki et al.
patent: 6244373 (2001-06-01), Kojo et al.
patent: 6246197 (2001-06-01), Kurishige et al.
patent: 6250417 (2001-06-01), Kaji et al.
patent: 6286621 (2001-09-01), Mukai et al.
patent: 6310458 (2001-10-01), Fenstermacher
patent: 6470994 (2002-10-01), Shimizu et al.
patent: 6483293 (2002-11-01), Chen et al.
patent: 6498409 (2002-12-01), Collier-Hallman et al.
patent: 6534970 (2003-03-01), Ely et al.
patent: 1 484 796 (1975-02-01), None
patent: 358215560 (1983-12-01), None
patent: 8-211081 (1996-08-01), None
patent: 974273 (1982-11-01), None
patent: 99/61868 (1999-02-01), None
“Motor Tachometer Circuit” IBM Technical Disclosure Bulletin vol. 14, Issue No. 7, pp. 1986-1987; Dec. 1, 1971.*
“Forms Motor Control System” IBM Technical Disclosure Bulletin vol. 21, Issue No. 4, pp. 1333-1334; Sep. 1, 1978.*
“DC Motor Acceleration Control” IBM Technical Disclosure Bulletin vol. 28, Issue No. 4, pp. 1561-1562; Sep. 1, 1985.*
Paul Horowitz & Winfield Hill, The Art of Electronics, Cambridge University Press, 1989, pp. 222-224.
PCT Written Opinion of International Application No.: PCT/US02/23719 Filed Jul. 26, 2002.
Bressette William J
Collier-Hallman Steven James
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