Patent US4286202A successfully refreshed from Google Patents.
US4286202A
Expired / Lapsed
US
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Electronic damping of stepper motor
Assignee: International Business Machines Corp
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Filing: 1979-07-16
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Granted: 1981-08-25
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Expires: 1999-07-16
Abstract
Abstract A damping control system for a three phase stepper motor. A reluctance velocity transducer is used for each of the three phases. The output of each of the transducers is proportional to the rotational velocity of the motor. Each of the transducers is rotationally phase shifted 3.75 with respect to one another and phased to the motor rotor rotationally such that the zero voltage crossings of the transducers correspond to the zero torque crossings of the motor. During damping or detenting of the motor the selected phase has current applied to it which is equal to a predetermined fixed value plus the feedback from its associated transducer. The windings on each side of the detent position have current applied to them which is proportional to the voltage from their respective feedback transducers. The voltage in each of the windings is amplified by a selected gain constant. The current in each of the windings is such that maximum torque is applied to drive the motor to the detent position with appropriate current reversals in the windings to damp out any kinetic energy in the rotor during detenting.
Inventors
- 👤 Douglas E. Clancy
- 👤 Richard F. Frankeny
- 👤 George P. Olson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:04
CPC Classifications
H; H02; H02P; H02P8/00; H02P8/32
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
126 words
A method of controlling a multi phase stepper motor having a set of windings for each of its phases to provide damping and detenting of the rotor of said motor under control of a damping signal at a selected final position in alignment with one of said sets of windings selected as the detent position, said method comprising: developing an analog feedback signal which is related to the angular velocity and position of said rotor during said damping mode, applying a unique current to each of said phase windings which is related to said analog signal in a direction to produce retardation of said rotor rotation as said rotor approaches said detent position, and applying an additional current to the phase windings of said detent phase.
Claim 2
Independent Claim
126 words
A method of controlling a multi phase stepper motor having a set of windings for each of its phases to provide damping and detenting of the rotor of said motor under control of a damping signal at a selected final position in alignment with one of said sets of windings selected as the detent position, said method comprising: developing an analog feedback signal which is related to the angular velocity and position of said rotor during said damping mode, applying a unique current to each of said phase windings which is related to said analog signal in a direction to produce retardation of said rotor rotation as said rotor approaches said detent position, and applying an additional current to the phase windings of said detent phase.
Claim 3
Dependent Claim
42 words
A motor control method of claim 1 further including the step of controlling the magnitude of unique current in the winding associated with said detent position by reversing the direction of said feedback signal after said rotor has passed said detent position.
Claim 4
Dependent Claim
39 words
The motor control method of claim 2 further including the step of developing said analog feedback signal for each of said phases and causing each of said feedback signals to timewise track the torque produced by its associated phase.
Claim 5
Dependent Claim
25 words
The motor control method of claim 3 further including the step of amplifying said unique current applied to each of said windings by a constant.
Claim 6
Dependent Claim
31 words
The method of claim 3 further including the step of time wise tracking causing the zero crossings of said unique current to correspond to the zero torque crossings of said motor.
Claim 7
Dependent Claim
67 words
The method of claim 5 further wherein the current of each of said windings is described by the following equations: I.sub.a =DC value+A feedback *Kl I.sub.b =B feedback *Kl I.sub.c =C feedback *Kl where I a , I b , and I c represent current in the respective windings which is constrained to be positive and Kl represents a gain constant with phase A the detented phase.
Claim 8
Dependent Claim
125 words
A three phase stepper motor control circuit for controlling the current applied to each of the three sets of phase windings of said motor to detent the rotor of said motor at a detent position in alignment with one of the sets of phase windings under control of a detent signal, the control circuit comprising: means for developing an analog signal related to the angular velocity and position of said motor during damping, means for developing a unique current related to said analog signal for each of said sets of phase windings, means for applying said currents to its associated set of windings during damping, and means for applying an additional current to the one of said sets of windings corresponding to said detent position.
Claim 9
Dependent Claim
125 words
A three phase stepper motor control circuit for controlling the current applied to each of the three sets of phase windings of said motor to detent the rotor of said motor at a detent position in alignment with one of the sets of phase windings under control of a detent signal, the control circuit comprising: means for developing an analog signal related to the angular velocity and position of said motor during damping, means for developing a unique current related to said analog signal for each of said sets of phase windings, means for applying said currents to its associated set of windings during damping, and means for applying an additional current to the one of said sets of windings corresponding to said detent position.
Claim 10
Dependent Claim
40 words
The motor control circuit of claim 7 further including means for causing the analog related current in said windings to be of a direction to produce retardation of said rotor rotation of said rotor as it approaches said detent position.
Claim 11
Dependent Claim
44 words
The motor control circuit of claim 8 further including means for controlling the magnitude of said analog related current in the winding associated with said detent position by reversing the direction of the transducer feedback voltage after said rotor has passed said detent position.
Claim 12
Dependent Claim
37 words
The motor control circuit of claim 9 further including means for developing a feedback signal for each of said phases and causing each of said feedback signals to timewise track the torque produced by its associated phase.
Claim 13
Dependent Claim
26 words
The motor control circuit of claim 10 further including means for amplifying the said analog related current applied to each of said windings by a constant.
Claim 14
Dependent Claim
32 words
The motor control circuit of claim 11 further including means for controlling said analog related current to cause it to have zero crossings corresponding to the zero torque crossings of said motor.
Claim 15
Dependent Claim
74 words
The motor control circuit of claim 12 further including means for causing the current in each of said windings to be as described by the following equations: I.sub.a =DC value+A feedback *Kl I.sub.b =B feedback *Kl I.sub.c =C feedback *Kl where I a , I b , and I c represent current in the respective windings which is constrained to be positive and Kl represents a gain constant with phase A the detented phase.
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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) | 1984-08-24 | 1985-02-23 | 1985-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-24 | 1989-02-23 | 1989-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-24 | 1993-02-23 | 1993-08-25 | $7700.00 | Window Closed / Lapsed |