Electronic damping of stepper motor
First Claim
1. 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, andapplying an additional current to the phase windings of said detent phase.
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Accused Products
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.
59 Citations
13 Claims
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1. 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:
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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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. 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:
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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. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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Specification