OCCLUSION DETECTION USING PULSE-WIDTH MODULATION AND MEDICAL DEVICE INCORPORATING SAME
First Claim
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1. A method of detecting an occlusion in a fluid path, the method comprising:
- applying a modulated voltage to a motor to produce rotation of a rotor of the motor, the rotation of the rotor resulting in delivery of fluid via the fluid path;
adjusting a duty cycle of the modulated voltage to achieve a commanded rotation of the rotor; and
identifying an occlusion condition based on the duty cycle.
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Abstract
Apparatus are provided for motor control systems and related medical devices. In one embodiment, a control system includes a motor having a rotor, a modulation module coupled to the motor, and a control module coupled to the modulation module. The modulation module generates a modulated voltage that is applied to the motor and rotates the rotor to deliver fluid via a fluid path. The control module adjusts a duty cycle of the modulated voltage to achieve a commanded rotation of the rotor and detects an occlusion condition in the fluid path based on the duty cycle.
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Citations
20 Claims
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1. A method of detecting an occlusion in a fluid path, the method comprising:
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applying a modulated voltage to a motor to produce rotation of a rotor of the motor, the rotation of the rotor resulting in delivery of fluid via the fluid path; adjusting a duty cycle of the modulated voltage to achieve a commanded rotation of the rotor; and identifying an occlusion condition based on the duty cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of detecting an occlusion in a fluid path, the method comprising:
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applying a modulated voltage to a motor to produce rotation of a rotor of the motor, the modulated voltage oscillating between a first voltage and a second voltage, the modulated voltage being equal to the first voltage for a percentage of a time interval, the percentage corresponding to a duty cycle, the rotation of the rotor resulting in delivery of fluid via the fluid path; adjusting the duty cycle of the modulated voltage to achieve a commanded rotation of the rotor; and identifying an occlusion condition based on the duty cycle.
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20. A method of detecting an occlusion in a fluid path, the method comprising:
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applying a modulated voltage to a stepper motor to produce a commanded number of motor steps of rotation of a rotor of the stepper motor, the rotation of the rotor resulting in delivery of fluid via the fluid path; determining an expected number of incremental rotations expected to be detected by a sensor coupled to the stepper motor in response to applying the modulated voltage to the stepper motor to produce the commanded number of motor steps based on the commanded number of motor steps; obtaining a measured number of incremental rotations of the rotor from the sensor in response to applying the modulated voltage to the stepper motor to produce the commanded number of motor steps; adjusting a duty cycle of the modulated voltage to achieve the commanded number of motor steps in response to a difference between the expected number and the measured number; and identifying an occlusion condition based on the duty cycle.
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Specification