Motor health monitoring and medical device incorporating same
First Claim
Patent Images
1. A system comprising:
- a stepper motor having a rotor and sets of windings;
a sensor to detect incremental rotations of the rotor;
a modulation module to generate a 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;
a motor driver module coupled between the modulation module and the stepper motor to apply the modulated voltage to one or more of the sets of windings; and
a control module coupled to the sensor, the modulation module, and the motor driver module to;
operate the motor driver module to sequentially apply the modulated voltage to the one or more of the sets of windings in a particular order to produce a commanded number of motor steps of rotation by the rotor;
obtain a measured number of the incremental rotations from the sensor after the stepper motor is operated to provide the commanded number of motor steps;
increase the duty cycle for the modulated voltage in response to a difference between an expected number of incremental rotations corresponding to the commanded number of motor steps and the measured number of the incremental rotations; and
detect a degradation 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 motor and the modulation module. The modulation module generates a modulated voltage that is applied to the motor, and the control module adjusts a duty cycle of the modulated voltage to achieve a commanded rotation of the rotor and detects a degradation condition based on the duty cycle.
268 Citations
20 Claims
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1. A system comprising:
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a stepper motor having a rotor and sets of windings; a sensor to detect incremental rotations of the rotor; a modulation module to generate a 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; a motor driver module coupled between the modulation module and the stepper motor to apply the modulated voltage to one or more of the sets of windings; and a control module coupled to the sensor, the modulation module, and the motor driver module to; operate the motor driver module to sequentially apply the modulated voltage to the one or more of the sets of windings in a particular order to produce a commanded number of motor steps of rotation by the rotor; obtain a measured number of the incremental rotations from the sensor after the stepper motor is operated to provide the commanded number of motor steps; increase the duty cycle for the modulated voltage in response to a difference between an expected number of incremental rotations corresponding to the commanded number of motor steps and the measured number of the incremental rotations; and detect a degradation condition based on the duty cycle. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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2. An infusion device, comprising:
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a motor having a rotor; a shaft mechanically coupled to the rotor, the shaft being displaced to deliver fluid in response to rotation of the rotor; a modulation module coupled to the motor, the modulation module generating a modulated voltage applied to 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; and a control module coupled to the modulation module to adjust the duty cycle to achieve a commanded rotation of the rotor and identify a degradation condition based on the duty cycle. - View Dependent Claims (3, 4)
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5. A system comprising:
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a motor having a rotor; a modulation module coupled to the motor, the modulation module generating a modulated voltage applied to 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; and a control module coupled to the motor and the modulation module to adjust the duty cycle to achieve a commanded rotation of the rotor and detect a degradation condition based on the duty cycle.
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Specification