Stepper Motor Duty Cycle Control for Infusion Pump Power Optimization
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Solution Overview
Problem
Infusion pump devices face challenges in reducing power consumption of stepper motors, which are typically used in battery-powered medical devices, leading to reduced battery life and inefficient energy use due to continuous power consumption and reliance on open-loop control schemes without feedback mechanisms.
Innovation Solution
A motor control system that employs a modulation module to generate a modulated voltage and a control module to adjust the duty cycle of the voltage, allowing for precise control of motor rotation and detection of degradation conditions, thereby optimizing energy use and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stepper motor is supplied with direct current voltage to control and maintain position, then the motor achieves precise position control and meets torque requirements, but the motor continuously consumes power during use
Solution Approach 1:
The patent applies periodic action by using pulse-width modulated voltage instead of continuous DC voltage. The motor receives voltage in periodic pulses where the duty cycle is adjusted to provide the necessary average torque while allowing the motor to coast during off-periods, thereby reducing continuous power consumption while maintaining position control precision
Solution Approach 2:
The patent implements dynamics by transitioning from static continuous voltage application to dynamic pulse-width modulated voltage control. The duty cycle is dynamically adjusted based on the motor's position, velocity, and torque requirements, enabling precise control with reduced energy consumption by applying voltage only when and where needed
2Force
If a large voltage is applied to the stepper motor to ensure sufficient torque, then the motor achieves commanded steps reliably, but the power consumption increases
Solution Approach 1:
The patent applies parameter changes by using pulse-width modulation to vary the effective voltage applied to the motor. Instead of applying a constantly large voltage, the system changes the duty cycle parameter to provide high voltage only during periods when torque is needed, reducing overall power consumption while maintaining sufficient torque output when required
3Device complexity
If open-loop control is used without feedback mechanisms, then the device complexity is reduced, but the ability to detect motor degradation and occlusions is limited
Solution Approach 1:
The patent implements feedback by monitoring the duty cycle required to achieve commanded motor steps and using this information to detect motor degradation and occlusions. The control system compares the actual duty cycle with expected values to identify anomalies, providing reliability enhancement without significantly increasing system complexity
Solution Approach 2:
The patent applies self-service by enabling the motor control system to monitor its own performance through duty cycle analysis. The system automatically detects degradation conditions and occlusions by analyzing its own control parameters, eliminating the need for separate complex monitoring systems while maintaining reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system dynamically adjusts the duty cycle of the modulated voltage to achieve commanded motor rotations, reducing power consumption and prolonging battery life while detecting anomalies such as occlusions or degradation, ensuring reliable and efficient operation of infusion pumps.
Implementation Method 1
A motor control system is provided. The 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
Data Source
AI summary
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.