Infusion Pump Motor Drive Sequence for Cogging Torque Reduction
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Solution Overview
Problem
Conventional infusion pumps face challenges with cogging torque, which increases the initial torque required to start the motor, leading to larger and more power-consuming devices due to manufacturing and assembly tolerances causing rotor misalignment.
Innovation Solution
The motor first rotates the rotor in a counterclockwise direction for less than a full rotation to a 'windup' position, then reverses direction, reducing the torque needed to overcome cogging torque and allowing continuous operation by leveraging kinetic energy gained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional electromagnetic motors are used in infusion pumps, then the motor can drive the dispenser, but cogging torque increases the initial torque requirement, leading to larger and more power-consuming devices
Solution Approach 1:
The system performs a preliminary action by rotating the rotor in the first direction (opposite to the intended driving direction) before normal operation. This preliminary rotation positions the rotor to reduce cogging torque effects during subsequent startup and operation, thereby reducing peak torque requirements and power consumption while maintaining reliable motor operation
2Volume of moving object
If smaller infusion pumps are designed, then portability and user comfort improve, but tighter tolerances are required to operate properly
Solution Approach 1:
By implementing the preliminary rotation in the first direction, the system compensates for manufacturing tolerances and rotor misalignment that would otherwise be critical in smaller pumps. This preliminary action ensures reliable motor operation despite tighter tolerances inherent in miniaturized designs, allowing the pump to achieve proper operation without requiring excessively tight manufacturing precision
3Power
If the rotor is rotated in the first direction before operation, then peak torque requirements are reduced, but additional rotation cycles are required
Solution Approach 1:
The system uses periodic action by implementing a two-directional rotation sequence: first rotating in the opposite direction to reduce cogging torque, then reversing to the driving direction. This periodic bidirectional rotation pattern reduces peak torque requirements while the controller optimizes the timing to minimize the overall startup time penalty
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
This approach reduces peak torque requirements, allowing for smaller and more power-efficient infusion pumps while maintaining reliable operation.
Implementation Method 1
supplying a first signal to a stator of the electromagnetic motor, thereby rotating a rotor of the electromagnetic motor from an initial position in a first direction for a first rotational amount less than a full rotation
Implementation Method 2
supplying a second signal to the stator, thereby rotating the rotor in a second, opposite direction for a second rotational amount greater than the first rotational amount to drive medicament out of the infusion device
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~3A
AI summary
Systems and methods for driving electrical motors of medicament infusion pumps are disclosed. An infusion device for delivering a medicament to a body of a user can include a reservoir to contain medicament, a dispenser to cause medicament to be moved out of the reservoir, and a motor operably coupled to the dispenser. The motor can include a stator defining a central opening and a rotor removably disposed therein. A controller coupled to the stator is configured to (1) supply a first signal to the stator to cause the rotor to rotate in a first direction for a first rotational amount less than a full rotation; and (2) to then supply a second signal to the stator to cause the rotor to rotate in a second, opposite direction for a second rotational amount greater than the first, thereby causing medicament to be dispensed from the reservoir via the dispenser.