Occlusion Recognition in Medical Administering Apparatus
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Solution Overview
Problem
Existing medical administering apparatuses struggle to reliably recognize occlusions during short discharging events, leading to potential undersupply or oversupply of medicaments, due to false alarms caused by motor inertia during acceleration and deceleration.
Innovation Solution
A device with a motor control arrangement that follows a predefined speed profile, using load sensors and correction modules to account for inertia, and a monitoring arrangement to emit occlusion signals based on corrected load signals, allowing for reliable detection of occlusions even during short events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motor current is monitored to detect occlusions, then occlusion recognition capability is improved, but false alarms occur during motor acceleration and deceleration due to inertia effects
Solution Approach 1:
The system performs preliminary calibration by measuring motor current during acceleration and deceleration phases without occlusion, storing these values as correction factors. This preliminary action enables the system to compensate for inertia effects during actual operation, distinguishing true occlusion signals from normal operational variations.
Solution Approach 2:
The system changes the parameter being monitored from raw motor current to corrected motor current, where the correction factor accounts for acceleration and deceleration effects. This parameter transformation eliminates false alarms while preserving true occlusion detection capability.
2Device complexity
If simple motor current threshold monitoring is used, then device complexity is reduced, but measurement precision deteriorates due to inability to distinguish inertia effects from occlusion
Solution Approach 1:
A calibration phase is performed during system initialization or factory setup to measure and store correction factors for acceleration and deceleration phases. This preliminary characterization of normal operational behavior enables accurate occlusion detection without requiring complex real-time analysis during patient use.
Solution Approach 2:
The system uses feedback from the correction factors (derived from preliminary calibration measurements) to adjust the interpretation of motor current readings. This feedback mechanism allows the simple threshold-based monitoring to achieve high precision by compensating for known operational variations.
3Productivity
If motor current monitoring is applied during all phases including acceleration and deceleration, then productivity is improved by continuous monitoring, but reliability deteriorates due to false alarms from inertia
Solution Approach 1:
The system performs preliminary measurements during acceleration and deceleration phases to establish correction factors. These pre-characterized values enable the system to accurately interpret motor current readings during all phases of operation, including transient phases, without generating false alarms.
Solution Approach 2:
The monitoring approach transitions from using raw motor current values to using corrected motor current values that account for acceleration and deceleration effects. This parameter transformation enables continuous monitoring across all operational phases while maintaining high alarm accuracy.
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
Enables early and accurate recognition of occlusions, reducing the risk of medicament undersupply or oversupply, and providing timely warnings to prevent life-threatening conditions such as hypoglycemia.
Implementation Method 1
a load sensor for determining load signals that constitute a measure for the electrical load formed by the motor
Data Source
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AI summary
A device and a method for controlling a medical administering apparatus are disclosed. An electrical motor of the medical administering apparatus is activated during defined discharging events. The motor is controlled as per a predefined speed profile with a plurality of regions (Pi). A load sensor establishes load signals (Imot) that constitute a measure of the electrical load formed by the motor, e.g. load signals that represent the motor current. A monitoring arrangement compares a variable derived from the load signals with at least one predefined condition and emits an occlusion signal if the condition is satisfied. In order to compensate for acceleration effects, the load signals are corrected as a function of the current region by an associated correction value (I1; I2; I3). This allows reliable recognition of occlusions even in the case of short discharging events.