Dynamic Sampling Sensor for Drug Delivery Dose Logging
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Solution Overview
Problem
Current drug delivery devices lack efficient and reliable methods for capturing and logging dose data, particularly due to the non-linear axial movement of piston rods made from elastomeric materials, which complicates accurate determination of expelled drug amounts.
Innovation Solution
A sensor system with adjustable sampling frequencies is integrated into the drug delivery assembly, allowing for high sampling rates during initial elastomeric compression and lower rates during steady-state drug expulsion, utilizing both low and high power consumption sensors to accurately measure rotational position and speed of an indicator component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sampling frequency is used throughout the entire drug expulsion process, then measurement precision of rotational position is improved, but power consumption increases excessively
Solution Approach 1:
The patent applies dynamics by making the sampling frequency variable rather than static. The sensor system dynamically adjusts its sampling rate based on the operational phase: using high sampling frequency during initial elastomeric compression when non-linear movement occurs, and switching to low sampling frequency during steady-state expulsion when linear movement occurs. This dynamic adjustment resolves the contradiction between measurement precision and power consumption.
Solution Approach 2:
The patent changes the parameter of sampling frequency based on the operational conditions. By detecting whether the piston rod is in the compression phase or steady-state expulsion phase, the system adjusts the sampling frequency parameter accordingly. This parameter change allows the system to maintain measurement precision when needed while minimizing power consumption during stable operation.
2Use of energy by moving object
If low sampling frequency is used throughout the entire drug expulsion process, then power consumption is reduced, but measurement precision deteriorates during initial elastomeric compression
Solution Approach 1:
The system dynamically switches between low and high sampling frequencies based on the operational phase. During initial elastomeric compression when the piston rod exhibits non-linear movement, the system transitions to high sampling frequency to ensure accurate measurement. During steady-state expulsion with linear movement, it uses low sampling frequency to conserve power. This dynamic switching resolves the contradiction between power consumption and measurement precision.
Solution Approach 2:
The sampling frequency parameter is changed based on the detected operational phase. The processor monitors the movement characteristics and adjusts the sampling frequency parameter accordingly - using low frequency during steady-state to reduce power consumption, and switching to high frequency during compression phase to maintain measurement precision.
3Device complexity
If uniform sampling frequency is used, then device complexity is reduced, but reliability of dose determination deteriorates due to non-linear piston movement
Solution Approach 1:
The patent implements a dynamic sampling strategy that adapts to the non-linear movement characteristics of elastomeric piston rods. By switching between high and low sampling frequencies based on the operational phase, the system reliably captures the non-linear compression behavior while maintaining simplicity in steady-state. This dynamic approach improves dose determination reliability without significantly increasing device complexity.
Solution Approach 2:
The sampling frequency parameter is changed based on the operational phase to match the piston rod's movement characteristics. During compression phase with non-linear movement, high sampling frequency is applied to capture accurate dose information. During steady-state with linear movement, low sampling frequency suffices. This parameter adaptation ensures reliable dose determination while managing device complexity.
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 enables reliable and power-efficient determination of drug doses, addressing the complexities of elastomeric piston movement and ensuring accurate logging of injection data without excessive power consumption.
Implementation Method 1
The sensor assembly comprises at least one magnet sensor adapted to measure one or more components of a magnetic field
Data Source
AI summary
A drug delivery assembly comprising a sensor system in combination with an indicator arranged to rotate, the amount of rotation being indicative of the size of an expelled dose amount. The sensor system comprises a sensor assembly adapted to measure a rotational position and/or a rotational movement of the indicator, the sensor assembly comprising a sensor element adapted to be operated at a non-constant sampling frequency. A processor is configured to determine on the basis of measured values from the sensor element rotational position(s) and/or amount of rotational movement of the indicator, as well as rotational speed of the indicator. To optimize energy consumption the processor is configured to dynamically control the sampling frequency in response to the determined rotational speed.