MEMS Accelerometer Stiction Detection in Implantable Devices

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Implantable medical devices (IMDs) face challenges in maintaining reliable accelerometer signals due to stiction, which can lead to loss of motion sensing capability and affect therapy delivery and data accuracy.

Innovation Solution

The implementation of automatic detection methods in IMDs using MEMS sensors to determine signal amplitude and detect stiction, allowing for corrective actions such as generating alerts or adjusting therapy control parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an accelerometer is used to monitor patient motion in an IMD, then motion sensing capability is improved, but stiction can cause loss of reliable signal and affect therapy delivery accuracy

Engineering Contradiction:
Improveaccelerometer signal reliabilityVSAvoidstiction
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary diagnostic analysis of accelerometer signals to detect stiction conditions before they completely compromise therapy delivery. By monitoring signal characteristics and identifying stiction patterns in advance, the system can take corrective actions such as switching to alternative sensors or adjusting therapy algorithms before unreliable signals affect patient care

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors accelerometer signal quality and provides feedback to the control module. When stiction is detected through signal analysis, the feedback loop triggers corrective actions such as generating integrity alerts, switching to backup sensing methods, or adjusting therapy delivery parameters to maintain reliable operation despite sensor degradation

Inventive Principle:
Principle #23Feedback

2Reliability

If automatic detection methods are implemented to detect stiction, then signal reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesensor signal reliabilityVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The accelerometer system performs self-diagnosis by automatically analyzing its own signal characteristics to detect stiction conditions. The control module monitors signal amplitude, frequency content, and temporal patterns without requiring external intervention, enabling the device to self-identify sensor degradation and trigger appropriate corrective actions

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system detects stiction by monitoring changes in signal parameters such as amplitude, frequency spectrum, and temporal variability. By analyzing deviations from normal signal characteristics, the system can identify stiction conditions through parameter changes rather than requiring additional hardware sensors, thereby maintaining reliability while limiting complexity increases

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9522276B2Accelerometer integrity alert
Publication Date: 2016.12.20 MEDTRONIC INC
  • US9522276B2 patent drawing
  • US9522276B2 patent drawing
  • US9522276B2 patent drawing

AI summary

A medical device and associated method determine a signal amplitude of a sensor signal produced by a MEMS sensor, compare the signal amplitude to a stiction detection condition, detect stiction of the MEMS sensor in response to the signal amplitude meeting the stiction detection condition, and automatically provide a corrective action in response to detecting the stiction.