Adaptive IMU Filter Using Data-Driven Parameter Model

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Solution Overview

Problem

Inertial measurement units (IMUs) face challenges in obtaining accurate measurements under variable operating conditions due to sensitivity to temperature, ambient pressure, mechanical stress, and electromagnetic fields, which affects the preprocessing of raw sensor signals.

Innovation Solution

An adaptive filtering method is implemented in the IMU using a data-driven filter parameter model that continuously adapts filter parameters based on real-time sensor data and operating conditions, allowing for optimal selection and configuration of filter elements to improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional filtering with fixed parameters is used, then the device complexity is low, but the measurement precision deteriorates under variable operating conditions

Engineering Contradiction:
Improvesensor signal accuracyVSAvoidfilter parameter adaptation system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements dynamic filter parameters that adapt in real-time based on operating conditions such as temperature, acceleration, and signal characteristics. Instead of fixed filter parameters, the system continuously adjusts cutoff frequencies and filter orders to match current operating conditions, resolving the contradiction between maintaining low device complexity and achieving high measurement precision under variable conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes filter parameters (cutoff frequency, filter order) based on detected operating conditions. When temperature or acceleration exceeds thresholds, the filter parameters are automatically adjusted to maintain signal accuracy. This parameter adaptation allows the system to maintain high measurement precision without requiring a completely complex adaptive system, as changes are triggered only when necessary.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If fixed filter parameters are used, then the ease of operation is high, but the adaptability to different operating conditions deteriorates

Engineering Contradiction:
Improvefilter adaptation to operating conditionsVSAvoidfilter configuration
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The filter system performs self-adjustment based on sensor inputs from temperature sensors, acceleration sensors, and signal analysis. The system automatically detects operating conditions and adjusts filter parameters without requiring manual intervention or complex user configuration. This self-service approach maintains ease of operation while achieving high adaptability to different operating conditions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses feedback from temperature sensors, acceleration sensors, and signal quality metrics to automatically adjust filter parameters. The feedback loop continuously monitors operating conditions and adjusts the filter configuration accordingly, enabling the system to adapt to different conditions without requiring complex manual setup or user expertise.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If compensation tables are used for preprocessing, then the manufacturing precision can be improved, but the loss of time increases due to calibration requirements

Engineering Contradiction:
Improvesensor signal compensationVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary compensation by storing correction values in lookup tables that are pre-populated with temperature and acceleration compensation data. During operation, the system quickly retrieves appropriate compensation values based on current sensor readings, avoiding time-consuming real-time calculations. This preliminary preparation maintains high measurement precision while minimizing calibration and setup time during actual use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The compensation system transitions from static pre-calibrated tables to dynamic, condition-based compensation. The system adjusts compensation parameters in real-time based on detected operating conditions such as temperature and acceleration levels, allowing it to maintain high measurement precision across varying conditions without requiring extensive recalibration time for each new operating scenario.

Inventive Principle:
Principle #15Dynamics

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 the IMU to provide accurate output sensor data by dynamically adapting to changing conditions, enhancing the precision of motion measurements and reducing errors from misalignment and dynamic influences.

Implementation Method 1

A standard IMU may be implemented as a MEMS-based system and does usually include a sensor unit based on spring-biased masses which are capacitively coupled to provide a variable capacitance output depending on a motion-induced force, such as an inertial force

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS20230400305A1Inertial measurement unit and method for operating a measurement unit
Publication Date: 2023.12.14 PEPPERL & FUCHS SE
  • US20230400305A1 patent drawing
  • US20230400305A1 patent drawing

AI summary

An inertial measurement unit for providing output sensor data according to a force or motion applied on the inertial measurement unit. The inertial measurement unit includes a sensor unit including one or more sensor elements for detecting motion. A filter unit includes one or more filter elements. The filter unit is configured to apply one or more filter elements on the sensor data according to filter parameters. A filter parameter unit includes a data-driven filter parameter model for providing filter parameters to the filter unit in response to the sensor data obtained from the sensor elements.