Wireless Magnetic Capsule Pose Detection via Internal Sensor Fusion

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Solution Overview

Problem

Magnetic coupling-based medical devices face challenges in accurate real-time localization and pose determination within the body due to the strong magnetic fields used for manipulation, which interfere with external sensing systems.

Innovation Solution

A system equipped with sensors such as magnetometers and inertial sensors inside the medical capsule wirelessly transmits data to an external system, allowing for real-time determination of the capsule's position, orientation, and pressure on surrounding tissues, using magnetic field and inertial data to accurately control the capsule's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a strong magnetic field is applied to manipulate the magnetic capsule, then the capsule can be effectively controlled and moved within the body, but external electromagnetic field-based localization techniques become inadequate and cannot accurately determine the capsule's position and orientation

Engineering Contradiction:

Improvemagnetic coupling force for capsule manipulationVSAvoidlocalization accuracy of capsule position and orientation

Core Design Contradiction:

ForceVSMeasurement precision

Solution Approach 1:

Instead of using external sensors to detect the capsule's position (external-to-internal sensing), the patent inverts the approach by placing sensors inside the capsule to detect the magnetic field and inertial data (internal-to-external sensing). The capsule itself becomes the sensing platform, using onboard magnetometers and inertial sensors to measure its own position and orientation relative to the applied magnetic field, thereby resolving the interference problem between the strong magnetic field and external localization systems

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces an intermediary wireless transmission system that carries sensor data from the capsule through the body wall to external processing systems. This intermediary communication channel allows the capsule to report its position and orientation data externally without requiring direct electromagnetic field-based localization, thus bypassing the interference issue while maintaining effective magnetic manipulation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If sensors are placed inside the magnetic capsule to enable real-time pose detection, then accurate position and orientation information can be obtained, but the device complexity increases

Engineering Contradiction:

Improvereal-time pose detection accuracyVSAvoidcapsule structure with integrated sensors

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the magnetic capsule multi-functional by integrating multiple sensor types (magnetometers for magnetic field detection, inertial sensors for acceleration and orientation) into a single device. These sensors serve dual purposes: characterizing the magnetic field environment for localization and providing inertial measurement for pose determination, thereby achieving high measurement precision without proportionally increasing complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines multiple sensing functions (magnetic field sensing, inertial sensing, wireless communication) into an integrated capsule system. By merging these functions into a single compact device rather than using separate external systems, the patent reduces overall system complexity while maintaining high measurement precision for real-time pose detection

Inventive Principle:

Principle #5Merging (Combining)

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 precise control and movement of magnetic capsules within the body with an accuracy of 8 mm in position detection and 2.5 degrees for yaw detection, providing safe and effective navigation through the body cavity.

Implementation Method 1

A set of sensors (e.g., a magnetometer, inertial sensors, etc.) are placed inside the magnetic capsule

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

Magnetic coupling is one of the few physical phenomena capable of transmitting actuation forces across a physical barrier

Methodology Applied

Scientific EffectMagnetic coupling: Magnetism

Implementation Method 3

Sensor data, including inertial data from an inertial sensor and magnetic field data

Methodology Applied

Scientific EffectInertial sensing: Inertia

Data Source

PatentUS10485409B2Real-time pose and magnetic force detection for wireless magnetic capsule

Publication Date: 2019.11.26 VANDERBILT UNIV

AI summary

Systems and methods are described for determining an orientation and position of a capsule inserted into the body of a patient. A magnetic field is applied to an area of the patient where the capsule is located. Sensor data, including inertial data from an inertial sensor and magnetic field data indicative of the applied magnetic field as detected by at least one magnetic field sensor, is wirelessly received from the capsule. An orientation angle of the capsule is determined based at least in part on the inertial data. The magnetic field data is compared to known characteristics of the applied magnetic field and a location of the capsule is determined based on the comparison.