Electromagnetic Localization System Pose Accuracy
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Solution Overview
Problem
Electromagnetic localization systems in surgical robotics and navigation are prone to magnetic field disturbances from conductive and magnetic materials, leading to inaccurate measurements due to eddy currents and field distortions, which current compensation methods fail to adequately address, limiting their reliability and precision.
Innovation Solution
An electromagnetic localization system with locating units and a processing unit that determines the pose of objects by measuring magnetic fields, calculates accuracy indicators, compares them to predefined thresholds, and generates instructions to displace transducers when disturbances are detected, either manually or automatically, to improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electromagnetic localization is used in surgical robotics, then line-of-sight constraints are eliminated and minimally invasive surgery is enabled, but magnetic field disturbances from conductive and magnetic materials cause measurement inaccuracies
Solution Approach 1:
The system performs preliminary actions by calculating accuracy indicators before final pose determination, comparing these indicators against thresholds to detect potential measurement errors caused by disturbing materials, and only proceeding with pose determination when accuracy criteria are met
Solution Approach 2:
The system implements feedback by continuously monitoring magnetic field measurements, calculating accuracy indicators based on these measurements, comparing indicators to thresholds, and using this feedback to determine whether to trust the measured pose or request repositioning of transducers
2Measurement precision
If transducers are placed close to anatomical structures for precise measurement, then working distance is reduced, but disturbing materials must be kept at least 4-5 times the working distance away, creating space constraints
Solution Approach 1:
The system calculates accuracy indicators in advance based on the spatial arrangement of transducers and disturbing materials, allowing operators to assess whether the current configuration will yield accurate measurements before proceeding with surgical operations
Solution Approach 2:
The system changes parameters by adjusting the threshold values for accuracy indicators based on different surgical scenarios and disturbing material configurations, allowing flexible adaptation to various spatial constraints in the operating room
3Reliability
If current electromagnetic localization systems are used, then basic pose determination is achieved, but reliability is limited due to inability to detect and compensate for magnetic field disturbances
Solution Approach 1:
The system performs preliminary calculations of accuracy indicators using the measured magnetic field values and known transducer configurations, determining in advance whether the measurement conditions are sufficient for reliable pose determination
Solution Approach 2:
The system serves itself by automatically detecting measurement quality issues through accuracy indicator calculations and autonomously determining whether to accept or reject pose measurements without requiring external validation
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
Enhances the reliability and precision of electromagnetic localization by minimizing the impact of disturbing materials, ensuring accurate determination of object poses and reducing measurement errors.
Implementation Method 1
a transmitter adapted to emit at least one magnetic field and at least one receiver adapted to receive and measure the magnetic field emitted by the transmitter
Implementation Method 2
Electrically conductive materials can give rise to eddy currents when these materials are placed in a varying magnetic field. The eddy currents that then circulate in this disturbing material in turn generate a disruptive magnetic field
Implementation Method 3
Magnetic materials (for example: ferromagnetic, diamagnetic, paramagnetic, antiferromagnetic, ferrimagnetic) can distort magnetic field they are placed in
Data Source
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AI summary
The present invention concerns an electromagnetic localization system (1) comprising at least one locating unit (10) and one processing unit (5), the locating unit (10) comprising at least two locating transducers (A, AA) wherein at least one locating transducer is a transmitter adapted to emit at least one magnetic field and at least one locating transducer is a receiver adapted to receive and measure the magnetic field emitted by the transmitter, wherein at least one first locating transducer (A) is adapted to be locked in a fixed position with respect to a first object (100) and at least one second locating transducer (AA) is adapted to be locked in a fixed position with respect to a second object (110), the processing unit (5) being configured to: a. determine a pose of the first locating transducer (A) with respect to the second locating transducer (AA) based on the measurement of the magnetic field emitted by the transmitter of the locating unit, b. calculate an indicator related to the accuracy of the measurement of the magnetic field, c. compare the calculated indicator with a predefined threshold, d. determine the pose of the first object (100) with respect to the second object (110), based on the determined pose of the transducers when the calculated indicator is below the predefined threshold, and e. generate an instruction to displace at least one of the locating transducers (A, AA) when the calculated indicator exceeds the predefined threshold, such instruction being executable manually by a user of the system or automatically by an actuator.