Magnetic Loop Error Compensation in Medical Positioning
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Solution Overview
Problem
Magnetic field-based medical positioning systems face interference from loops of wire separate from the sensor, leading to noise and errors in position and orientation determination due to magnetic pickup, which existing twisted pair arrangements do not completely resolve.
Innovation Solution
The solution involves forming a second magnetic loop equal in area and opposite in orientation to the existing loop, with connectors and cables being shielded using materials like mu metal to offset induced currents and minimize interference, and incorporating error compensation loops to remove noise from the signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If loops of wire are used to connect sensors in magnetic field-based medical positioning systems, then electrical connectivity is achieved, but magnetic pickup causes noise and errors in position and orientation determination
Solution Approach 1:
The patent forms a second magnetic loop equal in area and opposite in orientation to the first loop created by sensor leads. This second loop, initially a potential source of interference, is converted into a beneficial element that generates an equal and opposite magnetic signal to cancel the noise from the first loop, thereby eliminating magnetic pickup interference while maintaining electrical connectivity.
Solution Approach 2:
The patent introduces asymmetry by creating a second loop with opposite orientation to the first loop. This asymmetric arrangement ensures that the magnetic signals induced in both loops are equal in magnitude but opposite in polarity, allowing for effective cancellation of interference through differential signaling while maintaining the necessary electrical connections.
2Object-affected harmful factors
If connectors and cables are shielded using materials like mu metal, then magnetic interference is reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of adding complex shielding materials like mu metal to block magnetic interference, the patent converts the harmful magnetic pickup effect into a beneficial cancellation mechanism. By deliberately forming a second loop with opposite orientation, the system uses the same magnetic induction principle to generate canceling signals, eliminating interference without requiring additional shielding components or materials.
Solution Approach 2:
The patent extracts and isolates the interference-cancellation function into a dedicated second loop structure, separate from the primary sensor leads. This extracted approach allows the cancellation mechanism to operate independently while maintaining simplicity in the overall connector and cable design, avoiding the need for complex integrated shielding solutions.
3Object-affected harmful factors
If twisted pair arrangements are used for sensor leads, then some magnetic interference is reduced, but noise cancellation is incomplete
Solution Approach 1:
The patent goes beyond the partial protection of twisted pair arrangements by deliberately forming a second magnetic loop with opposite orientation. This active cancellation approach converts the magnetic induction effect, which twisted pairs only partially mitigate, into a beneficial force that completely eliminates noise through equal and opposite signal generation, achieving superior measurement precision.
Solution Approach 2:
The patent implements preliminary anti-action by pre-configuring the second loop with opposite orientation before the medical procedure begins. This pre-established cancellation mechanism proactively counteracts magnetic pickup interference throughout the procedure, rather than merely attenuating it as twisted pairs do, ensuring consistent high-precision sensor readings.
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 significantly reduces signal interference, enhancing the accuracy of position and orientation determination by offsetting induced currents and minimizing noise, thereby improving the precision of sensor readings.
Implementation Method 1
forming a second magnetic loop equal in area and opposite in orientation to the existing loop, with connectors and cables being shielded using materials like mu metal to offset induced currents and minimize interference
Implementation Method 2
connectors and cables being shielded using materials like mu metal to offset induced currents and minimize interference
Implementation Method 3
each magnetic sensor, which may comprise a magnetic coil, is configured to detect and generate a respective signal indicative of one or more characteristics of the magnetic field(s)
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A medical device assembly comprises a medical device comprising a shaft having proximal and distal end portions. The device further comprises a sensor at the distal end portion of the shaft that comprises first and second leads extending therefrom to the proximal end portion of the shaft. The device further comprises an electromechanical connector having a plurality of connection points at a first end thereof. First and second of the connection points are electrically connected to the first and second sensor leads, respectively. The connector further comprises an error loop segment electrically coupled to third and fourth connection points. The error loops segment assists in forming a compensation loop that can be used to correct for magnetic noise.