External Magnetic Actuation With Slip Detection for Implanted Adjusters
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Solution Overview
Problem
Magnetic slippage between the driving and driven magnets in external actuation devices for adjustable implanted medical devices can hinder the precise rotation and lengthening of these devices, affecting their adjustment accuracy and reliability.
Innovation Solution
An external actuation device with a motor-driven rotatable driving magnet and a strain gage to monitor magnetic coupling, ensuring proper alignment and detecting slip, utilizing a controller to manage motor operation and prevent slippage, and featuring a linear actuator for precise adjustment of the implanted device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple magnetic coupling system is used between driving and driven magnets, then the device complexity is reduced, but magnetic slippage occurs which deteriorates the reliability of device adjustment
Solution Approach 1:
The patent incorporates sensors that detect the position and orientation of the driven magnet relative to the driving magnet, and a controller that processes this feedback information to dynamically adjust motor operation. This closed-loop feedback system prevents magnetic slippage by making real-time corrections to maintain proper alignment, thereby resolving the contradiction between simple structure and reliable operation.
Solution Approach 2:
The patent employs a dynamic control system where the motor operation is continuously adjusted based on real-time magnetic coupling conditions. The controller modifies driving parameters dynamically to maintain optimal magnetic engagement, allowing the system to adapt to varying conditions and prevent slippage without requiring a fundamentally complex mechanical structure.
2Productivity
If the driving magnet is rotated to adjust the implanted device, then the device lengthening function is achieved, but magnetic slippage causes loss of precision in rotation control
Solution Approach 1:
Position sensors continuously monitor the rotational position of both driving and driven magnets, providing feedback to the controller. This enables precise tracking of rotation movements and real-time correction of any slippage, maintaining accurate rotation control throughout the device adjustment process.
Solution Approach 2:
The patent replaces purely mechanical magnetic coupling with a hybrid system that uses electronic sensing and control to supplement the magnetic interaction. This substitution of mechanical reliance with electronic feedback and control mechanisms preserves rotation precision even when magnetic coupling conditions vary.
3Object-affected harmful factors
If external actuation is used to adjust the implanted device non-invasively, then patient safety is improved, but the magnetic coupling is susceptible to slippage which deteriorates adjustment reliability
Solution Approach 1:
The feedback system continuously monitors magnetic coupling integrity and provides real-time information to the controller, enabling detection and correction of slippage conditions. This maintains reliable adjustment performance despite the non-invasive external actuation method.
Solution Approach 2:
The system performs preliminary alignment and establishes optimal magnetic coupling before beginning the adjustment process. The controller pre-positioning ensures maximum magnetic engagement is achieved before actuation begins, creating a more reliable foundation for subsequent adjustments.
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 precision and reliability of adjusting implanted medical devices by maintaining stable magnetic coupling and preventing slippage, allowing for accurate and controlled lengthening of the devices.
Implementation Method 1
The external actuation device includes a driving magnet that can be placed over the driven magnet to magnetically couple the driving magnet and the driven magnet together
Data Source
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AI summary
An external actuation device includes a housing, a motor, a driving magnet, a sensor, and a controller. The motor includes a driveshaft that is rotatable about a rotation axis. The driving magnet is rotatably coupled with the driveshaft and is rotatable together with the driveshaft about the rotation axis. The sensor is associated with the driving magnet and is configured to detect a magnetic force between the driving magnet and a driven magnet disposed adjacent to the driving magnet. The controller is in communication with the motor and the sensor.