Surgical Console Inductance Sensing for Low-Speed Motor Control
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Solution Overview
Problem
Existing surgical tool systems require multiple control consoles for different handpieces with varying power requirements, leading to clutter and inefficiencies in the operating suite, and struggle with controlling brushless, sensorless DC motors at low RPMs due to difficulties in measuring back electromotive force (BEMF) signals.
Innovation Solution
A surgical tool system with a control console that determines motor rotor position using inductance sensing at low speeds and BEMF sensing at higher speeds, allowing simultaneous actuation of multiple handpieces and reducing the need for multiple consoles by storing data in NOVRAM for each handpiece to regulate energization signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple control consoles are provided for different handpieces with varying power requirements, then each handpiece can receive appropriate energization signals, but the operating suite becomes cluttered and inefficient
Solution Approach 1:
The control console is designed to universally support multiple different handpieces with varying power requirements through a single unit. The console can dynamically adapt its output to match the specific energization needs of each connected handpiece, eliminating the need for multiple specialized consoles while maintaining reliability of operation for each tool type
2Reliability
If manual presetting of console electronics is required for each handpiece, then appropriate energization can be achieved, but medical personnel time is consumed away from patient care
Solution Approach 1:
The control console automatically detects the connected handpiece type and configures its internal electronics to provide the appropriate energization signals without requiring manual presetting. The system self-identifies the handpiece requirements and adjusts its output parameters automatically, freeing medical personnel from time-consuming configuration tasks while ensuring reliable operation
3Device complexity
If BEMF sensing is used for brushless sensorless DC motors at low RPMs, then motor control is simplified, but measurement of BEMF signals becomes difficult and unreliable
Solution Approach 1:
The system changes the measurement parameter from BEMF voltage to winding inductance for low-speed motor control. By measuring the inductance of the motor windings rather than relying on BEMF signals, the system maintains accurate rotor position detection and control at low RPMs where BEMF measurements are unreliable, while keeping the control mechanism relatively simple
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 efficient and simultaneous operation of multiple handpieces with different power requirements, improving operational efficiency and reducing clutter in the operating suite, while effectively controlling brushless, sensorless DC motors across a range of speeds.
Implementation Method 1
determines motor rotor position using inductance sensing at low speeds
Implementation Method 2
struggle with controlling brushless, sensorless DC motors at low RPMs due to difficulties in measuring back electromotive force (BEMF) signals
Data Source
AI summary
A powered surgical tool system capable of providing energization signals to plural powered surgical handpieces. The system includes a console to which at least one footswitch is attached. The footswitch can be mapped to control any one of the handpieces connected to the console. The console includes a display on which representations of the footswitch and handpieces connected to the console are presented. The representations of the handpieces are in different colors. When the footswitch is mapped to a specific handpiece, the representation of the footswitch is presented in the same color as the representation of the handpiece to which the footswitch is mapped. When plural footswitches are attached to the console, the representation of each footswitch is presented in a color corresponding to the color of the representation of the handpiece to which the footswitch is mapped.