Optical Force Sensor for Robotic Surgical Jaw Deflection
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Solution Overview
Problem
Robotic surgical systems lack accurate measurement of forces exerted by or on the jaw members during minimally invasive procedures, which is crucial for precise tissue manipulation and instrument functionality.
Innovation Solution
Integration of optical force sensors within the jaw members of surgical instruments, utilizing a light source, reflector, and light receiver to directly measure deflection and correlate it with force, providing accurate feedback to clinicians.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If robotic surgical systems are used for minimally invasive procedures, then surgical precision and patient recovery are improved, but accurate measurement of forces exerted by jaw members is lost
Solution Approach 1:
The optical force sensor is nested within the jaw member structure itself. The reflector is positioned inside the cavity of the jaw member, and the optical components are integrated into the existing surgical instrument architecture, allowing force measurement without adding external bulky equipment.
Solution Approach 2:
An optical intermediary system is introduced to measure force indirectly. Instead of directly measuring force with mechanical sensors, the system uses light reflection off a movable reflector to detect jaw member displacement, which is then correlated to force measurements through optical levers and light path modulation.
2Measurement precision
If optical force sensors are integrated into jaw members, then force measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical force sensors with an optical measurement system. Instead of using strain gauges or mechanical load cells that would add complexity and potential failure points, the system uses light sources, mirrors, and photodetectors to measure jaw member deflection optically, achieving high precision with a different physical domain.
Solution Approach 2:
The force measurement is achieved by measuring displacement in a different dimension. Rather than directly measuring force along the clamping axis, the optical system measures the perpendicular displacement of the reflector caused by jaw member deflection, converting a force measurement problem into a position measurement problem that can be solved with optical interferometry.
3Reliability
If direct measurement of jaw member deflection is implemented, then force measurement reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The optical components are pre-aligned and rigidly mounted during manufacturing. The light source, reflector, and photodetector are positioned and secured in fixed relationships to each other and to the jaw member structure before the instrument is put into service, eliminating the need for field calibration and ensuring consistent measurement reliability.
Solution Approach 2:
The reflector is positioned within a cavity of the jaw member and is oriented to reflect light back along its incident path when the jaw is in the neutral position. This geometric arrangement creates a self-aligning optical path where small manufacturing variations are compensated by the symmetric light reflection geometry, reducing the impact of manufacturing tolerances on measurement accuracy.
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 force measurement and feedback, enhancing the functionality of instruments like graspers, staplers, electrosurgical forceps, and endoscopic suturing devices by preventing under or over-clamping, optimizing tissue sealing, cutting, and coagulating, and detecting suture slippage.
Implementation Method 1
a reflector disposed within the cavity of the first jaw member and configured to reflect light emitted from the light source
Implementation Method 2
The optical force sensor directly measures the deflection of the respective jaw member in one or more directions to determine force exerted on or by the respective jaw member
Data Source
AI summary
According to an aspect of the present disclosure, a surgical instrument is provided and includes a housing; an elongate shaft extending from the housing; and a tool assembly supported by a distal portion of the elongate shaft, the tool assembly including first and second jaw member. The at least one of the first and second jaw members is moveable relative to the other jaw member between a neutral configuration in which the first and second jaw members are spaced apart relative to one another; and a clamping configuration in which the first and second jaw members are approximated relative to one another with tissue grasped therebetween, the first jaw member defining a cavity.