Triaxial Force Sensor Decoupling Axial and Transverse Forces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current force sensing technologies in retinal microsurgery lack the ability to independently measure axial and transverse forces with sufficient resolution and precision within the small dimensions required for retinal microsurgery, leading to challenges in delicate tissue manipulation due to human physiological limitations and the fragility of eye tissues.
Innovation Solution
A miniaturized triaxial force sensor integrated into the tool shaft, utilizing a flexure section to decouple axial and transverse force sensing, with fiber optic strain sensors providing independent measurement capabilities, allowing for precise force feedback and minimizing noise from transverse forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force sensors are mounted in the handle of the microsurgical tool, then force sensing capability is provided, but the force sensor cannot distinguish the force exerted at the tool tip and the contact force at the sclerotomy
Solution Approach 1:
The tool is divided into segments with force sensors positioned at the distal portion (tool tip) and proximal portion (handle), allowing separate measurement of forces at different locations. The distal force sensor measures tissue interaction forces while the proximal sensor measures handle contact forces, enabling differentiation between these force sources.
Solution Approach 2:
A flexible coupling mechanism serves as an intermediary between the distal tool tip and the proximal handle, transmitting mechanical forces while allowing independent sensor measurements. This flexible coupling enables the system to distinguish between forces applied at the tool tip and forces applied at the handle by measuring deformations in the flexible section.
2Measurement precision
If conventional force sensing technologies are used, then force sensing is provided, but independent measurement of axial and transverse forces with sufficient resolution and precision is not achieved
Solution Approach 1:
Conventional strain gauge-based force sensors are replaced with fiber optic force sensors that use optical measurement principles. These fiber optic sensors measure forces through changes in optical properties (such as birefringence or Bragg wavelength) when subjected to mechanical stress, providing independent axial and transverse force measurements with high precision and immunity to electromagnetic interference.
Solution Approach 2:
The fiber optic force sensing system is designed to simultaneously measure multiple force components (axial and transverse forces) using a single integrated sensor platform. This multi-functional capability allows independent measurement of different force directions without requiring separate sensor systems for each measurement type.
3Length of moving object
If the tool dimensions are reduced for retinal microsurgery, then the tool can access the small constrained space, but force sensing capability with sufficient resolution becomes difficult to implement
Solution Approach 1:
Mechanical strain gauge sensors are replaced with fiber optic sensors that can be implemented in miniaturized form while maintaining high measurement precision. The fiber optic sensing mechanism relies on optical property changes rather than mechanical amplification, allowing accurate force measurement in extremely small tool dimensions suitable for retinal microsurgery.
Solution Approach 2:
The force sensing system utilizes changes in optical parameters (wavelength, intensity, or polarization) in response to applied forces. By measuring these optical parameter changes rather than mechanical deformations, the system achieves high force sensing resolution in miniaturized tools where mechanical sensor implementation would be insufficient.
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 accurate and independent measurement of axial and transverse forces with high sensitivity, reducing crosstalk noise and improving force sensing performance, thereby enhancing the precision and safety of retinal microsurgical procedures.
Implementation Method 1
fiber optic strain sensors providing independent measurement capabilities
Implementation Method 2
a flexure section attached at a first end to the distal end of the tool shaft, a tool tip operatively connected to the flexure section such that axial forces applied to the tool tip are coupled primarily to a first portion of the flexure section and transverse forces applied to the tool tip are coupled primarily to a second portion of the flexure section
Data Source
AI summary
A force-sensing tool includes a tool shaft that has a proximal end and a distal end, a flexure section attached at a first end to the distal end of the tool shaft, a tool tip operatively connected to the flexure section such that axial forces applied to the tool tip are coupled primarily to a first portion of the flexure section and transverse forces applied to the tool tip are coupled primarily to a second portion of the flexure section, an axial force sensor coupled to the first portion of the flexure section, and a transverse force sensor coupled to the second portion of the flexure section. The axial force sensor responds to axial forces applied to the tool tip substantially independently of the transverse forces applied to the tool tip under a designed operating range of forces, and the transverse force sensor responds to transverse forces applied to the tool tip substantially independently of the axial forces applied to the tool tip under the designed operating range of forces.