Force Sensing Apparatus with Fiber Bragg Gratings for Surgical Robots
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Solution Overview
Problem
Current force sensing apparatuses for surgery robots are unable to accurately measure forces in multiple directions, are difficult to mount in limited spaces, and malfunction in strong electromagnetic fields, with a limited range of measurable forces.
Innovation Solution
A force sensing apparatus with a deformable body featuring fiber Bragg gratings (FBGs) and elastic beams, designed to measure forces along multiple axes without electromagnetic interference, incorporating stoppers for safety and enhanced durability, and optimized for increased sensitivity and measurement range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional force sensing apparatuses are installed at the operational end of a surgery robot, then force measurement capability is provided, but accurate measurement of forces in multiple directions cannot be achieved
Solution Approach 1:
The force sensing apparatus is segmented into multiple independent FBG sensors, with at least three FBGs arranged at different positions and orientations on the deformable body. Each FBG measures force in a specific direction, and the combined data provides comprehensive multi-axis force measurement capability.
Solution Approach 2:
The measurement capability is extended from single-axis to multi-axis by adding spatial dimensionality. FBGs are positioned at different locations and orientations (azimuth angles) on the body, enabling measurement of forces in multiple directions simultaneously through optical wavelength shifts.
2Reliability
If force sensing apparatuses are mounted on the arm portion of a surgery robot, then force sensing is enabled, but mounting is difficult due to limited space
Solution Approach 1:
The sensing apparatus uses a thin, deformable body with FBGs attached to its surface. This flexible membrane structure provides the necessary force sensing capability while occupying minimal space, allowing easy mounting on the limited surface area of the robot arm portion.
Solution Approach 2:
The force sensing function is extracted from a bulky conventional sensor assembly and implemented through thin FBG markers attached to a deformable body. This extraction reduces the mounting footprint while maintaining sensing reliability.
3Measurement precision
If conventional force sensing apparatuses are used in a surgery robot environment, then force measurement is provided, but malfunction occurs in strong electromagnetic fields
Solution Approach 1:
The conventional electromagnetic-based force sensors are replaced with an optical sensing system using FBGs. The FBGs detect force through optical wavelength shifts caused by mechanical deformation of the body, eliminating susceptibility to electromagnetic field interference while maintaining measurement precision.
Solution Approach 2:
Optical fibers serve as an intermediary medium between the mechanical deformation (force application) and the detection system. The FBGs modulate light wavelength in response to mechanical strain, providing an electromagnetic-field-immune measurement pathway.
4Measurement precision
If conventional force sensing apparatuses are installed, then force sensing is enabled, but the range of measurable forces is relatively small
Solution Approach 1:
The measurement range is extended by changing the physical parameters of the sensing system. The deformable body is designed with appropriate elastic properties and geometry, and multiple FBGs are positioned to detect different deformation modes, enabling accurate measurement across a broader range of force magnitudes and directions.
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
Accurately measures forces across multiple axes with enhanced sensitivity and range, while maintaining durability and resistance to electromagnetic fields, enabling precise force feedback for surgical operations.
Implementation Method 1
at least three fiber Bragg gratings (FBGs) attached to a surface of the body
Implementation Method 2
a light detector detecting light reflected by each of the FBGs or light that has passed through each of the FBGs
Implementation Method 3
a body that is elastically deformable and has a pipe form extending along an axial direction of the body
Data Source
AI summary
A multi-axis force sensing apparatus that is installed at an operational end of a surgery robot and is capable of measuring force acting upon the operational end and a robot arm including the force sensing apparatus includes a body that is elastically deformable and has a pipe form extending along an axial direction of the body, an optical fiber strain gauge attached to a surface of the body to measure a tension and compression of the body in at least three directions. The optical fiber strain gauge may include at least three fiber Bragg gratings (FBGs) that are attached to the surface of the body and extended in an axial direction of the body, a light source providing light to each of the FBGs, and a light detector detecting light reflected by the FBGs or light that has passed through the FBGs.