Surgical Instrument Force Measurement via Distance Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing surgical instrument devices face challenges in precisely measuring forces applied to surgical instruments due to variations in contact resistance and strain gauge placement, leading to inaccurate force transmission and measurement.
Innovation Solution
A surgical instrument device with a force transmitting member and a distance change detecting unit that calculates force based on changes in distance between two points on the force transmitting member, using displacement detecting units and a conversion equation to achieve precise force measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a strain gauge is provided in the surgical instrument portion to detect force, then force detection capability is achieved, but measurement precision deteriorates due to variation in contact resistance from attachment and detachment
Solution Approach 1:
The patent replaces the electrical strain gauge measurement system with a mechanical distance change detection system. Instead of using strain gauges that require electrical connections and are sensitive to contact resistance variations, the invention uses a mechanism that directly measures distance changes between two points on the force transmitting member. This mechanical approach eliminates the electrical connection issues and provides stable, reliable measurements even when the surgical instrument portion is attached and detached.
2Reliability
If the strain gauge is provided in the surgical instrument device body, then connection stability is improved, but measurement precision deteriorates due to increased distance from the force application point
Solution Approach 1:
The patent divides the force transmitting member into two functional segments: a first force transmitting member in the surgical instrument portion and a second force transmitting member in the device body, connected through a connection portion. The distance change detecting unit measures the distance between points on these two segments, effectively capturing the force transmission while maintaining both measurement precision and connection stability. This segmentation allows the measurement system to benefit from the stability of the device body connection while remaining close to the force application point.
3Ease of manufacture
If the surgical instrument portion is made detachable for sterilization, then ease of manufacture and maintenance are improved, but measurement precision deteriorates due to connection variation
Solution Approach 1:
The patent replaces the electrical strain gauge system with a mechanical distance measurement system that is insensitive to connection variations. The distance change detecting unit measures physical distance changes between two points on the force transmitting member, a method that remains accurate regardless of attachment and detachment operations. This allows the surgical instrument portion to be easily detached for sterilization and reused without compromising measurement precision.
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 highly precise force measurement on surgical instrument portions with a simple configuration, reducing measurement errors and maintaining accuracy across attachable and detachable connections.
Implementation Method 1
a force transmitting member which is formed in a shaft shape, of which one end portion in an axial direction is connected to the surgical instrument portion and the other end portion in the axial direction is supported by the surgical instrument device body, and which transmits a force between the surgical instrument portion and the surgical instrument device body
Implementation Method 2
a distance change detecting unit which detects a change in distance between two points away from each other in the axial direction on the force transmitting member based on a distance when no load is applied to the surgical instrument portion
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A surgical instrument device (1) includes a surgical instrument portion (32) which is used in a surgical operation, a slave arm (31) which holds the surgical instrument (32), a driving rod (34) which is formed in a shaft shape, of which one end portion in the axial direction is connected to the surgical instrument (32) and the other end portion in the axial direction is supported by the slave arm (31), and which transmits a force between the surgical instrument (32) and the slave arm (31), a distance change detecting unit which detects a change in distance between two points in the axial direction of the driving rod (34) based on a distance when no load is applied to the surgical instrument (32), and a force calculating unit which calculates a force applied from the surgical instrument (32) or the slave arm (31) to the driving rod (34) based on the change in distance detected by the distance change detecting unit.