Force Sensing Unit with Shaft Translation and Roll
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Solution Overview
Problem
Current force-sensing technologies in minimally invasive surgical instruments face challenges in providing accurate haptic feedback within the spatial constraints of these instruments, particularly in measuring axial forces while allowing for translational and rotational movements, which is essential for precise surgical procedures.
Innovation Solution
The implementation of a surgical instrument design that includes a support structure, a shaft with a translation carriage and a roll carriage, a shaft roll drive group, and a force sensor unit, which allows for precise measurement of forces along the shaft axis while enabling translation and rotation, using components like springs and inductive sensors to generate signals associated with force and position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a force sensor unit is attached to the proximal mechanical structure to measure axial forces, then haptic feedback accuracy is improved, but the device complexity increases due to additional sensors and mechanical components
Solution Approach 1:
The force sensor unit is integrated within the proximal mechanical structure rather than being attached externally. The support structure, force sensor unit, shaft translation carriage, and shaft roll carriage are combined into a unified assembly that measures forces while providing necessary degrees of freedom, reducing overall device complexity while maintaining measurement accuracy
Solution Approach 2:
The proximal mechanical structure serves multiple functions: it provides structural support, houses the force sensor unit for measurement, enables shaft translation along the axis, and allows shaft rotation about the axis. This multi-functionality eliminates the need for separate components, reducing device complexity while maintaining force measurement capability
2Measurement precision
If the shaft is constrained to measure axial forces accurately, then measurement precision is improved, but the ease of operation deteriorates due to restricted translational and rotational movement
Solution Approach 1:
The mechanical system is segmented into distinct functional components: the force sensor unit measures axial forces, the shaft translation carriage provides translational movement along the axis, and the shaft roll carriage enables rotation about the axis. Each component handles a specific degree of freedom, allowing accurate force measurement while maintaining operational flexibility
Solution Approach 2:
The shaft translation carriage and shaft roll carriage act as intermediaries between the force sensor unit and the shaft. These carriages decouple the force measurement function from the movement functions, allowing the shaft to translate and rotate freely while the force sensor unit accurately measures axial forces without being affected by these movements
3Adaptability or versatility
If multiple degrees of freedom are provided for shaft movement, then the adaptability is improved, but the device complexity increases due to additional mechanical connectors and movement mechanisms
Solution Approach 1:
The proximal mechanical structure is designed as a universal assembly that simultaneously provides shaft translation along the axis and shaft rotation about the axis through integrated carriages. This multi-functional design achieves multiple degrees of freedom without requiring separate mechanical connectors for each movement type, thereby reducing device complexity while maintaining adaptability
Solution Approach 2:
The shaft translation carriage and shaft roll carriage are merged into a coordinated system that works together with the force sensor unit. This combination allows the shaft to have both translational and rotational degrees of freedom while using a unified mechanical architecture rather than separate independent mechanisms, reducing overall device complexity
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
This design enhances the accuracy of force measurements and haptic feedback, enabling more precise surgical maneuvers by effectively constraining and measuring axial forces while allowing for the necessary degrees of freedom in movement within the limited spatial constraints of minimally invasive surgical instruments.
Implementation Method 1
an inductive sensor configured to generate an electrical signal in response to the axial force
Implementation Method 2
a spring configured to be displaced in proportion to a force imparted to the shaft in a direction along the shaft axis
Data Source
AI summary
A surgical instrument includes a support structure, a shaft, a shaft translation carriage including a shaft roll carrier, a shaft roll drive group, and a force sensor unit. The shaft comprises a proximal end and a distal end, and a shaft axis is defined by the proximal and distal ends. The shaft is coupled to the support structure by the shaft roll carrier. The shaft roll drive group is configured to rotate the shaft about the shaft axis and comprises a shaft roll driver, a shaft roll drive receiver, and a shaft roll drive coupling. The shaft roll drive receiver translates along the shaft axis relative to the shaft roll driver as the shaft translates along the shaft axis. The force sensor unit is configured to produce a the shaft axis.