Crimped Flexure Force Sensor for Surgical Robotics
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Solution Overview
Problem
Existing force sensors for linear media like wires and rods are not easily attachable and require complex setups to measure tension and compression forces effectively, limiting their application in miniaturized and portable devices such as surgical robotic systems.
Innovation Solution
A flexure body with strategically placed stress concentration features and strain gages is attached to the linear medium by crimping, allowing for compact and reliable measurement of forces through a bridge circuit connected to a remote device via insulated leads or a flexible lead carrier, enabling miniaturization and robust signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional tensiometers with frames and rollers are used to measure force in linear media, then force measurement capability is achieved, but device complexity and ease of attachment are worsened
Solution Approach 1:
The sensor is segmented into distinct functional components: a flexure body with integrated strain gages for force sensing, a separate jacket for protection and lead routing, and modular attachment mechanisms. This segmentation allows each component to be optimized independently while simplifying overall assembly and attachment to the linear medium.
Solution Approach 2:
Multiple functions are merged into the flexure body: the force-sensing element, the strain gage mounting substrate, and the structural component that transmits force from the linear medium are all integrated into a single flexure body. This merging eliminates the need for separate frames and rollers, reducing device complexity while maintaining measurement capability.
2Measurement precision
If traditional tensiometers with frames and rollers are used, then force measurement is achieved, but ease of attachment to linear media is worsened
Solution Approach 1:
The flexure body is pre-configured with integrated attachment features including the jacket and lead routing structures before deployment. The strain gages are pre-mounted on the flexure body in the correct orientation, allowing the entire sensor assembly to be attached to the linear medium as a single unit through a simplified process rather than requiring complex on-site assembly.
3Adaptability or versatility
If the sensor is miniaturized for surgical robotic applications, then adaptability to portable devices is improved, but device complexity increases
Solution Approach 1:
The sensor employs a nested structure where the strain gages are mounted on the flexure body, which is then enclosed by the jacket. The leads are routed through the jacket structure, and the entire assembly is compacted to fit within small surgical robotic end effectors. This nesting allows multiple components to occupy overlapping spatial volumes, achieving miniaturization without proportionally increasing assembly 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
The solution provides a compact, reliable, and sensitive force measurement system capable of withstanding significant forces, suitable for surgical robotic applications, with embodiments demonstrating durability and accuracy in transmitting tension and compression forces.
Implementation Method 1
The body carries a bridge circuit of strain gages strategically attached to it for producing signals representing tension and/or compression forces transmitted by and through the medium
Data Source
AI summary
A device for attachment to a linear force transmission medium such as a wire or rod includes a flexure body having axially aligned tubular extensions on opposite ends that can receive and be crimped to the medium to create a continuous path for tensile force transmission. The flexure carries strain gages on top and bottom planar surface portions that are connected into a bridge circuit that responds to stress in the flexure body. Leads are protected against disconnection from solder pads by wrapping the leads and a carrier for them around the exterior circumferential surface of a jacket that fits on and around the flexure body. An FPC plug embodiment is disclosed.