Ribbed Force Sensor for Robotic Surgery
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Solution Overview
Problem
Current surgical robot systems face challenges in providing accurate feedback of forces and torques to surgeons during robotic-assisted surgery, particularly due to the need to route delicate wires or optic fibers through flexible wrist joints, which complicates the mechanical actuation of end effectors and affects user control and awareness.
Innovation Solution
A force sensor apparatus is designed with a tube portion featuring radial ribs and strain gauges positioned proximal to the wrist joint, allowing for accurate sensing and feedback of forces and torques without errors, and eliminating the need to route wires or optic fibers through the wrist joint by integrating the sensor as a modular component or part of the instrument shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force sensors are placed distal to the wrist joints, then force sensing capability is achieved, but wires or optic fibers must be routed through the flexing wrist joint and yaw and grip axes must be on separate pivot axes
Solution Approach 1:
The force sensing capability is extracted from the distal end effector and relocated to the proximal instrument shaft. The strain gauges are mounted on the instrument shaft proximal to the wrist joint, eliminating the need to route delicate wires or optic fibers through the flexing wrist joint while maintaining force sensing capability.
Solution Approach 2:
The instrument shaft acts as an intermediary element that transmits force information from the distal end effector to the proximal sensing location. By mounting strain gauges on the instrument shaft, the system uses the shaft itself as a mediator to capture force data without requiring direct sensor placement at the distal end.
2Loss of information
If wires or optic fibers are routed through the wrist joint, then force feedback can be provided, but the mechanical actuation of end effectors is complicated and user control is affected
Solution Approach 1:
The force feedback sensing function is extracted from the wrist joint area and relocated to the proximal instrument shaft. This eliminates the interference of wire routing through the wrist joint, simplifying the mechanical actuation of end effectors and improving user control while maintaining force feedback capability.
3Device complexity
If strain gauges are mounted on the instrument shaft proximal to the wrist joint, then wire routing is simplified, but accurate force and torque sensing must be achieved without errors from wrist configuration changes
Solution Approach 1:
The system incorporates feedback mechanisms to compensate for wrist configuration changes. By monitoring the wrist joint positions and using this information to correct the force and torque measurements taken at the proximal instrument shaft, the system maintains measurement precision despite the relocated sensor position.
Solution Approach 2:
The instrument shaft serves as an intermediary that transmits force information from the distal end effector to the proximal sensing location. The shaft's mechanical properties and positioning allow accurate force and torque sensing while simplifying wire routing, as the shaft naturally transmits the forces without requiring direct distal sensor placement.
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 solution enhances the accuracy and reliability of force and torque feedback to surgeons, improving user control and awareness during robotic surgery while simplifying the integration of mechanical actuation components within the constrained space of surgical instruments.
Implementation Method 1
a strain gauge positioned over each of the plurality of radial ribs
Data Source
AI summary
In one embodiment, a force sensor apparatus is provided including a tube portion having a plurality of radial ribs and a strain gauge positioned over each of the plurality of radial ribs, a proximal end of the tube portion that operably couples to a shaft of a surgical instrument that operably couples to a manipulator arm of a robotic surgical system, and a distal end of the tube portion that proximally couples to a wrist joint coupled to an end effector.