Surgical Tool Holder Interface for Fast Safe Robot Exchange

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Solution Overview

Problem

Current tool exchange mechanisms in cooperative surgical robots are inadequate for quick and safe tool removal during surgeries, particularly in delicate procedures like retinal microsurgery, as they fail to balance firm tool holding with rapid release requirements, risking unintended break-away or slow withdrawal.

Innovation Solution

A system with a tool holder that constrains motion along the tool axis, uses sensors to detect tool engagement, and automatically selects movements based on detected forces to reengage the tool when a predetermined removal force is sensed, allowing for low-force removal and safe quick release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a simple d-tenting mechanism or magnet is used to hold the tool, then the tool can be held firmly enough to permit operator guidance, but the required release force becomes too large to remove the tool quickly and safely

Engineering Contradiction:
Improvetool holding forceVSAvoidtool removal speed
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The tool holder uses a dynamic spring-loaded ball mechanism that adapts its holding force based on operational needs. During normal use, the spring maintains firm engagement through the ball-and-socket connection. During emergency removal, the system dynamically transitions to allow quick release by overcoming the spring force, enabling both firm holding and rapid removal

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the engagement parameter from a fixed strong connection to a controllable variable connection. The spring constant and ball diameter are selected to provide appropriate engagement strength during surgery while allowing quick disengagement when needed, effectively changing the force parameter between operational states

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a strong engagement mechanism is used to prevent unintended break-away, then the tool is held securely, but the tool cannot be removed quickly when safety requires immediate withdrawal

Engineering Contradiction:
Improvetool engagement stabilityVSAvoidtool removal speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The tool holder system is designed to be self-regulating through the spring-loaded mechanism. The spring automatically adjusts to maintain reliable engagement during normal operation, and the same mechanism enables quick release when force is applied in the removal direction, providing both reliability and speed without external intervention

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the tool holder mechanism is designed for quick release capability, then the tool can be removed safely, but the mechanism may impede the robot's function or the surgeon's ability to perform desired tasks

Engineering Contradiction:
Improvetool removal capabilityVSAvoidtool holder mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The tool holder is segmented into distinct functional components: the ball retention feature with spring-loaded mechanism, the socket feature for engagement, and the interface portion for robot coupling. This segmentation allows each component to perform its specific function efficiently while maintaining overall system simplicity and robot compatibility

Inventive Principle:
Principle #1Segmentation

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 rapid and safe tool exchange during surgeries by ensuring the tool is firmly held during procedures and can be quickly removed when necessary, enhancing operational efficiency and safety.

Implementation Method 1

a small spring-loaded ball or pin in the tool holder engages a socket or groove on the tool shaft to hold the tool in place

Methodology Applied
Scientific EffectSpring-loaded mechanism: Spring

Implementation Method 2

Another approach is to use a magnet

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentEP2600788B1Tool exchange interface and control algorithm for cooperative surgical robots
Publication Date: 2023.07.26 JOHNS HOPKINS UNIVERSITY
  • EP2600788B1 patent drawingFigure 1A~1B
  • EP2600788B1 patent drawingFigure 2A~2B
  • EP2600788B1 patent drawing

AI summary

A system and method for tool exchange during surgery for cooperatively controlled robots comprises a tool holder for receiving a surgical tool adapted to be held by a robot and a surgeon, a tool holding element for constraining downward motion of the tool while allowing low force removal of the surgical tool from the holder, a first sensor for detecting if the surgical tool is docked within the tool holder, and a selector for automatically selecting different movements or actions of the tool holder to be performed based upon information detected by the first sensor. The system and method of the present invention provides an advantage to an often slow moving cooperative robot, by increasing the speed by which the tool holder may move in the direction away from the patient.