Variable-Stiffness End Effector Coupling for Surgical Vibration Isolation
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Solution Overview
Problem
Robotic surgical systems face challenges in decoupling vibrations from end effectors due to high rigidity, leading to undesired system dynamics and natural frequency vibrations during procedures like spinal surgery.
Innovation Solution
A variable stiffness end effector assembly that allows quick decoupling between the end effector support and the tool insertion device, switching between rigid and compliant modes to absorb vibrations and reduce natural frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the robotic arm uses high rigidity for stable positioning, then positioning stability is improved, but natural frequency vibrations occur during surgical procedures
Solution Approach 1:
The end effector support assembly incorporates a variable stiffness mechanism that allows dynamic switching between rigid and compliant modes. During drilling operations, the system transitions from a rigid coupling (providing positioning stability) to a compliant coupling (absorbing vibrations), thereby resolving the contradiction between stable positioning and vibration reduction
Solution Approach 2:
The system changes the stiffness parameter of the end effector support assembly by switching between rigid and compliant modes. This parameter change allows the system to adapt to different operational requirements: high stiffness for positioning accuracy and low stiffness for vibration absorption, thus resolving the contradiction
2Manufacturing precision
If the end effector is rigidly coupled for precision, then manufacturing precision is improved, but vibrations are transmitted to the robotic arm
Solution Approach 1:
The coupler mechanism enables dynamic adjustment of the coupling stiffness between the tool insertion device and end effector support. The system uses a rigid coupling for precise tool positioning and a compliant coupling to isolate vibrations, resolving the contradiction between precision and vibration transmission
Solution Approach 2:
The end effector support assembly acts as an intermediary between the robotic arm and the surgical tool. By incorporating a variable stiffness mechanism, it serves as a mediator that can transmit forces for positioning while filtering out harmful vibrations, thus resolving the contradiction
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 system effectively reduces natural frequency vibrations, improving procedural stability and reducing harmonic vibrations in the robotic arm, enhancing the precision and comfort of surgical operations.
Implementation Method 1
The system dynamics may occur in natural vibrations at a high frequency due to the high stiffness in the system
Implementation Method 2
coupling using a compliant mechanism of the parts of the end effector support
Data Source
AI summary
A variable stiffness end effector assembly for a medical robotic guidance system includes an end effector support and a tool insertion device disposed within and spaced apart from the end effector support. The assembly further includes a coupler coupling the tool insertion device within the end effector support. The coupler includes a first mode wherein the tool insertion device is rigidly coupled within the end effector support and second mode wherein the tool insertion device is compliantly coupled within the end effector support.