Kinematic Structures for Robotic Microsurgical Tool Stability
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Solution Overview
Problem
Existing robotic systems for microsurgical procedures, such as cataract surgery, face challenges in maintaining tool stability and preventing unwanted rolling of end effectors during complex movements, particularly for non-symmetrical tools, which can compromise surgical precision and efficiency.
Innovation Solution
A robotic system with multi-jointed arms and rotatable arched links accommodates the rolling of end effectors about an eccentric axis, compensated by the tool rotating about its own axis, and includes a sterile drape system to maintain sterility while allowing motion transmission across sterile and non-sterile zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-jointed arms are used to enable complex movements of the end effector, then the versatility and range of motion are improved, but unwanted rolling of the end effector occurs, compromising tool stability
Solution Approach 1:
The system incorporates sensors to detect the rolling motion of the end effector during complex movements, and the control system processes this feedback information to calculate compensatory rotations. The robotic arms then execute these compensatory movements in real-time to counteract the unwanted rolling, maintaining tool stability throughout the surgical procedure.
Solution Approach 2:
The control system acts as an intermediary between the robotic arms and the end effector. It receives motion commands for complex movements, calculates the resulting unwanted rolling, determines the necessary compensatory rotations, and translates these into specific arm movements that achieve both the desired complex motion and maintain end effector stability.
2Adaptability or versatility
If the end effector is allowed to roll about an eccentric axis to accommodate complex movements, then the adaptability is improved, but the tool rolls uncontrollably, reducing surgical precision
Solution Approach 1:
The control system calculates the unwanted rolling that will result from permitted end effector rotation about an eccentric axis, and applies compensatory rotations in advance or in real-time to counteract this effect. This preliminary anti-action ensures that the tool maintains its intended orientation and precision throughout the complex movements required for microsurgical procedures.
3Reliability
If a sterile drape is introduced to maintain sterility between robotic arms and surgical site, then the safety is improved, but the complexity of the system increases due to motion transmission across sterile and non-sterile zones
Solution Approach 1:
The sterile drape acts as an intermediary barrier that physically separates the non-sterile robotic arms from the sterile surgical site. The system incorporates motion transmission mechanisms that pass through or across the drape, allowing controlled movement of surgical tools while maintaining the sterile barrier. This intermediary approach preserves safety while enabling the necessary motion transmission.
Solution Approach 2:
The sterile drape is implemented as a flexible barrier that can accommodate the motion requirements of the surgical procedure. The drape's flexibility allows it to transmit or accommodate movements while maintaining the sterile boundary, reducing system complexity compared to rigid isolation methods.
Data Source
AI summary
Apparatus and methods are described for performing a procedure using a robotic unit. A tool-actuation arm is driven to move linearly, to thereby move at least the portion of the tool linearly with respect to the end effector. The tool-actuation arm is driven to become retracted to a given distance from the tool mount, thereby causing the tool-actuation arm to fold automatically by actuating an automatic tool-actuation arm folding mechanism. Other applications are also described.