Sterile Drape Kinematics for Robotic Microsurgery Tool Roll Compensation
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Solution Overview
Problem
Existing robotic systems for microsurgical procedures face challenges in maintaining tool stability and sterility during intraocular surgery, particularly in preventing tools from rolling with respect to the patient's eye and ensuring seamless motion transmission across sterile and non-sterile zones.
Innovation Solution
The system employs multi-jointed arms with rotatable arched links to accommodate eccentric rolling of the end effector, coupled with a sterile drape and gear mechanisms to maintain tool stability and sterility, allowing tools to rotate about their own axis to compensate for unwanted rolling, and linear motion transmission using a linear tool motor within a non-sterile zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a robotic system with multi-jointed arms is used to perform microsurgical procedures, then the range of motion and accessibility to surgical sites is improved, but rolling errors occur causing imprecise tool alignment
Solution Approach 1:
The system incorporates sensors to detect the actual position and orientation of the tool, and a control processor compares this feedback with the desired position. The system automatically calculates and applies corrective rotational movements to compensate for rolling errors, ensuring precise tool alignment throughout the surgical procedure
Solution Approach 2:
The system dynamically adjusts the rotational parameter (roll angle) of the tool based on real-time detection of rolling errors. By changing the rotational state of the tool in response to detected deviations, the system maintains precise alignment while preserving the multi-jointed arm's range of motion
2Adaptability or versatility
If non-rotationally symmetrical tools are used for surgical procedures, then the functional capability and precision of the surgical tool is improved, but rolling errors cause misalignment of the tool
Solution Approach 1:
Sensors mounted on or near the tool detect its actual orientation in space, and the control processor uses this feedback to calculate the correct rotational compensation needed. This allows non-rotationally symmetrical tools to maintain their functional advantages while achieving precise orientation through active error compensation
Solution Approach 2:
The system proactively applies counter-rotational movements to the tool in advance of or during rolling errors. By detecting the tendency for rolling and applying opposing rotational force, the system prevents misalignment before it affects surgical precision
3Reliability
If a sterile drape is placed between the robotic arm and tool mount to maintain sterility, then the sterility of the surgical field is improved, but the transmission of motion and precision may be affected
Solution Approach 1:
The system uses a flexible sterile drape that can transmit mechanical motion while maintaining the sterile barrier. The drape is designed with appropriate mechanical properties to allow controlled transmission of robotic arm movements to the tool mount without compromising sterility or significantly degrading motion precision
Solution Approach 2:
The sterile drape acts as an intermediary element between the non-sterile robotic arm and the sterile surgical field. It selectively transmits necessary mechanical motions while blocking contamination, and the control system compensates for any motion degradation to maintain surgical precision
4Ease of operation
If the end effector is allowed to roll with respect to the base, then the ease of operation and range of motion is improved, but rolling errors accumulate causing loss of precision
Solution Approach 1:
The control system continuously monitors the actual position and orientation of the end effector and tool, comparing it with the commanded position. When rolling deviations are detected, the system automatically applies corrective rotational movements to maintain precise tool positioning despite the operational flexibility gained from allowing roll motion
Data Source
AI summary
Apparatus and methods are described for performing a procedure using a robotic unit. A sterile drape is placed around a drape plate, such that the sterile drape forms an interface between a non-sterile zone and a sterile zone, such that the tool mount is disposed within the sterile zone, and one or more robotic arms and a tool motor are disposed within the non-sterile zone. The tool is driven to roll with respect to the end effector via at least one gear mechanism disposed within the sterile zone, and a motion-transmission portion configured to transmit motion from the tool motor to the at least one gear mechanism, while maintaining a seal between the sterile zone and the non-sterile zone. Other applications are also described.