Passive Axis Gimbal Linkage Splaying Prevention
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Solution Overview
Problem
Robotic surgical systems face a reduction in the degrees-of-freedom of gimbals due to linkages becoming splayed, encountering singular conditions, or reaching limit stops, which impairs the surgeon's ability to manipulate the end effector effectively during surgical procedures.
Innovation Solution
A passive axis system is introduced to maintain the degrees-of-freedom of the gimbal by inducing an opposite relative motion of a joint at the base of the gimbal to the rotation of a control arm, preventing linkages from splaying or nesting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control arm is rotated about the first axis during surgical procedures, then the surgeon can manipulate the end effector, but the linkages of the gimbal become splayed or nested, reducing the degrees-of-freedom
Solution Approach 1:
A passive axis system with a pulley and cable mechanism is introduced as an intermediary between the control arm rotation and the gimbal support arm. This intermediary mechanism automatically induces opposite rotation of the support arm to counteract splaying or nesting, maintaining the gimbal's degrees-of-freedom without requiring active control from the surgeon.
2Adaptability or versatility
If the gimbal linkages are allowed to move freely during control arm rotation, then the gimbal can adapt to different positions, but the linkages encounter singular conditions or limit stops that reduce operational capability
Solution Approach 1:
The passive axis system applies preliminary anti-action by pre-configuring the pulley-cable mechanism to automatically induce opposite rotation of the support arm. This prevents the linkages from reaching singular conditions or limit stops before they occur, ensuring continuous operational capability throughout the control arm's range of motion.
3Adaptability or versatility
If a passive axis system is added to maintain degrees-of-freedom, then the gimbal can rotate freely, but the device complexity increases
Solution Approach 1:
The passive axis system is designed to be self-service, automatically maintaining the gimbal's degrees-of-freedom through the pulley and cable mechanism without requiring external power, control systems, or active intervention. The system self-regulates based on the control arm's position, minimizing the added complexity while ensuring reliable operation.
Data Source
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Figure 2A~2C
Figure 3
AI summary
A robotic surgical system has a user interface with a control arm that includes a passive axis system for maintaining degrees-of-freedom of a gimbal rotatably supported on the control arm as the gimbal is manipulated during a surgical procedure. The control arm includes a swivel member, a first member, and a second member. The swivel member is rotatable about a first axis. The first member rotatably coupled to the swivel member about a second axis that is orthogonal to the first axis. The second member rotatably coupled to the first member about a third axis that is parallel to the second axis. The gimbal rotatably supported by the second member about a fourth axis that is orthogonal to the third axis. The passive axis system correlating rotation of the swivel member about the first axis with rotation of the gimbal about the fourth axis.