Compact Surgical Wrist With Linked Tension Members for Torque Transfer
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Solution Overview
Problem
Existing minimally invasive surgical tools face challenges in transmitting desired torques and forces through compact articulated wrists, limiting their effectiveness and precision in telesurgical tasks.
Innovation Solution
A two-degree-of-freedom wrist mechanism is introduced, featuring an intermediate wrist member pivotally coupled with the instrument shaft and an end effector body, allowing for rotation about two orthogonal axes, along with internal passages to guide control cables and prevent tension alterations, enabling smooth and responsive articulation of the end effector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a compact articulated wrist is used in surgical tools, then the maneuverability and flexibility of the end effector is improved, but the ability to transmit desired torques and forces across the wrist deteriorates
Solution Approach 1:
The wrist mechanism is divided into multiple segments including an intermediate wrist member, a distal wrist member, and an end effector body, each capable of independent rotation about specific axes. This segmentation allows the system to achieve complex orientations while maintaining force transmission paths through each segment's rotation axes, resolving the contradiction between maneuverability and force transmission capability.
2Adaptability or versatility
If a compact articulated wrist is used in surgical tools, then the freedom of interaction with tissue is enhanced, but the precision and response time for telesurgical control deteriorates
Solution Approach 1:
The wrist mechanism incorporates sensors that detect the actual orientation and position of the end effector, providing feedback to the control system. This feedback enables real-time adjustments to maintain precision and response time despite the complex multi-axis articulation, allowing the system to achieve both freedom of interaction and precise control.
3Adaptability or versatility
If a two-degree-of-freedom wrist mechanism is introduced, then the maneuverability is improved, but the device complexity increases
Solution Approach 1:
The wrist mechanism merges multiple rotational degrees of freedom into a compact integrated structure where the intermediate wrist member and distal wrist member share common rotation axes. This merging approach achieves two-degree-of-freedom maneuverability while minimizing the number of separate components and reducing overall device complexity.
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
This solution enhances the maneuverability and force transmission capabilities of surgical tools, mimicking the natural action of a surgeon's wrist, thereby improving the reliability and precision of minimally invasive surgical procedures.
Implementation Method 1
an intermediate wrist member is pivotally coupled with a distal end of an instrument shaft so as to rotate about a first axis transverse to the shaft, and an end effector body is pivotally coupled to the intermediate member so as to rotate about a second axis transverse to the first axis
Implementation Method 2
The wrist mechanism includes internal passages to guide control cables and prevent tension alterations
Data Source
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AI summary
Surgical tools having a two degree-of-freedom wrist (70), wrist articulation by linked tension members (218, 220, 222, 224), mechanisms (372, 390) for transmitting torque through an angle, and minimally invasive surgical tools incorporating these features are disclosed. An elongate intermediate wrist member (80) is pivotally coupled with a distal end of an instrument shaft (74) so as to rotate about a first axis transverse to the shaft, and an end effector body (72) is pivotally coupled with the intermediate member so as to rotate about a second axis that is transverse to the first axis. Linked tension members (218, 220, 222, 224) interact with attachment features (180, 182, 184, 186) to articulate the wrist. A torque-transmitting mechanism (372, 390) includes a coupling member (384, 394), coupling pins (398, 400), a drive shaft (392), and a driven shaft (396). The drive shaft is coupled with the driven shaft so as to control the relative orientations of the drive shaft, the coupling member, and the driven shaft.