Robotic Surgical Joint Assembly With Low-Friction Tendon Actuation
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Solution Overview
Problem
Current robotic surgical assemblies face challenges in achieving precise kinematic control and miniaturization due to friction and mechanical constraints, limiting their ability to perform complex microsurgical procedures with high accuracy and versatility, and require lengthy training for surgeons to operate effectively.
Innovation Solution
A medical instrument with a jointed device and tendon driving system that uses convex contact surfaces and a pusher assembly to minimize friction and allow for precise, intuitive control, enabling extreme miniaturization and efficient manufacturing while maintaining reliability and sterility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional tendon driving systems with grooves and channels are used, then the tendons are guided and constrained, but friction increases and device miniaturization is limited
Solution Approach 1:
The patent removes the traditional grooves and channels from the tendon driving system. Instead of guiding tendons through fixed pathways, the tendons are allowed to move freely within the device, eliminating the friction-causing contact surfaces while maintaining actuation functionality through a different mechanical arrangement.
Solution Approach 2:
The patent introduces a novel intermediary mechanism that couples tendon actuation to joint movement without direct tendon-channel contact. This intermediary system transmits force while minimizing friction, enabling precise kinematic control without the harmful friction effects of traditional guided systems.
2Stability of the object's composition
If multiple joints are articulated further from the tip to improve stability, then structural support is enhanced, but the operating field becomes cluttered and accessibility is reduced
Solution Approach 1:
The patent redistributes joint articulations along the longitudinal axis of the instrument rather than concentrating them at the tip. This spatial reconfiguration maintains structural stability through proper joint placement while clearing the operating field of clutter, improving surgeon accessibility to the surgical site.
3Measurement precision
If robotic assemblies use master-slave teleoperation with multiple degrees of freedom, then surgical precision is improved, but the system becomes complex and requires lengthy surgeon training
Solution Approach 1:
The patent designs the robotic instrument with universal, intuitive control characteristics that replicate natural hand-eye coordination. The system maintains multiple degrees of freedom for surgical precision while using control mechanisms that are familiar to surgeons, reducing training requirements by making the interface universal rather than specialized.
4Volume of moving object
If the instrument is miniaturized for microsurgery, then access to small surgical sites is improved, but friction and mechanical constraints increase relative to size
Solution Approach 1:
By removing the groove and channel structures entirely, the patent eliminates the primary sources of friction that would disproportionately affect miniaturized instruments. This extraction of friction-causing elements enables successful instrument miniaturization for microsurgery applications.
Solution Approach 2:
The patent replaces traditional mechanical tendon-guiding structures with a friction-minimized actuation mechanism. This substitution eliminates the mechanical constraints and friction that would otherwise limit miniaturization, enabling the instrument to achieve the small sizes required for microsurgery.
Data Source
AI summary
A medical instrument for surgery includes at least one frame and at least one jointed device. The jointed device includes at least one first joint member, or first link, adapted to connect to at least one portion of the frame and at least one second joint member, or second link. The first joint member is connected by a rotational joint to the second joint member. The medical instrument includes at least a pair of tendons, adapted to move the second joint member with respect to the first joint member. Each of the first joint member and the second joint member includes a main structural body made in a single piece with one or more convex contact surfaces. Each of the convex contact surfaces is a ruled surface formed by straight line portions all parallel to each other and substantially parallel to a joint movement axis.