Lead-Screw Cable Accumulator for Robotic Surgical End Effectors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing robotic surgical tools face challenges in efficiently controlling end effector operations, particularly in minimally invasive surgical procedures, due to limitations in cable-based accumulation systems.
Innovation Solution
A robotic surgical tool with a handle providing a drive input, an elongate shaft with an end effector, and an accumulator system operatively coupled to the drive input, which alters the length or force in at least one drive cable to affect end effector operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cable-based accumulation system is used to transmit force from the handle to the end effector, then the surgical tool can achieve minimally invasive operation through a long shaft, but the control precision and force transmission efficiency deteriorate due to cable slack and accumulation errors
Solution Approach 1:
The patent replaces the traditional cable-based mechanical transmission system with a rod-based direct transmission system. The rod extends through the entire shaft length, providing rigid mechanical coupling between the handle and end effector, eliminating cable slack and improving control precision while maintaining minimally invasive capability
Solution Approach 2:
The patent introduces an intermediary mechanism (the rod with pulley system) that mediates between the handle input and end effector output. The rod acts as a stable intermediary that transmits force without the accumulation errors inherent in flexible cables, while the pulley system provides the necessary mechanical advantage
2Adaptability or versatility
If multiple drive cables are used to control end effector articulation and operation, then the surgical tool achieves multiple degrees of freedom, but the system complexity and difficulty of cable management increase
Solution Approach 1:
The patent segments the drive mechanism into independent rod-based units, each controlling a specific degree of freedom. This segmentation allows for simpler individual components that can be managed separately, reducing the overall complexity compared to a unified cable system
Solution Approach 2:
The patent substitutes rigid rods for flexible cables in the transmission mechanism. This substitution simplifies the mechanical system by eliminating the need for complex cable routing, tensioning, and maintenance while achieving the same articulation functionality
3Length of stationary object
If a long shaft is used to separate the handle from the end effector for minimally invasive access, then the surgical tool can reach deep anatomical structures, but the force transmission efficiency and operational responsiveness deteriorate
Solution Approach 1:
The patent replaces flexible cable transmission with rigid rod transmission through the long shaft. This substitution maintains force transmission efficiency over the extended length by eliminating cable elasticity and slack, ensuring responsive operation despite the long distance between handle and end effector
Solution Approach 2:
The patent incorporates a pulley system that creates mechanical advantage through curved surfaces. The pulleys convert rotational motion at the handle into linear motion at the end effector, amplifying the applied force and improving transmission efficiency through the long shaft
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
The solution enhances the control and precision of end effector operations, improving the effectiveness and ease of minimally invasive surgical procedures.
Implementation Method 1
a lead screw extending from the drive input, a nut threadably mounted to the lead screw such that rotation of the lead screw causes the nut to axially traverse the lead screw
Implementation Method 2
actuation of the drive input moves the first pulley towards or away from the second pulley
Data Source
AI summary
A robotic surgical tool includes a handle providing a drive input, a shaft extendable through the handle and having an end effector arranged at an end of the shaft, and an accumulator system housed within the handle. The accumulator system includes a lead screw extending from the drive input, a nut threadably mounted to the lead screw, a first pulley operatively coupled to the nut such that axial movement of the nut correspondingly moves the first pulley, and a second pulley rotatably coupled to the handle and vertically offset from the first pulley. The surgical tool further includes first and second drive cables threaded through the first and second pulleys and extending distally along the shaft. Operation of the accumulator system alters at least one of a length or a force in the first and second drive cables to affect end effector operation.