Surgical Robot Wrist With Three-Axis Compound Joint
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Solution Overview
Problem
Existing surgical robotic components, particularly wrist articulations, face limitations in mobility and control, making it difficult to perform a wide range of surgical procedures efficiently due to kinematic constraints and the need for large, heavy drive motors to achieve smooth motion.
Innovation Solution
A surgical robotic component featuring an articulated terminal portion with an intermediate compound joint allowing relative rotation about three axes, comprising three revolute joints that are independently driven, enabling a wider range of motion and eliminating kinematic singularities, thus allowing the end effector to face any direction within a hemisphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a typical wrist articulation with roll and pitch joints is used, then the instrument can occupy a hemisphere workspace, but large rotation of the roll joint is needed to produce small lateral movements when the pitch joint is offset, requiring large and heavy drive motors
Solution Approach 1:
The wrist articulation is divided into three separate revolute joints (first, second, and third) instead of the traditional two-joint roll-pitch configuration. Each joint is independently driven, allowing distributed control of motion and eliminating the need for large drive motors to compensate for kinematic singularities.
Solution Approach 2:
The patent introduces a three-dimensional joint configuration where the first, second, and third axes are transverse to the axial directions of the basal and distal segments. This adds an extra degree of freedom compared to traditional two-joint wrists, enabling smoother motion control without requiring oversized motors.
2Ease of operation
If the pitch joint is offset by a small angle from the straight position, then lateral movements of the instrument tip can be achieved, but very fast operation of the roll joint drive is required to move the end effector smoothly
Solution Approach 1:
The wrist articulation uses three independently driven revolute joints that can dynamically adjust their motion characteristics. This allows the system to operate smoothly across the full range of motion without requiring extremely fast operation speeds, as each joint can be controlled independently to maintain optimal performance.
3Reliability
If stiff links and articulations are used to support large drive motors, then the motors can react against the links without jolting the position, but the links become larger and heavier
Solution Approach 1:
By segmenting the wrist into three separately driven joints, the patent eliminates the need for oversized drive motors. This allows the use of lighter links and articulations that do not require excessive stiffness to support large motor masses, reducing the overall weight while maintaining stability.
4Device complexity
If a traditional two-joint wrist articulation is used, then the structure is simpler, but the range of motion and ability to perform diverse surgical procedures is limited
Solution Approach 1:
The wrist articulation is segmented into three independently controlled revolute joints instead of two, providing an additional degree of freedom. This enables the end effector to achieve any orientation within a hemisphere and perform a broader range of surgical procedures while maintaining a relatively simple modular structure.
Solution Approach 2:
The three-joint wrist configuration provides universal orientation capability, allowing the end effector to face any direction within a hemisphere. This multi-functional capability enables the robotic system to perform diverse surgical procedures with a single articulated structure.
Data Source
AI summary
A surgical robotic component comprising an articulated terminal portion, the terminal portion comprising: a distal segment having an attachment for a surgical tool; a basal segment for attaching the terminal portion to the remainder of the surgical robotic component; and an intermediate compound joint between the distal segment and the basal segment, the intermediate compound joint permitting relative rotation of the distal segment and the basal segment about first, second and third axes; the terminal portion being arranged such that, in at least one configuration of the intermediate compound joint: (i) the axial direction of the basal segment is parallel to the axial direction of the distal segment, and (ii) the first, second and third axes are transverse to the axial directions of the basal and distal segments.