Shared-DoF Surgical Robot Kinematics for Collision-Free Tool Positioning

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Solution Overview

Problem

Existing robotic systems for medical procedures face challenges in avoiding collisions between robotic arms and other objects while maintaining the position and orientation of medical tools, particularly in procedures requiring close spacing of access points, which limits the ability to position tools effectively.

Innovation Solution

The system employs a configuration with redundant degrees of freedom, allowing robotic arms to move within a null space to avoid collisions while maintaining the remote center of movement and tool position, utilizing shared degrees of freedom between robotic arms, adjustable arm supports, and patient platforms to achieve kinematic optimization and collision avoidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If robotic arms are positioned close together to access internal regions through limited incisions, then the minimally invasive nature of the procedure is maintained, but the risk of collision between robotic arms increases

Engineering Contradiction:

Improvedistance between robotic armsVSAvoidcollision risk

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a base degree of freedom that moves the entire robotic arm assembly in the vertical dimension (towards or away from the patient), while null space motions adjust the horizontal positioning of individual arms. This dimensional separation allows close spacing of access points without increasing collision risk, as arms can be vertically separated when not in use.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system dynamically adjusts the configuration of robotic arms through null space motions, continuously optimizing arm positions to maintain safety margins while preserving access to the remote center of movement. The base degree of freedom also provides dynamic vertical positioning capability.

Inventive Principle:

Principle #15Dynamics

2Reliability

If robotic arms are moved to avoid collisions with other objects, then safety is improved, but the ability to maintain precise tool position and orientation deteriorates

Engineering Contradiction:

Improvecollision avoidanceVSAvoidtool position precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent segments the degrees of freedom into two functional categories: base DoF for safety-oriented vertical movement of the entire arm assembly, and null space DoFs for collision avoidance while maintaining tool position. This segmentation allows independent optimization of safety and precision functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The null space motions act as an intermediary mechanism that mediates between the conflicting requirements of collision avoidance and position maintenance. By utilizing degrees of freedom that do not affect the remote center of movement, the system can adjust arm configurations to avoid collisions while keeping tools precisely positioned.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If redundant degrees of freedom are added to enable null space motion, then collision avoidance capability is improved, but system complexity increases

Engineering Contradiction:

Improvecollision avoidance capabilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The base degree of freedom serves multiple functions: it enables vertical positioning of robotic arms, provides collision avoidance capability, and maintains the remote center of movement constraint. This multi-functionality reduces the need for additional specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the base positioning function with the collision avoidance function by using the same base degree of freedom for both purposes. The null space motions are integrated into the existing robotic arm structure rather than being added as separate systems.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11771510B2Systems and methods for kinematic optimization with shared robotic degrees-of-freedom

Publication Date: 2023.10.03 AURIS HEALTH INC

AI summary

Robotic medical systems can be capable of kinematic optimization using shared robotic degrees-of-freedom. A robotic medical system can include a patient platform, an adjustable arm support coupled to the patient platform, and at least one robotic arm coupled to the adjustable arm support. The at least one robotic arm can be coupled to a medical tool. The robotic medical system includes a first link and a second link. Each of the first link and the second link includes a first end coupled to the adjustable arm support and a second end coupled to a base of the patient platform, for rotating the adjustable arm support relative to the patient platform. The robotic medical system can also include a processor configured to adjust a position of the adjustable arm support and the at least one robotic arm while maintaining a remote center of movement of the medical tool.