Surgical Robot End Unit Retraction System

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Solution Overview

Problem

Surgical robots face challenges in safely retracting their end units to prevent accidental contact or excessive force on patients, especially during power loss or when excessive force is applied.

Innovation Solution

A retraction system comprising a processor, memory, and a retraction assembly with an electric coil and biasing member, which moves the end unit between extended and retracted states based on signals indicating working or retracting conditions, ensuring safe positioning and protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the end unit is extended to reach patient anatomy during surgical procedures, then the robot can perform surgical tasks, but the risk of accidental contact or excessive force on the patient increases

Engineering Contradiction:

Improveability to reach patient anatomyVSAvoidaccidental contact or excessive force on patient

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The retraction assembly is configured to automatically retract the end unit when excessive force is detected or during power loss, preventing harmful contact with the patient. The biasing member continuously exerts a retraction force to counteract extension, ensuring safety by default while allowing extension only when actively controlled

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system monitors force applied by the end unit and automatically triggers retraction when force thresholds are exceeded. The processor receives force data and generates retraction instructions based on this feedback, creating a closed-loop safety mechanism that prevents excessive force application

Inventive Principle:

Principle #23Feedback

2Device complexity

If the retraction assembly uses only a biasing member for retraction, then the structure is simpler, but the system cannot actively extend the end unit against the biasing force during power loss

Engineering Contradiction:

Improveretraction assembly structureVSAvoidend unit positioning control during power loss

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The retraction assembly merges a biasing member (spring) that provides passive retraction force with an electric coil that provides active extension force. This combination allows the system to both retract automatically during power loss and actively extend when needed, achieving reliable bidirectional control while maintaining structural simplicity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The electric coil generates an opposing force to counteract the biasing member's retraction force during active extension. The coil and spring work in opposition, with the spring providing default retraction and the coil providing active extension when energized, ensuring the end unit can be positioned reliably in both directions

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Adaptability or versatility

If the electric coil is configured to move the end unit in both directions, then the system has greater versatility, but the control logic becomes more complex

Engineering Contradiction:

Improvebidirectional movement capabilityVSAvoidcontrol logic

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of using two separate actuators for bidirectional movement, the system uses a single electric coil that can be energized in opposite directions. The coil reverses its magnetic field polarity to change movement direction, simplifying the actuator configuration while maintaining bidirectional capability through inverted control signals

Inventive Principle:

Principle #13The other way round (Inversion)

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 system effectively prevents end units from undesirably contacting patients or applying excessive force, providing a safer environment for patients and surgical teams by ensuring automatic retraction during power loss or excessive force conditions.

Implementation Method 1

an electric coil configured to move the end unit between a first state and a second state

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

a biasing member configured to exert a biasing force to bias the end unit to the second state

Methodology Applied

Scientific EffectElastic force: Elasticity

Data Source

PatentUS12303112B2Retraction systems, assemblies, and devices

Publication Date: 2025.05.20 MAZOR ROBOTICS

AI summary

Retraction systems, assemblies, and devices for retracting an end unit are provided. A retraction assembly may be configured to move the end unit of a robot between a first state and a second state. A first signal may be received indicating a working condition. A first instruction may be generated to move the end unit from the second state to the first state. The retraction assembly may be caused to move the end unit from the second state to the first state based on receiving the first signal and the first instruction. The end unit may be held in the first state when the first signal is being received and the retraction assembly may move the end unit from the first state to the second state when the first signal is not received.