Bone-Connected Surgical Robot Arm With Flexible Base Link

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Solution Overview

Problem

Existing robotic surgical systems face challenges in maintaining accuracy over large surgical areas without being cumbersome or requiring frequent reattachment, especially when patient movement occurs, such as during breathing or surgical manipulation.

Innovation Solution

A robotic surgical system with a flexible robotic base arm that can absorb patient motion while maintaining precise end actuator positioning, using adjustable stiffness and a switchable bone connection unit to allow larger movements without detachment, combined with collision avoidance and power failure safety features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the robotic arm is rigidly attached to the patient's bone to maintain precise positioning, then the positioning accuracy is improved, but the patient's comfort deteriorates due to excessive constraint on natural body movements

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpatient discomfort
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by making the robotic arm's mechanical rigidity adjustable rather than fixed. The system can dynamically modify the rigidity parameter to match the patient's physiological movement characteristics, allowing the arm to be compliant during breathing cycles and rigid during surgical intervention, thereby resolving the contradiction between positioning accuracy and patient comfort

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by enabling the robotic arm to transition between different rigidity states in real-time. The arm dynamically adapts its mechanical properties based on the surgical phase and patient movement, switching from a compliant state that accommodates natural body motion to a rigid state that ensures precise tool placement

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If the robotic system uses maximum rigidity to maintain accuracy, then the positioning precision is improved, but the system's ability to absorb patient motion deteriorates

Engineering Contradiction:
Improveend actuator positioning accuracyVSAvoidmotion absorption capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the rigidity parameter of the robotic arm based on real-time feedback from motion sensors. When patient motion is detected, the system reduces rigidity to absorb the motion, and when stability is required, it increases rigidity to maintain positioning accuracy

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback through motion sensors that continuously monitor patient body movements and feed this information back to the control system. This feedback loop enables the robotic arm to automatically adjust its rigidity parameter in response to detected motion, maintaining accuracy while accommodating physiological movements

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the robotic arm is made flexible to accommodate patient motion, then the adaptability is improved, but the positioning accuracy deteriorates

Engineering Contradiction:
Improvemotion accommodationVSAvoidend actuator positioning accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements dynamics by enabling the robotic arm to transition between compliant and rigid states. During phases requiring motion accommodation, the arm operates in a flexible mode, and during surgical intervention, it switches to a rigid mode to ensure precise positioning, thus resolving the contradiction between adaptability and accuracy

Inventive Principle:
Principle #15Dynamics

4Measurement precision

If a miniature bone-mounted robot is used to maintain precision, then the positioning accuracy is improved, but the operating envelope deteriorates due to limited reach

Engineering Contradiction:
Improverelative positioning accuracyVSAvoidoperating envelope
Core Design Contradiction:
Measurement precisionVSArea of moving object

Solution Approach 1:

The patent applies segmentation by dividing the robotic system into a mobile base unit and a separate end effector assembly. This allows the system to cover a large operating envelope by moving the base to different body locations while maintaining precise positioning through the rigid connection between the base and the surgical tool

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements universality by designing a robotic system that can perform multiple surgical tasks across different body regions. The mobile base and standardized end effector interface enable the system to adapt to various surgical locations and procedures, providing both wide coverage and precise positioning

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables precise surgical procedures over a wide range with reduced patient discomfort and operating time, allowing single-position performance of complex spinal surgeries like XLIF and pedicle screw insertion, and reducing the need for patient repositioning.

Implementation Method 1

the mechanical rigidity of the first section is configured to be less than that of the second section

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3402414B1Surgical robotic system
Publication Date: 2026.03.11 MAZOR ROBOTICS
  • EP3402414B1 patent drawingFigure 1
  • EP3402414B1 patent drawingFigure 2
  • EP3402414B1 patent drawingFigure 3

AI summary

A surgical robot system whose robotic arm is divided into two parts, and is connected to the patient at the junction of the two parts, by means of a bone connector. The section between the bone connector and the robotic base has a predetermined level of flexibility, enabling the bone connector limited movement. Consequently, the patient's body can also move without the bone connector exerting excess forces on the patient, and without detachment from the patient. The arm section between the bone connection link and the end actuator has high rigidity, such that the pose of the end actuator relative to the patient is accurately maintained. As the patient undergoes small movements, such as in breathing or coughing, the bone connector and base connection arm section, move together with motion of the patient's bone, while the pose of the end actuator relative to the patient is accurately maintained.