Virtual-Center Pitch Linkage for Lightweight Surgical Instrument Motion

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Solution Overview

Problem

Conventional pitch control systems for robotic surgical instruments are either heavy and bulky, limiting patient access and mobility, or prone to failure due to reliance on software controls for maintaining a stationary virtual center.

Innovation Solution

A pitch system using angled and parallel linkage bodies with rotary joints and rigid members to mechanically enforce a stationary virtual center, reducing size and weight while enhancing reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional pitch systems use curvilinear rails for pitch control, then stability and pitch maintenance are improved, but weight and size increase, limiting patient access and mobility

Engineering Contradiction:

Improvepitch stabilityVSAvoidsystem weight

Core Design Contradiction:

Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The pitch control system is divided into separate functional modules: a yaw system for horizontal rotation and a pitch system for vertical rotation. Each system operates independently with its own linkage mechanism, allowing the pitch system to be optimized for stability while the overall system remains lightweight and mobile.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pitch system employs asymmetric linkage geometry with angled linkage bodies (first and second linkage bodies at different angles) and offset pivot points. This asymmetric design creates a mechanical advantage that maintains pitch stability while using fewer and lighter components compared to symmetric curvilinear rail designs.

Inventive Principle:

Principle #4Asymmetry

2Adaptability or versatility

If conventional pitch systems use linkages with overlapping metal bands and belts and pulleys, then pitch control range is improved, but system width increases, limiting physical access to the patient

Engineering Contradiction:

Improvepitch control rangeVSAvoidsystem width

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The pitch control mechanism transitions from a horizontal belt-and-pulley arrangement to a vertical linkage system with angled arms. By orienting the primary motion in a different dimensional plane (vertical rather than horizontal), the system achieves the required pitch control range without increasing the horizontal footprint, thereby maintaining physical access to the patient.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If conventional pitch systems use computer controlled coordinated motion of linkages, then pitch control precision is improved, but reliability decreases due to increased failure risk

Engineering Contradiction:

Improvepitch control precisionVSAvoidsystem reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces computer-controlled coordinated motion with a purely mechanical linkage system. The first and second linkage bodies are mechanically connected through rigid members and pivot joints, creating a mechanical enforcement of the stationary virtual center. This mechanical approach eliminates software complexity and computational failure modes while maintaining pitch control precision through geometric constraints.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Object-affected harmful factors

If conventional pitch systems use a stationary virtual center, then patient safety is improved by reducing damage from movement, but system complexity increases when enforcing the stationary center mechanically

Engineering Contradiction:

Improvepatient damage from movementVSAvoidmechanical enforcement complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The mechanical linkage system is designed to automatically maintain the stationary virtual center through its inherent geometric constraints. The angled linkage bodies and rigid members are configured such that the virtual center remains fixed by the laws of mechanics itself, without requiring active control or complex enforcement mechanisms. The system serves itself by using the weight and gravity of its components to maintain the desired geometric relationship.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20250345089A1Systems and methods for pitch angle motion about a virtual center

Publication Date: 2025.11.13 VICARIOUS SURGICAL INC

AI summary

Systems and methods for controlling pitch motions of surgical instruments about a virtual center are provided herein. An example system includes at least one angled linkage body, at least one parallel linkage body, and a pitch housing assembly having a pitch housing, a first rotary joint having a first rotation axis, and an actuator assembly. The system further includes a second rotary joint having a second rotation axis parallel to the first rotation axis, a third rotary joint having a third rotation axis parallel to the first rotation axis, at least one angled rigid member configured to cause a rotation of the at least one parallel linkage body relative to the at least one angled linkage body about the second rotary joint, and at least one parallel rigid member configured to cause a positioning arm rotation relative to the at least one parallel linkage body about the third rotary joint.