Surgical Robotic Arm Transmission Layout for Lower Joint Inertia

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing surgical robotic arms suffer from complex structures and limited long-distance force transmission due to bulky motors and numerous components, leading to increased inertia and fatigue for surgeons during prolonged operations.

Innovation Solution

A surgical robotic arm design with a power unit positioned away from the joints, utilizing a first and second transmission assembly with a drive shaft connecting them, and a non-parallel drive axis configuration to enable long-distance force transmission without affecting joint rotation, featuring a simple structure and reduced inertia.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the motor with a relatively large mass is arranged at the rear to reduce equivalent inertia, then the controllability of the main manipulator is improved, but the transmission distance is limited and the structure becomes complex

Engineering Contradiction:
ImprovecontrollabilityVSAvoidtransmission structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical transmission systems (gears, cables) with a magnetic coupling transmission system. The power unit uses a motor to generate rotational motion, which is transmitted through magnetic coupling to drive the manipulator arms. This substitution eliminates complex mechanical components while maintaining transmission effectiveness over longer distances, resolving the contradiction between improved controllability and reduced structural complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Force

If numerous components are involved in gear transmission or cable transmission, then the driving force can be transmitted, but the structure becomes complex and the transmission distance is limited

Engineering Contradiction:
Improvedriving force transmissionVSAvoidnumber of components
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent extracts and removes the complex intermediate transmission components (gears, cables, belts) from the power transmission system. By using direct magnetic coupling between the power unit and the manipulator arms, the system achieves force transmission with minimal components. This extraction of unnecessary components simplifies the overall structure while maintaining effective driving force transmission over the required distance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Weight of moving object

If the motor is arranged close to the base, then the equivalent inertia of multiple joints is reduced, but the transmission distance becomes limited

Engineering Contradiction:
Improveequivalent inertiaVSAvoidtransmission distance
Core Design Contradiction:
Weight of moving objectVSLength of stationary object

Solution Approach 1:

The patent employs magnetic coupling transmission to overcome the limitation of transmission distance. The motor in the power unit generates rotational motion that is transmitted through magnetic fields to drive the manipulator arms at a distance. This magnetic transmission mechanism allows the motor to be positioned at the base (reducing equivalent inertia) while effectively transmitting power over longer distances compared to traditional mechanical systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP4699566A1Surgical robotic arm and surgical robot
Publication Date: 2026.02.25 RONOVO (SHANGHAI) MEDICAL SCI & TECH LTD
  • EP4699566A1 patent drawingFigure 1
  • EP4699566A1 patent drawingFigure 2
  • EP4699566A1 patent drawingFigure 3

AI summary

Disclosed in the present application are a surgical robotic arm (10) and a surgical robot (100). In the surgical robotic arm (10) provided by the present application, a first rotating arm (1) is rotatably connected to a second rotating arm (2); a power unit (3) is provided on the first rotating arm (1), and an execution unit (4) is provided on the second rotating arm (2); the first rotating arm (1) is provided with a first transmission assembly (51), and the second rotating arm (2) is provided with a second transmission assembly (52); the driving force of the power unit (3) is transmitted to the second transmission assembly (52) by means of the first transmission assembly (51) and a transmission shaft (6), and then the second transmission assembly (52) drives the execution unit (4) to act; the driving axis of the execution unit (4) is not parallel to the driving axis of the power unit (3).