Robotic Surgery Instrument Force Feedback via Distal Sensors

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Solution Overview

Problem

Current robotic surgery instruments lack tactile sensitivity, as they do not effectively reflect real forces and torques to the surgeon, leading to reduced surgical precision and increased risk of tissue damage during minimally invasive procedures.

Innovation Solution

An instrument with an articulation assembly and integrated force sensors that detect forces and torques independently of frictional forces, allowing for precise movement and force feedback, featuring a cross-like supporting member with bevel-gear mechanisms and force sensors on the effector arms to provide accurate force perception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If robotic surgery instruments use cable-based transmission systems for actuation, then the instruments can achieve complex movements and articulations, but the friction forces in the transmission system reduce tactile sensitivity and force feedback to the surgeon

Engineering Contradiction:
Improvemovement capabilityVSAvoidtactile sensitivity
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The force sensors are extracted from the proximal control device and placed at the distal effector means, where they directly measure forces at the patient interface without being affected by cable friction. This separates the force measurement function from the cable transmission system, eliminating the friction interference.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Force sensors act as intermediaries between the effector means and the control system, providing accurate force measurements that are not corrupted by the cable transmission system. The sensors serve as a mediator that translates physical forces into measurable signals independent of transmission friction.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If force sensors are placed outside the patient's body in the control device, then the system can detect surgeon hand movements, but it cannot compensate for friction generated by manipulator robot elements like cables

Engineering Contradiction:
Improveforce detection accuracyVSAvoidfriction interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The force sensors are extracted from the control device and relocated to the effector means at the distal end of the instrument. This physical relocation removes the sensors from the friction-affected cable transmission path, allowing direct measurement of forces at the patient interface without cable friction interference.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If the clamp closing force is not measured by the sensor, then the instrument structure can be simpler, but the surgeon cannot perceive real forces and torques applied to tissues

Engineering Contradiction:
Improvesensor system complexityVSAvoidforce perception accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The force measurement function is merged with the effector means structure itself. The force sensors are integrated into the effector assembly, combining the surgical function and measurement function in one unit, which simplifies the overall system while enabling complete force measurement.

Inventive Principle:
Principle #5Merging (Combining)

4Measurement precision

If multiple force sensors are integrated into the effector means with cross-like supporting members and bevel-gear mechanisms, then complete force and torque perception is achieved, but the device complexity increases

Engineering Contradiction:
Improveforce and torque detection accuracyVSAvoidarticulation assembly complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The effector means serves multiple functions: it performs surgical operations (gripping, cutting, suturing) and simultaneously measures all forces and torques through integrated sensors. This multi-functionality reduces the need for separate measurement devices, offsetting the increased complexity within the effector assembly.

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

Enhances surgical precision by accurately reflecting real forces and torques, improving surgeon skill and minimizing tissue damage, while being compact and suitable for minimally invasive procedures with easy effector replacement and cost-effective production.

Implementation Method 1

sensor means for detecting forces and torques which are applied by an external dynamic load on the effector means

Methodology Applied
Scientific EffectForce sensing: Force

Implementation Method 2

The sensor means comprises six strain gauges arranged in a Wheatstone bridge configuration

Methodology Applied
Scientific EffectStrain measurement:

Data Source

PatentEP2364825B1Instrument for robotic surgery
Publication Date: 2016.05.18 SURGICA ROBOTICA
  • EP2364825B1 patent drawingFigure 1
  • EP2364825B1 patent drawingFigure 2~3
  • EP2364825B1 patent drawingFigure 4~5

AI summary

An instrument for robotic surgery that can be mounted at the distal end (2) of an operative arm (3) of an apparatus for robotic surgery, which instrument (1) comprises an effector device (27) for performing a given action on the body of a patient during a surgical operation, an articulation assembly (4) for supporting the effector member (27) and connecting it to the distal end (2) of the operative arm (3), a transmission assembly (6) connected to the articulation assembly (4) for moving and actuating the effector device (27), and sensors (28) mounted on the articulation assembly (4) for detecting the forces and torques applied to the effector device (27). The articulation assembly (4) has a cross-shaped supporting and movement member (18; 180) articulated to the distal end (2) of the operative arm (3) for supporting the effector device (27) in a mobile way.