Force Feedback Control for Flexible Elongate Medical Devices

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Solution Overview

Problem

Minimally invasive medical procedures using flexible and steerable elongate devices pose risks due to the inability of teleoperational operators to directly sense forces exerted on tissues, leading to potential excessive force application and tissue damage.

Innovation Solution

A medical device system that includes a flexible elongate instrument, an actuator, and a control unit configured to determine forces exerted on patient tissue, set force thresholds, and provide feedback to operators when excessive forces are detected, using shape, actuator force, and proximal end force measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If teleoperational control is used to operate the flexible elongate device, then the operator can control the device from a distance, but the operator cannot directly sense the forces being exerted on patient tissue

Engineering Contradiction:

Improveteleoperational control capabilityVSAvoidforce feedback to operator

Core Design Contradiction:

Ease of operationVSLoss of information

Solution Approach 1:

The system implements force sensing at the distal end of the flexible elongate device and transmits this force information back to the operator through the control system. This feedback loop allows the operator to perceive the forces being exerted on patient tissue during teleoperational control, resolving the information loss problem while maintaining remote operation capability.

Inventive Principle:

Principle #23Feedback

2Reliability

If the operator exerts force directly on the proximal end of the device, then the operator can sense the forces, but the device may still apply excessive force to patient tissue

Engineering Contradiction:

Improveforce sensing accuracyVSAvoidexcessive force on tissue

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system replaces direct mechanical force sensing by the operator with electronic force sensors at the distal end of the device. These sensors electronically measure the forces being exerted on patient tissue and transmit this data to the control system, which can then provide appropriate feedback or control adjustments to prevent excessive force application.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If force sensors are installed at the distal end of the flexible elongate device, then accurate force measurement is achieved, but the device complexity increases

Engineering Contradiction:

Improveforce measurement accuracyVSAvoiddevice structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system incorporates force sensors within the flexible structure of the elongate device itself, utilizing the device's flexible shell to integrate sensing capabilities. This approach allows accurate force measurement at the distal end while maintaining the device's flexibility and minimizing structural complexity through integrated design.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS11992188B2Systems and methods for detecting environmental forces on an elongate device

Publication Date: 2024.05.28 INTUITIVE SURGICAL OPERATIONS INC

AI summary

A medical system includes a flexible elongate instrument and a control unit. The control unit is configured to determine a force exerted by the flexible elongate instrument on tissue of a patient, determine a driving state of the flexible elongate instrument, set a force threshold based on the driving state, and provide feedback to an operator in response to the determined force being higher than the force threshold. Different driving states are associated with different force thresholds.