Isolation Mechanism for Robotic Force/Torque Sensor

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Solution Overview

Problem

Robotic surgical systems face challenges in accurately sensing external forces and torques due to undesired forces induced by joint transmissions, which interfere with the force/torque sensor's ability to position surgical tools accurately.

Innovation Solution

A robotic manipulator with an isolation mechanism that includes a body comprising elastic and rigid parts, configured to deform in response to forces induced by the transmission, mechanically isolating the force/torque sensor from these undesired forces, allowing it to accurately sense external forces and torques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the force/torque sensor is directly coupled to the transmission output, then the sensor can sense forces and torques, but the sensor is subjected to undesired forces induced by the transmission which interfere with accurate sensing

Engineering Contradiction:
Improveforce sensing accuracyVSAvoidtransmission-induced forces
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

An isolation mechanism is introduced as an intermediary component between the transmission output and the force/torque sensor. This isolation mechanism includes elastic parts that deform to absorb and isolate the undesired transmission-induced forces, while allowing the sensor to accurately measure external forces applied to the surgical tool. The intermediary structure protects the sensor from harmful vibrations and forces generated by the transmission system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the isolation mechanism is added between the transmission and sensor, then the sensor is protected from transmission forces, but the device complexity increases

Engineering Contradiction:
Improveforce sensing reliabilityVSAvoidmechanical structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The isolation mechanism utilizes elastic parts and flexible elements that can deform under load to provide isolation. These flexible components are designed with specific geometric features and material properties that allow them to selectively filter out high-frequency transmission vibrations while maintaining structural integrity and force transmission capability for external forces.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The isolation mechanism is designed with specific elastic properties and geometric parameters that can be optimized to achieve the desired isolation effect. By carefully selecting the elastic modulus, dimensions, and configuration of the isolation elements, the system achieves effective force isolation while minimizing added complexity and maintaining compactness.

Inventive Principle:
Principle #35Parameter changes

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

The isolation mechanism effectively reduces interference from transmission-induced forces, enabling the force/torque sensor to accurately sense applied forces and torques, thereby improving the precision of surgical tool positioning in robotic surgical systems.

Implementation Method 1

The elastic part is configured to deform in response to forces induced by the transmission to mechanically isolate the force/torque sensor from forces induced by the transmission

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS20240315791A1Isolation Mechanism For Force/Torque Sensor
Publication Date: 2024.09.26 MAKO SURGICAL CORP
  • US20240315791A1 patent drawing
  • US20240315791A1 patent drawing
  • US20240315791A1 patent drawing

AI summary

An isolation mechanism that is configured for a robotic manipulator is provided. The robotic manipulator includes an arm to be driven by a transmission, a force/torque sensor, and one or more sensing elements configured to sense forces and torques applied to the force/torque sensor, wherein the isolation mechanism includes a body for coupling to an output of the transmission and for coupling to the force/torque sensor, wherein the body deforms in response to forces induced by the transmission to mechanically isolate the force/torque sensor from forces induced by the transmission.