Surgical Robot Drive Module Failure Detection via Velocity Feedback

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Solution Overview

Problem

Current surgical robotic systems lack effective real-time monitoring capabilities to detect failures in their drive modules, which can lead to operational disruptions during minimally invasive procedures.

Innovation Solution

A surgical robotic system that includes a robotic arm with a motor and sensors, a main controller to output drive commands, and a safety observer that calculates an observed velocity by comparing measured velocity from sensors, including joint and motor torque sensors, to detect failures and output errors when velocity differences exceed a predetermined range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If real-time monitoring of motor velocity is implemented using sensors, then failure detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvefailure detection capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the safety observer continuously monitors the relationship between commanded velocity and actual motor velocity. When the difference between these velocities exceeds a threshold, the system detects a failure and triggers an alarm. This feedback loop enables real-time failure detection without requiring complex additional hardware beyond standard motor controllers and velocity sensors.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If multiple sensors including torque sensors are added to monitor joint and motor parameters, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvevelocity measurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The safety observer is designed as a multi-functional monitoring system that processes data from multiple sensors (velocity sensors and torque sensors) using a unified algorithm. The same observer framework handles both velocity monitoring and torque-based failure detection, eliminating the need for separate monitoring systems for each parameter and reducing overall system complexity despite multiple sensors being used.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4094713A1Real time monitoring of a robotic drive module
Publication Date: 2022.11.30 COVIDIEN LP
  • EP4094713A1 patent drawingFigure 1
  • EP4094713A1 patent drawingFigure 2
  • EP4094713A1 patent drawingFigure 3

AI summary

The surgical robotic system includes a robotic arm having one or more joints, each having a motor and at least one torque sensor and a velocity sensor. The system also includes a main controller, which outputs a drive command to the motor thereby actuating the motor. The system further includes a safety observer, which receives a measured velocity of the motor from the sensor, calculates an observed velocity, and detects a failure in operation of the at least one joint based on the observed velocity and the measured velocity.