Surgical Robot Arm Watchdog Circuitry for Processor Fault Locking

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Solution Overview

Problem

Existing surgical robotic systems lack effective mechanisms to ensure safe operation in case of processor faults, potentially leading to uncontrolled movement of robotic arms during surgical procedures.

Innovation Solution

Incorporation of watchdog circuitry in the surgical robot arm controller to monitor sequence values from the processor, disable communication links if sequence errors or timeouts occur, and send preset signals to maintain joint positions or reset the processor, thereby preventing uncontrolled movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dedicated fault communication network is implemented to ensure safe operation during processor faults, then safety and reliability are improved, but device complexity increases

Engineering Contradiction:
Improvesafety during processor faultsVSAvoidcommunication network structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the fault detection function with the existing communication link between processor and joint controller. The watchdog circuitry utilizes the same communication infrastructure to both send joint driving signals and monitor processor health through sequence values, eliminating the need for a separate dedicated fault communication network while maintaining safety during processor faults.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If watchdog circuitry continuously monitors sequence values and disables communication links on detection of faults, then safety is improved, but loss of time occurs during fault response

Engineering Contradiction:
Improvesafety during operationVSAvoidtime to respond to processor fault
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The watchdog circuitry continuously monitors sequence values in real-time as they are transmitted, rather than checking periodically. This continuous monitoring allows the system to detect sequence errors or timeouts immediately when they occur, enabling instantaneous disabling of the communication link and preventing any uncontrolled movement of the robotic arm.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements immediate feedback when a sequence value mismatch or timeout is detected. The watchdog circuitry instantly disables the communication link and sends preset joint driving signals to hold the joint in position, creating a rapid closed-loop safety response that minimizes the time between fault occurrence and safety intervention.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4110222B1Watchdog circuitry of a surgical robot arm
Publication Date: 2026.04.01 CMR SURGICAL LTD
  • EP4110222B1 patent drawingFigure 1
  • EP4110222B1 patent drawingFigure 2
  • EP4110222B1 patent drawingFigure 3

AI summary

A surgical robot comprising a surgical robot arm and a surgical robot arm controller. The surgical robot arm comprises a set of joints and a joint controller. The joint controller is configured to drive a joint of the set of joints. The surgical robot arm controller comprises a processor and watchdog circuitry. The processor is configured to send joint driving signals to the joint controller on a communication link. The watchdog circuitry is configured to: receive sequence values from the processor; determine whether each received sequence value matches a next expected value of a predetermined sequence; and if the received sequence value does not match the next expected value of the predetermined sequence, disable the communication link between the processor and the joint controller.