Operating Table Actuator Control With Challenge-Response Authentication

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Solution Overview

Problem

Existing medical devices with actuators face high complexity and manufacturing costs due to redundant safety measures, which increase the risk of incorrect component movement and pose safety hazards.

Innovation Solution

A control system with dual microcontrollers is implemented, where a first microcontroller manages communication with the user interface microcontroller and a second microcontroller performs authentication through a challenge-response process, ensuring actuator movement only after verifying the user interface and control device functionality, reducing the need for redundant hardware and communication channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant hardware and communication channels are implemented for first-fault safety, then reliability of actuator control is improved, but device complexity and manufacturing costs increase

Engineering Contradiction:

Improveactuator control safetyVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces hardware redundancy with a software-based challenge-response authentication mechanism. Instead of duplicating communication channels and hardware components, the system uses cryptographic authentication protocols running on existing microcontrollers to verify actuator commands, thereby maintaining reliability while reducing physical complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a virtual copy of the authentication process through challenge-response protocols. Rather than creating physical redundancies, the system creates a verified copy of the command authentication through cryptographic challenges and responses, ensuring safety without duplicating hardware

Inventive Principle:

Principle #26Copying

2Reliability

If redundant hardware and communication channels are implemented for first-fault safety, then reliability of actuator control is improved, but manufacturing costs increase

Engineering Contradiction:

Improveactuator control safetyVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent substitutes expensive redundant hardware with software-based authentication mechanisms. The challenge-response protocol implemented in firmware eliminates the need for duplicate communication channels and safety hardware, significantly reducing component counts and assembly costs while maintaining first-fault safety

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses computationally lightweight challenge-response authentication that can be implemented with simple microcontrollers and basic cryptographic libraries. This approach uses inexpensive computational resources rather than expensive redundant hardware, making the safety mechanism cost-effective

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If multiple microcontrollers with separate communication channels are used, then reliability of actuator control is improved, but device complexity increases

Engineering Contradiction:

Improvecontrol verificationVSAvoidcommunication channel complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a challenge-response authentication protocol as an intermediary mechanism between microcontrollers. Instead of requiring separate communication channels for verification, the authentication protocol mediates the verification process through standardized message exchanges on existing channels, reducing communication infrastructure complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent makes existing communication channels multi-functional by using them for both regular control commands and security authentication. The same communication infrastructure handles both data transmission and security verification, eliminating the need for dedicated separate channels

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4295831B1Operating table and method for controlling actuators in an operating table

Publication Date: 2025.10.15 MAQUET GMBH

Figure 1~2
Figure 3~4
Figure 5

AI summary

An operating table with a patient support surface, comprising at least one component which can be moved by an actuator (15), includes: a user interface (11, 12) through which a user can input an instruction to move the component to a user interface microcontroller (18); and a control unit (13) which is designed to query and authenticate data from the user interface microcontroller (18) and, upon successful authentication, to control the actuator (15) to move the component according to the user's instruction.