Robot Arm Joint Brake Using Magnetic Hysteresis to Cut Heat

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing brake devices in robot arms, particularly for microsurgery, consume high power and generate excessive heat, leading to thermal expansion and precision issues.

Innovation Solution

A joint arrangement for a robot arm with a brake device configured for minimal power consumption, utilizing a hysteresis effect through a gap between a permanent magnet and an electromagnet, allowing for efficient engagement and disengagement with reduced power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the brake device is operated in a current-carrying state to neutralize the braking effect, then the braking function is disabled, but power consumption increases and heat generation occurs

Engineering Contradiction:

Improvebraking function controlVSAvoidpower consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The brake device operates in periodic cycles between engagement and disengagement states. The control system activates the electromagnet periodically to disengage the brake when motion is required, then deactivates it to engage the brake for holding position, creating a rhythmic on-off pattern that reduces continuous power consumption while maintaining operational capability

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The permanent magnet provides the braking effect automatically without requiring external power input. Once the electromagnet is deactivated, the permanent magnet's magnetic field naturally engages the brake mechanism to hold the robot arm in position, eliminating the need for continuous power application and enabling self-sustained braking functionality

Inventive Principle:

Principle #25Self-service

2Reliability

If power is ramped up above neutralization value to ensure disengagement, then reliable operation is achieved, but power consumption and heat generation increase

Engineering Contradiction:

Improvebrake disengagement reliabilityVSAvoidheat generation

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The control system monitors the brake device state and adjusts power application accordingly. When disengagement is detected or required, power is applied to the electromagnet; when engagement is achieved, power is reduced or eliminated. This feedback-based control ensures reliable operation while preventing excessive power application that would generate unnecessary heat

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the power parameter dynamically based on operational requirements. Power is applied at specific thresholds to achieve disengagement, then reduced to minimal levels or zero to maintain the disengaged state without excessive heat generation. The permanent magnet's field strength parameter naturally provides the braking force without requiring continuous high power input

Inventive Principle:

Principle #35Parameter changes

3Force

If the brake device generates high temperatures, then braking effect is maintained, but thermal expansion affects precision in microsurgery applications

Engineering Contradiction:

Improvebraking effectVSAvoidsurgical precision

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The permanent magnet's magnetic field, which naturally causes heat generation during continuous operation, is instead used as the primary braking mechanism without requiring continuous power application. By leveraging the hysteresis effect and magnetic remanence, the system converts what would be a continuous heat-generating process into an on-demand operation, where heat is only generated briefly during state transitions rather than continuously during holding operations

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system replaces a purely electromagnetic braking system with a hybrid system using permanent magnets. This substitution eliminates the need for continuous electrical power application to maintain braking force, thereby eliminating continuous heat generation and its associated thermal expansion problems that would compromise surgical precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If the brake device is switched frequently between engagement and disengagement, then operational flexibility is improved, but power consumption increases due to repeated ramping

Engineering Contradiction:

Improveoperational flexibilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The permanent magnet is pre-configured to provide the braking effect immediately when power is removed, without requiring gradual ramping down. Similarly, the electromagnet can be pre-positioned to provide immediate disengagement when activated. This preliminary configuration of magnetic fields enables rapid state transitions without the energy-wasting gradual ramping process

Inventive Principle:

Principle #10Preliminary action

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 solution reduces power consumption by up to 75% and minimizes heat generation, enhancing precision and safety by reducing thermal expansions.

Implementation Method 1

a magnetic field provided by a permanent magnet

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

the magnetic field provided by said permanent magnet is usually displaced by an opposing electro-magnetic field

Methodology Applied

Scientific EffectElectromagnetic field: Electromagnet

Implementation Method 3

the hysteresis effect of the brake device may occur in a range between a power required for disengagement and a power required for engagement

Methodology Applied

Scientific EffectHysteresis effect: Hysteresis

Data Source

PatentUS20250276457A1Joint arrangement for a robot arm for providing an energy-efficient braking function

Publication Date: 2025.09.04 MICROSURE BV

AI summary

The present invention provides a joint arrangement for a robot arm, especially a robot arm for use in microsurgery, comprising: at least one brake device being configured for engagement and for disengagement and comprising a stator assembly and a rotor assembly, wherein the brake device is further configured to be operable at a minimal power consumption in a disengagement state. The present invention further provides a method for operating a brake device in a joint arrangement for a robot arm, especially a robot arm for use in microsurgery, the method at least comprising the following step: the brake device is provided and configured for engagement and for disengagement, the brake device comprising a stator assembly and a rotor assembly, wherein the brake device is further operated at a minimal power consumption in a disengagement state.