External Relay Braking for Robotic Exoskeleton BLDC Motors

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Solution Overview

Problem

Existing robotic exoskeletons lack efficient and cost-effective brake systems, particularly for brushless DC motors, which require significant structural redesign and increased weight, complicating development and increasing costs.

Innovation Solution

A safety device is installed externally to the motor, utilizing a relay module to short-circuit the three-phase power lines of the motor for emergency braking, eliminating the need for internal brake systems and reducing development time and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a brake system is installed inside the motor box, then emergency braking function is achieved, but device complexity and weight increase significantly

Engineering Contradiction:

Improveemergency braking functionVSAvoidstructural redesign

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The brake system is separated from the motor structure. Instead of integrating the brake inside the motor box, the patent uses an external brake device that acts on the motor shaft through a transmission mechanism, dividing the motor and brake into independent modules.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A transmission mechanism serves as an intermediary between the external brake device and the motor shaft. This intermediary transfers the braking force from the external brake to the motor shaft without requiring internal motor modifications.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a brake system is installed inside the motor box, then emergency braking function is achieved, but development time and cost increase

Engineering Contradiction:

Improveemergency braking functionVSAvoiddevelopment time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

By separating the brake system from the motor, the patent allows the motor to remain as a standard off-the-shelf component, eliminating the need for custom motor redesign and assembly, thus significantly reducing development time.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The external brake device can be applied to different motor types without modifying the motor itself, making the solution universally applicable and reducing development time across multiple projects.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a brake system is installed inside the motor box, then emergency braking function is achieved, but weight increases significantly

Engineering Contradiction:

Improveemergency braking functionVSAvoidmotor weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The brake system is placed outside the motor box, separating the weight of the brake from the motor weight. This allows the motor to maintain its original lightweight design while the brake system is positioned elsewhere in the overall mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of adding weight in the same spatial dimension (inside the motor box), the brake system is positioned in a different spatial arrangement, allowing weight distribution optimization and reducing the concentrated weight at the motor location.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Reliability

If custom brake system is installed, then emergency braking function is achieved, but ease of manufacture decreases

Engineering Contradiction:

Improveemergency braking functionVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the system into standard motor components and separate brake components, allowing each to be manufactured using standard processes without requiring complex custom integration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The transmission mechanism acts as a standardized intermediary component that can be manufactured independently and assembled, simplifying the manufacturing process compared to custom-integrated brake systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Provides safe and reliable emergency braking without altering the motor's structure, ensuring patient safety and reducing development complexity and weight, while maintaining motor functionality.

Implementation Method 1

utilizing a relay module to short-circuit the three-phase power lines of the motor for emergency braking

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250379530A1Safety device and method for emergency braking of robotic exoskeleton and computer-readable storage medium

Publication Date: 2025.12.11 FUTRONICS NA CORP

AI summary

A safety device is electrically connected to a motor of a robotic exoskeleton for implementing emergency stop of the robotic exoskeleton. The safety device includes a safety controller; a relay module electrically connected to the safety controller and three-phase power lines of the motor; and an emergency braking activation device electrically connected to the safety controller. The safety controller is to send a first relay control signal to the relay module in response to receiving a braking signal sent by the emergency braking activation device, and the first relay control signal is to control the relay module to short-circuit the three-phase power lines of the motor to brake the motor.