Electric Rollator Speed Control for Fall Prevention

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Solution Overview

Problem

Existing walking assistance devices for the elderly often fail to prevent users from falling, as they rely solely on handle-based detection mechanisms that cannot accurately determine when the user is about to fall, leading to involuntary movement and potential accidents.

Innovation Solution

An electric walking assistance device equipped with a motor, control unit, and speed limiting unit that adjusts wheel revolutions based on user input and detects changes in speed, acceleration, and attitude to prevent falls, using sensors for leg movement, ground contact, and attitude detection to control motor operations and apply brakes as necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the wheel speed is increased to improve mobility and reduce user effort, then the user can move faster and with less fatigue, but the user may fall due to involuntary movement and loss of stability

Engineering Contradiction:
Improvewheel speedVSAvoiduser stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The control unit continuously monitors wheel speed and compares it against a predetermined threshold. When the wheel speed exceeds this threshold, the control unit automatically activates the brake mechanism to limit speed, creating a closed-loop feedback system that prevents user falls while maintaining mobility when safe

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the operating parameter of wheel speed by comparing actual speed against a predetermined threshold and adjusting the speed through brake activation, transforming a potentially dangerous high-speed state into a safe controlled state

Inventive Principle:
Principle #35Parameter changes

2Power

If the motor provides strong driving force to assist user movement, then the user can overcome terrain difficulties, but the device becomes harder to control and may cause user injury

Engineering Contradiction:
Improvemotor driving forceVSAvoiddevice controllability
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The control unit monitors motor operation and wheel speed continuously, using feedback to determine when to activate the brake mechanism. This feedback loop ensures the motor's strong driving force is balanced with appropriate speed limitation, maintaining both power assistance and user controllability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The brake mechanism is pre-configured and automatically activated when wheel speed exceeds the predetermined threshold, providing preliminary counter-action to the motor's driving force before the user can be harmed by excessive speed or loss of control

Inventive Principle:
Principle #9Preliminary anti-action

3Device complexity

If the device uses simple handle-based detection to reduce complexity, then the device structure remains simple, but it cannot accurately detect when the user is about to fall

Engineering Contradiction:
Improvedetection mechanism complexityVSAvoidfall detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The control unit serves multiple functions: it controls motor operation, monitors wheel speed, detects when speed exceeds thresholds, and activates the brake mechanism. This multi-functional approach improves fall detection accuracy without proportionally increasing device complexity

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

Solution Approach 2:

The control unit utilizes the existing motor and wheel speed data to automatically detect potential fall conditions and trigger the brake mechanism, allowing the device to self-monitor and self-protect without requiring additional complex detection hardware

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3000456B1Electric walking assistance device, program for controlling electric walking assistance device, and method of controlling electric walking assistance device
Publication Date: 2019.04.24 NABTESCO CORP
  • EP3000456B1 patent drawingFigure 1
  • EP3000456B1 patent drawingFigure 2
  • EP3000456B1 patent drawingFigure 3

AI summary

One object of the invention is to provide an electric walking assistance device with which it is possible to prevent a user from falling down, and to provide a program and method for controlling the electric walking assistance device. A power-assisted rollator 100 according to the invention includes a motor 320 powered by a battery 310. A control unit 400 performs an assist control of revolutions of a pair of rear wheels 230 through the motor 320. When it is determined that a rotational acceleration of the pair of rear wheels 230 is equal to or larger than a predetermined value, a speed limiting unit 500 or a control brake unit 700 limits the rotational acceleration of the pair of rear wheels 230.