Exoskeleton Thigh Attachment Distance Control

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Solution Overview

Problem

Existing exoskeletons for walking and bending support often cause discomfort due to thigh connections that chafe and hinder movement, requiring additional force and energy to overcome torque, and can be unsafe with pull straps.

Innovation Solution

Implementing a distance-based control system that allows thigh connections to maintain a predefined distance from the wearer's thighs during idle mode, switching to contact mode for support, using sensors like capacitive, optical, or ultrasonic distance sensors to track and adjust the position without physical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastic tension straps are used to ensure thigh attachment contact, then the attachment remains secure during backward movement, but the wearer must exert additional force against the straps and they can get caught on objects

Engineering Contradiction:
Improveattachment securityVSAvoidadditional force requirement and safety hazards
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention removes the tension straps entirely from the system. Instead of using straps to ensure contact, the system uses a torque-controlled actuator that can dynamically adjust the thigh attachment position, maintaining contact only when necessary for support while eliminating the harmful effects of straps during idle operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system transitions from a static strap-based contact mechanism to a dynamic torque-controlled mechanism. The actuator continuously adjusts the thigh attachment position based on real-time torque sensing, enabling the system to maintain contact during backward movement while allowing separation during forward movement, thus adapting to different operational states.

Inventive Principle:
Principle #15Dynamics

2Reliability

If torque control is used to maintain minimum torque on thighs, then attachment contact is ensured, but the wearer must always work against the applied torque and energy consumption increases

Engineering Contradiction:
Improveattachment contactVSAvoidactuator energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically switches between two operational states: a first state where the actuator maintains minimal torque to ensure contact during backward movement, and a second state where the actuator reduces or eliminates torque during forward movement. This dynamic state switching allows the system to maintain reliability only when necessary while significantly reducing energy consumption during idle operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The actuator torque parameter is dynamically adjusted based on the operational state. During backward movement, a minimum torque threshold is maintained to ensure attachment contact. During forward movement, the torque is reduced or eliminated, allowing the thigh to move freely without working against actuator force, thus optimizing energy efficiency.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If thigh attachments are firmly connected via straps, then contact during forward movement is maintained, but the attachments chafe skin and impede breathing

Engineering Contradiction:
Improveattachment contactVSAvoidskin chafing and breathing impairment
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system replaces static firm connection via straps with a dynamic torque-controlled connection. The actuator applies minimal torque only when necessary to maintain contact during backward movement, while allowing the thigh attachment to separate and move freely during forward movement. This eliminates continuous skin contact and chafing while maintaining attachment reliability when needed.

Inventive Principle:
Principle #15Dynamics

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

Enhances wearing comfort by reducing skin contact and energy consumption, eliminating the need for pull straps, and allowing seamless switching between idle and support modes for efficient muscle support.

Implementation Method 1

at least one capacitive, optical or ultrasonic distance sensor for contactless tracking of the extremity

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

at least one capacitive, optical or ultrasonic distance sensor for contactless tracking of the extremity

Methodology Applied
Scientific EffectOptical detection: Light

Implementation Method 3

at least one capacitive, optical or ultrasonic distance sensor for contactless tracking of the extremity

Methodology Applied
Scientific EffectUltrasonic detection: Ultrasound

Data Source

PatentEP4237208B1Method for contactless monitoring of an extremity in an exoskeleton, and exoskeleton
Publication Date: 2024.08.14 GERMAN BIONIC SYST GMBH
  • EP4237208B1 patent drawingFigure 1~2
  • EP4237208B1 patent drawingFigure 3
  • EP4237208B1 patent drawingFigure 4~5

AI summary

The invention relates to an exoskeleton (100) comprising - a torso attachment (101); - a hip frame (102) rigidly connected to the torso attachment (101); - a first and second actuator (103A/B), each of which is fastened to the hip frame (102), for supporting a walking or bending motion of a wearer; - a first and a second thigh attachment (8A/B; 104A/B), each of which is assigned to an actuator (103A/B); - a first and a second guide/carrier structure (3; 5; 106A/B) for transmitting forces between a thigh attachment (8A/B; 104A/B) and the actuator (103A/B) assigned to this thigh attachment (8A/B; 104A/B) in each case; and - a control unit for actuating the actuators (103A/B), wherein a distance sensor (10A/B) for contactless monitoring of the position of a thigh of the wearer relative to the thigh attachment (8A/B; 104A/B) is located in each thigh attachment (8A/B; 104A/B). The invention also relates to a method.