Upper-Limb Exoskeleton Linkage for Flexible Lift Assistance

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Solution Overview

Problem

Existing active upper-limb assistive devices suffer from stiff movements, limited lifting moment arms, and unsatisfactory torque output, leading to ergonomic discomfort, reduced operational efficiency, and increased risk of safety accidents and health issues like lumbar muscle strain.

Innovation Solution

A wearable active powered upper-limb assistive device with a flexible connection structure between the torso exoskeletal frame and upper support arm, incorporating an upper-limb linkage assembly and assistive lifting linkage assembly to enhance movement flexibility, stability, and torque output, featuring adjustable support assistance and modular design for adaptability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rotary shaft coupling is used to connect the upper support arm and the torso exoskeletal frame, then the connection is simple and structurally straightforward, but the movement flexibility is limited and movements become stiff

Engineering Contradiction:
Improvemovement flexibilityVSAvoidconnection structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The connection between the upper support arm and torso exoskeletal frame is segmented into multiple rotational degrees of freedom, allowing independent rotation around different axes. This segmentation enables complex flexible movements while maintaining relatively simple individual connection components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection structure transitions from a fixed rigid coupling to a dynamic multi-degree-of-freedom rotational joint that adapts its movement characteristics during operation, providing flexibility while maintaining structural integrity through controlled rotational movements.

Inventive Principle:
Principle #15Dynamics

2Force

If the lifting moment arm is kept short for structural compactness, then the device size is reduced, but the output torque becomes insufficient and assistive support is unsatisfactory

Engineering Contradiction:
Improveoutput torqueVSAvoidlifting moment arm length
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

The lifting moment arm is extended by utilizing the vertical dimension through the shoulder support structure. The assistive force is applied at a greater vertical distance from the rotation axis, effectively increasing the moment arm length and thus the output torque without significantly increasing the horizontal footprint of the device.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The device uses the user's body weight and gravity as counterforces, positioning the lifting mechanism to leverage gravitational force on the user's arm weight. This allows the system to generate sufficient torque by creating an efficient force balance rather than relying solely on motor output.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Ease of operation

If the connection between upper support arm and torso exoskeletal frame is rigid for structural stability, then the support is strong, but the movement becomes stiff and ergonomic discomfort increases

Engineering Contradiction:
Improveergonomic comfortVSAvoidconnection stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The connection structure transitions from a fixed rigid coupling to a dynamic multi-degree-of-freedom rotational joint that adapts its movement characteristics during operation, providing flexibility while maintaining structural integrity through controlled rotational movements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connection structure allows dynamic changes in rotational parameters (angles and orientations) during operation, enabling the system to adapt to different operational poses and maintain ergonomic comfort while preserving structural stability through controlled degrees of freedom.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4706894A1Wearable active power assist device for upper limbs
Publication Date: 2026.03.11 ULSROBOTICS CO LTD
  • EP4706894A1 patent drawingFigure 1
  • EP4706894A1 patent drawingFigure 2
  • EP4706894A1 patent drawingFigure 3

AI summary

The present application relates to the technical field of active assistive robotic exoskeletons, in particular discloses a wearable active powered upper-limb assistive device including a torso exoskeletal frame configured to be worn by an operator and a waist bag for the operator to wear around a waist, where the torso exoskeletal frame is connected with an upper support arm, the upper support arm is flexibly connected to the torso exoskeletal frame, an upper-limb linkage assembly is connected between the waist bag and the upper support arm, and the upper support arm is further drivingly coupled to an assistive lifting linkage assembly. The flexible connection structure is used to replace the original rotary shaft coupling of the upper support arm and the torso exoskeletal frame, and the upper-limb linkage assembly is used to support the upper support arm and the assistive lifting linkage assembly, the assistive lifting linkage assembly is used to increase a lifting moment arm of the active assistive device, so as to comprehensively improve the auxiliary operation effect of the active assistive device, reduce the operation discomfort, improve the operation efficiency, while reducing the occurrence of safety accidents and lumbar muscle strain and other health problems.