Antagonistic Spring-Link Exoskeleton for Variable Stiffness
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Solution Overview
Problem
Traditional finger force-feedback exoskeleton devices face limitations such as discomfort, excessive weight, complex structures, and open-loop control, which hinder their effectiveness in practical applications for elderly individuals.
Innovation Solution
A variable stiffness hand exoskeleton device based on antagonistic driving is developed, integrating nonlinear springs in an antagonistic configuration to simulate multi-axis rotation and force direction changes, enabling real-time joint stiffness adjustment through a closed-loop control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional rigid exoskeleton structures are used, then structural strength is ensured, but comfort and adaptability deteriorate due to inability to adjust to user's body contours and movement needs
Solution Approach 1:
The patent applies dynamics by transforming the rigid exoskeleton structure into a flexible and adaptable one through the introduction of spring elements. The spring-link composite transmission mechanism allows the exoskeleton to dynamically adjust its stiffness and contour to match the user's hand geometry and movement requirements, resolving the contradiction between adaptability and structural integrity
Solution Approach 2:
The patent implements parameter changes by varying the stiffness characteristics of the exoskeleton through spring pre-compression and antagonistic muscle pair activation. By adjusting the compression force on the springs, the system can change its mechanical properties to adapt to different users and movement conditions without increasing structural complexity
2Reliability
If heavy components are added to provide force feedback, then functionality is improved, but weight increases causing discomfort for elderly users
Solution Approach 1:
The patent replaces traditional heavy mechanical force feedback mechanisms with a spring-based compliant mechanism. The spring-link composite transmission provides force feedback through elastic deformation rather than heavy actuators, significantly reducing the moving weight while maintaining the force feedback functionality needed for elderly users
3Adaptability or versatility
If complex transmission mechanisms are used to achieve variable stiffness, then stiffness adjustment capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses flexible spring elements as the core transmission medium to achieve variable stiffness. The spring-link composite transmission mechanism utilizes the inherent flexibility and elasticity of springs to provide continuous stiffness adjustment without complex gear trains or hydraulic systems, simplifying the overall transmission mechanism while maintaining adjustability
Solution Approach 2:
The spring-based mechanism provides self-adjusting stiffness characteristics through elastic deformation. The system automatically adapts its stiffness based on the spring compression state and load conditions, reducing the need for complex external control mechanisms and lowering both device complexity and cost
4Ease of operation
If open-loop control is used, then system simplicity is maintained, but control precision and user comfort deteriorate
Solution Approach 1:
The patent implements feedback control by incorporating sensors that detect the user's hand position, force, and movement intent. This feedback is processed by a control system that adjusts the spring pre-compression and antagonistic muscle activation in real-time, achieving precise control and enhanced user comfort without excessive complexity
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 device provides more natural and flexible movement support, enhances comfort and usage efficiency, and offers precise haptics by dynamically adjusting joint stiffness, thereby improving reliability and practicality.
Implementation Method 1
adopts the application of nonlinear springs in an antagonistic configuration
Implementation Method 2
the rotary site C of the spring-link composite transmission mechanism is rotationally connected to the rotary support seat of the support base via the rotary bearing
Data Source
AI summary
A variable stiffness hand exoskeleton device based on antagonistic driving, includes a power mechanism, a support base, a spring-link composite transmission mechanism, and a distal finger sleeve connected to a power output end of the spring-link composite transmission mechanism for fingers. The power mechanism drives the fingers to perform rotational movements through the spring-link composite transmission mechanism. The distal finger sleeve is fixed to a distal joint periphery of a finger joint using a first elastic adjustment band, and provides force feedback to an end of the finger joint under driving force of a link structure. An inner surface of the support base is contoured to match a palm, and a back of the support base is provided with a rotary support seat and a motor fixing seat. A motor group of the power mechanism is mounted on the motor fixing seat.