Adjustable Torque Profile Mechanism for Passive Joint Assistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exoskeletons for motor rehabilitation lack the ability to provide a customizable and user-friendly torque profile across the full range of movement, requiring multiple tension elements to achieve desired torque, which is complex and costly.
Innovation Solution
A joint movement therapy and assistive device system utilizing a torque profile device with adjustable pins and tensioning components, such as springs, that form an additive torque profile by securing pins to connecting components at specific distances and angles, allowing for customizable torque generation across multiple joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple tension elements are used to achieve desired torque profile, then torque customization is improved, but device complexity increases
Solution Approach 1:
The device divides the torque generation function into multiple independent tension elements (springs, cables, or elastic elements) that can be selectively activated. Each tension element can be independently adjusted or removed, allowing customization of the torque profile without requiring all elements to be permanently installed. This segmentation enables flexible torque customization while managing overall device complexity through modular architecture.
Solution Approach 2:
The moment arm of each tension element is made adjustable through dynamic reconfiguration mechanisms. The line of action of each tension element can be shifted by rotating its attachment along a circular path or adjusting cable routing, allowing the moment arm to vary with joint angle. This dynamic adjustment enables a single tension element to provide variable torque characteristics, reducing the total number of elements needed while maintaining torque profile customization capability.
2Ease of operation
If moment arm adjustment is used to control torque, then torque regulation is improved, but mechanical complexity increases
Solution Approach 1:
The device employs passive mechanical elements (springs, cables, pulleys) that automatically adjust the moment arm based on joint position without requiring active control systems. The tension elements naturally follow curved paths or rotate around pivot points, causing the moment arm to vary with joint angle in a self-regulating manner. This passive self-adjustment provides torque control while minimizing mechanical complexity and eliminating the need for motors or electronic controllers.
Solution Approach 2:
The device changes the geometric parameters (moment arm length, line of action angle) of the tension elements as functions of joint angle. By designing the attachment paths and cable routing such that these parameters naturally vary with position, the system achieves torque regulation through geometric transformation rather than active mechanical reconfiguration. This parameter-based approach simplifies the mechanical structure while maintaining effective torque control.
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 system effectively generates personalized torque profiles, eliminating the need for motors and controllers, making it user-friendly, safe, and cost-effective, while providing accurate gravity compensation and error augmentation.
Implementation Method 1
a torque profile device having a plurality of connecting components, a longitudinal axis, and a center... a plurality of tensioning components removably and selectively secured to the plurality of connecting components... The plurality of tensioning components form an additive torque profile
Data Source
AI summary
A joint movement therapy and assistive device system. The system includes a torque profile device having a plurality of connecting components, a longitudinal axis, and a center. Each connecting component of the plurality of connecting components is disposed at a selected distance relative to the center and a selected angle relative to the longitudinal axis. The system also includes at least one segment end and a plurality of tensioning components removable secured to the plurality of connecting components of the torque profile device and the at least one segment end. The plurality of tensioning components forms an additive torque profile when coupled between the torque profile device and the at least one segment end.