Powered Lower Limb Orthosis with Intuitive Intent Control
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Solution Overview
Problem
Individuals with paraplegia face significant challenges in mobility due to the high energy requirements and limited effectiveness of existing passive and powered orthoses, which often necessitate considerable upper body strength and do not allow for intuitive control of movements like sitting, standing, and walking without external assistance or buttons.
Innovation Solution
A powered lower limb orthosis that provides sagittal plane assistive torques at hip and knee joints, featuring a lightweight design without shoulder or shoe components, and a control architecture that enables users to autonomously switch between sitting, standing, and walking based on upper body movement, supplemented with functional electrical stimulation to enhance muscle contractions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If passive orthoses are used to provide legged mobility, then structural support is achieved, but high upper body strength and physical exertion are required
Solution Approach 1:
The patent replaces the passive mechanical support system with an active powered orthosis that uses electric motors to generate torques at the hip and knee joints. This substitution eliminates the need for high upper body strength by using electrical actuation instead of human-powered mechanical leverage.
Solution Approach 2:
The powered orthosis enables self-service mobility by automatically providing the necessary torques for gait generation. The system monitors user intentions and autonomously actuates the joints to produce walking movements without requiring continuous manual manipulation or upper body effort.
2Speed
If powered orthoses with multiple motors are used to assist locomotion, then gait speed increases, but device mass increases
Solution Approach 1:
The patent divides the orthosis into modular segments with motors strategically placed at the hip and knee joints. This segmentation allows for optimized power distribution where each motor is sized appropriately for its specific function, reducing overall mass compared to a monolithic design while maintaining gait assistance capabilities.
Solution Approach 2:
The patent applies local quality by providing powered assistance only at the hip and knee joints where it is most needed for gait generation, rather than powering all joints uniformly. This selective actuation reduces the total motor mass while maintaining effective gait support.
3Ease of operation
If conventional orthoses are used, then mobility support is provided, but intuitive control of movements is not enabled
Solution Approach 1:
The patent incorporates sensors that monitor joint angles, user position, and movement intentions to provide real-time feedback to the control system. This feedback enables the orthosis to automatically adjust its actuation patterns to match user intentions, achieving intuitive control without requiring manual input.
Solution Approach 2:
The control system operates autonomously by interpreting user intentions from sensor data and automatically generating appropriate motor commands. This self-service capability eliminates the need for buttons or external controls, allowing users to naturally initiate and control movements through their own body motions.
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 orthosis reduces the physical exertion needed for mobility, allows for intuitive control of legged movements, and helps in reversing physiological impairments associated with immobility, such as muscular atrophy and bone loss, while providing efficient and repeatable gait assistance.
Implementation Method 1
The FES can be controlled by the DES to provide as much movement as possible, with the remaining movement provided by the assistance device
Data Source
AI summary
A apparatus includes an a exoskeleton system with a plurality of sensors for generating signals indicating a current motion and a current arrangement of at least the exoskeleton system, a hip segment, and at least one lower limb. The lower limb includes thigh and shank segments for coupling to a lateral surface of a user's leg. The thigh segment includes a first powered joint coupling the thigh segment to the hip segment, a second powered joint coupling the thigh segment to the shank segment, and a controller coupled to the sensors, the first powered joint, and the second powered joint. The controller is configured for determining a current state of the exoskeleton system and a current intent of the user based on the signals and generating control signals for the first and second powered joints based on the current state and the current intent.