Soft Inflatable Exosuit Knee Rehabilitation
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Solution Overview
Problem
Current rigid exoskeletons for rehabilitation are heavy, bulky, and not portable, leading to discomfort and increased dependency on supervised therapy, and they can cause unnatural gait and joint misalignment, making it difficult for stroke and ACL injury patients to perform everyday mobility tasks like stair climbing.
Innovation Solution
A lightweight, soft-inflatable exosuit using thermoplastic polyurethane actuators with I and O cross-section designs, integrated with insole sensors to provide transparent assistance during knee joint motion, reducing muscle activity by 7% as shown in preliminary testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid exoskeletons are used for rehabilitation, then joint support and stability are improved, but device weight and bulk increase leading to discomfort and reduced portability
Solution Approach 1:
The patent replaces rigid exoskeleton structures with soft robotic actuators made of flexible materials including elastomers, shape memory alloys, and pneumatic chambers. These flexible components provide necessary joint support while dramatically reducing device weight and bulk, allowing the rehabilitation device to be worn comfortably during daily activities without requiring supervised therapy sessions.
Solution Approach 2:
The patent employs pneumatic actuators with inflatable chambers that use compressed air to generate controlled forces for joint support. This pneumatic system provides adjustable and adaptive support strength while maintaining a lightweight and compact form factor, resolving the contradiction between reliability and device weight.
2Strength
If rigid exoskeletons are used for rehabilitation, then structural support is improved, but compliance to user motion decreases causing unnatural gait
Solution Approach 1:
The patent implements dynamic adaptability through controllers that receive input from sensors detecting user motion intent and adjust actuator activation accordingly. The system dynamically modulates the support force provided by soft actuators to match the user's natural gait patterns and movement requirements, ensuring high compliance while maintaining adequate structural support throughout the rehabilitation process.
Solution Approach 2:
The patent incorporates sensor feedback systems that monitor user motion and provide real-time information to the control algorithm. This feedback loop enables the system to detect when the user intends to move and adjust actuator activation to assist rather than resist natural motion, thereby improving compliance and preventing unnatural gait patterns while maintaining necessary structural support.
3Force
If heavy rehabilitation devices are used, then assistance force is improved, but user comfort and independence decrease
Solution Approach 1:
The patent utilizes pneumatic actuators that generate substantial assistance forces through compressed air chambers, providing adequate support for rehabilitation without the need for heavy mechanical structures. The pneumatic system delivers high force output relative to its weight, improving user comfort and enabling greater independence in daily activities while maintaining necessary assistance force for effective rehabilitation.
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 soft-inflatable exosuit assists in reducing muscle activity during the swing phase of walking, providing a more natural gait and improving rehabilitation outcomes for patients with paresis or hemi-paresis by offering partial assistance, thus enhancing mobility and reducing the effort required for stair mobility.
Implementation Method 1
The use of soft orthotic devices aiding the rehabilitation of disabled limbs could minimize or eliminate these issues. Despite the recent advancements of inflatable actuators, enough literature is not published on the modeling and development of inflatable actuators for rehabilitative applications.
Implementation Method 2
The fabrication procedure of both types of actuators is disclosed as well as their integration into a light-weight, low-cost and body-conforming interface. Each actuator is configured to be inserted and removed from a corresponding actuator pocket.
Data Source
AI summary
A soft-inflatable exosuit for knee rehabilitation is fabricated in two different beam-like structures (I and O cross-section actuators) and mechanically characterized for their torque performance in knee-extension assistance. The fabrication procedure of both types of actuators is presented as well as their integration into a light-weight, low-cost and body-conforming interface. To detect the activation duration of the device during the gait cycle, a soft-silicone insole with embedded force-sensitive resistors (FSRs) is used. In evaluation studies, the soft inflatable exosuit device is tested for its ability to reduce muscle activity during the swing phase of the knee. Using sEMG (surface electromyography) sensors, the rectus femoris muscle group of a healthy individual is recorded while walking on a treadmill at a constant speed, with and without the soft device.