Search

AbstractExosuits for the lower limb have developed rapidly as an affordable, light, and more cost-effective alternative to the bulkier, traditional exoskeletons. The synergy-based approach aims at further emphasizing such advantages, providing even lighter and cheaper solutions, thanks to its reduction in actuators and the subsequent simplification of the actuation unit. In this paper, a design approach based on dynamic synergies is proposed to reduce the number of required actuators, thus decreasing the price and weight of walking-assistance exosuits. Also, in this work, we propose a methodology to calculate motor torque output and cable forces during assisted gait. Mechanical designs for the actuation unit are proposed along with experimental and computer-based testing and simulation. Lastly, actuation units with one and two motors are studied and compared, regarding control, mechanical complexity, and metabolic cost reduction. The results show that dynamic synergies can indeed contribute to the design of these assistive devices, with its own set of advantages and disadvantages when compared to the previously proposed postural synergies: while the latter led to a higher cumulative variance of the first principal component and the transmission system is simpler, control may be more unpredictable and forces upon the system, harder to estimate. With dynamic synergies, more related to muscle synergies, metabolic benefit on users may be more significant. [ABSTRACT FROM AUTHOR]

With ever-rising population comes a corresponding rise in people with mobility issues who have difficulty handling tasks in their daily lives. Such persons could benefit significantly from an active movement assistance device. This paper presents the design of a lower-limb exosuit designed to provide the wearer with useful gait assistance. While exoskeletons have existed for a while, soft exoskeletons or exosuits are relatively new. One challenge in the design of a gait-assistance device is the reduction of device weight. In order to facilitate this, the concept of kinematic synergies is implemented to reduce the number of actuators. In this prototype, the exosuit can actuate the hip, ankle, and knee of both legs using just one single motor, and a transmission system consisting of gears and clutches. The implementation of these synergies and their advantages are detailed in this paper, as well as preliminary tests to assess performance. This was performed by testing the exosuit worn by a subject on a treadmill while taking EMG readings and measuring cable tension produced. Significant reductions by up to 35% in certain muscle activations were observed, demonstrating the validity of this prototype for gait assistance. [ABSTRACT FROM AUTHOR]

Ageing results in the eventual loss of muscle mass and strength, joint problems, and overall slowing of movements, with a greater risk of suffering falls or other such accidents. The use of gait assistance exoskeletons can help in the active aging of this segment of the population. Given the user specificity of the mechanics and control these devices need, the facility used to test different design parameters is indispensable. This work deals with the modeling and construction of a modular test bench and prototype exosuit to test different mounting and control schemes for a cable-driven exoskeleton or exosuit. The test bench allows the experimental implementation of postural or kinematic synergies to assist multiple joints by using only one actuator and the optimization of the control scheme to better adapt to the characteristics of the specific patient. The design is open to the research community and it is expected to improve the design of cable-driven systems for exosuits. [ABSTRACT FROM AUTHOR]

Copyright of Revista Iberoamericana de Ingeniería Mecánica is the property of Editorial UNED and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)