Towards Soft Wearable Adaptive Garments Based on Small-Strain Fabric Actuators

As the world develops an increasingly older population, more individuals suffer from chronic diseases that impede mobility and quality of life. Current assistive robots allow users to regain some of the lost functionality, but due to the focused approach to dedicated joints and the components used in their designs these end up being heavy, bulky, costly, without the ability to deliver optimum biomechanical effects. Soft wearable adaptive garments are discussed in this chapter as a path forward in exploring undergarment robotic lower-limb exosuits that can assist people affected by conditions such as rheumatic and musculoskeletal diseases to perform activities of daily living. Pneumatically actuated flexible and lightweight actuators that offer small-strain will need to be first realized to provide joint torque support, minimize musculoskeletal loading, and improve impaired gait patterns. Such garments will aim to exploit the mechanical anisotropy of fabric materials to exhibit modulation of stiffness in inflatable actuators made from fabrics and elastomeric films. Weight of the system in this approach will need to be kept low utilizing a single pressurization source that can be used instead to control all the soft modules of the system in a distributed control architecture. To enable a holistic, poly-articular approach for synergetic assistance, the small-strain fabric-based actuators will have to simultaneously be able to control their stiffness. By surrounding all the involved biological joints, the system will be able to provide a biomechanically positive motor outcome allowing at the same time each actuator to determine its optimum stiffness/motion relative to the module and the user globally. User-in-the-loop explorations in biomechanics and ergonomics studies will be needed to identify key design challenges. Soft sensor fusion and user intent estimation algorithms will also play an important role allowing for the creation of personalized adaptive controllers that effectively regulate the garment. Able-bodied and impaired participants, along with clinicians, will finally need to be part of such process to evaluate performance and efficacy.