We present the design and evaluation of a multi-articular soft exosuit that is portable, fully autonomous, and provides assistive torques to the wearer at the ankle and hip during walking. ...Traditional rigid exoskeletons can be challenging to perfectly align with a wearer’s biological joints and can have large inertias, which can lead to the wearer altering their natural motion patterns. Exosuits, in comparison, use textiles to create tensile forces over the body in parallel with the muscles, enabling them to be light and not restrict the wearer’s kinematics. We describe the biologically inspired design and function of our exosuit, including a simplified model of the suit’s architecture and its interaction with the body. A key feature of the exosuit is that it can generate forces passively due to the body’s motion, similar to the body’s ligaments and tendons. These passively generated forces can be supplemented by actively contracting Bowden cables using geared electric motors, to create peak forces in the suit of up to 200 N. We define the suit–human series stiffness as an important parameter in the design of the exosuit and measure it on several subjects, and we perform human subjects testing to determine the biomechanical and physiological effects of the suit. Results from a five-subject study showed a minimal effect on gait kinematics and an average best-case metabolic reduction of 6.4%, comparing suit worn unpowered versus powered, during loaded walking with 34.6 kg of carried mass including the exosuit and actuators (2.0 kg on both legs, 10.1 kg total).
An exosuit is a wearable robot that supports human muscular strength from outside the human body through multiple actuators. These actuators, which have similar functions to human muscles, reduce the ...weight compared to existing exoskeletons and minimize awareness of the different degrees of freedom. In this study, we developed an exosuit system that assists stair ascent and descent by supporting the power of the knee joint. To develop the hardware, we designed the entire system including functional apparel and a wire-driven actuator module. To provide the exosuit wearer with walking assistance, we established control strategies based on gait analysis and a force controller by applying the admittance control method. Then, to verify the usability of this system, we conducted an experiment comparing the muscle activity of users with and without the exosuit. The results revealed that the overall muscle activity of users decreased when they wore the proposed exosuit system. Specifically, the system reduced the muscle activity of the rectus femoris by up to 47% and 31% during stair ascent and descent, respectively. Therefore, the proposed exosuit system provides effective walking assistance.
Many previous works of soft wearable exoskeletons (exosuit) target at improving the human locomotion assistance, without considering the impedance adaption to interact with the unpredictable dynamics ...and external environment, preferably outside the laboratory environments. This article proposes a novel hierarchical human-in-the-loop paradigm that aims to produce suitable assistance powers for cable-driven lower limb exosuits to aid the ankle joint in pushing off the ground. It includes two primary loop layers: impedance learning in the external loop and human-in-the-loop adaptive management in the inner loop. Considering unknown terrains, its impedance model can be transferred to a quadratic programming problem with specified constraints, which a designed primal-dual optimization prototype then solves. Then, the presented impedance learning strategy is introduced to regulate the impedance model with the adaptive assistant powers for humans on different terrains. An adaptive controller is designed in the inner loop to balance the nonlinearities and compliance existing in the human-exosuit coexistence, while the robust mechanism compensates for disturbances to facilitate trajectory management without employing the general regressor. The advantage of the proposed technique over conventional solutions with fixed impedance parameters is that it can improve human walking performance over different terrains. Experiments demonstrate the significance of the approach.
Soft exosuit for hip assistance Asbeck, Alan T.; Schmidt, Kai; Walsh, Conor J.
Robotics and autonomous systems,
11/2015, Volume:
73
Journal Article
Peer reviewed
Exoskeletons comprised of rigid load-bearing structures have been developed for many years, but a new paradigm is to create “exosuits” that apply tensile forces to the body using textiles and utilize ...the body’s skeletal structure to support compressive forces. Exosuits are intended to augment the musculature by providing small to moderate levels of assistance at appropriate times in the walking cycle. They have a number of substantial benefits: with their fabric construction, exosuits eliminate problems of needing to align a rigid frame precisely with the biological joints and their inertia can be extremely low. In this paper, we present a fully portable hip-assistance exosuit that uses a backpack frame to attach to the torso, onto which is mounted a spooled-webbing actuator that connects to the back of the users thigh. The actuators, powered by a geared brushless motor connected to a spool via a timing belt, wind up seat-belt webbing onto the spool so that a large travel is possible with a simple, compact mechanism. Designed to be worn over the clothing, the webbing creates a large moment arm around the hip that provides torques in the sagittal plane of up to 30% of the nominal biological torques for level-ground walking. Due to its soft design, the system does not restrict the motion of the hip in the ab- and adduction directions or rotation about the leg axis. Here we present the design of the system along with some initial measurements of the system in use during walking on level ground at 1.25 m/s, where it creates a force of up to 150 N on the thigh, equivalent to a torque of 20.5 Nm to assist hip extension.
•Soft exosuit to actuate hip extension.•Applies 30% of thenominal biological torques during walking at 1.25 m/s.•New spooled-webbing actuator.
An analysis of industrial accidents revealed that workers in the manufacturing field suffered from various injuries resulting in a huge loss of workdays. In order for an exosuit to better support ...physical activities including strengthening the human body, we expect to develop it further that can prevent worker injuries and improve work efficiency at the same time in the field. This study aims to develop an algorithm to distinguish between the gait, lifting, and lowering motions using inertial measurement units (IMUs). We also plan to make a soft exosuit that can help lifting heavy objects using actuators enhancing muscular assistance in gait, lifting, and lowering motions. In the design of an exosuit, elastic bands are used to ensure wearer comfort and we try to make the weight of actuators as light as possible so as to more efficiently assist the human body. With the total weight 0.52 kg of the exosuit, the algorithm can detect the gait motion with a weighted F1 score of 0.8525 and the lifting and lowering motions with the 0.9494. Furthermore, in consideration of rectus femoris which is agonist muscle for walking, lifting, and lowering movements, it appears that the root mean square (RMS) values of the electromyograms (EMGs) for the left and right rectus femoris during the standing up activity are decreased by 24.22% and 20.86%, respectively, compared with the values measured without wearing the exosuit. Additionally, the assisting effect on other major muscles is also significant, demonstrating that the exosuit can assist in improving muscle strength.
Soft exosuits are a promising solution for the assistance and augmentation of human motor abilities in the industrial field, where the use of more symbiotic wearable robots can avoid excessive worker ...fatigue and improve the quality of the work. One of the challenges in the design of soft exosuits is the choice of the right amount of softness to balance load transfer, ergonomics, and weight. This article presents a cable-driven based soft wrist exosuit for flexion assistance with the use of an ergonomic reinforced glove. The flexible and highly compliant three-dimensional (3D)-printed plastic structure that is sewn on the glove allows an optimal force transfer from the remotely located motor to the wrist articulation and to preserve a high level of comfort for the user during assistance. The device is shown to reduce fatigue and the muscular effort required for holding and lifting loads in healthy subjects for weights up to 3 kg.
Abstract Background During inpatient rehabilitation, physical therapists (PTs) often need to manually advance patients’ limbs, adding physical burden to PTs and impacting gait retraining quality. ...Different electromechanical devices alleviate this burden by assisting a patient’s limb advancement and supporting their body weight. However, they are less ideal for neuromuscular engagement when patients no longer need body weight support but continue to require assistance with limb advancement as they recover. The objective of this study was to determine the feasibility of using a hip flexion exosuit to aid paretic limb advancement during inpatient rehabilitation post-stroke. Methods Fourteen individuals post-stroke received three to seven 1-hour walking sessions with the exosuit over one to two weeks in addition to standard care of inpatient rehabilitation. The exosuit assistance was either triggered by PTs or based on gait events detected by body-worn sensors. We evaluated clinical (distance, speed) and spatiotemporal (cadence, stride length, swing time symmetry) gait measures with and without exosuit assistance during 2-minute and 10-meter walk tests. Sessions were grouped by the assistance required from the PTs (limb advancement and balance support, balance support only, or none) without exosuit assistance. Results PTs successfully operated the exosuit in 97% of sessions, of which 70% assistance timing was PT-triggered to accommodate atypical gait. Exosuit assistance eliminated the need for manual limb advancement from PTs. In sessions with participants requiring limb advancement and balance support, the average distance and cadence during 2-minute walk test increased with exosuit assistance by 2.2 ± 3.1 m and 3.4 ± 1.9 steps/min, respectively ( p < 0.017). In sessions with participants requiring balance support only, the average speed during 10-meter walk test increased with exosuit by 0.07 ± 0.12 m/s ( p = 0.042). Clinical and spatiotemporal measures of independent ambulators were similar with and without exosuit ( p > 0.339). Conclusions We incorporated a unilateral hip flexion exosuit into inpatient stroke rehabilitation in individuals with varying levels of impairments. The exosuit assistance removed the burden of manual limb advancement from the PTs and resulted in improved gait measures in some conditions. Future work will understand how to optimize controller and assistance profiles for this population.
Sensing in Soft Robotics Hegde, Chidanand; Su, Jiangtao; Tan, Joel Ming Rui ...
ACS nano,
08/2023, Volume:
17, Issue:
16
Journal Article
Peer reviewed
Open access
Soft robotics is an exciting field of science and technology that enables robots to manipulate objects with human-like dexterity. Soft robots can handle delicate objects with care, access remote ...areas, and offer realistic feedback on their handling performance. However, increased dexterity and mechanical compliance of soft robots come with the need for accurate control of the position and shape of these robots. Therefore, soft robots must be equipped with sensors for better perception of their surroundings, location, force, temperature, shape, and other stimuli for effective usage. This review highlights recent progress in sensing feedback technologies for soft robotic applications. It begins with an introduction to actuation technologies and material selection in soft robotics, followed by an in-depth exploration of various types of sensors, their integration methods, and the benefits of multimodal sensing, signal processing, and control strategies. A short description of current market leaders in soft robotics is also included in the review to illustrate the growing demands of this technology. By examining the latest advancements in sensing feedback technologies for soft robots, this review aims to highlight the potential of soft robotics and inspire innovation in the field.
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