1,150 research outputs found
Knee Exoskeletons Design Approaches to Boost Strength Capability: A Review
Exoesqueleto para incrementar la fuerza en las rodillasThere are different devices to increase the strength capacity of people with walking
problems. These devices can be classified into exoskeletons, orthotics, and braces. This review
aims to identify the state of the art in the design of these medical devices, based on an analysis
of patents and literature. However, there are some difficulties in processing the records due to
the lack of filters and standardization in the names, generating discrepancies between the search
engines, among others. Concerning the patents, 74 patents were analyzed using search engines
such as Google Patents, Derwent, The Lens, Patentscope, and Espacenet over the past ten years. A
bibliometric analysis was performed using 63 scientific reports from Web of Science and The Lens
in the same period for scientific communications. The results show a trend to use the mechanical
design of exoskeletons based on articulated rigid structures and elements that provide force to move
the structure. These are generally two types: (a) elastic elements and (b) electromechanical elements.
The United States accounts for 32% of the technological patents reviewed. The results suggest that
the use of exoskeletons or orthoses customized to the users’ needs will continue to increase over
the years due to the worldwide growth in disability, particularly related to mobility difficulties and
technologies related to the combined use of springs and actuators
A flexible sensor technology for the distributed measurement of interaction pressure
We present a sensor technology for the measure of the physical human-robot interaction pressure developed in the last years at Scuola Superiore Sant'Anna. The system is composed of flexible matrices of opto-electronic sensors covered by a soft silicone cover. This sensory system is completely modular and scalable, allowing one to cover areas of any sizes and shapes, and to measure different pressure ranges. In this work we present the main application areas for this technology. A first generation of the system was used to monitor human-robot interaction in upper- (NEUROExos; Scuola Superiore Sant'Anna) and lower-limb (LOPES; University of Twente) exoskeletons for rehabilitation. A second generation, with increased resolution and wireless connection, was used to develop a pressure-sensitive foot insole and an improved human-robot interaction measurement systems. The experimental characterization of the latter system along with its validation on three healthy subjects is presented here for the first time. A perspective on future uses and development of the technology is finally drafted
A unilateral robotic knee exoskeleton to assess the role of natural gait assistance in hemiparetic patients.
Background: Hemiparetic gait is characterized by strong asymmetries that can severely affect the quality of life of
stroke survivors. This type of asymmetry is due to motor deficits in the paretic leg and the resulting compensations in
the nonparetic limb. In this study, we aimed to evaluate the effect of actively promoting gait symmetry in hemiparetic
patients by assessing the behavior of both paretic and nonparetic lower limbs. This paper introduces the design and
validation of the REFLEX prototype, a unilateral active knee–ankle–foot orthosis designed and developed to naturally
assist the paretic limbs of hemiparetic patients during gait.
Methods: REFLEX uses an adaptive frequency oscillator to estimate the continuous gait phase of the nonparetic
limb. Based on this estimation, the device synchronically assists the paretic leg following two different control
strategies: (1) replicating the movement of the nonparetic leg or (2) inducing a healthy gait pattern for the paretic
leg. Technical validation of the system was implemented on three healthy subjects, while the effect of the generated
assistance was assessed in three stroke patients. The effects of this assistance were evaluated in terms of interlimb
symmetry with respect to spatiotemporal gait parameters such as step length or time, as well as the similarity
between the joint’s motion in both legs.
Results: Preliminary results proved the feasibility of the REFLEX prototype to assist gait by reinforcing symmetry. They
also pointed out that the assistance of the paretic leg resulted in a decrease in the compensatory strategies developed
by the nonparetic limb to achieve a functional gait. Notably, better results were attained when the assistance
was provided according to a standard healthy pattern, which initially might suppose a lower symmetry but enabled a
healthier evolution of the motion of the nonparetic limb.
Conclusions: This work presents the preliminary validation of the REFLEX prototype, a unilateral knee exoskeleton for
gait assistance in hemiparetic patients. The experimental results indicate that assisting the paretic leg of a hemiparetic
patient based on the movement of their nonparetic leg is a valuable strategy for reducing the compensatory mechanisms
developed by the nonparetic limb.post-print6406 K
A Review of Lower Limb Exoskeletons
In general, exoskeletons are defined as wearable robotic mechanisms for providing mobility. In the last six decades, many research work have been achieved to enhance the performance of exoskeletons thus developing them to nearly commercialized products. In this paper, a review is made for the lower limb exoskeleton concerning history, classification, selection and development, also a discussion for the most important aspects of comparison between different designs is presented. Further, some concluding remarks are withdrawn which could be useful for future work. Keywords: Exoskeletons, Lower extremity exoskeleton, Wearable robot
State of the Art Lower Limb Robotic Exoskeletons for Elderly Assistance
https://ieeexplore.ieee.org/document/8759880/keywords#keywordsThe number of elderly populations is rapidly increasing. Majority of elderly people face difficulties while walking because the muscular activity or other gait-related parameters start to deteriorate with aging. Therefore, the quality of life among them can be suffered. To make their life more comfortable, service providing robotic solutions in terms of wearable powered exoskeletons should be realized. Assistive powered exoskeletons are capable of providing additional torque to support various activities, such as walking, sit to stand, and stand to sit motions to subjects with mobility impairments. Specifically, the powered exoskeletons try to maintain and keep subjects' limbs on the specified motion trajectory. The state of the art of currently available lower limb assistive exoskeletons for weak and elderly people is presented in this paper. The technology employed in the assistive devices, such as actuation and power supply types, control strategies, their functional abilities, and the mechanism design, is thoroughly described. The outcome of studied literature reveals that there is still much work to be done in the improvement of assistive exoskeletons in terms of their technological aspects, such as choosing proper and effective control methods, developing user friendly interfaces, and decreasing the costs of device to make it more affordable, meanwhile ensuring safe interaction for the end-users
Advancements in Sensor Technologies and Control Strategies for Lower-Limb Rehabilitation Exoskeletons: A Comprehensive Review
Lower-limb rehabilitation exoskeletons offer a transformative approach to enhancing recovery in patients with movement disorders affecting the lower extremities. This comprehensive systematic review delves into the literature on sensor technologies and the control strategies integrated into these exoskeletons, evaluating their capacity to address user needs and scrutinizing their structural designs regarding sensor distribution as well as control algorithms. The review examines various sensing modalities, including electromyography (EMG), force, displacement, and other innovative sensor types, employed in these devices to facilitate accurate and responsive motion control. Furthermore, the review explores the strengths and limitations of a diverse array of lower-limb rehabilitation-exoskeleton designs, highlighting areas of improvement and potential avenues for further development. In addition, the review investigates the latest control algorithms and analysis methods that have been utilized in conjunction with these sensor systems to optimize exoskeleton performance and ensure safe and effective user interactions. By building a deeper understanding of the diverse sensor technologies and monitoring systems, this review aims to contribute to the ongoing advancement of lower-limb rehabilitation exoskeletons, ultimately improving the quality of life for patients with mobility impairments
Review of control strategies for robotic movement training after neurologic injury
There is increasing interest in using robotic devices to assist in movement training following neurologic injuries such as stroke and spinal cord injury. This paper reviews control strategies for robotic therapy devices. Several categories of strategies have been proposed, including, assistive, challenge-based, haptic simulation, and coaching. The greatest amount of work has been done on developing assistive strategies, and thus the majority of this review summarizes techniques for implementing assistive strategies, including impedance-, counterbalance-, and EMG- based controllers, as well as adaptive controllers that modify control parameters based on ongoing participant performance. Clinical evidence regarding the relative effectiveness of different types of robotic therapy controllers is limited, but there is initial evidence that some control strategies are more effective than others. It is also now apparent there may be mechanisms by which some robotic control approaches might actually decrease the recovery possible with comparable, non-robotic forms of training. In future research, there is a need for head-to-head comparison of control algorithms in randomized, controlled clinical trials, and for improved models of human motor recovery to provide a more rational framework for designing robotic therapy control strategies
Comfort-Centered Design of a Lightweight and Backdrivable Knee Exoskeleton
This paper presents design principles for comfort-centered wearable robots
and their application in a lightweight and backdrivable knee exoskeleton. The
mitigation of discomfort is treated as mechanical design and control issues and
three solutions are proposed in this paper: 1) a new wearable structure
optimizes the strap attachment configuration and suit layout to ameliorate
excessive shear forces of conventional wearable structure design; 2) rolling
knee joint and double-hinge mechanisms reduce the misalignment in the sagittal
and frontal plane, without increasing the mechanical complexity and inertia,
respectively; 3) a low impedance mechanical transmission reduces the reflected
inertia and damping of the actuator to human, thus the exoskeleton is
highly-backdrivable. Kinematic simulations demonstrate that misalignment
between the robot joint and knee joint can be reduced by 74% at maximum knee
flexion. In experiments, the exoskeleton in the unpowered mode exhibits 1.03 Nm
root mean square (RMS) low resistive torque. The torque control experiments
demonstrate 0.31 Nm RMS torque tracking error in three human subjects.Comment: 8 pages, 16figures, Journa
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