Result of Clinical Trials With Children With Spinal Muscular Atrophy Using the Atlas 2020 Lower-Limb Active Orthosis

Sanz‐Merodio, Daniel; Pérez, María Dolores Esteban; Prieto, Manuel Ángel Rodríguez; Sancho, Juan; García, Elena

doi:10.1142/9789813231047_0009

Cited by 5 publications

(4 citation statements)

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“…To investigate the bandwidth of the torque control, the input human knee angle θ h was set to zero. The closed-loop transfer function of torque control was derived as equation (10), where I gain k i was set to zero for simplicity, and winding inductance L was set to 0 due to its small value.…”

Section: B Human-robot Interaction Model Of Torque Controlmentioning

confidence: 99%

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Design and Actuator Optimization of Lightweight and Compliant Knee Exoskeleton for Mobility Assistance of Children with Crouch Gait

Zhang¹,

Huang²,

Jiao³

et al. 2021

Preprint

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Pediatric exoskeletons offer great promise to increase mobility for children with crouch gait caused by cerebral palsy. A lightweight, compliant and user-specific actuator is critical for maximizing the benefits of an exoskeleton to users. To date, pediatric exoskeletons generally use the same actuators as adult exoskeletons, which are heavy and resistive to natural movement.There is yet no easy way for robotic exoskeletons to accommodate the changes in design requirements that occur as a child ages. We developed a lightweight (1.65 kg unilateral mass) and compliant pediatric knee exoskeleton with a bandwidth of 22.6 Hz that can provide torque assistance to children with crouch gait using high torque density motor. Experimental results demonstrated that the robot exhibited low mechanical impedance (1.79 Nm average backdrive torque) under the unpowered condition and 0.32 Nm with zero-torque tracking control. Root mean square (RMS) error of torque tracking result is less than 0.73 Nm (5.7% with respect to 12 Nm torque). To achieve optimal age-specific performance, we proposed the first optimization framework that considered both motor and transmission of the actuator system that can produce optimal settings for children between 3 and 18 years old. The optimization generated an optimal motor air gap radius that monotonically increases with age from 0.011 to 0.033 meters, and optimal gear ratio varies from 2.6 to 11.6 (3-13 years old) and 11.6 to 10.2 (13-18 years old), leading to actuators of minimal mass.

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Section: B Human-robot Interaction Model Of Torque Controlmentioning

confidence: 99%

“…Furthermore, user engagement and effort are discouraged by bulky and heavy devices. Exoskeletons are often limited by their weight [10], [11], and state-of-the-art knee exoskeletons report high stiffness (low compliance) [12].…”

Section: Introductionmentioning

confidence: 99%

Design and Actuator Optimization of Lightweight and Compliant Knee Exoskeleton for Mobility Assistance of Children with Crouch Gait

Zhang¹,

Huang²,

Jiao³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…While children with gait impairments stand to benefit from RAGT, most commercially available exoskeletons are adult-oriented [8,9] and are not designed to serve the pediatric population [10]. Representative pediatric devices currently include the pediatric Lokomat [11], the Trexo robotic walker [12], the very small-sized Hybrid Assistive Limb (2S-HAL) [13], the ATLAS 2020 and 2030 [7,14], the MOTION exoskeleton by Bioengineering 2024, 11, 590 2 of 16 Zhang et al [15], and the exoskeletons developed by Lerner et al at the NIH [5]. Of the pediatric devices that do exist, few devices combine the characteristics of a lightweight form factor, community setting mobility, adjustability, and ease of use.…”

Section: Introductionmentioning

confidence: 99%

Preliminary Virtual Constraint-Based Control Evaluation on a Pediatric Lower-Limb Exoskeleton

Goo,

Laubscher,

Wajda

et al. 2024

Bioengineering

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Pediatric gait rehabilitation and guidance strategies using robotic exoskeletons require a controller that encourages user volitional control and participation while guiding the wearer towards a stable gait cycle. Virtual constraint-based controllers have created stable gait cycles in bipedal robotic systems and have seen recent use in assistive exoskeletons. This paper evaluates a virtual constraint-based controller for pediatric gait guidance through comparison with a traditional time-dependent position tracking controller on a newly developed exoskeleton system. Walking experiments were performed with a healthy child subject wearing the exoskeleton under proportional-derivative control, virtual constraint-based control, and while unpowered. The participant questionnaires assessed the perceived exertion and controller usability measures, while sensors provided kinematic, control torque, and muscle activation data. The virtual constraint-based controller resulted in a gait similar to the proportional-derivative controlled gait but reduced the variability in the gait kinematics by 36.72% and 16.28% relative to unassisted gait in the hips and knees, respectively. The virtual constraint-based controller also used 35.89% and 4.44% less rms torque per gait cycle in the hips and knees, respectively. The user feedback indicated that the virtual constraint-based controller was intuitive and easy to utilize relative to the proportional-derivative controller. These results indicate that virtual constraint-based control has favorable characteristics for robot-assisted gait guidance.

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“…The ATLAS 2020 (Marsi Bionics S.L.) is a pediatric device with 10 actuated degrees of freedom (DOF) for children ages 3 to 12 years old [24][25][26]. Due to the large number of actuators and DOF, the device is bulky and heavy, weighing approximately 12 kg [24].…”

Section: Introductionmentioning

confidence: 99%

Design and Evaluation of a Pediatric Lower-Limb Exoskeleton Joint Actuator

et al. 2020

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Lower-limb exoskeletons have undergone significant developments for aiding in the ambulation of adults with gait impairment. However, advancements in exoskeletons for the pediatric population have comparatively been lacking. This paper presents a newly developed joint actuator designed to drive the hip and knee joints of a pediatric lower-limb exoskeleton. The performance requirements associated with the actuators were determined based on a target audience of children ages 6–11 years old. The developed actuators incorporate a hybrid belt-chain transmission driven by a frameless brushless DC motor. One actuator underwent benchtop testing to evaluate its performance with respect to their torque production, bandwidth properties, backdrivability in terms of inertia and friction characteristics, speed capabilities, and operational noise levels. As a preliminary validation, a set of actuators were placed in a prototype orthosis to move a pediatric test dummy in gait tracking via state-feedback control. The results showed that the newly developed actuators meet the design specifications and are suitable for use in the pediatric exoskeleton being developed.

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Result of Clinical Trials With Children With Spinal Muscular Atrophy Using the Atlas 2020 Lower-Limb Active Orthosis

Cited by 5 publications

References 0 publications

Design and Actuator Optimization of Lightweight and Compliant Knee Exoskeleton for Mobility Assistance of Children with Crouch Gait

Design and Actuator Optimization of Lightweight and Compliant Knee Exoskeleton for Mobility Assistance of Children with Crouch Gait

Preliminary Virtual Constraint-Based Control Evaluation on a Pediatric Lower-Limb Exoskeleton

Design and Evaluation of a Pediatric Lower-Limb Exoskeleton Joint Actuator

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