Assisting Human Balance in Standing With a Robotic Exoskeleton

Farkhatdinov, Ildar; Ebert, Julia; Oort, Gijs van; Vlutters, Mark; Asseldonk, Edwin H.F. van; Burdet, Etienne

doi:10.1109/lra.2018.2890671

Cited by 40 publications

(22 citation statements)

References 24 publications

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“…Our results can apply to both biological or man-made systems, e.g. for autonomous locomotion [63][64][65][66][67] or robotics for gait and balance assistance [68,69], with the need to navigate in the absence of external references other than the ambient gravity field.…”

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confidence: 99%

Gravito-inertial ambiguity resolved through head stabilization

et al. 2019

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It has been frequently observed that humans and animals spontaneously stabilize their heads with respect to the gravitational vertical during body movements even in the absence of vision. The interpretations of this intriguing behaviour have so far not included the need, for survival, to robustly estimate verticality. Here we use a mechanistic model of the head/otolith organ to analyse the possibility for this system to render verticality ‘observable’, a fundamental prerequisite to the determination of the angular position and acceleration of the head from idiothetic, inertial measurements. The intrinsically nonlinear head-vestibular dynamics is shown to generally lack observability unless the head is stabilized in orientation by feedback. Thus, our study supports the hypothesis that a central function of the physiologically costly head stabilization strategy is to enable an organism to estimate the gravitational vertical and head acceleration during locomotion. Moreover, our result exhibits a rare peculiarity of certain nonlinear systems to fortuitously alter their observability properties when feedback is applied.

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Gravito-inertial ambiguity resolved through head stabilization

et al. 2019

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“…The result presented here complements recent developments in the field [22,23,24,25] by demonstrating that head stabilization significantly improves the quality of verticality estimation. This result has many applications in the control of humanoid robots, rovers, drones, as well as human mobility assistance robots [26,27].…”

Section: Discussionmentioning

confidence: 95%

Idiothetic Verticality Estimation Through Head Stabilization Strategy

Farkhatdinov

Michalska

Berthoz

et al. 2019

IEEE Robot. Autom. Lett.

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The knowledge of the gravitational vertical is fundamental for the autonomous control of humanoids and other freemoving robotic systems such as rovers and drones. This article deals with the hypothesis that the so-called 'head stabilization strategy' observed in humans and animals facilitates the estimation of the true vertical from inertial sensing only. This problem is difficult because inertial measurements respond to a combination of gravity and fictitious forces that are hard to disentangle. From simulations and experiments, we found that the angular stabilization of a platform bearing inertial sensors enables the application of the separation principle. This principle, which permits one to design estimators and controllers independently from each other, typically applies to linear systems, but rarely to nonlinear systems. We found empirically that, given inertial measurements, the angular regulation of a platform results in a system that is stable and robust and which provides true vertical estimates as a byproduct of the feedback. We conclude that angularly stabilized inertial measurement platforms could liberate robots from ground-based measurements for postural control, locomotion, and other functions, leading to a true idiothetic sensing modality, that is, not based on any external reference but the gravity field. Index Terms-Biologically-Inspired Robots; Biomimetics; Sensor-based Control I. INTRODUCTION F OR humans, as for other living creatures, it is substantial to know the spatial orientation of our body with respect to the external world. Most of our sensory systems can contribute to this task. Interestingly, visual, auditory, tactile, proprioceptive, or olfactory sensory inputs can be easily put out of action, but the vestibular inputs are always available, even in the absence of gravity [1]. In artificial systems, robots in particular, inertial measurement units (IMUs) often play the role of a 'robotic vestibular system'. These IMUs sense the movements of the robot and provide its control system Manuscript

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“…These results imply that current exoskeleton capabilities should extend beyond step placement to include stabilization control with the ankle or upper body in the sagittal and frontal planes. Recent work on assistive devices include evaluating how balance control algorithms for the ankle [65,66] or for stepping [67] assist recovery after anterior–posterior perturbations during standing.…”

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confidence: 99%

Human biomechanics perspective on robotics for gait assistance: challenges and potential solutions

2021

Proc. R. Soc. B.

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Technological advancements in robotic devices have the potential to transform human mobility through gait assistance. However, the integration of physical hardware and software control algorithms with users to assist with impaired gait poses several challenges, such as allowing the user to adopt a variety of gaits and the process for evaluating the efficacy and performance of these assistive devices. Here, I discuss some of the challenges in the development of assistive devices and the use of biomechanical concepts and tools for control and test validation. Several potential solutions are proposed through the case study of one project that aimed to provide gait assistance for individuals with a spinal cord injury. Further challenges and future directions are discussed, with emphasis that diverse perspectives and approaches in gait assistance will accelerate engineering solutions towards regaining mobility.

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Assisting Human Balance in Standing With a Robotic Exoskeleton

Cited by 40 publications

References 24 publications

Gravito-inertial ambiguity resolved through head stabilization

Gravito-inertial ambiguity resolved through head stabilization

Idiothetic Verticality Estimation Through Head Stabilization Strategy

Human biomechanics perspective on robotics for gait assistance: challenges and potential solutions

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