Optimal Estimator Model for Human Spatial Orientation<sup>a</sup>

Borah, Joshua; Young, Laurence R.; Curry, Renwick E.

doi:10.1111/j.1749-6632.1988.tb19555.x

Cited by 137 publications

(106 citation statements)

References 21 publications

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“…Other models utilized techniques borrowed from optimal estimation (Borah et al 1988;Ormsby and Young 1977). Ormsby's model included the influence of rotational cues on the orientation of gravity using a mechanism resembling an internal model of a physical relationship.…”

Section: Other Models Of Sensory Integrationmentioning

confidence: 99%

Neural Processing of Gravitoinertial Cues in Humans. III. Modeling Tilt and Translation Responses

Merfeld

Zupan

2002

Journal of Neurophysiology

148

114

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. All linear accelerometers measure gravitoinertial force, which is the sum of gravitational force (tilt) and inertial force due to linear acceleration (translation). Neural strategies must exist to elicit tilt and translation responses from this ambiguous cue. To investigate these neural processes, we developed a model of human responses and simulated a number of motion paradigms used to investigate this tilt/translation ambiguity. In this model, the separation of GIF into neural estimates of gravity and linear acceleration is accomplished via an internal model made up of three principal components: 1) the influence of rotational cues (e.g., semicircular canals) on the neural representation of gravity, 2) the resolution of gravitoinertial force into neural representations of gravity and linear acceleration, and 3) the neural representation of the dynamics of the semicircular canals. By combining these simple hypotheses within the internal model framework, the model mimics human responses to a number of different paradigms, ranging from simple paradigms, like roll tilt, to complex paradigms, like postrotational tilt and centrifugation. It is important to note that the exact same mechanisms can explain responses induced by simple movements as well as by more complex paradigms; no additional elements or hypotheses are needed to match the data obtained during more complex paradigms. Therefore these modeled response characteristics are consistent with available data and with the hypothesis that the nervous system uses internal models to estimate tilt and translation in the presence of ambiguous sensory cues. I N T R O D U C T I O NAll linear accelerometers (e.g., otolith organs) measure gravity and linear acceleration. The nervous system must process these cues to elicit appropriate responses during translation [e.g., translational vestibuloocular reflex (VOR)] and tilt (e.g., postural control). It has been shown that neural processes of sensory integration are used to separate otolith measures of gravitoinertial force to yield responses for both tilt and translation. For example, canal cues influence the processing of tilt (Hess and

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Section: Other Models Of Sensory Integrationmentioning

confidence: 99%

Neural Processing of Gravitoinertial Cues in Humans. III. Modeling Tilt and Translation Responses

Merfeld

Zupan

2002

Journal of Neurophysiology

148

114

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“…Research on modeling the vestibular signal processing aimed at developing theories of human spatial orientation perception, and was applied mainly to aerospace physiological studies. L. R. Young and his group proposed an optimal estimator model in [22]. He introduced the concept of internal model which comprised the dynamic model information about the sensory organs and head-neck system.…”

Section: Mathematical Models Of Vestibular Systemmentioning

confidence: 99%

“…Assumptions about sensor dynamics and noise statistics of the internal model were used to correct the estimated states which represented spatial orientation. Estimated states, called perceptions in [22], contained angular orientation of the head, its angular velocity, inertial translation and inertial velocity. Some nonlinear elements were added to the model in order to reproduce the delay of the onset of visually induced motion.…”

Section: Mathematical Models Of Vestibular Systemmentioning

confidence: 99%

Modeling Verticality Estimation During Locomotion

Farkhatdinov

Michalska

Berthoz

et al. 2013

Romansy 19 – Robot Design, Dynamics and Control

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In this thesis, a nonlinear model of the vestibular system is proposed, with special reference to humans and other locomoting animals. The vestibular system is essential for stable locomotion since it provides idiothetic measurements of spatial orientation that are needed for postural control. The model was constructed from general considerations regarding the Newton-Euler dynamics governing the three-dimensional movements of bodies constrained to oscillate in non-inertial frames, such as the otoliths, which were modeled as spherical damped pendula. Two configurations were considered. The medial model considered only one inner ear located in the center of a head. The lateral model considered two inner ears located laterally with respect to the center of rotation of the head. The differences between these two models were analyzed and the importance of having two vestibular organs discussed. To this end, a nonlinear algebraic observability test was used to verify whether the reconstruction of the head orientation with respect to the gravitational vertical was possible from otoliths measurements only. It could be shown that in order for the head vertical orientation to be observable, the head had to be stabilized during locomotion. Moreover, it was shown that the gravitoinertial ambiguity inherent to inertial idiothetic sensing could be resolved if the head was horizontally stabilized. These results were applied to solve the head vertical orientation estimation problem in the linearized case (Luenberger observer, Kalman filter) as well as in the nonlinear case (Extended Kalman filter, Newton method based observation). These observers were designed and tested in simulations. The simulations indicated that the estimation errors were smaller and the observers converged faster when head was stabilized during locomotion, leading to a nonlinear, combined observation-control system that could be stabilized with respect to the gravitational vertical based on no other information than the prior knowledge of the Newton-Euler dynamics. The results were further tested with a specifically designed experimental setup that comprised an actuated gimbal mechanism to represent the head-neck articulation and a liquid-based inclinometer that represented the otoliths organs. The findings derived from this research would be helpful for analyzing spatial perception in humans and animals, and for improving the perceptual capabilities of robotic systems, such as humanoid robots, rough terrain vehicles, or free-moving drones.Keywords: vestibular system, head-neck system, nonlinear system, observation, estimation, verticality, spatial perception, locomotion, humanoid robot. 3 RésuméDans cette thèse, nous proposons un modèle non-linéaire du système vestibulaire, en particulier chez l'humain et autres animaux mobiles. Le système vestibulaire est essentiel pour une locomotion stable dans la mesure où il fournit des mesures idiothétiques d'orientation spatiale nécessairesà la stabilité posturale. Le développement du modèle est basé sur l...

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“…Borah [11] suggested that the CNS functions were analogous to a Kalman optimal estimator when combining sensory cues, and introduced additional dynamics into vestibular responses due to these central processes.…”

Section: Observer Modelmentioning

confidence: 99%