Aerospace medicine and biology: A continuing bibliography with indexes

This bibliography lists 224 reports, articles and other documents introduced into the NASA scientific and technical information system in February 1984

Aerospace medicine and biology: A cumulative index to a continuing bibliography (supplement 306)

This publication is a cumulative index to the abstracts contained in the Supplements 294 through 305 of Aerospace Medicine and Biology: A Continuing Bibliography. It includes seven indexes - subject, personal author, corporate source, foreign technology, contract number, report number, and accession number

Visually Guided Control of Movement

The papers given at an intensive, three-week workshop on visually guided control of movement are presented. The participants were researchers from academia, industry, and government, with backgrounds in visual perception, control theory, and rotorcraft operations. The papers included invited lectures and preliminary reports of research initiated during the workshop. Three major topics are addressed: extraction of environmental structure from motion; perception and control of self motion; and spatial orientation. Each topic is considered from both theoretical and applied perspectives. Implications for control and display are suggested

Aerospace medicine and biology. A continuing bibliography with indexes, supplement 195

This bibliography lists 148 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1979

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 233, June 1982

This bibliograhy lists 387 reports, articles, and other documents introduced into the NASA scientific and technical information system in May 1982

Development and application of smart actuation methods for vehicle simulators

Driving simulators are complex virtual reality systems that integrate visual displays, sound rendering systems, motion platforms, and human-machine-interface devices. They are used in different research areas and consequently, different studies are conducted using these systems, in conditions that would not be safe to be carried out in the real world. However, driving simulators are very expensive research tools. When building such a system, a compromise usually has to be made. Although a driving simulator cannot reproduce 1:1 real life situations or sensations because of its limitations, researchers still need to use such a device for training and research purposes, due to the realistic driving experience it has to offer to its driver. This work focuses on developing a three-degrees of freedom Essential Function Driving Simulator that integrates cost and design constraints, the human perception of motion and real vehicle motion achieved through simulated vehicle models, and the classical motion cueing strategy. The goal is, on the first hand, to immerse the driver to a certain extend into the simulation environment by using this virtual reality device and, on the second hand, to investigate the degree of realism of such a solution. Different actuation solutions are modelled and discussed in this research, with respect to the available workspace, singularity configurations, the system’s behaviour and the maximum forces needed in the frame of the overall cost constraints. A solution was chosen following kinematical and dynamical analyses, as a trade off solution among the above mentioned constraints. The human body finds itself in continuous movement and interaction with the environment. Motion is sensed by the human being through the vestibular system and the skin. The human motion perception mechanisms are mathematically modelled and studied, in order to apply their characteristics in the three-degrees of freedom driving simulator. Due to the limited workspace and degrees of freedom of the discussed simulator, the motion of the simulated vehicle cannot be identically reproduced by the motion system. Thus, special algorithms are designed to transform the motion of the vehicle model in achievable positions for the three actuators, and additionally, to render correct motion cues. The influence of the three variable parameters on the overall subjective degree of freedom is investigated using an optimisation method. The studied parameters are: motion, optical flow and haptic response, introduced by using a lane departure warning assistance system. It is shown in this research that the influence of motion cues on the subjective degree of realism rated by the drivers is of 84%. The vibrations in the steering wheel improve the realism of the simulation and have a 15% impact. The participants of these experiments could easily adapt to the provided assistance system and their immersion in the simulated environment was significantly influenced by the activation of the lane departure warning option. It has also been shown that drivers rated the motion and the accelerations felt in the simulator with 70.41%, compared to the experience of driving a real vehicle. These results are interpreted in this research by putting the emphasis on the fact that irrespective of the DOF of the actuation mechanism, a motion driving simulator should provide correct motion cues. The development of the vehicle models and of the motion cueing algorithms should be approached, so that the system provides motion as similar as possible to the real vehicle, as it is further discussed here.Entwicklung und Anwendung von intelligenten Ansteuerungsmethoden für Fahrzeugsimulatoren Fahrsimulatoren sind Virtual-Reality Systeme, die aus geeigneten Mensch-Maschinen-Schnittstellen, optische und akustische Wiedergabe und, wenn das Bedarf besteht, aus einen Bewegungsapparat bestehen. Sie werden in unterschiedlichen Forschungsfeldern verwendet um verschiedene Studien durchzuführen. Unter anderem können dadurch Manöverstudien durchgeführt werden, die in realen Fahrsituationen zu gefährlich für den Fahrer wären. Der Bau komplexer und hochauflösender Fahrsimulationen ist jedoch sehr Kostenintensiv. Obwohl ein Fahrsimulator die in realen Fahrsituationen empfundenen Fahrgefühle nicht originalgetreu wiedergegeben kann, durch den begrenzten Arbeitsraum, eignet sich ein solches Gerät zu Lehr- und Forschungszwecken. Diese Arbeit befasst sich mit der Entwickelung eines kostengünstigen Fahrsimulators mit drei Freiheitsgraden, der durch eine geeignete Motion-Cueing Strategie dem Fahrer ein ausreichendes Fahrgefühl widergibt. Es werden verschiedene Aktuierungslösungen in Bezug auf den begrenzten Arbeitsraum, singulären Stellungen, des maximalen Kraftbedarfs modelliert, verglichen und diskutiert. Es wurde eine Kompromisslösung gefunden basierend auf der kinematischen und dynamischen Analyse, die diese Begrenzungen berücksichtigt. Der menschliche Körper befindet sich in einer kontinuierlichen Bewegung und interagiert dabei mit der Umgebung. Die Bewegung wird durch das Vestibularorgan und durch die Haut wahrgenommen. Die menschliche Wahrnehmung wird durch ein geeignetes mathematisches Modell widergegeben. Der Bewegungsablauf des Fahrsimulators wurde unter Berücksichtigung der menschlichen Wahrnehmung ausgelegt und untersucht. Wegen dem begrenztem Arbeitsraum und der geringen Anzahl von Systemfreiheitsgraden kann der Simulator die reelle Fahrdynamik nicht im vollen Umfang an die Testperson weitergeben. Deshalb werden angepasste Algorithmen entwickelt um den Bewegungsablauf beschränkt durch drei Aktuatoren in einem akzeptablem umfang widerzugeben. Der Einfluss der drei Aktuatorparameter auf den Bewegungsablauf wird durch geeignete Optimierungsmethoden untersucht. Die Größen die anschließend durch das Fahrsimulator Setup untersucht werden sind unter anderem der Bewegungsablauf, die optische Darstellung und die haptische Wiedergabe. Die Wichtigkeit der empfundenen Fahrbewegung wurde durch die Probanden, im Vergleich zu einem statischen Fahrsimulator, mit 84% bewertet. Die Vibrationen im Lenkrad erhöhen das Realitätsempfinden um 15%. Die Testpersonen konnten sich schnell an die aktuierten Fahrsimulation anpassen und auch Assistenzsysteme wie Spurhalteassistent benutzen. Es wurde gezeigt, dass die im Fahrsimulator gefühlten Beschleunigungen zu ca. 70% an die im realen Fahrbetrieb empfundenen Beschleunigungen herankommen. Es hat sich gezeigt, dass der Immersionsgrad vor allem vom verwendeten Fahrzeugmodellen und den Motion-Cueing Algorithmus abhängig ist

Industrial seating and spinal loading

Little information is available in the literature concerning an ergonomic systems view of industrial seats. This study has been aimed at expanding knowledge of industrial seat design. For this purpose, a model for evaluating industrial seats has been proposed, listing demands and restrictions from the task and the workplace. It also includes responses and effects on the sitter, and methods of measurement for evaluating industrial work seats. The appropriateness of work seat design has been assessed in laboratory and field studies, using methods to measure body loads, their effects and responses. These have been body height shrinkage, biomechanical methods, subjective assessment, and posture assessment. The shrinkage method, including equipment and procedures, has been developed in this project. It assesses the effect of loads on the spine in vivo by using body height changes as a measure of disc creep. The results are well correlated with spinal loads. The method is sensitive enough to differentiate between spinal loads of 100 N difference. The results are also related to the perception of discomfort. Biomechanical methods have been developed for calculating compressive, shear, and momental loads on the spine. Ratings of discomfort, body mapping, interviews, video recordings, and prototype equipment for the recording of head posture have also been used. The methods have been shown to be appropriate for seat evaluation. Work seats have been evaluated in different tasks, incorporating back-rests of different height, width and shape, conventional seat pans and sit-stand seats. It has been shown that advantageous chair features could be referred to each particular task. The tasks evaluated included forward force exertion (high backrests advantageous), vision to the side (low backrests advantageous), work with restricted knee-room (seats allowing increased trunk-thigh angle advantageous), grinding (high, narrow backrests advantageous), punch press work (increased seat height advantageous), and fork lift truck driving (medium height backrest advantageous). The work task has been shown to be a major influence on seat design, and must therefore always be thoroughly considered