Central Nervous System (CNS) Based Motion Control

Motion simulators are widely used in several applications ranging from research to commercial training and entertainment in order to replicate real movement situation. These motions can be sensed by human perception organ called Central Nervous System (CNS). This research presents a novel control algorithm called Central Nervous System (CNS) based control that aims to create realistic perception of vehicle simulation. CNS-based motion control was evaluated by computer simulation to classical, adaptive and optimal washout filter. In addition, comparisons of human motion perception are performed on Force Dynamics 301 simulator for longitudinal acceleration driving test of all four washout filters. The subjects were seated in the simulator. Their motion perceptions were measured through vestibulo-ocular reflex (VOR) using EyeSeeCam vHit camera and compared to the estimated VOR from CNS model. The results revealed that CNS-based motion control can crucially reduce the workspace and provide realistic motion sensation.   &nbsp

Adaptive Washout Filter Based on Fuzzy Logic for a Motion Simulation Platform With Consideration of Joints Limitations

Motion simulation platforms (MSPs) are widely used to generate driving/flying motion sensations for the users. The MSPs have a restricted workspace area due to the dynamical and physical restrictions of the Motion Platforms active joints as well as the physical limitations of its passive joints. The motion cueing algorithm (MCA) is the reproduction of the motion signal including linear accelerations and angular velocities. It aims to simultaneously respect the MSP's workspace limitations and make the same motion feeling for the user as a real vehicle. The Classical washout filter (WF) is a well-known type of MCA. The classical WF is easy to set-up, offers a low computational burden and high functionality but has some major drawbacks such as fixed WF parameters tuned according to worst-case scenarios and no consideration of the human vestibular system. As a result, adaptive WFs were developed to consider the human vestibular system and enhance the efficiency of the method using time-varying filters. The existing adaptive WFs only cogitate the boundaries of the end-effector in the Cartesian coordinate space as a substitute for the active and passive joints limitations, which is MSP's main limiting factor. This conservative assumption reduces the available workspace area of the MSP and increases the motion sensation error for the MSPs user. In this study, a fuzzy logic-based WF is developed, to consider the dynamical and physical boundaries of the active joints as well as the physical boundaries of the passive joints. A genetic algorithm is used to select the membership functions values of the active and passive joints boundaries. The model is designed using MATLAB /Simulink and the outcomes demonstrate the efficiency of the proposed method versus existing adaptive WFs

Evaluating Semi-Natural Travel and Viewing Techniques in Virtual Reality

With seated virtual reality (VR), the use cases based on seating conditions need to be considered while designing the travel and viewing techniques. The most natural method in seated VR, for viewing interactions is the standard 360-degree rotation, for which a swivel chair that spins around the vertical axis is commonly used. However, the VR users will not have the affordances of a swivel chair or the physical space to turn around, all the time. This limits their VR usage based on the availability of certain physical setups. Moreover, for prolonged usage, users might prefer to have convenient viewing interactions by sitting on a couch, not rotating physically all the way around. Our research addresses these scenarios by studying new and existing semi-natural travel and viewing techniques that can be used when full 360-degree rotation is not feasible or is not preferred. Two new techniques, guided head rotation and user-controlled resetting were developed and were compared with existing techniques in three controlled experiments. Standard 360- degree rotation and three joystick-control based viewing techniques (discrete rotation, continuous rotation and continuous rotation with reduced fov) were the existing techniques compared in our experiments. Since the new techniques and some of the existing techniques involve some rotation manipulations that are not natural, they could disorient the users during a virtual experience. So, two VR puzzle games were designed to study the effects of the techniques on spatial awareness of the users. Convenience, simulator sickness, comfort and preferences for home entertainment were the other factors investigated in the experiments. From the experiments, we found out that the results were based on 3D gaming experience of the participants. Participants who played 3D games one or more hours per week had higher tolerance towards the new techniques that had rotational manipulations compared to the participants who did not play any 3D game. Among the joystick rotation techniques, discrete rotation was rated the best by users in terms of simulator sickness. In addition to these experiments, we also present a case study that demonstrates the application of guided head rotation in an experiment that studied natural hand interaction with virtual objects under constrained physical conditions

Etude des lois de commande de la plateforme de simulation de conduite et influence sur le mal de simulateur

La simulation de conduite est fortement utilisée dans la recherche et le développement pour l'industrie automobile. Les simulateurs de conduite sont utilisés pour évaluer les prototypes véhicules pour la dynamique du véhicule et les systèmes d'aide à la conduite. Cependant, l'utilisation des simulateurs de conduite induit une problématique scientifique qui peut limiter son développement. En raison de son principe même, le simulateur de conduite ne restitue pas des mouvements du véhicule à l'échelle 1. Ce verrou cause des phénomènes de mal du simulateur qu'il est important d'étudier.Cette thèse propose d'étudier des méthodes et outils à mettre en œuvre dans les simulateurs de conduite statique ou dynamique. De cette mise en œuvre, des études sur le mal du simulateur sont menées grâce à des mesures objectives (via un capteur de suivi de mouvement, plate-forme de stabilité du corps, électromyographie) et subjectives (par l'intermédiaire de questionnaires). Des solutions algorithmiques et matérielles sont proposées et évaluées dans le contexte de la simulation de conduite.Les approches proposées dans cette thèse pour réduire le mal du simulateur sont:- Elaborer et évaluer les algorithmes de contrôle de la plate-forme mobile hexapode: sept algorithmes différents sont mis en œuvre.- Mesurer les effets liés au mal de simulateur sur les sujets aux niveaux vestibulaire, neuromusculaire et posturale.- Evaluer l'influence de l'implication des sujets sur le mal de simulateur (conducteurs et passagers).Simulation has been intensively involved nowadays in research and development for automotive industry. Driving simulators are one of those simulation techniques which are used to evaluate the prototypes for the vehicle dynamics and driving assistance systems. However with the driving simulator, there is a lock associated with its use. Because representing a permanent scenario as scale 1 is quite difficult. Because of that difficulty, motion/simulator sickness is an inevitably important topic to study.This thesis proposes to explore methods and tools to implement in static or dynamic simulators. In this implementation, studies of simulator sickness are conducted with objective measures (via a motion tracking sensor, platform for body stability, electromyography) and subjective (through questionnaires). These algorithmic or hardware solutions studies should be defined and applied at simulators. The proposed approaches to reduce or avoid simulator sickness in this thesis are:- Building control algorithms of motion hexapod platform: seven different algorithms are implemented.- Measuring the effects of inertia on subjects at vestibular, neuromuscular and postural levels.- Assessing the involvement of subjects (drivers and passengers).PARIS-Arts et Métiers (751132303) / SudocSudocFranceF