Full motion simulators are traditionally used in the flight industry to train pilots. They are used to add the sensation of acceleration in simulation to make it more "realistic". Clearly the motion envelop of the simulator is limited by physical constraints so the motion platform has to be stopped and returned to the center position after an acceleration cue, called washout. A key question is: which acceleration can a subject feel and which not, called the acceleration threshold. We are also interested in strength of accelerations for which a subject can detect the direction. Literature gives several results, but we found that some of these values seemed very low to us and the experiments were conducted on very specific groups of people like pilots, A.J.Benson and H.Vogel (1986), Schroeder (1999). Furthermore, we are simulating moving vehicles like a car or an air plane and are interested in the acceleration ranges in a noisy environment. Noisy, the noise is a result from the vibration of engines, rough roads and disturbances that are Gaussian. This thesis gives a literature review, implement the cueing procedure to make motion and vibration to do different experiment and analyze the results. / Thesis / Master of Computer Science (MCS)

Self-motion perception is based on the integration of visual (optic flow) and vestibular (inertial) sensory information. Previous research has shown that the relative contribution of visual and vestibular cues can change in real time based on the reliability of that information. The present study assessed whether initial velocity and acceleration magnitude influence the relative contribution of these cues to the detection of self-acceleration. Participants performed a simple response time task with visual and vestibular self-acceleration cues as targets. Visual optic flow was presented at three possible initial velocities of 3, 9, or 15 m/s, and accelerated to result in three possible final velocities of 21, 27, or 33 m/s. Corresponding vestibular cues were presented at magnitudes between 0.01 and 0.04 g. The self-acceleration cues were presented at three possible stimulus onset asynchronies (SOAs): visual-first (by 100 ms), in-sync, and vestibular-first (by 100 ms). We found that presenting the cues in-sync resulted in the fastest responses across all velocities and acceleration magnitudes. Interestingly, presenting the visual cue first resulted in a relative advantage over vestibular-first at the slowest initial velocity of 3 m/s, and vice versa for the fastest initial velocity of 15 m/s. The fastest overall responses for visual-first and in-sync were observed at 9 m/s. The present results support the hypothesis that velocity of optic flow can alter the relative contribution of visual and vestibular cues to the detection of self-acceleration. / Thesis / Master of Science (MSc) / This thesis contributes valuable insight into the emerging literature on how visual and vestibular cues are integrated to result in reliable self-motion perception. Specifically, this thesis provides evidence that velocity of optic flow plays an important role in mediating the relative weighting of visual and vestibular cues during acceleration perception.

[pt] No presente trabalho desenvolveu-se o projeto básico de um Simulador de Movimentos em Escala, que é um equipamento utilizado para reproduzir as excitações de base provocadas pelo pavimento sobre o qual um veículo em escala trafega. Utilizando modelos consagrados na literatura, obteve-se a representação matemática do Simulador, que é tratado como 3 subsistemas acoplados entre si, mediante a aplicação de um procedimento baseado no Fluxo de Potência. Para o tratamento dos modelos em escala é empregada a Teoria de Similaridade, através da qual são determinados números adimensionais que relacionam o sistema real com o seu equivalente reduzido ou ampliado. São apresentadas 3 metodologias, das quais duas tradicionais, e uma outra que é conhecida como Método por Inspeção. Aplicam-se estes procedimentos a modelos de veículos com 1, 2, 4 e 7 graus de liberdade. Emprega-se também a Análise Dimensional para achar um modelo em escala do Simulador e do sistema completo, isto é um conjunto Simulador – Veículo acoplado. Para todos os casos são realizadas simulações para os modelos real e em escala, utilizando parâmetros típicos encontrados na literatura ou em manuais de operação de equipamentos semelhantes, com o objetivos de verificar o comportamento dos sistemas, determinar a influência da redução ou ampliação do tamanho, e validar os procedimentos empregados. / [en] In this work a Scale Ground Simulator was developed. This is na equipment used to reproduce the base motion in a vehicle, due the Road where it is running. Using a procedure based on the Power flow, coupling the 3 main Simulator subsystems, a mathematical representation for the Simulator was obtained, from classical models mentioned in the bibliography. The scale models treatment was perfomed using the Similarity Theory, that permits the determination of non dimensional numbers relating the real system with its equivalent reduced or amplified. It was presented 3 methodologies, two of them are traditional and other one which is known as Inspection Method. These procedures were applied to 1, 2, 4, and 7 degrees of freedom vehicle models. Dimensional Analysis is also used to find scale models for the Simulator and for the complete system, i.e. the coupled set Simulator – Vehicle. Simulations were made for all situations, in real and scale models, using typical parameters found in literature or in equipment operation manuals, aiming to verify the systems performance, to determine the size reduction or amplification influence of and to validate the procedures presented.

Residential solar Photovoltaic (PV) installations are increasing at a very high pace in the United States. In 2017 there are approximately one million residential solar PV installations in the US. A significant share of these installations are downstream of distribution transformers and thus connected to the secondary. To precisely analyze voltage variations induced by PV systems into distribution systems, accurate models of load and PV systems connected to the secondary side of distribution transformers are required. In the work here we consider two secondary circuit modeling approaches, simple secondary and detailed secondary models. In simple secondary models all loads and all PV generators below a distribution transformer are modeled as an aggregate load and an aggregate PV generator. In the detailed secondary models all loads and PV systems below the distribution transformers are modeled individually and secondary conductors and service drops are also modeled. Using a cloud motion simulator, it is observed that employing the simple secondary models can lead to inaccurate and conservative results. Moreover, the locations with the greatest voltage changes are different in the two modeling approaches. This paper highlights the importance of utilizing detailed secondary models over simple secondary models in analyzing PV generation. / Master of Science

No description available.

Power generation from solar energy has significantly increased, and the growth is projected to continue in the foreseeable future. The main challenge of dealing with solar energy is its intermittent nature. The received irradiation energy of the sun on the earth's surface can fluctuate in a matter of seconds and cause voltage issues to power systems. Considering the high growth rate of solar photovoltaic (PV) resources, it is essential to be prepared to encounter and manage their high penetration levels. Currently, simplified approaches are used to model the impacts of cloud shadows on power systems. Using outdated standards also limits the penetration levels more than required. Approximately 40% of the new PV installations are residential, or installed at a low voltage level. Currently, all components between utility distribution transformers and customers/loads are either ignored or modeled with oversimplification. Furthermore, large PV systems require a considerable amount of land. However, point sensor models are currently used to simulate those systems. With a point model, the irradiance values measured at a point sensor are used to represent the output of a large PV system. However, in reality, clouds cover photovoltaic resources gradually and if the solar arrays are widespread over a large geospatial area, it takes some time for clouds to pass over the solar arrays. Finally, before 2014, participation of small-scale renewable resources was not allowed in controlling voltage. However, they can contribute significantly in voltage regulation. The main objective of this dissertation is to address the abovementioned issues in order to increase the penetration levels as well as precisely identify and locate voltage problems. A time-series analysis approach is used in modeling cloud motion. Using the time-series approach, changes of the received irradiation energy of the sun due to cloud shadows are simulated realistically with a Cloud Motion Simulator. Moreover, the use of the time-series approach allows implementation of new grid codes and standards, which is not possible using the old step change methods of simulating cloud impacts. Furthermore, all electrical components between utility transformers and customers are modeled to eliminate the inaccuracy due to using oversimplified models. Distributed PV models are also developed and used to represent large photovoltaic systems. In addition, the effectiveness of more distributed voltage control schemes compared to the traditional voltage control configurations is investigated. Inverters connect renewable energy resources to the power grid and they may use different control strategies to control voltage. Different control strategies are also compared with the current practice to investigate voltage control performance under irradiation variations. This dissertation presents a comprehensive approach to study impacts of solar PV resources. Moreover, simulation results show that by using time-series analysis and new grid codes, as well as employing distributed PV models, penetration of solar PV resources can increase significantly with no unacceptable voltage effects. It is also demonstrated that detailed secondary models are required to accurately identify locations with voltage problems. / PHD

[pt] Esta tese tem como principal objetivo o estudo do comportamento cinemático de um simulador de movimentos de 6 (seis) graus de liberdade, utilizando um novo conceito de análise computacional.Inicialmente, foi apresentado um software comercial, Working Model 3D, que teve seu desempenho matemático validado comparando-se seus resultados computacionais com os de outro software comercial, conhecido como Matlab.Foi introduzido, então, o conceito de mecanismos paralelos. Analisou-se, primeiramente, o mecanismo paralelo planar com três juntas rotacionais, conhecido como 3RRR. Foram feitas as análises cinemáticas e os estudos de algumas singularidades, apresentando-se ainda algumas recomendações para futuros trabalhos. O estudo do mecanismo paralelo usado em aplicações como simuladores de movimentos foi também apresentado, através da análise plataforma Stewart- Gough. A exeqüibilidade deste novo conceito de análise cinemática foi comprovada através de diversas simulações, incluindo o acoplamento de um objeto, representado por um chassi veicular, na plataforma. / [en] This thesis presents the kinematic behavior of a motion simulator with six degrees of freedom,using a new computational analysis approach. A well-known simulation software with proven performance, Matlab, is used to validate another software environment, Working Model 3D, which is used to develop and study kinematic models of parallel mechanisms.Planar mechanism using three rotational joints, 3RRR, are studied through kinematic analysis and some singularity studies are developed, which resulted in some suggestions for future analysis and studies. Also, an introductory study of spatial-parallel mechanisms is presented regarding motion simulators with six degrees of freedom through simulation studies of Stewart-Gough platform. The feasibility of this new kinematic analysis was proven by means of several simulations, including the coupling of a vehicular chassis in the platform modeling.