An Omnidirectional System for Navigation in Virtual Environments

Part 8: Robotics and ManufacturingInternational audienceVirtual Reality (VR) is one of the newest technological domains with revolutionary applicability for the tomorrow’s Future Internet, including visions of the Internet of Things. The sensation of total immersion in Virtual Environment (VE) is still unresolved. Therefore, our work proposes a new omnidirectional locomotion interface for navigation in VEs. The novel interface was built from an ordinary unidirectional treadmill, a new mechanical device, a motion capturing system to track the human walking and a control method using artificial intelligence techniques. A neural network is used to predict the motion of the new interface based on user’s body motion and information about VE. The feasibility of the proposed system is verified through experiments and the preliminary results suggest that the new interface performs very well in a simplest VE based on our control method

Active Training and Assistance Device for an Individually Adaptable Strength and Coordination Training

Das Altern der Weltbevölkerung, insbesondere in der westlichen Welt, stellt die Menschheit vor eine große Herausforderung. Zu erwarten sind erhebliche Auswirkungen auf den Gesundheitssektor, der im Hinblick auf eine steigende Anzahl von Menschen mit altersbedingtem körperlichem und kognitivem Abbau und dem damit erhöhten Bedürfnis einer individuellen Versorgung vor einer großen Aufgabe steht. Insbesondere im letzten Jahrhundert wurden viele wissenschaftliche Anstrengungen unternommen, um Ursache und Entwicklung altersbedingter Erkrankungen, ihr Voranschreiten und mögliche Behandlungen, zu verstehen. Die derzeitigen Modelle zeigen, dass der entscheidende Faktor für die Entwicklung solcher Krankheiten der Mangel an sensorischen und motorischen Einflüssen ist, diese wiederum sind das Ergebnis verringerter Mobilität und immer weniger neuer Erfahrungen. Eine Vielzahl von Studien zeigt, dass erhöhte körperliche Aktivität einen positiven Effekt auf den Allgemeinzustand von älteren Erwachsenen mit leichten kognitiven Beeinträchtigungen und den Menschen in deren unmittelbarer Umgebung hat. Diese Arbeit zielt darauf ab, älteren Menschen die Möglichkeit zu bieten, eigenständig und sicher ein individuelles körperliches Training zu absolvieren. In den letzten zwei Jahrzehnten hat die Forschung im Bereich der robotischen Bewegungsassistenten, auch Smarte Rollatoren genannt, den Fokus auf die sensorische und kognitive Unterstützung für ältere und eingeschränkte Personen gesetzt. Durch zahlreiche Bemühungen entstand eine Vielzahl von Ansätzen zur Mensch-Rollator-Interaktion, alle mit dem Ziel, Bewegung und Navigation innerhalb der Umgebung zu unterstützen. Aber trotz allem sind Trainingsmöglichkeiten zur motorischen Aktivierung mittels Smarter Rollatoren noch nicht erforscht. Im Gegensatz zu manchen Smarten Rollatoren, die den Fokus auf Rehabilitationsmöglichkeiten für eine bereits fortgeschrittene Krankheit setzen, zielt diese Arbeit darauf ab, kognitive Beeinträchtigungen in einem frühen Stadium soweit wie möglich zu verlangsamen, damit die körperliche und mentale Fitness des Nutzers so lang wie möglich aufrechterhalten bleibt. Um die Idee eines solchen Trainings zu überprüfen, wurde ein Prototyp-Gerät namens RoboTrainer-Prototyp entworfen, eine mobile Roboter-Plattform, die mit einem zusätzlichen Kraft-Momente-Sensor und einem Fahrradlenker als Eingabe-Schnittstelle ausgestattet wurde. Das Training beinhaltet vordefinierte Trainingspfade mit Markierungen am Boden, entlang derer der Nutzer das Gerät navigieren soll. Der Prototyp benutzt eine Admittanzgleichung, um seine Geschwindigkeit anhand der Eingabe des Nutzers zu berechnen. Desweiteren leitet das Gerät gezielte Regelungsaktionen bzw. Verhaltensänderungen des Roboters ein, um das Training herausfordernd zu gestalten. Die Pilotstudie, die mit zehn älteren Erwachsenen mit beginnender Demenz durchgeführt wurde, zeigte eine signifikante Steigerung ihrer Interaktionsfähigkeit mit diesem Gerät. Sie bewies ebenfalls den Nutzen von Regelungsaktionen, um die Komplexität des Trainings ständig neu anzupassen. Obwohl diese Studie die Durchführbarkeit des Trainings zeigte, waren Grundfläche und mechanische Stabilität des RoboTrainer-Prototyps suboptimal. Deswegen fokussiert sich der zweite Teil dieser Arbeit darauf, ein neues Gerät zu entwerfen, um die Nachteile des Prototyps zu beheben. Neben einer erhöhten mechanischen Stabilität, ermöglicht der RoboTrainer v2 eine Anpassung seiner Grundfläche. Dieses spezifische Merkmal der Smarten Rollatoren dient vor allem dazu, die Unterstützungsfläche für den Benutzer anzupassen. Das ermöglicht einerseits ein agiles Training mit gesunden Personen und andererseits Rehabilitations-Szenarien bei Menschen, die körperliche Unterstützung benötigen. Der Regelungsansatz für den RoboTrainer v2 erweitert den Admittanzregler des Prototypen durch drei adaptive Strategien. Die erste ist die Anpassung der Sensitivität an die Eingabe des Nutzers, abhängig von der Stabilität des Nutzer-Rollater-Systems, welche Schwankungen verhindert, die dann passieren können, wenn die Hände des Nutzers versteifen. Die zweite Anpassung beinhaltet eine neuartige nicht-lineare, geschwindigkeits-basierende Änderung der Admittanz-Parameter, um die Wendigkeit des Rollators zu erhöhen. Die dritte Anpassung erfolgt vor dem eigentlichen Training in einem Parametrierungsprozess, wo nutzereigene Interaktionskräfte gemessen werden, um individuelle Reglerkonstanten fein abzustimmen und zu berechnen. Die Regelungsaktionen sind Verhaltensänderungen des Gerätes, die als Bausteine für unterstützende und herausfordernde Trainingseinheiten mit dem RoboTrainer dienen. Sie nutzen das virtuelle Kraft-Feld-Konzept, um die Bewegung des Gerätes in der Trainingsumgebung zu beeinflussen. Die Bewegung des RoboTrainers wird in der Gesamtumgebung durch globale oder, in bestimmten Teilbereichen, durch räumliche Aktionen beeinflusst. Die Regelungsaktionen erhalten die Absicht des Nutzers aufrecht, in dem sie eine unabhängige Admittanzdynamik implementieren, um deren Einfluss auf die Geschwindigkeit des RoboTrainers zu berechnen. Dies ermöglicht die entscheidende Trennung von Reglerzuständen, um während des Trainings passive und sichere Interaktionen mit dem Gerät zu erreichen. Die oben genannten Beiträge wurden getrennt ausgewertet und in zwei Studien mit jeweils 22 bzw. 13 jungen, gesunden Erwachsenen untersucht. Diese Studien ermöglichen einen umfassenden Einblick in die Zusammenhänge zwischen unterschiedlichen Funktionalitäten und deren Einfluss auf die Nutzer. Sie bestätigen den gesamten Ansatz, sowie die gemachten Vermutungen im Hinblick auf die Gestaltung einzelner Teile dieser Arbeit. Die Einzelergebnisse dieser Arbeit resultieren in einem neuartigen Forschungsgerät für physische Mensch-Roboter-Interaktionen während des Trainings mit Erwachsenen. Zukünftige Forschungen mit dem RoboTrainer ebnen den Weg für Smarte Rollatoren als Hilfe für die Gesellschaft im Hinblick auf den bevorstehenden demographischen Wandel

Design and Gait Control of a Rollerblading Robot

We present the design and gait generation for an experimental ROLLERBLADER1. The ROLLERBLADER is a robot with a central platform mounted on omnidirectional casters and two 3 degree-of-freedom legs. A passive rollerblading wheel is attached to the end of each leg. The wheels give rise to nonholonomic constraints acting on the robot. The legs can be picked up and placed back on the ground allowing a combination of skating and walking gaits. We present two types of gaits for the robot. In the first gait, we allow the legs to be picked up and placed back on the ground while in the second, the wheels are constrained to stay on the ground at all times. Experimental gait results for a prototype robot are also presented

Collaborative human-machine interfaces for mobile manipulators.

The use of mobile manipulators in service industries as both agents in physical Human Robot Interaction (pHRI) and for social interactions has been on the increase in recent times due to necessities like compensating for workforce shortages and enabling safer and more efficient operations amongst other reasons. Collaborative robots, or co-bots, are robots that are developed for use with human interaction through direct contact or close proximity in a shared space with the human users. The work presented in this dissertation focuses on the design, implementation and analysis of components for the next-generation collaborative human machine interfaces (CHMI) needed for mobile manipulator co-bots that can be used in various service industries. The particular components of these CHMI\u27s that are considered in this dissertation include: Robot Control: A Neuroadaptive Controller (NAC)-based admittance control strategy for pHRI applications with a co-bot. Robot state estimation: A novel methodology and placement strategy for using arrays of IMUs that can be embedded in robot skin for pose estimation in complex robot mechanisms. User perception of co-bot CHMI\u27s: Evaluation of human perceptions of usefulness and ease of use of a mobile manipulator co-bot in a nursing assistant application scenario. To facilitate advanced control for the Adaptive Robotic Nursing Assistant (ARNA) mobile manipulator co-bot that was designed and developed in our lab, we describe and evaluate an admittance control strategy that features a Neuroadaptive Controller (NAC). The NAC has been specifically formulated for pHRI applications such as patient walking. The controller continuously tunes weights of a neural network to cancel robot non-linearities, including drive train backlash, kinematic or dynamic coupling, variable patient pushing effort, or slope surfaces with unknown inclines. The advantage of our control strategy consists of Lyapunov stability guarantees during interaction, less need for parameter tuning and better performance across a variety of users and operating conditions. We conduct simulations and experiments with 10 users to confirm that the NAC outperforms a classic Proportional-Derivative (PD) joint controller in terms of resulting interaction jerk, user effort, and trajectory tracking error during patient walking. To tackle complex mechanisms of these next-gen robots wherein the use of encoder or other classic pose measuring device is not feasible, we present a study effects of design parameters on methods that use data from Inertial Measurement Units (IMU) in robot skins to provide robot state estimates. These parameters include number of sensors, their placement on the robot, as well as noise properties on the quality of robot pose estimation and its signal-to-noise Ratio (SNR). The results from that study facilitate the creation of robot skin, and in order to enable their use in complex robots, we propose a novel pose estimation method, the Generalized Common Mode Rejection (GCMR) algorithm, for estimation of joint angles in robot chains containing composite joints. The placement study and GCMR are demonstrated using both Gazebo simulation and experiments with a 3-DoF robotic arm containing 2 non-zero link lengths, 1 revolute joint and a 2-DoF composite joint. In addition to yielding insights on the predicted usage of co-bots, the design of control and sensing mechanisms in their CHMI benefits from evaluating the perception of the eventual users of these robots. With co-bots being only increasingly developed and used, there is a need for studies into these user perceptions using existing models that have been used in predicting usage of comparable technology. To this end, we use the Technology Acceptance Model (TAM) to evaluate the CHMI of the ARNA robot in a scenario via analysis of quantitative and questionnaire data collected during experiments with eventual uses. The results from the works conducted in this dissertation demonstrate insightful contributions to the realization of control and sensing systems that are part of CHMI\u27s for next generation co-bots

Analysis, modeling and wide-area spatiotemporal control of low-frequency sound reproduction

This research aims to develop a low-frequency response control methodology capable of delivering a consistent spectral and temporal response over a wide listening area. Low-frequency room acoustics are naturally plagued by room-modes, a result of standing waves at frequencies with wavelengths that are integer multiples of one or more room dimension. The standing wave pattern is different for each modal frequency, causing a complicated sound field exhibiting a highly position-dependent frequency response. Enhanced systems are investigated with multiple degrees of freedom (independently-controllable sound radiating sources) to provide adequate low-frequency response control. The proposed solution, termed a chameleon subwoofer array or CSA, adopts the most advantageous aspects of existing room-mode correction methodologies while emphasizing efficiency and practicality. Multiple degrees of freedom are ideally achieved by employing what is designated a hybrid subwoofer, which provides four orthogonal degrees of freedom configured within a modest-sized enclosure. The CSA software algorithm integrates both objective and subjective measures to address listener preferences including the possibility of individual real-time control. CSAs and existing techniques are evaluated within a novel acoustical modeling system (FDTD simulation toolbox) developed to meet the requirements of this research. Extensive virtual development of CSAs has led to experimentation using a prototype hybrid subwoofer. The resulting performance is in line with the simulations, whereby variance across a wide listening area is reduced by over 50% with only four degrees of freedom. A supplemental novel correction algorithm addresses correction issues at select narrow frequency bands. These frequencies are filtered from the signal and replaced using virtual bass to maintain all aural information, a psychoacoustical effect giving the impression of low-frequency. Virtual bass is synthesized using an original hybrid approach combining two mainstream synthesis procedures while suppressing each method‟s inherent weaknesses. This algorithm is demonstrated to improve CSA output efficiency while maintaining acceptable subjective performance

Locomotion in virtual reality in full space environments

Virtual Reality is a technology that allows the user to explore and interact with a virtual environment in real time as if they were there. It is used in various fields such as entertainment, education, and medicine due to its immersion and ability to represent reality. Still, there are problems such as virtual simulation sickness and lack of realism that make this technology less appealing. Locomotion in virtual environments is one of the main factors responsible for an immersive and enjoyable virtual reality experience. Several methods of locomotion have been proposed, however, these have flaws that end up negatively influencing the experience. This study compares natural locomotion in complete spaces with joystick locomotion and natural locomotion in impossible spaces through three tests in order to identify the best locomotion method in terms of immersion, realism, usability, spatial knowledge acquisition and level of virtual simulation sickness. The results show that natural locomotion is the method that most positively influences the experience when compared to the other locomotion methods.A Realidade Virual é uma tecnologia que permite ao utilizador explorar e interagir com um ambiente virtual em tempo real como se lá estivesse presente. E utilizada em diversas áreas como o entretenimento, educação e medicina devido à sua imersão e capacidade de representar a realidade. Ainda assim, existem problemas como o enjoo por simulação virtual e a falta de realismo que tornam esta tecnologia menos apelativa. A locomoção em ambientes virtuais é um dos principais fatores responsáveis por uma experiência em realidade virtual imersiva e agradável. Vários métodos de locomoção foram propostos, no entanto, estes têm falhas que acabam por influenciar negativamente a experiência. Este estudo compara a locomoção natural em espaços completos com a locomoção por joystick e a locomoção natural em espaços impossíveis através de três testes de forma a identificar qual o melhor método de locomoção a nível de imersão, realismo, usabilidade, aquisição de conhecimento espacial e nível de enjoo por simulação virtual. Os resultados mostram que a locomoção natural é o método que mais influencia positivamente a experiência quando comparado com os outros métodos de locomoção

A novel human-machine interface for guiding : the NeoASAS Smart Walker

In an aging society it is extremely important to develop devices, which can support and aid the elderly in their daily life. This demands tools that extend independent living and promote improved health. In this work it is proposed a new interface approach integrated into a walker. This interface is based on a joystick and it is intended to extract the user’s movement intentions. The interface is designed to be userfriendly, simple and intuitive, efficient and economic, meeting usability aspects and focused on a commercial implementation, but not being demanding at the user cognitive level. Preliminary sets of experiments were performed which showed the sensibility of the joystick to extract navigation commands from the user. These signals presented a higher frequency component that was attenuated by a Benedict-Bordner g-h filter. The presented methodology offers an effective cancelation of the undesired components from joystick data, allowing the system to extract in real-time voluntary user’s navigation commands. Based on this real-time identification of voluntary user’s commands, an approach to the control architecture of the robotic walker is being developed, in order to obtain stable and safe user assisted locomotion.(undefined

Development of a Locomotion and Balancing Strategy for Humanoid Robots

The locomotion ability and high mobility are the most distinguished features of humanoid robots. Due to the non-linear dynamics of walking, developing and controlling the locomotion of humanoid robots is a challenging task. In this thesis, we study and develop a walking engine for the humanoid robot, NAO, which is the official robotic platform used in the RoboCup Spl. Aldebaran Robotics, the manufacturing company of NAO provides a walking module that has disadvantages, such as being a black box that does not provide control of the gait as well as the robot walk with a bent knee. The latter disadvantage, makes the gait unnatural, energy inefficient and exert large amounts of torque to the knee joint. Thus creating a walking engine that produces a quality and natural gait is essential for humanoid robots in general and is a factor for succeeding in RoboCup competition. Humanoids robots are required to walk fast to be practical for various life tasks. However, its complex structure makes it prone to falling during fast locomotion. On the same hand, the robots are expected to work in constantly changing environments alongside humans and robots, which increase the chance of collisions. Several human-inspired recovery strategies have been studied and adopted to humanoid robots in order to face unexpected and avoidable perturbations. These strategies include hip, ankle, and stepping, however, the use of the arms as a recovery strategy did not enjoy as much attention. The arms can be employed in different motions for fall prevention. The arm rotation strategy can be employed to control the angular momentum of the body and help to regain balance. In this master\u27s thesis, I developed a detailed study of different ways in which the arms can be used to enhance the balance recovery of the NAO humanoid robot while stationary and during locomotion. I model the robot as a linear inverted pendulum plus a flywheel to account for the angular momentum change at the CoM. I considered the role of the arms in changing the body\u27s moment of inertia which help to prevent the robot from falling or to decrease the falling impact. I propose a control algorithm that integrates the arm rotation strategy with the on-board sensors of the NAO. Additionally, I present a simple method to control the amount of recovery from rotating the arms. I also discuss the limitation of the strategy and how it can have a negative impact if it was misused. I present simulations to evaluate the approach in keeping the robot stable against various disturbance sources. The results show the success of the approach in keeping the NAO stable against various perturbations. Finally,I adopt the arm rotation to stabilize the ball kick, which is a common reason for falling in the soccer humanoid RoboCup competitions