27 research outputs found
Soft Robotics: Design for Simplicity, Performance, and Robustness of Robots for Interaction with Humans.
This thesis deals with the design possibilities concerning the next generation of advanced Robots. Aim of the work is to study, analyse and realise artificial systems that are essentially simple, performing and robust and can live and coexist with humans. The main design guideline followed in doing so is the Soft Robotics Approach, that implies the design of systems with intrinsic mechanical compliance in their architecture. The first part of the thesis addresses design of new soft robotics actuators, or robotic muscles. At the beginning are provided information about what a robotic muscle is and what is needed to realise it. A possible classification of these systems is analysed and some criteria useful for their comparison are explained. After, a set of functional specifications and parameters is identified and defined, to characterise a specific subset of this kind of actuators, called Variable Stiffness Actuators. The selected parameters converge in a data-sheet that easily defines performance and abilities of the robotic system. A complete strategy for the design and realisation of this kind of system is provided, which takes into account their me- chanical morphology and architecture. As consequence of this, some new actuators are developed, validated and employed in the execution of complex experimental tasks. In particular the actuator VSA-Cube and its add-on, a Variable Damper, are developed as the main com- ponents of a robotics low-cost platform, called VSA-CubeBot, that
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can be used as an exploratory platform for multi degrees of freedom experiments. Experimental validations and mathematical models of the system employed in multi degrees of freedom tasks (bimanual as- sembly and drawing on an uneven surface), are reported.
The second part of the thesis is about the design of multi fingered hands for robots. In this part of the work the Pisa-IIT SoftHand is introduced. It is a novel robot hand prototype designed with the purpose of being as easily usable, robust and simple as an industrial gripper, while exhibiting a level of grasping versatility and an aspect comparable to that of the human hand. In the thesis the main theo- retical tool used to enable such simplification, i.e. the neuroscience– based notion of soft synergies, are briefly reviewed. The approach proposed rests on ideas coming from underactuated hand design. A synthesis method to realize a desired set of soft synergies through the principled design of adaptive underactuated mechanisms, which is called the method of adaptive synergies, is discussed. This ap- proach leads to the design of hands accommodating in principle an arbitrary number of soft synergies, as demonstrated in grasping and manipulation simulations and experiments with a prototype. As a particular instance of application of the method of adaptive syner- gies, the Pisa–IIT SoftHand is then described in detail. The design and implementation of the prototype hand are shown and its effec- tiveness demonstrated through grasping experiments. Finally, control of the Pisa/IIT Hand is considered. Few different control strategies are adopted, including an experimental setup with the use of surface Electromyographic signals
Planning and control of robotic manipulation actions for extreme environments
A large societal and economic need arises for advanced robotic capabilities, where we need to perform complex human-like tasks such as tool-use, in environments that are hazardous for human workers. This thesis addresses a collection of problems, which arise when robotic manipulators must perform complex tasks in cluttered and constrained environments. The work is illustrated by example scenarios of robotic tool use, grasping and manipulating, motivated by the challenges of dismantling operations in the extreme environments of nuclear decommissioning
Contrary to popular assumptions, legacy nuclear facilities (which can date back three-quarters of a century in the UK) can be highly unstructured and uncertain environments, with insufficient a-priori information available for e.g. conventional pre-programming of robot tasks. Meanwhile, situational awareness and direct teleoperation can be extremely difficult for human operators working in a safe zone that is physically remote from the robot. This engenders a need for significant autonomous capabilities. Robots must use vision and sensory systems to perceive their environment, plan and execute complex actions on complex objects in cluttered and constrained environments. Significant radiation, of different types and intensities, provides further challenges in terms of sensor noise. Perception uncertainty can also result from e.g. vision systems observing shiny featureless metal structures. Robotic actions therefore need to be: i) planned in ways that are robust to uncertainties; and ii) controlled in ways which enable the robust reaction to disturbances.
In particular, we investigate motion planning and control in tasks where the robot must: maintain contact while moving over arbitrarily shaped surfaces with end-effector tools; exert forces and withstand perturbations during forceful contact actions; while also avoiding collisions with obstacles; avoiding singularity configurations; and increasing robustness by maximising manipulability during task execution. Furthermore, we consider the issues of robust planning and control with respect to uncertain information, derived from noisy sensors in challenging environments.
We explore the Riemannian geometry and robot's manipulability to yield path planners that produce paths for both fixed-based and floating-based robots, whose tools always stay in contact with the object's surface. Our planners overcome disturbances in the perception and account for robot/environment interactions that may demand unexpected forces. The task execution is entrusted to a hybrid force/motion controller whose motion space behaves with compliance to accommodate unexpected stiffness changes throughout the contact.
We examine the problem of grasping a tool for performing a task. Firstly, we introduce a method for selecting the grasp candidate onto an object yielding collision-free motion for the robot in the post-grasp movements. Furthermore, we study the case of a dual-arm robot performing full-force tasks on an object and slippage on the grasping is allowed. We account for the slippage throughout the task execution using a novel controller based on the sliding mode controllers
Instrumentation and validation of a robotic cane for transportation and fall prevention in patients with affected mobility
Dissertação de mestrado integrado em Engenharia FĂsica, (especialização em Dispositivos, Microssistemas e Nanotecnologias)O ato de andar Ă© conhecido por ser a forma primitiva de locomoção do ser humano, sendo que este
traz muitos benefĂcios que motivam um estilo de vida saudável e ativo. No entanto, há condições de saĂşde
que dificultam a realização da marcha, o que por consequência pode resultar num agravamento da saúde,
e adicionalmente, levar a um maior risco de quedas. Nesse sentido, o desenvolvimento de um sistema de
deteção e prevenção de quedas, integrado num dispositivo auxiliar de marcha, seria essencial para reduzir
estes eventos de quedas e melhorar a qualidade de vida das pessoas. Para ultrapassar estas necessidades
e limitações, esta dissertação tem como objetivo validar e instrumentar uma bengala robótica, denominada
Anti-fall Robotic Cane (ARCane), concebida para incorporar um sistema de deteção de quedas e um
mecanismo de atuação que possibilite a prevenção de quedas, ao mesmo tempo que assiste a marcha.
Para esse fim, foi realizada uma revisĂŁo do estado da arte em bengalas robĂłticas para adquirir um
conhecimento amplo e aprofundado dos componentes, mecanismos e estratégias utilizadas, bem como os
protocolos experimentais, principais resultados, limitações e desafios em dispositivos existentes.
Numa primeira fase, foi estipulado o objetivo de: (i) adaptar a missĂŁo do produto; (ii) estudar as
necessidades do consumidor; e (iii) atualizar as especificações alvo da ARCane, continuação do trabalho de
equipa, para obter um produto com design e engenharia compatĂvel com o mercado. Foi depois estabelecida
a arquitetura de hardware e discutidos os componentes a ser instrumentados na ARCane. Em seguida foram
realizados testes de interoperabilidade a fim de validar o funcionamento singular e coletivo dos componentes.
Relativamente ao controlo de movimento, foi desenvolvido um sistema inovador, de baixo custo e
intuitivo, capaz de detetar a intenção do movimento e de reconhecer as fases da marcha do utilizador. Esta
implementação foi validada com seis voluntários saudáveis que realizaram testes de marcha com a ARCane
para testar sua operabilidade num ambiente de contexto real. Obteve-se uma precisĂŁo de 97% e de 90% em
relação à deteção da intenção de movimento e ao reconhecimento da fase da marcha do utilizador.
Por fim, foi projetado um método de deteção de quedas e mecanismo de prevenção de quedas para
futura implementação na ARCane. Foi ainda proposta uma melhoria do método de deteção de quedas, de
modo a superar as limitações associadas, bem como a proposta de dispositivos de deteção a serem
implementados na ARCane para obter um sistema completo de deteção de quedas.The act of walking is known to be the primitive form of the human being, and it brings many benefits
that motivate a healthy and active lifestyle. However, there are health conditions that make walking difficult,
which, consequently, can result in worse health and, in addition, lead to a greater risk of falls. Thus, the
development of a fall detection and prevention system integrated with a walking aid would be essential to
reduce these fall events and improve people quality of life. To overcome these needs and limitations, this
dissertation aims to validate and instrument a cane-type robot, called Anti-fall Robotic Cane (ARCane),
designed to incorporate a fall detection system and an actuation mechanism that allow the prevention of
falls, while assisting the gait. Therefore, a State-of-the-Art review concerning robotic canes was carried out to
acquire a broad and in-depth knowledge of the used components, mechanisms and strategies, as well as
the experimental protocols, main results, limitations and challenges on existing devices.
On a first stage, it was set an objective to (i) enhance the product's mission statement; (ii) study the
consumer needs; and (iii) update the target specifications of the ARCane, extending teamwork, to obtain a
product with a market-compatible design and engineering that meets the needs and desires of the ARCane
users. It was then established the hardware architecture of the ARCane and discussed the electronic
components that will instrument the control, sensory, actuator and power units, being afterwards subjected
to interoperability tests to validate the singular and collective functioning of cane components altogether.
Regarding the motion control of robotic canes, an innovative, cost-effective and intuitive motion
control system was developed, providing user movement intention recognition, and identification of the user's
gait phases. This implementation was validated with six healthy volunteers who carried out gait trials with
the ARCane, in order to test its operability in a real context environment. An accuracy of 97% was achieved
for user motion intention recognition and 90% for user gait phase recognition, using the proposed motion
control system.
Finally, it was idealized a fall detection method and fall prevention mechanism for a future
implementation in the ARCane, based on methods applied to robotic canes in the literature. It was also
proposed an improvement of the fall detection method in order to overcome its associated limitations, as
well as detection devices to be implemented into the ARCane to achieve a complete fall detection system
Fourth Annual Workshop on Space Operations Applications and Research (SOAR 90)
The proceedings of the SOAR workshop are presented. The technical areas included are as follows: Automation and Robotics; Environmental Interactions; Human Factors; Intelligent Systems; and Life Sciences. NASA and Air Force programmatic overviews and panel sessions were also held in each technical area
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Material agency and performative dynamics in the practices of media art
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityThis dissertation identifies a strategy of artistic inquiry within contemporary media art practice. It applies the concept of material that acts in an agential capacity, generating performative acts. It argues that the emergent potentials of materials and their interconnectedness with the compositional layers of a work can facilitate modes of effecting change in the artistic system. Through the theoretical investigation of the production processes of physical structures and environments, the thesis focuses on the compositional dynamics within which materials actively
perform. It examines how Lars Spuybroek’s architectural design method of Material Machines (2004), and both the tactile potential as well as tactical uses of materials as generators to the formtaking
process, might describe an open and active artistic strategy for employing the experimental capacities of such materialization processes. Building on philosophical and conceptual arguments that trace concepts of agency (Bruno Latour’s Actant-Network theory) and enactment (Karen Barad’s concept of intra-acting), the
thesis introduces the two installation works ANI_MATE (described as a performative pneumatic stage machine) and ON TRACK (described as a mechanic-robotic installation). These apply the introduced artistic strategies. The analyses of these two artworks traces the particular capacities of the materials involved (respectively, their elasticity or viscosity) to negotiate forces of physical
movement, which effect the system to transiently or irreversibly transform.
ANI_MATE is a machine that is artist-operated and that explores the relationship between liveanimation procedures and the transformability and flexibility of its material environment. In contrast, ON TRACK’s performative machine ecology removes human agency. The machines act autonomously, giving rise to chance in the artistic system and allowing agency to emerge from the
dynamic interconnectivity between materials, parts, and processes, eventually producing an
entropic scenario of spilling resources.
The thesis concludes that, in the context of a post digital paradigm in-development, such artistic practice offers a new strategy for an emergent aesthetics within contemporary physical-digital performance