8 research outputs found
Locomation strategies for amphibious robots-a review
In the past two decades, unmanned amphibious robots have proven the most promising and efficient systems ranging from scientific, military, and commercial applications. The applications like monitoring, surveillance, reconnaissance, and military combat operations require platforms to maneuver on challenging, complex, rugged terrains and diverse environments. The recent technological advancements and development in aquatic robotics and mobile robotics have facilitated a more agile, robust, and efficient amphibious robots maneuvering in multiple environments and various terrain profiles. Amphibious robot
locomotion inspired by nature, such as amphibians, offers augmented flexibility, improved adaptability, and
higher mobility over terrestrial, aquatic, and aerial mediums. In this review, amphibious robots' locomotion
mechanism designed and developed previously are consolidated, systematically The review also analyzes
the literature on amphibious robot highlighting the limitations, open research areas, recent key development
in this research field. Further development and contributions to amphibious robot locomotion, actuation, and
control can be utilized to perform specific missions in sophisticated environments, where tasks are unsafe
or hardly feasible for the divers or traditional aquatic and terrestrial robots
Interactive Learning of Probabilistic Decision Making by Service Robots with Multiple Skill Domains
This thesis makes a contribution to autonomous service robots, centered around two aspects. The first is modeling decision making in the face of incomplete information on top of diverse basic skills of a service robot. Second, based on such a model, it is investigated, how to transfer complex decision-making knowledge into the system. Interactive learning, naturally from both demonstrations of human teachers and in interaction with objects, yields decision-making models applicable by the robot
Aquatic escape for micro-aerial vehicles
As our world is experiencing climate changes, we are in need of better monitoring technologies.
Most of our planet is covered with water and robots will need to move in aquatic environments.
A mobile robotic platform that possesses efficient locomotion and is capable of operating in
diverse scenarios would give us an advantage in data collection that can validate climate models,
emergency relief and experimental biological research. This field of application is the driving
vector of this robotics research which aims to understand, produce and demonstrate solutions
of aerial-aquatic autonomous vehicles.
However, small robots face major challenges in operating both in water and in air, as well as
transition between those fluids, mainly due to the difference of density of the media.
This thesis presents the developments of new aquatic locomotion strategies at small scales that
further enlarge the operational domain of conventional platforms. This comprises flight, shallow
water locomotion and the transition in-between. Their operating principles, manufacturing
methods and control methods are discussed and evaluated in detail.
I present multiple unique aerial-aquatic robots with various water escape mechanisms, spanning
over different scales. The five robotic platforms showcased share similarities that are compared.
The take-off methods are analysed carefully and the underlying physics principles put into light.
While all presented research fulfils a similar locomotion objective - i.e aerial and aquatic motion
- their relevance depends on the environmental conditions and supposed mission. As such, the
performance of each vehicle is discussed and characterised in real, relevant conditions.
A novel water-reactive fuel thruster is developed for impulsive take-off, allowing consecutive
and multiple jump-gliding from the water surface in rough conditions. At a smaller scale, the
escape of a milligram robotic bee is achieved. In addition, a new robot class is demonstrated,
that employs the same wings for flying as for passive surface sailing. This unique capability
allows the flexibility of flight to be combined with long-duration surface missions, enabling
autonomous prolonged aquatic monitoring.Open Acces
Generating timed trajectories foran autonomous robot
Tese de Doutoramento Programa Doutoral em Engenharia Electrónica e ComputadoresThe inclusion of timed movements in control architectures for mobile navigation has
received an increasing attention over the last years. Timed movements allow modulat-
ing the behavior of the mobile robot according to the elapsed time, such that the robot
reaches a goal location within a specified time constraint. If the robot takes longer
than expected to reach the goal location, its linear velocity is increased for compen-
sating the delay. Timed movements are also relevant when sequences of missions are
considered. The robot should follow the predefined time schedule, so that the next
mission is initiated without delay. The performance of the architecture that controls
the robot can be validated through simulations and field experiments. However, ex-
perimental tests do not cover all the possible solutions. These should be guided by a
stability analysis, which might provide directions to improve the architecture design
in cases of inadequate performance of the architecture.
This thesis aims at developing a navigation architecture and its stability analysis
based on the Contraction Theory. The architecture is based on nonlinear dynamical
systems and must guide a mobile robot, such that it reaches a goal location within a
time constraint while avoiding unexpected obstacles in a cluttered and dynamic real
environment. The stability analysis based on the Contraction Theory might provide
conditions to the dynamical systems parameters, such that the dynamical systems are
designed as contracting, ensuring the global exponential stability of the architecture.
Furthermore, Contraction Theory provides solutions to analyze the success of the mis-
sion as a stability problem. This provides formal results that evaluate the performance
of the architecture, allowing the comparison to other navigation architectures.
To verify the ability of the architecture to guide the mobile robot, several experi-
mental tests were conducted. The obtained results show that the proposed architecture
is able to drive mobile robots with timed movements in indoor environments for large
distances without human intervention. Furthermore, the results show that the Con-
traction Theory is an important tool to design stable control architectures and to
analyze the success of the robotic missions as a stability problem.A inclusão de movimentos temporizados em arquitecturas de controlo para navegação
móvel tem aumentado ao longo dos últimos anos. Movimentos temporizados permitem
modular o comportamento do robô de tal forma que ele chegue ao seu destino dentro de
um tempo especificado. Se o robô se atrasar, a sua velocidade linear deve ser aumen-
tada para compensar o atraso. Estes movimentos são também importantes quando se
consideram sequências de missões. O robô deve seguir o escalonamento da sequência,
de tal forma que a próxima missão seja iniciada sem atraso. O desempenho da arqui-
tectura pode ser validado através de simulações e experiências reais. Contudo, testes
experimentais não cobrem todas as possíveis soluções. Estes devem ser conduzidos por
uma análise de estabilidade, que pode fornecer direcções para melhorar o desempenho
da arquitectura.
O objectivo desta tese é desenvolver uma arquitectura de navegação e analisar a sua
estabilidade através da teoria da Contracção. A arquitectura é baseada em sistemas
dinâmicos não lineares e deve controlar o robô móvel num ambiente real, desordenado
e dinâmico, de tal modo que ele chegue à posição alvo dentro de uma restrição de
tempo especificada. A análise de estabilidade baseada na teoria da Contracção pode
fornecer condições aos parâmetros dos sistemas dinâmicos de modo a desenha-los como
contracções, e assim garantir a estabilidade exponencial global da arquitectura. Esta
teoria fornece ainda soluções interessantes para analisar o sucesso da missão como um
problema de estabilidade. Isto providencia resultados formais que avaliam o desem-
penho da arquitectura e permitem a comparação com outras arquitecturas.
Para verificar a habilidade da arquitectura em controlar o robô móvel, foram con-
duzidos vários testes experimentais. Os resultados obtidos mostram que a arquitectura
proposta é capaz de controlar robôs móveis com movimentos temporizados em ambi-
entes interiores durante grandes distâncias e sem intervenção humana. Além disso,
os resultados mostram que a teoria da Contracção é uma ferramenta importante para
desenhar arquitecturas de controlo estáveis e para analisar o sucesso das missões efec-
tuadas pelo robô como um problema de estabilidade.Portuguese Science and Technology Foundation (FCT) SFRH/BD/68805/2010
Autonomous robot systems and competitions: proceedings of the 12th International Conference
This is the 2012’s edition of the scientific meeting of the Portuguese Robotics Open (ROBOTICA’ 2012). It aims to disseminate scientific contributions and to promote discussion of theories,
methods and experiences in areas of relevance to Autonomous Robotics and Robotic Competitions.
All accepted contributions
are included in this proceedings book. The conference program has also included an invited talk by Dr.ir. Raymond H. Cuijpers, from the Department of Human Technology Interaction of Eindhoven University of Technology, Netherlands.The conference is kindly sponsored by the IEEE Portugal Section / IEEE RAS ChapterSPR-Sociedade Portuguesa de Robótic
Investigating Sensorimotor Control in Locomotion using Robots and Mathematical Models
Locomotion is a very diverse phenomenon that results from the interactions of a body and its environment and enables a body to move from one position to another. Underlying control principles rely among others on the generation of intrinsic body movements, adaptation and synchronization of those movements with the environment, and the generation of respective reaction forces that induce locomotion. We use mathematical and physical models, namely robots, to investigate how movement patterns emerge in a specific environment, and to what extent central and peripheral mechanisms contribute to movement generation. We explore insect walking, undulatory swimming and bimodal terrestrial and aquatic locomotion. We present relevant findings that explain the prevalence of tripod gaits for fast climbing based on the outcome of an optimization procedure. We also developed new control paradigms based on local sensory pressure feedback for anguilliform swimming, which include oscillator-free and decoupled control schemes, and a new design methodology to create physical models for locomotion investigation based on a salamander-like robot. The presented work includes additional relevant contributions to robotics, specifically a new fast dynamically stable walking gait for hexapedal robots and a decentralized scheme for highly modular control of lamprey-like undulatory swimming robots