118 research outputs found
Coordinated multi-robot formation control
Tese de doutoramento. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 201
Dynamic Walking: Toward Agile and Efficient Bipedal Robots
Dynamic walking on bipedal robots has evolved from an idea in science fiction to a practical reality. This is due to continued progress in three key areas: a mathematical understanding of locomotion, the computational ability to encode this mathematics through optimization, and the hardware capable of realizing this understanding in practice. In this context, this review article outlines the end-to-end process of methods which have proven effective in the literature for achieving dynamic walking on bipedal robots. We begin by introducing mathematical models of locomotion, from reduced order models that capture essential walking behaviors to hybrid dynamical systems that encode the full order continuous dynamics along with discrete footstrike dynamics. These models form the basis for gait generation via (nonlinear) optimization problems. Finally, models and their generated gaits merge in the context of real-time control, wherein walking behaviors are translated to hardware. The concepts presented are illustrated throughout in simulation, and experimental instantiation on multiple walking platforms are highlighted to demonstrate the ability to realize dynamic walking on bipedal robots that is agile and efficient
Sistemas de suporte à condução autónoma adequados a plataforma robótica 4-wheel skid-steer: percepção, movimento e simulação
As competições de robótica móvel desempenham papel preponderante na difusão da ciência e da engenharia ao público em geral. E também um espaço dedicado ao ensaio e comparação de diferentes estratégias e abordagens aos diversos desafios da robótica móvel. Uma das vertentes que tem reunido maior interesse nos promotores deste género de iniciativas e entre o público em geral são as competições de condução autónoma. Tipicamente as Competi¸c˜oes de Condução Autónoma (CCA) tentam reproduzir um ambiente semelhante a uma estrutura rodoviária tradicional, no qual sistemas autónomos deverão dar resposta a um conjunto variado de desafios que vão desde a deteção da faixa de rodagem `a interação com distintos elementos que compõem uma estrutura rodoviária típica, do planeamento trajetórias à localização. O objectivo desta dissertação de mestrado visa documentar o processo de desenho e concepção de uma plataforma robótica móvel do tipo 4-wheel skid-steer para realização de tarefas de condução autónoma em ambiente estruturado numa pista que pretende replicar uma via de circulação automóvel dotada de sinalética básica e alguns obstáculos. Paralelamente, a dissertação pretende também fazer uma análise qualitativa entre o processo de simulação e a sua transposição para uma plataforma robótica física. inferir sobre a diferenças de performance e de comportamento.Mobile robotics competitions play an important role in the diffusion of science and engineering to the general public. It is also a space dedicated to test and compare different strategies and approaches to several challenges of mobile robotics. One of the aspects that has attracted more the interest of promoters for this kind of initiatives and general public is the autonomous driving competitions. Typically, Autonomous Driving Competitions (CCAs) attempt to replicate an environment similar to a traditional road structure, in which autonomous systems should respond to a wide variety of challenges ranging from lane detection to interaction with distinct elements that exist in a typical road structure, from planning trajectories to location. The aim of this master’s thesis is to document the process of designing and endow a 4-wheel skid-steer mobile robotic platform to carry out autonomous driving tasks in a structured environment on a track that intends to replicate a motorized roadway including signs and obstacles. In parallel, the dissertation also intends to make a qualitative analysis between the simulation process and the transposition of the developed algorithm to a physical robotic platform, analysing the differences in performance and behavior
Advanced Mobile Robotics: Volume 3
Mobile robotics is a challenging field with great potential. It covers disciplines including electrical engineering, mechanical engineering, computer science, cognitive science, and social science. It is essential to the design of automated robots, in combination with artificial intelligence, vision, and sensor technologies. Mobile robots are widely used for surveillance, guidance, transportation and entertainment tasks, as well as medical applications. This Special Issue intends to concentrate on recent developments concerning mobile robots and the research surrounding them to enhance studies on the fundamental problems observed in the robots. Various multidisciplinary approaches and integrative contributions including navigation, learning and adaptation, networked system, biologically inspired robots and cognitive methods are welcome contributions to this Special Issue, both from a research and an application perspective
Development of a flight control architecture for rotary wing UAVs with model based design approach
This thesis describes the design and implementation of various autopilot software architectures for mini/micro rotary-wing unmanned aerial vehicles by exploiting the modelbased design approach. Nowadays in fact, the tendency for software development is changing from manual coding to automatic code generation, in other words, it is becoming model-based. In general, models can be described as abstractions of systems, they are created to serve particular purposes, for example, to present a user-understandable description of the system or to present information in a more intuitive form. Model-based
techniques for software design enables the engineer to reduce drastically development time required for software corrections or modi�cations. Under the various chapters,
di�erent flight control techniques are presented with theoretical background and tested via simulations and experimental campaigns. All the navigation and control problems presented below arise in development of embedded software that exploits the innovative model-based design technology. In order to provide validations of the proposed solutions, software for simulation and implementation is specialized for the case of multirotor vehicles, which are becoming very helpful systems for many and varied civil operations.
This is the reason why part of the text is devoted to multirotor vehicle dynamics
Practical Issues in Formation Control of Multi-Robot Systems
Considered in this research is a framework for effective formation control of multirobot
systems in dynamic environments. The basic formation control involves two important
considerations: (1) Real-time trajectory generation algorithms for distributed control
based on nominal agent models, and (2) robust tracking of reference trajectories under
model uncertainties.
Proposed is a two-layer hierarchical architecture for collectivemotion control ofmultirobot
nonholonomic systems. It endows robotic systems with the ability to simultaneously
deal with multiple tasks and achieve typical complex formation missions, such as collisionfree
maneuvers in dynamic environments, tracking certain desired trajectories, forming
suitable patterns or geometrical shapes, and/or varying the pattern when necessary.
The study also addresses real-time formation tracking of reference trajectories under
the presence of model uncertainties and proposes robust control laws such that over each
time interval any tracking errors due to system uncertainties are driven down to zero prior to
the commencement of the subsequent computation segment. By considering a class of nonlinear
systems with favorable finite-time convergence characteristics, sufficient conditions
for exponential finite-time stability are established and then applied to distributed formation
tracking controls. This manifests in the settling time of the controlled system being finite
and no longer than the predefined reference trajectory segment computing time interval,
thus making tracking errors go to zero by the end of the time horizon over which a segment
of the reference trajectory is generated. This way the next segment of the reference trajectory is properly initialized to go into the trajectory computation algorithm. Consequently
this could lead to a guarantee of desired multi-robot motion evolution in spite of system
uncertainties.
To facilitate practical implementation, communication among multi-agent systems is
considered to enable the construction of distributed formation control. Instead of requiring
global communication among all robots, a distributed communication algorithm is employed
to eliminate redundant data propagation, thus reducing energy consumption and
improving network efficiency while maintaining connectivity to ensure the convergence of
formation control
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