89 research outputs found
Experiences of formation control of multi-robot systems with the Null-Space-based Behavioral Control
Mechanical design and position control of a modular mechatronic device (MechaCell)
Manufacturing techniques have advanced exponentially in recent years, providing means for production of smaller and more powerful electronics, which makes it compelling to design small and more powerful robots. Our work focuses on a mechanical design and position control of a modular mechatronic device called MechaCell. Mechacells are designed as modular semi-autonomous devices which can be used alone or part of a pack. In this paper our main focus is on the mechanical design of the Mechacell, especially the locomotion system which uses forces produced by a rotating unbalance that moves in a spherical domain for steering of the Mechacell. As part of the supervisory algorithm an overhead HD camera is used for position tracking of the Mechacell; the data is then sent to the Mechacells through a wireless connection. A proportional integral derivative controller is used as a base controller; then a friction compensation algorithm is added, based on the mathematical model of the Mechacell's locomotion system. Steering and locomotion controller of the Mechacell is validated using a complex motion profile in the developed testbed. © 2015 IEEE
Conference on Intelligent Robotics in Field, Factory, Service, and Space (CIRFFSS 1994), volume 1
The AIAA/NASA Conference on Intelligent Robotics in Field, Factory, Service, and Space (CIRFFSS '94) was originally proposed because of the strong belief that America's problems of global economic competitiveness and job creation and preservation can partly be solved by the use of intelligent robotics, which are also required for human space exploration missions. Individual sessions addressed nuclear industry, agile manufacturing, security/building monitoring, on-orbit applications, vision and sensing technologies, situated control and low-level control, robotic systems architecture, environmental restoration and waste management, robotic remanufacturing, and healthcare applications
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
Motion Coordination of Aerial Vehicles
The coordinated motion control of multiple vehicles has emerged as a field of major interest in the control community. This thesis addresses two topics related to the control of a group of aerial vehicles: the output feedback attitude synchronization of rigid bodies and the formation control of Unmanned Aerial Vehicles (UAVs) capable of Vertical Take-Off and Landing (VTOL). The information flow between members of the team is assumed fixed and undirected. The first part of this thesis is devoted to the attitude synchronization of a group of spacecraft. In this context, we propose control schemes for the synchronization of a group of spacecraft to a predefined attitude trajectory without angular velocity measurements. We also propose some velocity-free consensus-seeking schemes allowing a group of spacecraft to align their attitudes, without reference trajectory specification. The second part of this thesis is devoted to the control of a group of VTOL-UAVs in the Special Euclidian group SE(3), i.e., position and orientation. In this context, we propose a few position coordination schemes without linear-velocity measurements. We also propose some solutions to the same problem in the presence of communication time-delays between aircraft. To solve the above mentioned problems, several new technical tools have been introduced in this thesis to overcome the deficiencies of the existing techniques in this field
Planejamento de movimento de sistemas robóticos de intervenção subaquática baseado na teoria dos helicoides
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia MecânicaOs veÃculos subaquáticos não tripulados (ou UUV, do inglês Unmanned Underwater Vehicles) são responsáveis pela execução de grande parte das operações em ambientes imersos. Os sistemas veÃculo-manipulador subaquáticos (ou UVMS, do inglês Underwater Vehicle-Manipulator Systems) são UUV voltados para a execução de tarefas de intervenção. Além de aplicações em missões cientÃficas e de resgate, os UVMS são muito usados em instalações offshore de extração/distribuição de petróleo e gás em tarefas de construção, manutenção, inspeção e operação. A maioria dos sistemas de intervenção subaquática é teleoperada devido à s dificuldades de operação no ambiente imerso e à s caracterÃsticas cinemáticas e dinâmicas dos UVMS. A evolução desses sistemas de intervenção subaquática envolve o desenvolvimento de sua autonomia. Um requisito básico para isso é a capacidade do sistema planejar as ações necessárias para realizar as tarefas a ele especificadas. Esta tese estuda o planejamento de movimento dos UVMS durante a execução de tarefas de intervenção. Este problema consiste em definir os movimentos que o sistema (veÃculo e manipuladores) deve realizar para executar as tarefas especificadas atendendo à s restrições impostas pelo espaço de trabalho. O trabalho utiliza a análise cinemática baseada na teoria dos helicoides, teoria dos grafos e ferramentas derivadas para definir modelos cinemáticos dos UVMS em diferentes cenários de execução de tarefas de intervenção. A cooperação entre manipuladores de um mesmo UVMS e entre dois ou mais UVMS é estudada, assim como a variabilidade dos modelos cinemáticos em função de mudanças no contexto da operação. A partir da análise realizada, define-se uma sistematização da modelagem cinemática dos sistemas de intervenção por componentização, visando facilitar e automatizar esse processo. Um framework computacional é projetado para facilitar a implementação desses modelos. Com base nesses resultados, define-se uma estrutura geral para o desenvolvimento de estratégias de planejamento de movimento. Simulações de uso dessa estrutura em diferentes cenários de operação são apresentadas. Assim, este trabalho contribui para a autonomia de UUV/UVMS, considerada o principal objeto de pesquisa da área e que no caso dos sistemas de intervenção subaquática reduzirá custos de operação, além de possibilitar o uso destes em novas missões.Unmanned Underwater Vehicles (UUV, for short) are used in most immerse operations. Underwater Vehicle-Manipulator Systems (UVMS, for short) are a particular kind of UUV designed for intervention tasks. Besides their application in scientific and rescue missions, UVMS are much used in offshore oil and gas extraction/distribution facilities for construction, maintenance, inspection and operation tasks. Most underwater intervention systems are teleoperated due the operational difficulties in the immerse environment and the UVMS kinematic/dynamic features. The evolution of these underwater intervention systems involves the development of their autonomy. The system ability to plan the necessary actions to perform its assigned tasks is a basic requirement for that. This thesis studies the motion planning of UVMS while executing intervention tasks. The problem consists of defining the motion that the system (vehicle and manipulators) must do to execute the specified taks while complying with the workspace imposed restrictions. A computational framework is designed to aid the implementation of these models. A general structure to the developed of motion planning strategies based on these results is defined. Simulations using this strucute in different operation scenarios are presented. So, this work contributes to the autonomy of UUV/UVMS, which is considered a major research field and it will reduce operation costs of underwater intervention systems, besides allowing their use in new missions
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