Abstract To improve the modelling performance, one should either propose new modelling methodologies or make the best of existing models. In this paper, the study is concentrated on the latter solution, where a struct...
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Abstract To improve the modelling performance, one should either propose new modelling methodologies or make the best of existing models. In this paper, the study is concentrated on the latter solution, where a structure-free modelling paradigm is proposed to combine various modelling techniques in ‘symbiosis’ using a ‘master fuzzy system'. This approach is shown to be able to include the advantages of different modelling techniques altogether by minimising efforts relating optimisation of final structure. The proposed approach is then successfully applied to predict machining induced residual stresses for aerospace alloy components as well as mechanical properties of heat-treated alloy steels.
In this paper, the modules for the conceptual design of an innovative e-learning platform using satellite communications for teaching controlsystems theory courses are presented. All necessary tools and mechanisms ar...
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In this paper, the modules for the conceptual design of an innovative e-learning platform using satellite communications for teaching controlsystems theory courses are presented. All necessary tools and mechanisms are provided enabling real time text, and audio/video based communication between tutors and learners. The end-user driven services include: virtual classroom, offline operation, sharing of applications, private/ public chatting, audio/video streaming. A concise description of the pilot architecture which depends on the DVB-RCS standard is presented justifying further the choice of the proposed platform. Simulation results concerning the teaching of fundamental issues in Networked control Theory within the proposed architecture are provided. Connections with hybrid configurations such as wireless terrestrial broad-band technologies (DVB-RCS/WiMAX, DVB-RCS/Wi-Fi) are further justified.
Safety analysis is a key activity for the development of railway transportation systems. The analysis is used not only to determine whether new systems do not expose the general public to unduly high levels of risks, ...
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Safety analysis is a key activity for the development of railway transportation systems. The analysis is used not only to determine whether new systems do not expose the general public to unduly high levels of risks, but also to inform the development process itself through identification and allocation of appropriate requirements. Whilst inadequate and inaccurate safety analysis may have potentially catastrophic consequences, it is rarely validated in practice. This paper presents a case for validation of safety analysis of the railway systems along with a technical approach to such validation. The approach is based on the concept of Failure Injection and the Lightweight Refinement relation. The paper further argues that the safety analysis validation should be embedded in a wider uncertainty management framework and shows how this can be made consistent with the spirit of the existing safety standards of the railway domain.
In this paper, the distributed robust output regulation problem of linear multi-agent systems (MAS) is considered. The driving force from the active leaders or the environmental disturbances is formulated as an input ...
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In this paper, the distributed robust output regulation problem of linear multi-agent systems (MAS) is considered. The driving force from the active leaders or the environmental disturbances is formulated as an input of an exogenous system (or exosystem) of the considered multi-agent networks. A systematic distributed design approach is proposed to handle output regulation via dynamic output feedback with the help of canonical internal model (IM). With common solutions of regulator equations and Lyapunov functions, the distributed robust output regulation with switching interconnection topology is designed to achieve collective aims.
The central goal in multiagent systems is to design local control laws for the individual agents to ensure that the emergent global behavior is desirable with respect to a given system level objective. Ideally, a syst...
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ISBN:
(纸本)9781612848006
The central goal in multiagent systems is to design local control laws for the individual agents to ensure that the emergent global behavior is desirable with respect to a given system level objective. Ideally, a system designer seeks to satisfy this goal while conditioning each agent's control law on the least amount of information possible. Unfortunately, there are no existing methodologies for addressing this design challenge. The goal of this paper is to address this challenge using the field of game theory. Utilizing game theory for the design and control of multiagent systems requires two steps: (i) defining a local objective function for each decision maker and (ii) specifying a distributed learning algorithm to reach a desirable operating point. One of the core advantages of this game theoretic approach is that this two step process can be decoupled by utilizing specific classes of games. For example, if the designed objective functions result in a potential game then the system designer can utilize distributed learning algorithms for potential games to complete step (ii) of the design process. Unfortunately, designing agent objective functions to meet objectives such as locality of information and efficiency of resulting equilibria within the framework of potential games is fundamentally challenging and in many case impossible. In this paper we develop a systematic methodology for meeting these objectives using a broader framework of games termed state based potential games. State based potential games is an extension of potential games where an additional state variable is introduced into the game environment hence permitting more flexibility in our design space. Furthermore, state based potential games possess an underlying structure that can be exploited by distributed learning algorithms in a similar fashion to potential games hence providing a new baseline for our decomposition.
This paper presents a vision-tracking for mobile robots, which tracks a moving target based on robot motion and stereo vision information. The proposed system controls pan and tilt actuators attached to a stereo camer...
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This paper presents a vision-tracking for mobile robots, which tracks a moving target based on robot motion and stereo vision information. The proposed system controls pan and tilt actuators attached to a stereo camera, using the data from a gyroscope, robot wheel encoders, pan and tilt actuator encoders, and the stereo camera. Using this proposed system, the stereo camera always faces the moving target. The developed system calculates the angles of the pan and tilt actuators by estimating the relative position of the target with respect to the position of the robot. The developed system estimates the target position using the robot motion information and the stereo vision information. The movement of the robot is modeled as the transformation of the frame, which consists of a rotation and a translation. The developed system calculates the rotation using 3-axis gyroscope data and the translation using robot wheel encoder data. The proposed system measures the position of the target relative to the robot, combining the encoder data of pan and tilt actuators and the disparity map of the stereo vision. The inevitable mismatch of the data, which occurs from the asynchrony of the multiple sensors, is prevented by the proposed system, which compensates for the communication latency and the computation time. The experimental results show that the developed system achieves excellent tracking performance in several motion scenarios, including combinations of straights and curves and climbing of slopes.
Assembly and disassembly processes are similar from the viewpoint of automation. Assembly process is more or less a “classical” subject; disassembly process is more a quite new field. Flexible system are very import...
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Assembly and disassembly processes are similar from the viewpoint of automation. Assembly process is more or less a “classical” subject; disassembly process is more a quite new field. Flexible system are very important issue in the current industry when disassembling and recycling tasks have to be performed. These tasks can be performed by a human operator or by a robot system. In this paper an autonomous robot with manipulator system perform the required task for different operation. This system takes into consideration the necessary task to perform the disassembly of a component using robots synchronization with flexible line process. The proposed algorithm is to distribute the task among the robot and flexible line and takes into consideration the characteristics of each sequence that needs to be followed to perform the required disassembly of the product. The proposed system is validated by experiments using several types of components.
In this paper a sliding-mode observer for a class of non-linear systems is proposed. The observer is based on the equivalent control method. The mathematical tools required to design such an observer are also presente...
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In this paper a sliding-mode observer for a class of non-linear systems is proposed. The observer is based on the equivalent control method. The mathematical tools required to design such an observer are also presented. The proposed scheme can ensure finite time convergence of the observer and the reduction of chattering effect due to relay-type correction terms. Several examples are presented to illustrate the proposed method.
Electrical Impedance Tomography (EIT) has been the subject of intensive research since its development in the early 1980s by Barber and Brown at the department of Medical Physics and Clinical engineering, Hallamshire ...
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ISBN:
(纸本)9789898425355
Electrical Impedance Tomography (EIT) has been the subject of intensive research since its development in the early 1980s by Barber and Brown at the department of Medical Physics and Clinical engineering, Hallamshire Hospital in Sheffield (UK). In particular, pulmonary measurement has been the focus of most EIT related research. One of the relatively recent advances in EIT is the development of an absolute EIT system (aEIT) which can estimate absolute values of lung resistivity and lung volumes. However, there is still active research in the area of validating and improving the accuracy and consistency of the aEIT estimation of lung volumes towards characterising the system as suitable for clinical use. In this paper we present a new approach based on Computational Intelligence (CI) modelling to model the 'Resistivity - Lung Volume' relationship that will allow more accurate lung volume predictions. Eight (8) healthy volunteers were measured simultaneously by the Sheffield aEIT system and a Spirometer and the recorded results were used to develop subject-specific Neural-Fuzzy models able to predict absolute values of lung volume based only on absolute lung resistivity data. The developed models show improved accuracy in the prediction of lung volumes, as compared with the original Sheffield aEIT system. However the interindividual differences observed in the subject-specific modelling behaviour of the 'Resistivity-Lung Volume' curves suggest that a model extension is needed, whereby the modelling structure auto-calibrates to account for subject (or patient-specific) inter-parameter variability.
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