A good model is essential in simulating and analyzing a system satisfactorily. This paper proposes a new computer-aided modelling methodology to construct parsimonious models for dynamic physical systems. A set of dom...
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A good model is essential in simulating and analyzing a system satisfactorily. This paper proposes a new computer-aided modelling methodology to construct parsimonious models for dynamic physical systems. A set of domain-independent modelling principles and domain-dependent modelling constraints has been formulated to guide parsimonious model construction. Models and the knowledge base for the enhancement of models have been described by bond graphs. After a parsimonious model is generated, two types of qualitative analysis are conducted;one is to derive unknown states from known states and the other is to predict the effects of parameter changes on the whole system. This methodology is only applicable when the structure of a dynamic system is known beforehand. A detailed case study is presented to demonstrate this approach.
An approach for the modelling and motion planning of a mobile manipulator system with a non-holonomic constraint is presented in this paper. The Newton-Euler equations are used to obtain the complete dynamics of the s...
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An approach for the modelling and motion planning of a mobile manipulator system with a non-holonomic constraint is presented in this paper. The Newton-Euler equations are used to obtain the complete dynamics of the system. Given the trajectory of the end-effector of the manipulator, near-optimal trajectories for the mobile platform and manipulator joints are obtained by using an efficient genetic algorithm with torque and manipulability optimisation and obstacle avoidance. Various simulations of a platform with a 3-link onboard manipulator are presented to show the effectiveness of the presented method.
In this paper the general problem of output regulation when dealing with nonlinear MIMO systems is presented. In this context, normal forms for nonlinear systems are of great importance. Two normal forms for MIMO nonl...
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In this paper the general problem of output regulation when dealing with nonlinear MIMO systems is presented. In this context, normal forms for nonlinear systems are of great importance. Two normal forms for MIMO nonlinear systems are presented. The first one reveals the relative degrees vector and can be applied for square invertible systems (classic normal form), while the second can be used for non square systems and gives details on the system invertibility properties (recent normal form). The necessary conditions for solving the output regulation problem for the classical normal form and, respectively, the recent normal form are presented. From this discussion it results that the problem can be solved under weaker assumptions if considering the later form (obtained by using the infinite zero structure algorithm). This approach also permits discussing the regulation problem for non square MIMO systems.
Stabilizing allocations in coalitional games with transferable utility are studied within the framework of uncertain and dynamic stochastic systems. We assume that the excess of allocations relative to the evolution o...
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The purpose of this work is to present a method for rigid registration of medical images using 1D binary projections when a part of one of the two images is missing. We use 1D binary projections and we adjust the proj...
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The purpose of this work is to present a method for rigid registration of medical images using 1D binary projections when a part of one of the two images is missing. We use 1D binary projections and we adjust the projection limits according to the reduced image in order to perform accurate registration. We use the variance of the weighted ratio as a registration function which we have shown is able to register 2D and 3D images more accurately and robustly than mutual information methods. The function is computed explicitly for n=5 Chebyshev points in a [-9,+9] interval and it is approximated using Chebyshev polynomials for all other points. The images used are MR scans of the head. We find that the method is able to register the two images with average accuracy 0.3degrees for rotations and 0.2 pixels for translations for a y dimension of 156 with initial dimension 256. For y dimension 128/256 the accuracy decreases to 0.7 degrees for rotations and 0.6 pixels for translations.
Phase shift is very important in the frequency response analysis of non-linear systems and in this paper the phase response function is analysed and interpreted to provide a clear understanding of phase. Non-linear sy...
Phase shift is very important in the frequency response analysis of non-linear systems and in this paper the phase response function is analysed and interpreted to provide a clear understanding of phase. Non-linear systems which include delay elements are also discussed and simulations of both continuous and discrete time non-linear systems are included to demonstrate the concepts involved.
This paper refers to the fast implementation of the positional forward acceleration of the end effector of revolute robotic arms with spherical wrists, using the distributed arithmetic technique. The acceleration of t...
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This paper refers to the fast implementation of the positional forward acceleration of the end effector of revolute robotic arms with spherical wrists, using the distributed arithmetic technique. The acceleration of the end effector is calculated by a cascade configuration of two pipelined arrays that calculate the Jacobian matrix and its time derivative, as well as the centrifugal-Coriolis and linear accelerations. These partial accelerations are then added in the adder tree. The building blocks of the arrays are the distributed arithmetic-based circuits that implement the matrix-vector multiplications involved in the calculations. The digit-serial configuration of the proposed implementation of the positional forward acceleration of the end effector is described. The serial and the parallel configurations may result as special cases of the digit-serial configuration. The proposed distributed arithmetic (DA) implementation of the positional forward acceleration may be applied, after appropriate modifications, to the general case of robots having either revolute or prismatic joints, with any type of wrist.
The most common approach to multivariate fuzzy control is to extend the single-variable case by combining more state-variable pairs. This approach, however, results in high-dimensional rule-bases that may not be imple...
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The most common approach to multivariate fuzzy control is to extend the single-variable case by combining more state-variable pairs. This approach, however, results in high-dimensional rule-bases that may not be implementable in practical systems. Typically, for each additional state variable, the number of rules increases exponentially. Clearly, the number of rules, even for systems of moderate complexity, becomes impractical in real-time, due to the required processing time. This paper proposes and implements a simplified structure for a multi-variable fuzzy controller, which also reduces the total number of rules. This approach is suitable for machine-learning applications since different rules can be derived to infer the correct control actions, dependent on the controller structure and the way in which the input variables have been paired. The number of rules using this approach is minimal and is a linear function of the number of the state inputs. Furthermore, no fuzzification/defuzzification scaling factors are required for the controllers in intermediate levels of composition. The methodology is demonstrated on an anaesthesia simulation case study.
This paper presents a new method for synthesising decoupling controllers for linear time-invariant multivariable systems. The novel approach proposed is based on the idea of formulating, and subsequently solving, the ...
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This paper presents a new method for synthesising decoupling controllers for linear time-invariant multivariable systems. The novel approach proposed is based on the idea of formulating, and subsequently solving, the decoupling problem as an exact model-matching problem. This, in effect, results in reducing the decoupling problem to one of solving a linear system of equations.
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