State-of-the-art, uni-processor algebraic Riccati equation solvers for automatic control computations are investigated and compared for various problem sizes. General-purpose SLICOT solvers are very efficient for smal...
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ISBN:
(纸本)0780395670
State-of-the-art, uni-processor algebraic Riccati equation solvers for automatic control computations are investigated and compared for various problem sizes. General-purpose SLICOT solvers are very efficient for small-size problems, but they cannot compete for larger problems with specialized solvers designed for certain problem classes, such as Newton solvers using low rank Cholesky factors of the solutions of Lyapunov equations built at each iteration.
This paper concerns a mode-sequencing and switching-time optimization problem defined on autonomous switched-mode hybrid dynamical systems. The design parameter consists of two elements: (i) the sequence of dynamic-re...
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ISBN:
(纸本)0780395670
This paper concerns a mode-sequencing and switching-time optimization problem defined on autonomous switched-mode hybrid dynamical systems. The design parameter consists of two elements: (i) the sequence of dynamic-response functions associated with the modes, and (ii) the duration of each mode. The sequencing element is a discrete parameter which may render the problem of computing the optimal schedule exponentially complex. Therefore we are not seeking a global minimum, but rather a local solution in a suitable sense. To this end we endow the parameter space with a local continuous structure which allows us to apply gradient-descent techniques. With this structure, the problem is cast in the form of a nonlinear-programming problem defined on a sequence of nested Euclidean spaces with increasing dimensions. We characterize suboptimality in an appropriate sense, define a corresponding convergence criterion, and devise a provably-convergent optimization algorithm.
An attempt of combining the efficiency of problem-oriented numerical algorithms with the generality of mesh methods is made. The automatic procedure of decomposition of complicated waveguide structures is developed. I...
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ISBN:
(纸本)078392613
An attempt of combining the efficiency of problem-oriented numerical algorithms with the generality of mesh methods is made. The automatic procedure of decomposition of complicated waveguide structures is developed. It takes into account peculiarities of the given problem (symmetries, uniformity and so on) and tries to find out the best possible solution. Presented approach is successfully applied to create the electromagnetic simulator Microwave Desktop 2 (MWD 2). It allows one to solve a wide range of electromagnetic problems from analysis to optimization.
In this paper, Pareto optimal strategy for general multiparameter singularly perturbed systems is investigated. The main contribution is to propose a new computational method for obtaining the high-order Pareto near-o...
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In this paper, Pareto optimal strategy for general multiparameter singularly perturbed systems is investigated. The main contribution is to propose a new computational method for obtaining the high-order Pareto near-optimal strategy. Newton's method and two fixed point algorithms are combined. As a result, the new iterative algorithm achieves the quadratic convergence property and succeeds in reducing the computing workspace dramatically. It is newly shown that the resulting optimal strategy achieves the cost functional J j * + O (||μ|| 2 i ).
State-of-the-art, uni-processor linear matrix equation solvers for automatic control computations are investigated and compared for various problem sizes. General-purpose SLICOT solvers are the most efficient ones for...
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State-of-the-art, uni-processor linear matrix equation solvers for automatic control computations are investigated and compared for various problem sizes. General-purpose SLICOT solvers are the most efficient ones for small-size problems, but they cannot compete for larger problems with specialized solvers designed for certain problem classes.
An interval analysis approach for the design of robust state feedback controllers is proposed. It is shown that when regional pole placement specifications are represented as spectral sets of interval polynomials, the...
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An interval analysis approach for the design of robust state feedback controllers is proposed. It is shown that when regional pole placement specifications are represented as spectral sets of interval polynomials, the robust state feedback design problem can be entirely formulated and solved in the context of the concepts and methods of interval analysis. Explicit convex polyhedral representations of a class of robust state feedback controllers satisfying an interval Ackerman's equation are derived. A design procedure based on nonlinear programming which aims at maximizing the non-fragility of the resulting robust controller is introduced. numerical examples illustrate the design of robust state feedback controllers through the interval analysis approach proposed.
This paper presents a strategy to find an optimal gait for the model of the biomimetic swimmer developed at Caltech to transit forward minimizing control effort, or the integral of squared angular acceleration of the ...
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This paper presents a strategy to find an optimal gait for the model of the biomimetic swimmer developed at Caltech to transit forward minimizing control effort, or the integral of squared angular acceleration of the two joints. According to the previous works, it is accepted that a series of sinusoidal-type gaits generates forward transition. Using this sinusoidal gaits as initial guess for optimization, improved gaits are found using a numerical optimization software, NLPP Toolbox for Matlab. The performance of the determined gaits is tested using the Simulink model.
The Bezout equation over the rings of proper stable rational functions and matrices is studied in this paper. First, a relationship between the rational Bezout equation and a combined serial/parallel interconnection o...
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The Bezout equation over the rings of proper stable rational functions and matrices is studied in this paper. First, a relationship between the rational Bezout equation and a combined serial/parallel interconnection of linear systems is established. The controllability and observability properties that this scheme has to fulfill in order the Bezout equation to be satisfied yield a numerical procedure for finding a particular solution of the concerned equation. This routine is usable for problems of small-to-medium size as demonstrated by numerical experiments.
Purpose: We have designed and implemented a new stereotactic machine QA test. The method is used to characterize gantry sag, couch wobble, cone placement, MLC offset and room lasers position relative to radiation isoc...
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Purpose: We have designed and implemented a new stereotactic machine QA test. The method is used to characterize gantry sag, couch wobble, cone placement, MLC offset and room lasers position relative to radiation isocenter. An image containing a series of test patterns is generated in a direct and integrated fashion. Method and Materials: Two MLC star patterns, a cone pattern and the laser lines are recorded on the same imaging medium, enabling 0.1 mm accuracy measurements. Phosphor plates are used as the imaging medium due to their unique property that the red light of wall laser erases the radiation information stored on phosphor plates. The room lasers position relative to the radiation isocenter can be measured. The developed QA method consists of four images that measure the gantry sag between 0 0 and 180 0 gantry angles, the position and stability of couch rotational axis, the sag between 90 0 and 270 0 gantry angles, the accuracy of cone placement on the collimator and the position of laser lines relative radiation isocenter. Results: The inherent precision of the numerical algorithms developed is +/− 0.05mm. The inherent accuracy of the method as a whole is +/− 0.1mm. The total irradiation/illumination time is about 10 min per image. Automating the generation of collimator star patterns can reduce this time. The data analysis (including the phosphor plate scanning) is less than 5min. Conclusion: The presented method reproducibly characterizes the radiation isocenter geometry with the high accuracy required for stereotactic surgery. It can replace the standard ball test and it can provide a highly accurate QA procedure for the non-stereotactic machines.
Model problems of aircraft tracking are considered for the case when an aircraft moves in the horizontal plane under conditions of uncertainty in measurements of its geometric coordinates. Estimation of the phase stat...
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Model problems of aircraft tracking are considered for the case when an aircraft moves in the horizontal plane under conditions of uncertainty in measurements of its geometric coordinates. Estimation of the phase state is implemented by means of the informational sets. The results of numerical constructing the informational sets in the three- and four-dimensional phase spaces are discussed.
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