The authors present a magnetic heading system consisting of two fluxgate magnetometers and a single-chip microcomputer. The system, when compared to gyro compasses, is smaller in size, lighter in weight, simpler in co...
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The authors present a magnetic heading system consisting of two fluxgate magnetometers and a single-chip microcomputer. The system, when compared to gyro compasses, is smaller in size, lighter in weight, simpler in construction, quicker in reaction time, free from drift, and more reliable. Using a microcomputer in the system, heading error due to compass deviation, sensor offsets. scale factor uncertainty, and sensor tilts can be compensated with the help of an error model. The laboratory test of a typical system showed that the accuracy of the system was improved from more than 8 degrees error without error compensation to less than 0.3 degrees error with compensation.< >
This paper describes some possible applications of Artificial Intelligence methods in controlengineering. Due to the restriction of AI methods to well-defined knowledge domains (expert systems), the growing interest ...
This paper describes some possible applications of Artificial Intelligence methods in controlengineering. Due to the restriction of AI methods to well-defined knowledge domains (expert systems), the growing interest in fuzzy control methods and the possible application of simple neural networks, a large number of applications in all areas of technical science came into consideration. The recent availability of adequate software and lately also of special purpose hardware tools has accelerated this development.
A number of results have been presented recently on the statistical performance of the multiple signal characterization (MUSIC) and the maximum-likelihood (ML) estimators for determining the direction of arrival of na...
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A number of results have been presented recently on the statistical performance of the multiple signal characterization (MUSIC) and the maximum-likelihood (ML) estimators for determining the direction of arrival of narrowband plane waves using sensor arrays and the related problem of estimating the parameters of superimposed signals from noisy measurements. It is shown that in the class of weighted MUSIC estimators, the unweighted MUSIC achieves the best performance (i.e. the minimum variance of estimation errors) in large samples. The covariance matrix of the ML estimator is derived, and detailed analytic studies of the statistical efficiency of MUSIC and ML estimators are presented. These studies include performance comparisons of MUSIC and MLE with each other as well as with the ultimate performance corresponding to the Cramer-Rao bound (CRB).< >
In this paper we attempt to propose a method for preference degree analysis in multiobjective decisionmaking problems(MDMPs), called the multiple factor analysis method based on a hierarchical analysis model. The conc...
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In this paper we attempt to propose a method for preference degree analysis in multiobjective decisionmaking problems(MDMPs), called the multiple factor analysis method based on a hierarchical analysis model. The concept of preference degree(PD) is first discussed. Here a PD is used as a measurement for describing preference information of decision makers (DMs) to some value of an objective. A hierarchical model for analyzing the preference information is then deduced by defining objective domain of discourse (ODD), fuzzy degree domain of discourse (FDDD), factor domain of discourse (FDD) and sensitivity vector. Furthermore, some methods are explored for analyzing DMs* PDs of objective values according to a single factor and multiple factors, respectively. At last, an example is briefly introduced.
Auto-tuners for PID controllers have now been commercially available for a few years. These controllers are automating the task normally performed by an instrument engineer. The auto-tuners include some technique for ...
Auto-tuners for PID controllers have now been commercially available for a few years. These controllers are automating the task normally performed by an instrument engineer. The auto-tuners include some technique for extracting process dynamics from experiments and some control design method. They may even be able to select to use PI or PID control. For a higher degree of automation it is desirable to also automate tasks normally performed by process engineers. To do so it is necessary to provide the controllers with reasoning capability. This seems technically feasible with the increased computing power that is now available in single loop controllers. This paper describes a PID controller with such reasoning capabilities.
A program package, called MICRON, has been developed to offer a user-friendly implementation tool for multivariable controllers and control strategies on microcomputers. It can be used for the development and testing ...
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A program package, called MICRON, has been developed to offer a user-friendly implementation tool for multivariable controllers and control strategies on microcomputers. It can be used for the development and testing of control algorithms in simulated control systems and in real-time applications. The package can be used for low-cost automation projects as well as for educational purposes. The paper deals with the version of MICRON running on the IBM-PC with the Real Time Forth environment RTF. To implement control algorithms and control strategies in MICRON, it is necessary to describe the algorithm or strategy by means of a block structure which can be created at several levels. To start with, the user is provided with some elementary blocks. New blocks can be created connecting these elementary blocks, using the MICRON language. Once new blocks have been created they can be used as building blocks for new and more sophisticated blocks. So a block structure can be created with an increasing level of complexity in a structural and flexible way. There are various predefined blocks providing simple controllers, simple linear process models, signal generators, nonlinear functions, delays, vector and matrix operations. The number of elementary blocks is not fixed but can be expanded by programming in Forth, the implementation language of MICRON.
Necessary and sufficient conditions for the bivariate characteristic polynomial of a matrix to be a very strict Hurwitz polynomial (VSHP) are presented. These conditions are based on solving the Lyapunov equation for ...
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Necessary and sufficient conditions for the bivariate characteristic polynomial of a matrix to be a very strict Hurwitz polynomial (VSHP) are presented. These conditions are based on solving the Lyapunov equation for 2-D continuous systems using the Kronecker product and lead a simple test for the VSHP property. It requires testing only the eigenvalues of three stable matrices, which is simpler than the existing polynomial tests.< >
The majority of researchers in the field of bifurcation theory have applied powerful techniques such as normal forms method to study the richness of dynamics in chemical reactions. The catastrophe theory has been appl...
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The majority of researchers in the field of bifurcation theory have applied powerful techniques such as normal forms method to study the richness of dynamics in chemical reactions. The catastrophe theory has been applied together with singularity theory to understand the complex feature of multiplicity in the equilibrium states of numerous systems, but the main results have been obtained via the linearized equations in the time domain. In this paper we show that frequency domain analysis can be carried out via the known closed-loop feedback configurations. Both types of elementary bifurcations, Hopf or dynamic and limit point or static, are checked with the same formula in the frequency domain, which is a natural way to consider those phenomena. The formulation in the frequency domain generally simplifies the problem because the system's order is reduced. We show examples of chemically reacting systems with their order's reduction and their bifurcation curves in a plane of parameters. The algorithm is very simple for finding by "continuation" the bifurcation curves which separate domains with the same local stability, and it provides a method to detect higher order degeneracies. First we consider the single, irreversible, exothermic reaction A→B that takes place in a continuous stirred tank reactor (CSTR) with extraneous thermal capacitance. We show some typical configurations of limit cycles (oscillations) and their stability analysis. Moreover we consider the two consecutive, first order, irreversible, exothermic reactions A→B→C that take place in a CSTR. The results are presented by plotting the bifurcation curves in a three dimensional space, one for a state variable (equilibrium point) and the other for the main and auxiliary parameters. The stability of limit cycles emerging from dynamic bifurcations is given in the same plot and the projections of static bifurcation curves on the plane of parameters give us the singular catastrophe set.
Let P be a convex set of real polynomials. Consideration is given to the question of when there exists a real polynomial b(s), or, more generally, a real transfer function b(s), such that p(s)/b(s) is strictly positiv...
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Let P be a convex set of real polynomials. Consideration is given to the question of when there exists a real polynomial b(s), or, more generally, a real transfer function b(s), such that p(s)/b(s) is strictly positive real for all p(s) in P. Necessary and sufficient conditions are found for the transfer function case, and when the degree of the polynomials in P is restricted, such conditions are also found for the polynomial b(s) case. Closely related results are also obtained for a z-transform version of the problem. The results have application in adaptive systems.< >
Consideration is given to the problem of evaluating optimized control schedules for a class of multi-source and multi-reservoir water supply systems. The systems are characterized by having only fixed speed pumps and ...
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Consideration is given to the problem of evaluating optimized control schedules for a class of multi-source and multi-reservoir water supply systems. The systems are characterized by having only fixed speed pumps and by weak hydraulic interactions. For these systems the major operating costs are associated with electricity charges for pumped source supplies and with the operation of treatment plants. A complete theory of a solver for the optimal scheduling problem is presented. Numerical results of the solver application to Yorkshire Water Grid are shown and discussed.
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