摘要:

A new aircraft geometric height computation system based on a secondary surveillance radar (SSR) and an omni-directionat radar has recently been presented. One interesting aspect of this system is that it employs a simple analytical method to estimate and compensate for observable systematic errors, mainly created by the aircraft transponder. Herein, this off-line processing algorithm is extended to cover non-level flights by augmenting the aircraft vertical motion model.

ISSN:0020-7721    

DOI:10.1080/00207729408928985

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A robust tracking controller for rigid-link electrically driven (RLED) robot manipulators operating in free-space or under motion constraints is introduced. Using models of the robot dynamics and environmental constraints, a dynamic model with decoupled position and force degrees of freedom is obtained for the mechanical subsystem with respect to a set of task-space coordinates. A robust tracking control is then formulated for the decoupled manipulator dynamics and the electrical actuator dynamics, which yields a global uniform ultimate bounded (GUUB) stability result for the position and velocity tracking error. The controller is robust with respect to parametric uncertainties and additive bounded disturbances in the RLED dynamic model. The controller requires measurement of the robot link positions, link velocities, and motor armature currents.

ISSN:0020-7721    

DOI:10.1080/00207729408928986

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Two approaches are examined for the design a pulse width modulated (PWM) feedback control scheme regulating a full bridge buck converter in both stabilization and AC signal tracking tasks. The first approach is based on a direct strategy for the specification of a static PWM feedback control which accomplishes asymptotic stabilization to a preselected constant operating point for the output capacitor voltage. The same approach is also examined for the asymptotic output tracking of AC reference signals. The second approach, or indirect approach, proposes a dynamical feedback regulation scheme based on input inductor current stabilization or tracking using reference signals obtained via partial inversion of the system dynamics. The indirect approach emphasizes the use of Fliess' generalized observability canonical form of the average converter model.

ISSN:0020-7721    

DOI:10.1080/00207729408928987

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We consider the stability and design of the general non-symmetric Hopfield neural network. The stability of equilibria is analysed through the linearized system and a stability criterion is derived. Bounds of the equilibria are obtained and can be used to start off iterative processes in the computation of the equilibria. The design problem is shown to be equivalent to an inverse eigenvalue problem and is analysed using pole assignment techniques in control theory. The novel and efficient algorithm for the design of Hopfield neural networks with a given equilibrium is then presented. Two illustrative examples are given.

ISSN:0020-7721    

DOI:10.1080/00207729408928988

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A Kalman filter based image tracking algorithm is developed. When target is locked, a Kalman filter model is utilized to track the target under a partially shaded manoeuvring path and a set of invariant features of homomorphic skew-ness and kurtosis, which are derived from the spectrum histogram of the target image, is used to check whether the target has breaklocked or not in every image frame during the tracking phase. Another set of invariant features derived from the geometrical shape of the target image is used as checking indices. After simulations, we find that the tracking algorithm combining the Kalman filter model with the invariant features of skewness and kurtosis has a good performance even at a signal to noise ratio as low as 0·4 dB.

ISSN:0020-7721    

DOI:10.1080/00207729408928989

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The performance of hypercube architectures depends on the topology of the problem being solved. Specifically, they are unsuitable for knowledge-based applications where global data access is very often required. In this work, a new architecture is proposed that can be used in such applications. The proposed architecture uses both the shared memory and the distributed memories. In this architecture, shared memory is connected to the basic hypercubes using multistage interconnection networks (MINs). In this analysis, the Omega network is considered. When global memory and distributed memories are used, multiple copies of shared data deteriorate the system performance because of data invalidation traffic in the network, and the coherency implementation overhead. Maintaining single copies of the shared data can eliminate the invalidation traffic and the coherency related activities. However, the single copies are to be dynamically moved using a data movement policy to serve the memory references. Analytical modelling of data movement policies is developed using Markov chains. The performance measures of the proposed architecture are compared with that of hypercube architecture. The analysis includes measures for the proposed architecture with different basic hypercube sizes and compares them. In all cases, these measures demonstrate that the architecture is better than the traditional hypercube architecture for any given number of processing elements.

ISSN:0020-7721    

DOI:10.1080/00207729408928990

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A new idea of approximating a high order linear system by a low order model generated via a nearby non-minimal system in the parameter space is suggested. The approximation criterion is established on the basis of the topological notions called near-uncontrollability and near-unobservability. To obtain a joint measure for these two ‘abilities’, the parameter symmetric realizations and parametric balanced realizations are defined. Some theoretical results concerning the problems of parameter symmetrization, parametric balancing and near-uncontrollability/near-unobservability decomposition are derived. A model reduction algorithm based on these results is proposed with an illustrative example.

ISSN:0020-7721    

DOI:10.1080/00207729408928991

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Two stochastic models on the growth of software errors under an imperfect debugging environment are discussed. The errors that are introduced into the software during the developmental phase are called primary errors, and these are assumed to be distributed according to a non-homogeneous Poisson process. Imperfect debugging of primary errors generates further errors, called secondary errors, into the system. These secondary errors are assumed to be generated according to a cluster point process. Two types of cluster point processes are considered, the Neyman-Scott and the Bartlett-Lewis cluster processes. The mean value functions for the number of primary and secondary errors are developed for both models and we use these to obtain some important reliability measures. We also develop a cost model and obtain its corresponding optimal release policies. Finally, we discuss parameter estimation based on the criterion of maximum likelihood and present a numerical example.

ISSN:0020-7721    

DOI:10.1080/00207729408928992

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In the integral manifold approach, the dynamical behaviour of a non-linear singularly perturbed system is captured geometrically by the rapid approach of the fast system states to the design manifold and remaining on the manifold thereafter. A globally stabilizing composite feedback control, i.e. the sum of a slow control and a fast control, is proposed for a general class of non-linear singularly perturbed systems with fast actuators such that the design manifold becomes an exact slow integral manifold and the trajectories of the closed-loop systems, starting from any initial states, are steered along the integral manifold to the origin, i.e. the original non-linear singularly perturbed system is globally asymptotically stabilized.

ISSN:0020-7721    

DOI:10.1080/00207729408928993

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The widely used integral-equation approach for identification of continuous systems is investigated. Attention is focused on the initial condition problem which has been puzzling many researchers. A new calculation procedure for the multiple integrations of the system signal derivatives is proposed and a new integral-equation approach is proposed for which the initial conditions need not be identified as unknown parameters. Therefore, the burden of the identification algorithms can be greatly reduced compared to conventional methods. Discussions on the unification of the integral-equation approach with the other methods are also provided.

ISSN:0020-7721    

DOI:10.1080/00207729408928994

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor