Many physical systems that occur in applications are naturally passive, for example, mechanical systems with dual sensors and actuators, and electrical circuits with passive components. Taking advantage of this proper...
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Many physical systems that occur in applications are naturally passive, for example, mechanical systems with dual sensors and actuators, and electrical circuits with passive components. Taking advantage of this property, many controller schemes have been proposed with the property that the controller is strictly positive real. Due to design and implementation considerations, the plant or the controller may need to be approximated by a lower-order system. It is highly desirable for the reduced-order system to also possess the positive realness property to guarantee that the resulting closed-loop system remains stable. Motivated by this problem, this paper considers the general model-reduction problem for a positive real system under the constraint that the reduced system is also positive real. We present a solution based on the balanced stochastic truncation. When the higher-order system is strictly positive real, we derive an H(infinity) norm bound on the approximation error. We also consider alternate approaches of approximating the spectral factors with associated H(infinity) norm error bounds. An example is included to show the efficacy of this method and comparison with other approaches.
A series of piecewise multiple general orthogonal polynomials (PMGOPs) is introduced and applied to the parameter identication problem for a class of continuous nonlinear systems. After introducing PMGOPs and discussi...
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A series of piecewise multiple general orthogonal polynomials (PMGOPs) is introduced and applied to the parameter identication problem for a class of continuous nonlinear systems. After introducing PMGOPs and discussing their main properties, an effective procedure for the parameter identification of a large class of continuous systems, called parameter separable systems, is proposed. Some relevant algorithms are presented. The procedure given in the paper has the following advantages compared with other methods: the identification algorithm (IA) obtained is computationally fast and accurate;the IA can be implemented in a recursive fashion;the IA is effective for a small number of data points;the IA does not require a priori knowledge of the estimated parameters;the IA is tolerant to choices of expanding orders when PMGOPs are applied. Some numerical examples, together with an experimental example taken from a biochemical fermentation process, are given for illustrative purposes.
Reactive ion etching is an important process in the fabrication of microelectronic devices. This article reports on work in progress towards developing a strategy for controlling sidewall profile during this process. ...
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Reactive ion etching is an important process in the fabrication of microelectronic devices. This article reports on work in progress towards developing a strategy for controlling sidewall profile during this process. In this strategy, a response surf...
The task of guaranteeing that processes meet their deadlines is one of the most complex in the design of hard real-time controlsystems. This paper describes how process scheduling has been integrated into a framework...
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The task of guaranteeing that processes meet their deadlines is one of the most complex in the design of hard real-time controlsystems. This paper describes how process scheduling has been integrated into a framework of tools for the development of such systems. Functional specifications in the form of control system block diagrams are translated by the Framework into real-time source code which may be executed in a parallel processing environment. The automated off-line scheduling tool takes process specifications from the system under development and attempts to map these processes to the processors in such a way that all the system deadlines are met by using a detailed model of the run-time environment.
In this paper, we present a decoupled parameter estimation (DPE) algorithm for estimating sinusoidal parameters from both one-dimensional (1-D) and two-dimensional (2-D) data sequences corrupted by AR noise. In the fi...
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The robust stability and performance of a binary distillation column model is analysed using a minimal state space representation. The uncertainty modelling of the column is resulted in an LFT form with a four element...
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The robust stability and performance of a binary distillation column model is analysed using a minimal state space representation. The uncertainty modelling of the column is resulted in an LFT form with a four element diagonal block structure taking into account the dependence between the steady state gains. Robust analysis of the distillation column dynamics is performed and compared using µ - and l 1 -analysis tools. The magnitude of possible overshoots is determined by l 1 -test for robust performance and the dependence of this magnitude on the dominant time constant (i.e. the purity of the separation) is investigated. Futhermore the effect of the mi certainties in the time constants and the singular values on the robust performance is also analysed using l 1 -test. It has been found that the uncertainty in the time constants affects dominantly the robust performance of the open-loop system, i.e. the magnitude of possible overshoots.
This paper describes how the RELAX algorithm can be used for angle and waveform estimation of narrowband plane waves arriving at a uniform linear array in the presence of spatially colored noise. The RELAX algorithm i...
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In this paper, we describe the manufacturing testbed we have built to investigate the implementation of RW supervisors on programmable logic controllers (PLC). We discuss the modeling of the testbed and the design of ...
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In this paper, we describe the manufacturing testbed we have built to investigate the implementation of RW supervisors on programmable logic controllers (PLC). We discuss the modeling of the testbed and the design of its controllers. Finally, we present several theorems for verifying controllability and nonblocking on large systems.
In this paper, new theoretical and simulated results for the robust adaptive servomechanism problem considered in Miller and Davison (1987, 1992) for unknown MIMO systems are given. As in Miller and Davison (1989) and...
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In this paper, new theoretical and simulated results for the robust adaptive servomechanism problem considered in Miller and Davison (1987, 1992) for unknown MIMO systems are given. As in Miller and Davison (1989) and Chang and Davison (1995) the proposed controller is nonlinear and of the switching type, and has the properly that after a finite time, switching ceases, thereby resulting in the system being controlled by a LTI controller. The switching mechanism which the authors present is robust to all bounded piecewise continuous references y/sub ref/(t) and disturbances w(t), attempts to provide a "reasonable" transient response by "monitoring" plant output y(t) and/or error signal e(t), and, while limited to strictly proper finite dimensional MIMO systems, is computationally simpler than for the case of continuous reference and disturbance signals.
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