摘要:

Computer based methods are developed for the analysis, synthesis and design of linear compensators for a wide class of single-loop non-linear feedback systems characterized by a separable non-linear element of any general multivalued form. Preliminary analysis is performed in the complex frequency domain applying approximate analytical methods to predict and quantify possible modes of limit cycle operation. Graphical displays are used to determine initial compensator structure which will ensure the avoidance of the critical region in this domain. Subsequently, a numerical synthesis procedure is applied to adjusting the compensator parameters to meet a set of additional time domain functional subject to specified system constraints and, if possible, the absence of autonomous limit-cycle operation.

ISSN:0020-7721    

DOI:10.1080/00207728708967171

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The two-time technique is employed to obtain the solution of interconnected systems with fifth-degree non-linearity. Expressions for the amplitude and phase of periodic solutions are derived explicitly to the first order of approximation. The stability analysis of the solutions is carried out by Lyapunov's first method. The analytical results are verified by means of digital simulation.

ISSN:0020-7721    

DOI:10.1080/00207728708967172

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In the design of a control system, the derivative controller is often required to obtain a quick response. However, when the control system is subject to noise inputs, the functioning of the derivative controller may be jeopardized owing to its sensitivity to high-frequency noise. In order to overcome this problem, a new type of controller, called the proportional-integral-minus-delay (PIMD) controller is proposed in this paper. It is shown that in addition to exhibiting almost the same characteristics as the conventional proportional-plus-integral-plus-derivative (PID) controller, the PIMD controller is less sensitive to high-frequency noise. It seems that an appropriate PIMD controller would be a good replacement for a PID controller. The output time responses of the closed-loop system with a PIMD controller and the frequency-response characteristics of a PIMD controller are obtained by computer simulation.

ISSN:0020-7721    

DOI:10.1080/00207728708967173

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The paper proposes an input-output-waste (I-O-W) model as an extension of the input-output model to incorporate waste management (WM) aspects in national planning. The waste aspects have not been explicitly considered in the existing literature on input-output economics. It is visualized that in the economic structure the waste parameter has a significant role to play, and the I-O-W model will be a closer representation of the economy than that of conventional input-output models. Any unnecessary input to or any undesirable output from the system is considered as waste. The basic framework of an I-O-W model is presented, which consists of a technology matrix, a final-demand matrix, and a WM policy matrix. The resource balance has been established by treating the input to be equal to the sum of output and waste. The technological coefficients are interlinked by wastivity indices. The projections of a hypothetical economy consisting of one production sector and one WM sector have been determined for material resources and for different WM policies.

ISSN:0020-7721    

DOI:10.1080/00207728708967174

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The MRAC is applied to the control of an electrohydraulic system controlled by a solenoid valve. The adaptive algorithms proposed in this paper guarantee the asymptotic stability of the error between the plant output and that of the reference model. The robustness properties of the adaptive control system are examined based on the concept of a tuned system—an ideal converged (non-adaptive) closed-loop system when the gain of the valve is varying non-linearly. A modified adaptive law that guarantees the tracking error will be bounded in a residual region is proposed. The performance improvement is also studied by implementing the ternary mode solenoid valve. To illustrate the validity, the simulation results of a gun turret position control system are also included.

ISSN:0020-7721    

DOI:10.1080/00207728708967175

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The existing methods for estimating continuous-time MIMO linear dynamic models are mostly confined to the use of so-called indirect methods. However, such methods are possible only for those models that are parametrized in some special canonical forms, which usually do not embody the physical meaning of dynamic systems. Furthermore, the conversion from the discrete-time model to its corresponding continuous-time form is usually subject to limitations, and the results thus obtained are vague owing to the existence of stochastic noise. To circumvent the difficulties mentioned, a method that directly estimates the continuous-time MIMO linear dynamic model using hybrid parametrization is proposed. In this method, the continuous-time model can be parametrized according to the description of the physical system and then a discrete-time realization, which includes the parametrization of the stochastic noise, is formed as the basis for parameter estimation. This method is capable of estimating linear dynamic systems where both input disturbance and measurement noise, exist. It is also attempted to apply this method using the data from closed-loop operations for parameter estimations. Some numerical examples that enable comparison of the results thus obtained with those of some other methods are also included.

ISSN:0020-7721    

DOI:10.1080/00207728708967176

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Some solutions which involve iterative optimization techniques are given to improve adaptation transients in adaptive systems. Two suboptimal controllers are developed and applied to an equivalent discrete-time system valid for describing the behaviour of a recent adaptive control scheme when one of the (time-varying) parameters entering the adaptation algorithm varies within a closed domain admissible from a convergence point of view. The resulting suboptimal control strategies are translated into corrections of this parameter in order to recompute the adaptation algorithm over a finite horizon. Some numerical simulations illustrate the usefulness of the proposed scheme.

ISSN:0020-7721    

DOI:10.1080/00207728708967177

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In this paper, a dynamic simultaneous-equation model is developed, based on the flexible accelerator theory of investment, for describing and forecasting U.S. government investments. The dynamic model consists of five behavioural equations and eight identities, is estimated from quarterly data during the period 1963 through 1983 by the full-information maximum-likelihood method, and is tested for its validity and forecasting ability. The direction and magnitude of the impacts of shifts in the policy and non-policy exogenous variables are identified and discussed. In particular, the model's forecasting performance is assessed against the regression model originally proposed by Lin and an optimal forecasting model. It is concluded that the dynamic model improves the reliability and accuracy of forecasting.

ISSN:0020-7721    

DOI:10.1080/00207728708967178

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This study demonstrates the use of control engineering techniques to regulate the product inventory levels of a workshop in a manufacturing system by manipulating the number of machines and the labour time employed during production. The production policy that minimizes the production time is obtained by time-optimal control techniques.

ISSN:0020-7721    

DOI:10.1080/00207728708967179

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A new approach, based on non-linear time-delay estimation, is described for estimating the elevation angle in the combined presence of specular multipath and receiver noise—a situation that is encountered in the low-angle tracking radar environment. Estimation of the elevation angle is accomplished using the time delay between the signals impinging on the antenna array elements. Thus, the accuracy in the elevation angle estimation is dependent on the accuracy of the time-delay estimation algorithm. The formulation of the problem enables one to find the desired estimates independently of the reflection coefficient, which is a significant result. In the proposed approach, a newly derived non-linear filter due to the author (1986) is used. The filter structure is estimated using the Pontryagin minimum principle and the method of invariant imbedding, and is used to find an estimate for the delayed and undelayed signal. Subsequently, the time delay and the elevation angle are estimated.

ISSN:0020-7721    

DOI:10.1080/00207728708967180

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor