摘要:

AbstractContinuous‐ and discrete‐time differential dynamic programming (DDP) approaches to solve general optimal control problems are described and analysed. A comparison of the two approaches shows the continuous‐time approach to be more general and flexible compared with the discrete‐time approach, since it is not tied to any discretization scheme. A comparison of DDP with the non‐linear programming (NLP) approach is also given. Three structural control problems — a linear model of a space structure, a single degree of freedom non‐linear impact absorber and a non‐linear flexible beam subjected to an impulsive load — are used to numerically evaluate the continuous‐ and discrete‐time DDP approaches. Several grid sizes are used to show that the continuous‐time approach with a reasonable number of grid points is more accurate and efficient (in most cases) than the discrete‐time approach. It is therefore recommended to fully develop and evaluate the technique for the optimal contr

ISSN:0143-2087    

DOI:10.1002/oca.4660150202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractLinear and non‐linear recursive prediction error (RPE) methods have been employed for the purpose of identification of the dynamics of ship rudder—yaw and —roll motions. The evaluations of the goodness of model structures have been carried out by comparing simulated outputs from the identified model with real measurements. In the linear case Nomoto's first‐order model has been initially considered for the transfer functions between rudder—yaw and —sway, with a second‐order model for rudder—roll with coupling effects considered only between sway—yaw and —roll. Identification results have shown that such a model is not appropriate. Changing the model to second‐order between rudder—sway and —yaw and further considering the coupling effects between roll angle—sway and —yaw shows that a significant improvement is achieved, while the coupling effect between yaw and roll appears negligible. In the nonlinear case effects due to various non‐linear terms have been studied wi

ISSN:0143-2087    

DOI:10.1002/oca.4660150203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractA discrete time optimal control for linear time‐delay systems is developed to ensure that all closed‐loop eigenvalues will lie inside a circular region centred at (β;, 0) with radius α. It is shown that by suitable manipulations the problem can be reduced to a standard discrete time quadratic regulator problem. An illustrative example is included to demonstrate the applicability of the proposed m

ISSN:0143-2087    

DOI:10.1002/oca.4660150204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper further develops a methodology for designing fixed order compensators. The formulation uses an approximate loop transfer recovery (LTR) method to achieve performance and stability subject to a disturbance and unstructured uncertainty at either the plant input or the plant output. The approximate LTR methodology has the advantage that the quadratic performance index weighting matrices are uniquely defined. To reduce sensitivity to real parameter uncertainty, the performance index is modified to include a penalty on the closed‐loop sensitivity dynamics. The formulation avoids the explicit introduction of sensitivity states into the performance index and thus does not increase the overall dimension of the problem. An example design for the coupled mass benchmark control problem is provided to demonstrate this methodolog

ISSN:0143-2087    

DOI:10.1002/oca.4660150205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractIn this short communication we present new upper and lower performance bounds of LQ (linear—quadratic) systems with time‐varying parametric uncertainties. These new performance bounds improve on those proposed by Wang and Kuo by giving more accurate measures of performance robustness. We use the same example as that used by Wang and Kuo to show that the improvements are substant

ISSN:0143-2087    

DOI:10.1002/oca.4660150206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThis short communication discusses two recently proposed terrain‐tracking schemes, reformulates both schemes as special cases of a previously proposed optimal aim strategy, outlines a more precise and explicit continuous‐time control law based on a fixed‐point neural network, describes a more rapid and effective discrete‐time control law based on a fixed‐point iteration process, and derives criteria for matching reference models to the dynamical characteristics of individua

ISSN:0143-2087    

DOI:10.1002/oca.4660150207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

ISSN:0143-2087    

DOI:10.1002/oca.4660150201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY