摘要:

A model is presented which predicts the chip flow direction for nose radius tools with inclination angles. Experimental verification was made in turning that cut on the bars. A comparison of the predicted and experimental results shows excellent agreement, and the results are consistent with previous findings of other workers. The usefulness of the present model is its capacity to predict the chip flow for a given general tool used with any combination of cutting conditions, without any prior knowledge of the work material properties or any machining tests required to determine an empirical formula.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677557

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper presents and compares two systematic and effective approaches for the hydroelectric generation scheduling problem (HSP). The objective of the HSP is to determine the best substitution of hydro energy for thermal energy in electric generation so that the fuel cost is minimized while meeting the system load and constraints. In the first approach, HSP is formulated as an optimal control problem, for which a multiplier method‐based differential dynamic programming algorithm developed by Chen et al. [4] is adopted as the solution algorithm. The second approach exploits the network structure of the water balance relation and takes linear approximation of the first formulation to formulate HSP as a minimum cost, linear network flow problem. Bertsekas and Tsengs’ RELAX code is applied to solve such a large‐scale network optimization problem. Numerical results indicate that both approaches generate results close to TPC's empirical schedules, are efficient in computation and suggest predictive operation strategies. We address the differences between the two approaches in solution optimality and computational efficiency and provide necessary information for tradeoffs in selecting a suitable approach.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677558

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A finite element viscoplastic model with MARC as the tool is used in analyzing forming of a rectangular pan with superplastic Al‐Li 8090. The forming pressure control algorithm is that applied pressure increment is increased according to:

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677559

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In this paper, the full state and output feedback controllers with gains determined using either anH2or anH8–norm optimality criterion are presented. The problem is approached by transforming the frequency domain optimality criteria to the corresponding variational forms in the time domain. The variational approach allows formulation of theH8–optimal control problem without the limitations placed by the orthogonality assumptions. The state feedback gains and the observer gains are determined by solving two special Riccati equations. The tracking and the regulation problems are presented, and a computer algorithm is proposed for determining both the controller gains and the observer gains. The theoretical developments are applied to two examples for illustrative purposes.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677560

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677546

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor