The Calculus of Variations and Optimal Control
The Calculus of Variations and Optimal Control
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变分计算和最优控制
DOI:
10.1115/1.3139697
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发表时间:
1982
影响因子:
1.7
通讯作者:
D. Hrovat
中科院分区:
文献类型:
--
作者:
G. Leitmann;D. Hrovat
As its title alludes, the book is divided into two major parts: calculus of variations (Part I), and optimal control (Part II). This chronological division appears quite natural, so that Part II builds nicely on the more classical material presented in the first 73 pages. The first part treats only the simple problem of the calculus of variations, where the functional extremization is limited to integral functionals with fixed initial and final times. Furthermore, the associated integrands contain only the scalar dependent variablex (t) and its derivative x (t). These constraints as well as others are relaxed in the second part of the book which also includes the treatment of statedependent control constraints and nonautonomous systems. The second part is based on the author's original contribution to the field of optimal control viewed through the geometrical approach developed in his work with Professor Blaquiere. 2 Major theoretical developments are illustrated via augmented,(«+ l)-dimensional state-space where the (n+ l)-st axis is closely associated with the cost functional. It should be pointed out that only the deterministic optimal control problem is discussed in the book, so that, for example, the well-known LQG (Linear-Quadratic-Gaussian) theory is devoid of its" G-part" and the associated duality between the optimal regulator and Kalman-Bucy filter. A more detailed account of each chapter is now given below. The first three chapters develop the celebrated Euler's necessary conditions for weak local minima of integral functionals. Included in these chapters is a detailed treatment of the Euler-Lagrange equation and its associated special forms. Chapter 4 addresses an interesting inverse problem: given a second-order ordinary differential equation (candidate for the Euler-Lagrange equation) find the corresponding stationality principle. The necessary conditions for strong local minima (Weierstrass conditions) and necessary conditions under the assumption of smooth extremals (Jacobi's conditions) are introduced in Chapters 5 and 6, respectively. The first part ends with the Erdmann-Weierstrass corner conditions which must be met by piecewise smooth extremals.