摘要:

We consider in this paper the existence and numerical estimation of the distributed control of a nonlinear wave equation with an integral performance criterion and fixed final states. The problem is modified into one consisting of the minimization of a linear form over a set of pairs of positive measures satisfying linear constrains. The minimization in the new problem is global and can be approximated by a finite-dimensional linear programming problem. The solution of this problem is used to construct a nearly optimal control. An example is given to illustrate the procedure.

ISSN:0020-7179    

DOI:10.1080/00207179608921683

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A mixedH2/H∞control problem is formulated and solved for tracking control systems. The control problem, which combinesH2andH∞performance criteria, can be applied to the design of compensators which achieve robust tracking performance in the presence of plant uncertainties. The optimal mixedH2/H∞tracking controller has a separation property similar to those of linear quadratic andH∞tracking controllers, and its solution consists of anH∞-optimal state feedback tracking control problem and an associated mixedH2/H∞-optimal estimation problem.

ISSN:0020-7179    

DOI:10.1080/00207179608921684

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

TheH∞mixed sensitivity with measurement noise problem is considered for the scalar case using a polynomial description. The problem results in a 4-block general distance scalar problem which is solved in a general way by using a polynomial equation approach. As an example, the solution is then applied to the mixed sensitivity with measurement noise problem where all relevant simplifications are carried out. The solution requires solving two spectral factorization problems and one linear polynomial equation. Further, new insight into the connections with the Nehari problem is provided.

ISSN:0020-7179    

DOI:10.1080/00207179608921685

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper presents a sequential identification scheme for continuous nonlinear dynamical systems using neural networks. The nonlinearities of the dynamical systems are assumed to be unknown. The identification model is a gaussian radial basis function neural network that grows gradually to span the appropriate state space and of sufficient complexity to provide an approximation to the dynamical system. The sequential identification algorithm for continuous dynamical nonlinear systems is developed in the continuous-time framework instead of in discrete time. The approach, different from the conventional methods of optimizing a cost function, attempts to ensure stability of the overall system while the neural network learns the system dynamics. The stability and convergence of the overall identification scheme are guaranteed by parameter adjustment laws developed using the Lyapunov synthesis approach. To ensure that the modelling error can be reduced arbitrarily, a one-to-one mapping is proposed so that the states and inputs of the system are transferred into compact sets. The operation of the sequential identification scheme is illustrated using simulated experimental results.

ISSN:0020-7179    

DOI:10.1080/00207179608921686

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper presents a fast algorithm for the design of robust output feedback controllers for linear uncertain discrete-time systems. The algorithm utilizes a version of the Broyden-Fletcher-Goldfarb-Shanno (BFGS) optimization method of conjugate directions and minimizes a performance index that includes a linear quadratic regulator (LQR) term to optimize performance and a robustness term based on recently developed bounds. The minimization of only the robustness term which corresponds to the maximization of the uncertainty bound is also studied. The case of unstructured perturbations inAhas been the only one studied in the robust controller design literature; the present algorithm introduces a unified approach to both cases of unstructured and structured perturbations in the matrices of a state-space model. For the special case of unstructured perturbations inAonly, the algorithm is shown to improve considerably the existing unstructured uncertainty bound. Several examples, including an aircraft control system and a paper-machine head box, are presented to illustrate the results.

ISSN:0020-7179    

DOI:10.1080/00207179608921687

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The paper describes the development of a weighted minimum-variance control law with application to single-input single-output systems in which the control is applied at a slower rate than the available measurements of the plant output signal. The theory is extended to incorporate dynamic compensation in the controller and to encompass generalized system models. A time-domain modelling approach is employed, whereby the system dynamics and sampling operations are defined as a series of cyclically time-varying difference equations. The technique, in which the cost functions penalize both the control and a set of output signals, generates straightforward expressions for the closed-loop characteristic polynomial and is accordant with pole-placement synthesis methods. The control law suffers from similar difficulties with respect to non-minimum phase systems as its single-rate counterpart.

ISSN:0020-7179    

DOI:10.1080/00207179608921688

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

An adaptive regulator of the minimum-variance type in the presence of disturbance uncertainly is considered in the paper. Supposing a linear ARMAX model of the single input-single output system, a robustified direct adaptive control algorithm is derived using the robust statistical approach named M-estimation. The derived algorithm differs from the conventional linear algorithms by the insertion of a suitably chosen nonlinear transformation of the prediction error, which has to cut off the large noise realizations named outliers. The global stability of the proposed control system and self-optimizing property of the adaptive regulator is established theoretically using the martingale theory. The feasibility of the approach is demonstrated with simulation.

ISSN:0020-7179    

DOI:10.1080/00207179608921689

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Properties of flexible structures in modal and balanced coordinates are derived. From these properties the root-mean-square law of the Hankel singular values is obtained. It says that the squares of the Hankel singular values of a set of sensors and actuators is approximately a root-mean-square sum of the squares of the Hankel singular values for each individual sensor and actuator. This property allows us to evaluate each actuator and sensor in terms of the joint controllability and observability, and to serve as a tool of the actuator and/or sensor placement methodology.

ISSN:0020-7179    

DOI:10.1080/00207179608921690

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The paper explains two general and complementary concepts of system design that have direct relevance to the theory and design of control systems: the principle of matching and the method of inequalities. One aim of the paper is to supplement, clarify and unify the ideas and explanations contained in previous publications. To this end, the essential ideas are presented in their simplest forms to make the paper also serve the purposes of an introduction and a review of the field. Another aim is to discuss the effects of the concepts on the foundations of the control theory, without neglecting the practical aspects of design.

ISSN:0020-7179    

DOI:10.1080/00207179608921691

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper presents a computational method for generating time-optimal control (TOC) trajectories for robotic point-to-point motions. The algorithm is composed of two phases: initialization and refinement. In the initialization phase, a two-point boundary value problem (TPBVP) resulting from the perturbed TOC problem is solved for an appropriately chosen perturbation parameter. The solution obtained from the initialization phase is then refined by solving a set of initial value problems (IVPs) sequentially and/or in parallel until the desired solution is achieved. The proposed two-phase method is computationally efficient since the resulting TPBVP is solved onlyone timeand the remaining problem becomes solutions to a set of IVP subproblems. The algorithm was used to investigate the effects of robot parameters on the TOC structure through computer simulations on an example robot system with different motion configurations, including both regular and singular trajectories.

ISSN:0020-7179    

DOI:10.1080/00207179608921692

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor