摘要:

This work addresses the problem of minimum-time control (MTC) for rigid robotic manipulators with point-to-point motion subject to 'hard' constraints on the control torques. A hamiltonian canonical formulation of the robot dynamic equations is used. A perturbation-based transformation algorithm is applied to solve this category of the MTC problem. In this algorithm, the original MTC problem, possibly a partially singular one, is converted into a totally non-singular optimal control problem by introducing a perturbed energy term into the original objective functional. It is shown that in the limiting case the solution to the transformed problem is convergent to that of the original MTC problem. The numerical solutions to several example manipulators are presented to verify the theoretical result on the structure of the MTC law. Some of the characteristics of the resulting optimal trajectories are analyzed by using a dynamic scaling approach. The result provides new insight into the dynamic characteristics of robot arms, pertaining to both path planning and design specifications.

ISSN:0020-7179    

DOI:10.1080/00207179308934376

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A robust control procedure for precision pointing and tracking of fast moving elastic structures is proposed. Based on a combination of the sliding manifold approach with the theory of optimal interpolation, this design procedure generates a control effort capable of insuring high pointing and tracking performance in the presence of induced disturbances and modelling uncertainties. The uncertainties are handled by sliding control and estimation of the nonlinearly excited elastic elastic dynamics by an interpolator of the structure dynamic response. Chattering behaviour of the controller is avoided at the expense of tolerating a known tracking error. It is shown through analysis that a trade-off has to be set, by taking into account the main requirements of a given mission and the system hardware capabilities. For illustration purposes, a set of numerical simulations is then run to assess the system dynamical performance.

ISSN:0020-7179    

DOI:10.1080/00207179308934377

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We define the combination of the standard reduced-order observer with one-step-ahead state predictor as the prediction-type reduced-order observer. We first obtain a simple and significant relation that ensures the equivalence of the reduced and the full-order observers in the steady state. We show the fact that a prediction-type reduced-order does not always provide a reduced-order controller. We also discuss the implications of the equivalence of the observers on state-space representation of the doubly-coprime factorization and YJB parametrization. We use the equivalence relation to clarify the feedback properties achieved by the loop transfer recovery technique using the prediction-type reduced-order observer at both the input and output of a square and minimum phase plant. In addition, we discuss the computational requirements for the observer-based controllers.

ISSN:0020-7179    

DOI:10.1080/00207179308934378

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The local linearization approach to nonlinear filtering of time series generated from continuous time stochastic dynamical systems is discussed and a simple and powerful method for the nonlinear filtering is introduced. Some numerical results of applications of the filter are shown.

ISSN:0020-7179    

DOI:10.1080/00207179308934379

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An identification method for highly nonlinear processes is proposed based on a multi-model approach and Kolmogorov-Gabor polynomials. Owing to the large number of possible terms in this general model structure, the significant terms are selected by several statistical test procedures leading automatically to a minimal-order model realization. The performance of this method is evaluated in an in-depth case study using a simulated pHneutralization process. The effects of important variables such as range of operating conditions, signal-/noise-ratio, and data length are discussed.

ISSN:0020-7179    

DOI:10.1080/00207179308934380

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In this paper, we address the design of adaptive dynamical feedback strategies of the continuous and discontinuous types, for the output stabilization of nonlinear systems. The class of systems considered corresponds to nonlinear controlled systems exhibiting linear parametric uncertainty. Dynamical feedback controllers, ideally achieving output stabilization via exact linearization, are obtained by means of repeated output differentiation and, either, pole placement, or, sliding mode control techniques. The adaptive versions of the dynamical stabilizing controllers are then obtainable through standard, direct, overparametrized adaptive control strategies available for linearizable systems. Illustrative examples which deal with the regulation of electro-mechanical systems are provided.

ISSN:0020-7179    

DOI:10.1080/00207179308934381

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A two-Riccati state-space approach to the discrete-time H∞ control problem is presented. The main theoretical tool is the Kalman-Szego-Popov-Yakubovich system written in adequate forms in order to reduce the problems to a standard form for which the solutions are easily obtained. The necessity part of our main results uses a 'signed' counterpart of the positivity theorem.

ISSN:0020-7179    

DOI:10.1080/00207179308934382

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An algorithm that estimates the attracting basin boundary for a stable equilibrium point of a nonlinear system has been developed. This boundary is an important characterization of the global properties of a nonlinear dynamic system. The algorithm begins with a convex polytope that is entirely within the region of attraction and that surrounds the stable equilibrium point. The basin boundary of this stable equilibrium point is then approximated by a (possibly non-convex) polytope whose vertices are generated by integrating vertices of the initial polytope backwards in time. An accuracy test is applied on facets of the latter polytope. If any facet fails the test, then the approximation is refined by adding more vertices and facets to both the initial convex polytope and the final polytope. Three examples are presented to demonstrate the method. Examples include a third-order PID control system, a fourth-order balancing acrobot system, and a fourth-order lateral/directional aircraft system. For the PID position control system and for the acrobot, known limit cycles on the basin boundaries are plotted along with the approximate polytope boundary to show the reduced conservatism of the approximation. The algorithm can work with any order system, but computation time and memory requirements can grow rapidly with the state-space dimension.

ISSN:0020-7179    

DOI:10.1080/00207179308934383

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The errors in variables problem is that of parameter estimation where all observed variables are corrupted by noise. So far, the computation of parameter bounds for dynamical models has been performed using equation-error and output-error approaches. In this paper, parameter bounds for autoregres-sive-moving-average-exogenous (ARMAX) models are derived on the assumption that both input and output are affected by bounded noise. Parameter bounding by both the ‘bounded equation error’ and the ‘bounded errors-in-variables’ approach is outlined, together with the approximation of the feasible parameter region by an orthotope outer-bounding set, and is tested on simulated data.

ISSN:0020-7179    

DOI:10.1080/00207179308934384

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In this paper, two main results for uncertain time-delay systems are derived. The first result is the presentation of a new robust stability criterion for uncertain time-delay systems. The second result is the successful application of the concept of variable structure control to the stabilization problem of uncertain time-delay systems. The robustness and stability degree of perturbed systems in the sliding mode are also discussed. Last, some examples are included to illustrate our results.

ISSN:0020-7179    

DOI:10.1080/00207179308934385

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor