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This paper addresses the problem of stabilization of linear systems subject to both model uncertainties, additive disturbance and input limits. A design technique, based both on the solution of a r-parameterized family of Riccati equations and the use of the S-procedure, is proposed to compute a piecewise linear state feedback control law. The links and tradeoffs between tolerance to the additive...
This paper presents the design, development and implementation of a Hybrid Adaptive Fuzzy Controller (HAFC) suitable for real-time industrial applications. The developed HAFC consists of a weighted combination of the Direct Adaptive Fuzzy Controller (DAFC) and Indirect Adaptive Fuzzy Controller (IAFC) and a gradually activated supervisory controller. The unique feature of the HAFC is that no mathematical...
In this paper the trajectory tracking control problem for a certain class of propagation processes modeled as Quasi-Linear Parameter Varying systems is considered. The propagation physical models are generally described by means of PDEs (partial differential equations). However in real world control problems the PDE models are usually converted into ODEs (ordinary differential equations) models adopting...
Nonlinear optimal control problems, in which state trajectories are permitted to be discontinuous at a finite number of times, and the jump times are choice variables, are analysed. Problems such as these arise in economics, lazer technique, and robototechnique. Necessary conditions for optimality, in the form of a Maximum Principle, for the impulse optimal control problems with general terminal and...
In many applications of motion control, problems associated with imprecisely measured or changing load (mass or moment of inertia) constitute a serious obstacle in the design of satisfactory controlling systems, more and more often compelling the introduction of various forms of uncertainties to engineering solutions. This paper deals with the time-optimal control for mechanical systems with uncertain...
Given paper presents practically a question statement on the possibility of unpredictable behaviour of the car. In the state space of the linearized model an untypical attractor is revealed which is similar to the Lorenz strange attractor generating an unregular trajectory behaviour. It is shown an opportunity of getting the complete conformity with the Lorenz system for which a strange attractor...
This paper presents the synthesis of a control law which guarantees asymptotic stability for a wheeled mobile robot under slip conditions subject to both constraints and system dynamics. This control law is obtained using Linear Matrix Inequalities. The improvements provided by the pro- posed adaptive control are compared with other control laws, dealing with slip effect, through simulation.
In this paper, an optimization-based iterative learning control approach is presented. Given a desired trajectory to be followed, the proposed learning algorithm improves the system performance from trial to trial by exploiting the experience gained from previous repetitions. Taking advantage of the a-priori knowledge about the systems dominating dynamics, a data-based update rule is derived which...
An optimal tracking controller design approach for non-linear non minimum-phase systems based on the concept of modified optimal control is presented. We extend the existing design strategy of modified optimal control to non-linear time-variant systems, since tracking a desired trajectory results in a time-variant non-linear system for the tracking error. We obtain an optimal control law which achieves...
This paper describes a hybrid control scheme to swing-up a pendulum mounted on a cart (cart-pole system) or on another pendulum (pendubot system). Switches between equilibria of the actuated link are used to swing-up the free link. It is argued that this hybrid design is robust and versatile, considerably simplifies the closed-loop analysis, and is well-suited for performance optimization.
This paper reports a complete formulation of a model predictive control strategy having guaranteed nominal asymptotic stability. The formulation includes a successive linearisation procedure to obtain a linear model from a non-linear plant model. It gives a complete state-space derivation including long-range prediction, trajectory tracking and modelling of both measured feedforward disturbances and...
By using robust control techniques, this paper proposes an adaptive control for rigid robots with the following important features: under a parameter-dependent PE (Persistent Excitation) condition, it gives a guaranteed transient performance of tracking a smooth desired trajectory while assuring the parameter estimation error to go to a residual set of the origin arbitrarily fast. Simulations are...
One of the most important problems in nonlinear H∞ control is how to solve its main equation i.e., HJI equation. We propose two new and efficient methods to solve this problem in state feedback set up, based on state dependent Riccati equation. Superiority of these suggested methods in comparison with some methods proposed before is shown through computer simulations.
This paper considers the impulsive-smooth behavior of a switched system interconnection described by the first-order kernel representation. The switched interconnection consists of past and future trajectories which are switched at a certain instant by an external switching mechanism. We derive necessary and sufficient conditions for the concatenability of the past and future behaviors both in the...
In this note we extend the design tool presented in [6] for robust stabilization of nonminimum-phase nonlinear systems to the case of output regulation problems. As in [6] we take advantage from a design tool known in the linear literature as “vibrational feedback” to handle the presence of unstable zero dynamics in output regulation problems in presence of uncertainties. This work frames in a research...
This paper attempts to provide a tutorial mode presentation of a time-optimal transfer problem in the geometric framework. The control objective is to change both the orientation and position of a ball sandwiched between two plates in minimum time. The lower plate is fixed and the upper plate can be actuated in two lateral directions. In the geometric framework, the problem of time-optimal reorientation...
This paper discusses the usage of direct methods of calculus of variations for real-time optimization of a final turn-into-the-wind maneuver for autonomous guided parafoil-based delivery systems. It reviews several approaches that are currently being pursued by different developers of such systems and discusses the necessity of usage and applicability of a direct method to optimize the final turn...
This paper examines the capturability of a guidance law that provides a desired angular acceleration of the heading angle to a pursuer. The guidance law has originally been proposed by Fajen and Warren[13], in order to explain the behavior of walking humans. It is shown that the relative rotational motion between a pursuer and an evader can be represented by an equation similar to the equation of...
A novel optimal control algorithm incorporating a cost structure implied by quantity discounts is applied to a differential equation model of an inventory system. Rather than using a demand forecast, this approach is intended to regulate the system in real time in response to inventory variations. Some examples illustrate how the system response is generated and how it is affected by quantity discounts...
A smooth trajectory generator useful in motion control systems is presented. The considered generator is a second order nonlinear system which receives as input a standard reference signal (step, ramp, etc.) and provides as output a smooth reference signal satisfying proper nonlinear constraints on the state variables as, for example, bounds on the first time-derivative x of the output x, or bounds...
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