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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...
Path planning for robot manipulators is a complex subject, which is why most research has been restricted to static environments, where off-line path planning is acceptable, and very little work has been done on dynamic environments. On-line path planning is normally based on local algorithms that end up being inefficient due to their lack of global information (local minima problems). In this paper...
This work proposes a globally convergent state estimation method for non-linear discrete-time systems, based on interval techniques. This approach is based on a Moving Horizon State Estimation method and a global optimisation technique by interval arithmetic. This state estimation algorithm provides a solution with global convergence properties, even for non-linear model. The performances of the method...
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...
In this paper we present a sufficient condition for global observability of nonlinear systems on manifolds that generalizes Aeyels' global observability result for Morse-Smale systems. Our main theorem establishes global observability under considerably weaker assumptions than Aeyels' Morse-Smale condition. However, we have to assume additionally real analyticity of the system. With this result at...
In this paper, we propose an architecture for formation reconfiguration of a team of autonomous agents navigating within an obstacle-populated environment. Our approach is based on abstracting the agent formation by a rectangular grid. We develop a coordination strategy that ensures collision-free transitions between arbitrarily defined formations. This coordination strategy is based on a well-established...
We propose a novel method for velocity estimation and detection of a moving object in an image sequence. This purpose is achieved by using discrete wavelet transform and parallel bank of extended complex Kalman filter in the transform/spatio-temporal mixed-domain. In the mixed-domain, image sequence processing is replaced by l-dimensional(l-D) complex signal processing. Then, trajectory signal with...
In this paper, the problem of the determination of the maximal controlled invariant set of linear systems subject to polyhedral input and state constraints, together with the corresponding state-feedback control law is investigated. Instead of computing one-step reachable sets or maximizing the volume of a specific invariant set, the proposed method consists of the iterative expansion of an initial...
This paper describes a solution to the problem of trajectory tracking control of autonomous surface craft (ASC) in the presence of constant ocean currents. The solution proposed is rooted in nonlinear model predictive control (MPC) techniques and addresses explicitly state and input constraints. Whereas state saturation constraints are added to the underlying optimization cost functional as penalties,...
POCP is a new Matlab package running jointly with GloptiPoly 3 and, optionally, YALMIP. It is aimed at nonlinear optimal control problems for which all the problem data are polynomial, and provides an approximation of the optimal value as well as some control policy. Thanks to a user-friendly interface, POCP reformulates such control problems as generalized problems of moments, in turn converted by...
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 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...
We use the behavioural approach to provide definitions and characterisations of invariant zeros of nD systems. In particular we show that the definitions are equivalent in the 1D case to those in the classical literature. We provide new results on the structural relations of nD invariant and transmission zeros.
In this paper we define the second variation at a bang-bang trajectory as the one of the sub-problem obtained by moving the switching times. Under a suitable regularity condition on the Hamiltonian we give an algorithm to test the positivity of the second variation, complete proofs will be contained in a forthcoming paper [2].
A vector-valued impulsive control problem is considered whose dynamics, defined by a differential inclusion, have to satisfy state constraints and are such that the vector fields associated with the singular term do not satisfy the so called Frobenius condition. A concept of robust solution based on a new reparametrization procedure is adopted in order to derive necessary conditions of optimality...
A general question one has to face in the study of an optimal control problem is the representation of the closure of the set of trajectories. Loosely speaking, two main problems lie at the basis of the non triviality of this question: the lack of sufficient convexity assumptions (which is at the origin of the introduction of the so-called chattering controls) and the occurrence of unbounded controls...
The central object of interest of this paper are systems of linear constant coefficient ordinary differential equations of arbitrary order of the form s(d/dt)w = M(d/dt)f with G and M given, but otherwise arbitrary, polynomial matrices. In these equations w and f are vector-valued functions of which f is assumed to be given, while w is the solution to (1) that we are looking for. Alongside (1) we...
The problem of the path generation for the autonomous robot vehicle in environment with stationary and moving obstacles is considered. An algorithm, named MKBC, based on modified Kohonen rule and behavioral cloning is developed. The MKBC algorithm, as improvement of RBF neural network, uses the training values as weighting values, rather then values from the previous time. This enables an intelligent...
Event-based control aims at reducing the communication effort within a control loop by closing the feedback only after events have indicated a substantial control error. This paper presents a method to approximate a continuous state-feedback controller by an event-based controller with reduced communication effort such that the closed-loop system has a comparable performance. The relation between...
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