A class of one-dimensional parabolic optimal boundary control problems is considered. The discussion includes Neumann, Robin, and Dirichlet boundary conditions. The reachability of a given target state in final time is discussed under box constraints on the control. As a mathematical tool, related exponential moment problems are investigated. Moreover, based on a detailed study of the adjoint s...

The problem of maintaining acceptable performance of a perturbed control system during a disruption of the feedback signal is addressed. The objective is to maximize the time during which performance remains within desirable bounds without feedback, given that the parameters of the controlled system are within a specified neighborhood of their nominal values. The existence of an optimal open-lo...

It is well-known that a system with linear structure subjected to bounded control inputs for optimal closed-loop control yields nonlinear feedback of discontinuous bang-bang type. This paper investigates new types of nonlinear feedback in the case of optimal impulsive closedloop control which may naturally generate discontinuous trajectories. The realization of such feedback under impulsive inp...

Nonstationary queueing networks are notoriously difficult to analyze and control. One reason is that steady state analysis and techniques are not useful since the model parameters in practice are not constant and depend on time. In this work, we analyze two optimal control problems for nonstationary Jackson networks with abandonment where our main goal is to optimally control the number of serv...

The problem of maintaining acceptable performance of a perturbed control system under conditions of feedback failure is considered. The objective is to maximize the time during which performance remains within desirable bounds without feedback, given that the parameters of the controlled system are within a specified neighborhood of their nominal values. It is shown that there is an optimal ope...

A method is proposed to cool down atoms in a harmonic trap without phase-space compression as in a perfectly slow adiabatic expansion, i.e., keeping the same populations of instantaneous levels in the initial and final traps, but in a much shorter time. This may require that the harmonic trap become transiently an expulsive parabolic potential. The cooling times achieved are shorter than those ...

Point-to-point fast hand movements, often referred to as ballistic movements, are a class of movements characterized by straight paths and bell-shaped velocity profiles. In this paper we propose a bang-bang optimal control policy that can achieve such movements. This optimal control policy is accomplished by minimizing the L∞ norm of the jerk profile of ballistic movements with known initial po...

In this article we formulate frictionless atom cooling in harmonic traps as a time-optimal control problem, permitting imaginary values of the trap frequency for trasient time intervals during which the trap becomes an expulsive parabolic potential. We show that the minimum time solution has “bang-bang” form, where the frequency jumps suddenly at certain instants and then remains constant, and ...

Conventional Active Magnetic Bearings (AMB) are operated using a bias current (or flux) to achieve greater linearity and dynamic capability. Bias, however, results in undesirable rotating losses and consequent rotor heating. In this paper, optimal control of a magnetic bearing without bias is investigated. A single degree-of-freedom system consisting of a mass and two opposing electromagnets is...

Controlled gliding during descent has been thought of as a crucial intermediate step toward the evolution of powered flight in a variety of animals. Here we develop and analyse a model for the controlled descent of thin bodies in quiescent fluids. Focusing on motion in two dimensions for simplicity, we formulate the question of steering an elliptical body to a desired landing location with a sp...