Search results for "Optimal control"
showing 10 items of 209 documents
Numerical methods to compute sentinels for parabolic systems with an application to source terms identification
1994
We apply the method of sentinels to the identification of source terms in parabolic systems. We present two numerical approaches; the first one is based on the solution of an optimal control problem, and the second one is based on the solution of a linear system of equations. In numerical experiments, we compare these approaches in terms of accuracy and computational cost.
Towards safe reinforcement-learning in industrial grid-warehousing
2020
Abstract Reinforcement learning has shown to be profoundly successful at learning optimal policies for simulated environments using distributed training with extensive compute capacity. Model-free reinforcement learning uses the notion of trial and error, where the error is a vital part of learning the agent to behave optimally. In mission-critical, real-world environments, there is little tolerance for failure and can cause damaging effects on humans and equipment. In these environments, current state-of-the-art reinforcement learning approaches are not sufficient to learn optimal control policies safely. On the other hand, model-based reinforcement learning tries to encode environment tra…
Robust optimality of linear saturated control in uncertain linear network flows
2008
We propose a novel approach that, given a linear saturated feedback control policy, asks for the objective function that makes robust optimal such a policy. The approach is specialized to a linear network flow system with unknown but bounded demand and politopic bounds on controlled flows. All results are derived via the Hamilton-Jacobi-Isaacs and viscosity theory.
Dynamic Analysis of a 7 DOF Robot Using Fuzzy Logic for Inverse Kinematics Problem
2019
Abstract In this paper, a dynamic analysis for a redundant, serial robot, with seven degrees of freedom is presented. The dynamic model of the robot is based on importing a tri-dimensional CAD model of the robot into MATLAB®, Simulink®-Simscape™-SimMechanics™. One can import complete CAD assemblies, including all masses, inertias, joints, constraints, and tri-dimensional geometries, into the model. The first step for executing a dynamic analysis is to resolve the Inverse Kinematics (IK) problem for the redundant robot. Because this type of robot has seven degrees of freedom the IK resolution implies an infinite number of solutions. So, to be able to resolve the IK for this kind of robot a F…
Optimal control and Clairaut-Liouville metrics with applications
2014
The work of this thesis is about the study of the conjugate and cut loci of 2D riemannian or almost-riemannian metrics. We take the point of view of optimal control to apply the Pontryagin Maximum Principle in the purpose of characterize the extremals of the problem considered.We use geometric, numerical and integrability methods to study some Liouville and Clairaut-Liouville metrics on the sphere. In the degenerate case of revolution, the study of the ellipsoid uses geometric methods to fix the cut locus and the nature of the conjugate locus in the oblate and prolate cases. In the general case, extremals will have two distinct type of comportment which correspond to those observed in the r…
Optimal control of quantum superpositions in a bosonic Josephson junction
2012
We show how to optimally control the creation of quantum superpositions in a bosonic Josephson junction within the two-site Bose-Hubbard model framework. Both geometric and purely numerical optimal control approaches are used, the former providing a generalization of the proposal of Micheli et al [Phys. Rev. A 67, 013607 (2003)]. While this method is shown not to lead to significant improvements in terms of time of formation and fidelity of the superposition, a numerical optimal control approach appears more promising, as it allows to create an almost perfect superposition, within a time short compared to other existing protocols. We analyze the robustness of the optimal solution against at…
Optimal control of the inversion of two spins in Nuclear Magnetic Resonance
2012
International audience; We investigate the optimal control of the inversion of two spin 1/2 particles in Nuclear Magnetic Resonance. The two spins, which differ by their resonance offset, are controlled by the same radio frequency magnetic field. Using the Pontryagin Maximum Principle, we compute the optimal control sequence which allows to reach the target state in a given time, while minimizing the energy of the magnetic field. A comparison with the time-optimal solution for bounded control amplitude realizing the same control in the same time is made. An experimental illustration is done using techniques of Nuclear Magnetic Resonance.
Connected and Autonomous Vehicles cooperate with the pedestrian in industrial sites based on trajectory optimization and vehicle signalization system
2020
Connected and autonomous vehicles (CAV) is the development trend in the field of transportation systems. Recent studies show that the resources sharing between pedestrians and CAV is a big challenge. Considering traffic safety and efficiency at that sharing point not only requires a collision avoidance system but also more communicative behaviors of the CAV. More precisely, pedestrian needs to understand the intention of the incoming CAV whether it will cross first or not according to its speed profile. This paper uses the optimal trajectory control to provide CAV with a communicative behavior. A scenario where CAV and pedestrian cooperate together to cross a conflict zone is studied. A com…
Robust control of a Hammerstein model of DC/DC converters
2007
This paper deals with the robust control of a Hammerstein mathematical model of DC/DC converters, consisting of the nonlinear static characteristics of the converter followed by one of a few number of linear time- invariant models which describe the converter in the useful working range. One of these models is assumed as the nominal model of the system and the remaining models are used for describing the model uncertainty. Nominal behaviour is assured using H-2 optimal control method, Robust stability and behaviour are assured by imposing H-infin specifications. The closed loop control system consisting of the converter Hammerstein model and the robust controller is analyzed by means of sim…
Extremal Problems for Elliptic Systems
1998
The specific properties of optimal control problems for elliptic systems, if compared with the case of a single equation, are described. Within them are: strong closures of sets of feasible states; the relaxability via convexification; the type of necessary optimality conditions.