Design of Neural Network Mobile Robot Motion Controller

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Search-based optimal motion planning for automated driving

This paper presents a framework for fast and robust motion planning designed to facilitate automated driving. The framework allows for real-time computation even for horizons of several hundred meters and thus enabling automated driving in urban conditions. This is achieved through several features. Firstly, a convenient geometrical representation of both the search space and driving constraints enables the use of classical path planning approach. Thus, a wide variety of constraints can be tackled simultaneously (other vehicles, traffic lights, etc.). Secondly, an exact cost-to-go map, obtained by solving a relaxed problem, is then used by A*-based algorithm with model predictive flavour in order to compute the optimal motion trajectory. The algorithm takes into account both distance and time horizons. The approach is validated within a simulation study with realistic traffic scenarios. We demonstrate the capability of the algorithm to devise plans both in fast and slow driving conditions, even when full stop is required.Comment: Preprint accepted to 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2018). A supplementary video is available at https://youtu.be/D5XJ5ncSuq

Structure and Evolution of Ordered Domains in Deeply Quenched Polyrthelene Melt

Solidification of polymeric materials, a complex process in which the entangled polymer melt becomes a composite of amorphous and crystalline domains, strongly depends on how the melt is cooled below its crystallization temperature. If cooling is at moderate rates, the most common and well. understood mechanism is via nucleation and growth of spherulites, but special cases exist where crystallization is preceded by a pre pre-transition state induced by density fluctuations. Such multi-step crystallization scenarios are suggested by many experiments, and recent theoretical and simulation work. Via energetic and geometric analyses, we have examined the structure of mesomorphic domains and the dynamics of their formation and evolution, including atomic scale details of molecular addition to ordered domains, as well as particle dynamics in the system, including high mobility jumps in the ordered domains at wavelengths matching the monomer spacing

Less than 50% sublattice polarization in an insulating S=3/2 kagome' antiferromagnet at low T

We have found weak long range antiferromagnetic order in the quasi-two-dimensional insulating oxide $KCr_3(OD)_6(SO_4)_2$ which contains Cr$^{3+}$ S=3/2 ions on a kagom\'{e} lattice. In a sample with $\approx$ 76% occupancy of the chromium sites the ordered moment is 1.1(3)$\mu_B$ per chromium ion which is only one third of the N\'{e}el value $g\mu_BS=3\mu_B$. The magnetic unit cell equals the chemical unit cell, a situation which is favored by inter-plane interactions. Gapless quantum spin-fluctuations ($\Delta/k_B >$T_N$= 1.6K are the dominant contribution to the spin correlation function,$S(Q,\omega)$ in the ordered phase.Comment: 18 pages, RevTex/Latex, with 6 figure

Decoupling of self-diffusion and structural relaxation during afragile-to-strong cross-over in a kinetically constrained latticegas

We present an interpolated kinetically constrained lattice gas model which exhibits a transition from fragile to strong supercooled liquid behavior. We find non-monotonic decoupling that is due to this crossover and is seen in experiment

Corresponding States of Structural Glass Formers

The variation with respect to temperature T of transport properties of 58 fragile structural glass forming liquids (68 data sets in total) are analyzed and shown to exhibit a remarkable degree of universality. In particular, super-Arrhenius behaviors of all super-cooled liquids appear to collapse to one parabola for which there is no singular behavior at any finite temperature. This behavior is bounded by an onset temperature To above which liquid transport has a much weaker temperature dependence. A similar collapse is also demonstrated, over the smaller available range, for existing numerical simulation data.Comment: 6 pages, 2 figures. Updated References, Table Values, Submitted for Publicatio