Esters of (S)-1,2-propanediol and (R,R)-2,3-butanediol — Chiral Compounds Inducing Cholesteric Phases with a Helix Inversion ·

Mesogenic chiral esters of optically active (S)-1,2-propanediol and (R,R)-2,3-butanediol were synthesized. The compounds, added to a nematic phase induce cholesteric phases exhibiting a helix inversion with temperature variation. This effect is independent of the molecular structure of the nematic solvent. The inversion temperature varies only slightly with concentration but can be influenced by the mesogenic substituent

Towards tuneable thin film filters with the use of liquid crystals

For many years, liquid crystals have been used in display devices. In the present study, the usability of liquid crystal thin films for tunable optical filters has been investigated. In contrast to display devices, where the effect of polarization is utilized, the change of the refractive index by an applied electrical field was used to modify the spectral properties. A single-cavity Fabry-Perot filter is presented, which is based on a liquid crystal film located between two ITO-substrates each coated with dielectric mirrors stacks. A fast switching in the msec range could be demonstrated with the thickness of the liquid crystallayer being less than 1 μm. Tunable color filters for the colors red, green and blue are presented. A tuning range of some 10 nm has been obtained

High performance relaying of C++11 objects across processes and logic-labeled finite-state machines

Comunicació presentada a: SIMPAR 2014: International Conference on Simulation, Modeling, and Programming for Autonomous Robots, celebrat del 20 al 23 d'octubre de 2014 a Bèrgam, Itàlia.We present gusimplewhiteboard, a software architecture analogous to ROS:services and ROS: messages, that enables the construction and extremely efficient inter-process relaying of message-types as C++11 objects, All gusimplewhiteboard objects reside in shared memory. Moreover, our principle is to use idempotent message communication, in direct contrast to previously released platforms for robotic-module communication, that are based on an event-driven subscriber model that queues and multi-threads. We combine this with compiled, time-triggered, logic-labeled finite state machines (llfsms) the are executed concurrently, but scheduled sequentially, in an extremely efficient manner, removing all race conditions and requirements for explicit synchronisation. Together, these tools enable effective robotic behaviour design, where arrangements of llfsms can be organised as hierarchies of machines and submachines, enabling composition of very complex systems. They have proven to be very powerful for Model-Driven Development, capable of simulation, validation, and formal verification

GermanTeam 2003

The GermanTeam is a joint project of several German universities in the Sony Legged Robot League. This report describes the software developed for the RoboCup 2003 in Padova. It presents the software architecture of the system as well as the methods that were developed to tackle the problems of motion, image processing, object recognition, self-localization, and robot behavior. The approaches for both playing robot soccer and mastering the challenges are presented. In addition to the software actually running on the robots, this document will also give an overview of the tools the GermanTeam used to support the development process. In an extensive appendix, several topics are described in detail, namely the installation of the software, how it is used, the implementation of inter-process communication, streams, and debugging mechanisms, and the approach of the GermanTeam to model the behavior of the robots

GermanTeam 2004, Technical Report of the RocoCup-Team in the Sony Legged Robot League

The GermanTeam is a joint project of four German universities in the Sony Legged Robot League. This report describes the software developed for the RoboCup 2004 in Lisbon. It presents the software architecture of the system as well as the methods that were developed to tackle the problems of motion, image processing, object recognition, self-localization, and robot behavior. The approaches for both playing robot soccer and mastering the challenges are presented. In addition to the software actually running on the robots, this document will also give an overview of the tools the GermanTeam used to support the development process. The report serves as detailed documentation of the work that has been done and aims at enabling other researchers to make use of it. In an extensive appendix, several topics are described in detail, namely the installation of the software, how it is used, the implementation of inter-process communication, streams, and debugging mechanisms, and the approach of the GermanTeam to model the behavior of the robots