Multi-objective optimisation of machine tool error mapping using automated planning

Error mapping of machine tools is a multi-measurement task that is planned based on expert knowledge. There are no intelligent tools aiding the production of optimal measurement plans. In previous work, a method of intelligently constructing measurement plans demonstrated that it is feasible to optimise the plans either to reduce machine tool downtime or the estimated uncertainty of measurement due to the plan schedule. However, production scheduling and a continuously changing environment can impose conflicting constraints on downtime and the uncertainty of measurement. In this paper, the use of the produced measurement model to minimise machine tool downtime, the uncertainty of measurement and the arithmetic mean of both is investigated and discussed through the use of twelve different error mapping instances. The multi-objective search plans on average have a 3% reduction in the time metric when compared to the downtime of the uncertainty optimised plan and a 23% improvement in estimated uncertainty of measurement metric when compared to the uncertainty of the temporally optimised plan. Further experiments on a High Performance Computing (HPC) architecture demonstrated that there is on average a 3% improvement in optimality when compared with the experiments performed on the PC architecture. This demonstrates that even though a 4% improvement is beneficial, in most applications a standard PC architecture will result in valid error mapping plan

PLEX : una herramienta para realizar experimentos en planificación automática

En este documento se explica el desarrollo de la herramienta PLEX (PLanning EXperimenter). El contexto de esta herramienta es la Planificació Automática. PLEX proporciona facilidades para plantear y realizar experimentos con la finalidad de comparar el comportamiento de distintos planifi cadores. Además, permite analizar los resultados de los experimentos proporcionando distintos tipos de grá ficas y tablas. Una de las características principales de PLEX es la flexibilidad, puesto que su diseño está pensado para que se puedan incorporar nuevos planifi cadores fácilmente. El documento empieza con el capítulo 2 dónde se explican los motivos que justi can el desarrollo de una herramienta como PLEX. A continuación, en el capítulo 3, se detallan los objetivos planteados para el Proyecto Fin de Carrera. Después de estos dos putos se realiza una breve introducción al mundo de la Plani fiicación Automática. Así, en el capítulo 4, se describen los plani ficadores más importantes y las técnicas que aplican. A continuación, se estudian las herramientas existentes, orientadas a facilitar el uso y la comprensión de distintos planificadores desde el punto de vista del usuario. El documento continua con el capítulo 5 en el que se detallan las principales características de la herramienta. Con este capítulo se pretende dar al lector una visión general de lo que se ha desarrollado. El desarrollo técnico de la herramienta PLEX se detalla en el capítulo 6. En este capítulo se describen los requisitos, el diseño y el funcionamiento de la aplicación. Finalmente, se incluyen las conclusiones (capítulo 7) y los trabajos futuros (capítulo 8). El documento concluye con dos apéndices. El apéndice A es un pequeño manual de usuario, mientras que el apéndice B detalla la gestión del proyecto.Ingeniería en Informátic

Planning with numerical expressions in LPG

Abstract. We present some techniques for handling planning problems with numerical expressions that can be specified using the standard planning language PDDL. These techniques are implemented in LPG, a fully-automated planner based on local search that was awarded at the third international planning competition (2002). First, we present a plan representation for handling numerical expressions called Numerical Action Graph (NA-graph). Then, we propose some extensions of LPG to guide a search process where the search states are NA-graphs. Finally, we give some experimental results showing that our techniques are very effective in terms of CPU-time or plan quality, and that they significantly improve the previous version of the planner

Planning with Numerical Expressions in LPG

Abstract. We present some techniques for handling planning problems with numerical expressions that can be specified using the standard planning language PDDL. These techniques are implemented in LPG, a fully-automated planner based on local search that was awarded at the third international planning competition (2002). First, we present a plan representation for handling numerical expressions called Numerical Action Graph (NA-graph). Then, we propose some extensions of LPG to guide a search process where the search states are NA-graphs. Finally, we give some experimental results showing that our techniques are very effective in terms of CPU-time or plan quality, and that they significantly improve the previous version of the planner.