Skill-based reconfiguration of industrial mobile robots

Caused by a rising mass customisation and the high variety of equipment versions, the exibility of manufacturing systems in car productions has to be increased. In addition to a exible handling of production load changes or hardware breakdowns that are established research areas in literature, this thesis presents a skill-based recon guration mechanism for industrial mobile robots to enhance functional recon gurability. The proposed holonic multi-agent system is able to react to functional process changes while missing functionalities are created by self-organisation. Applied to a mobile commissioning system that is provided by AUDI AG, the suggested mechanism is validated in a real-world environment including the on-line veri cation of the recon gured robot functionality in a Validity Check. The present thesis includes an original contribution in three aspects: First, a recon - guration mechanism is presented that reacts in a self-organised way to functional process changes. The application layer of a hardware system converts a semantic description into functional requirements for a new robot skill. The result of this mechanism is the on-line integration of a new functionality into the running process. Second, the proposed system allows maintaining the productivity of the running process and exibly changing the robot hardware through provision of a hardware-abstraction layer. An encapsulated Recon guration Holon dynamically includes the actual con guration each time a recon guration is started. This allows reacting to changed environment settings. As the resulting agent that contains the new functionality, is identical in shape and behaviour to the existing skills, its integration into the running process is conducted without a considerable loss of productivity. Third, the suggested mechanism is composed of a novel agent design that allows implementing self-organisation during the encapsulated recon guration and dependability for standard process executions. The selective assignment of behaviour-based and cognitive agents is the basis for the exibility and e ectiveness of the proposed recon guration mechanism

Análisis de la Relajación Lagrangiana como método de programación de talleres flexibles en un entorno multiagente

Esta tesis está relacionada con la programación de operaciones de tipo distribuido y analiza el método de Relajación Lagrangiana para su aplicación como mecanismo de generación de precios en el contexto de las subastas combinatorias iterativas. El desarrollo de los sistemas multiagente ha permitido la implementación de sistemas distribuidos de programación y control de la producción. En ellos, los mecanismos de coordinación utilizados son un importante campo de investigación. En este trabajo se estudia la resolución del problema de programación de talleres flexibles mediante el método de Relajación Lagrangiana, que permite descomponerlo para ser implementado en un sistema multiagente. El sistema resultante puede ser entendido como una subasta combinatoria utilizada como mecanismo de negociación. Se han analizado las características y limitaciones de las distintas alternativas para ser implementadas de forma asíncrona y descentralizada, en base a la calidad de la solución propuesta y velocidad de convergencia. ______________________________ This thesis is related to operations scheduling in distributed systems and analyzes the application of the Lagrangian Relaxation method as price mechanism in the context of iterative combinatorial auctions. The development of multiagent systems has enabled the implementation of distributed production scheduling systems. The coordination mechanism is crucial in these systems and its design is an important field of research. In this work we study the resolution of the flexible job shop scheduling problem by the Lagrangian relaxation method. It decomposes the problem to be implemented in a multiagent system. The resulting system can be understood as a combinatorial auction that is used as a negotiation mechanism among the agents. The aim of this work is to study the characteristics and limitations of the different alternatives to be implemented asynchronously and in a decentralized structure, based on the quality and convergence of the solution