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Assembly planning is difficult and tedious, but is necessary for complex products. This thesis presents a novel approach to automating assembly planning utilizing graph grammars. Computational geometric reasoning is used to produce a label rich graph from a CAD model. This graph is then modified by graph grammar rules to produce candidate assembly sequences which are run in conjunction with a tree search algorithm. An evaluation system then evaluates partial assembly sequences, which are used by the tree- search to find near-optimal assembly sequences. / text

No description available.

No description available.

Computer-aided fixture planning (CAFP) is an essential part of Computer-aided design and manufacturing (CAD/CAM) integration. Proper fixture planning can dramatically reduce the manufacturing cost, the lead-time, and labor skill requirements in product manufacturing. However, fixture planning is a highly experience-based activity. Due to the extreme diversity and complexity of manufacturing workpieces and processes, there are not many fixture planning tools available for industry applications. Moreover, existing CAFP methods rarely consider integrating fixture environmental factors into fixture planning. Automatic fixture planning using VR can provide a viable way for industries. This thesis develops automated approaches to fixture planning in a virtual environment (VE). It intends to address two important issues: automatic algorithms for fixture planning, and the VE to support high fidelity evaluation of fixture planning. The system consists of three parts including fixture assembly planning, feasibility analysis of assembly tools, and motion planning for fixture loading and unloading. The virtual fixture planning system provides the fixture designer a tool for fixture planning and evaluation. Geometrical algorithms are developed to facilitate the automatic reasoning. A Web-based VE for fixture planning is implemented. The three-dimensional (3D) model visualization enables the fixture simulation and validation effectively to investigate existing problems. Approaches to construct desktop-based large VEs are also investigated. Cell segmentation methods and dynamic loading strategies are investigated to improve the rendering performance. Case studies of virtual building navigation and product assembly simulations are conducted. The developed algorithms can successfully generate the assembly plan, validate the assembly tools, and generate moving paths for fixture design and applications. The VE is intuitive and sufficient to support fixture planning, as well as other virtual design and manufacturing tasks.

Computer-aided fixture planning (CAFP) is an essential part of Computer-aided design and manufacturing (CAD/CAM) integration. Proper fixture planning can dramatically reduce the manufacturing cost, the lead-time, and labor skill requirements in product manufacturing. However, fixture planning is a highly experience-based activity. Due to the extreme diversity and complexity of manufacturing workpieces and processes, there are not many fixture planning tools available for industry applications. Moreover, existing CAFP methods rarely consider integrating fixture environmental factors into fixture planning. Automatic fixture planning using VR can provide a viable way for industries. This thesis develops automated approaches to fixture planning in a virtual environment (VE). It intends to address two important issues: automatic algorithms for fixture planning, and the VE to support high fidelity evaluation of fixture planning. The system consists of three parts including fixture assembly planning, feasibility analysis of assembly tools, and motion planning for fixture loading and unloading. The virtual fixture planning system provides the fixture designer a tool for fixture planning and evaluation. Geometrical algorithms are developed to facilitate the automatic reasoning. A Web-based VE for fixture planning is implemented. The three-dimensional (3D) model visualization enables the fixture simulation and validation effectively to investigate existing problems. Approaches to construct desktop-based large VEs are also investigated. Cell segmentation methods and dynamic loading strategies are investigated to improve the rendering performance. Case studies of virtual building navigation and product assembly simulations are conducted. The developed algorithms can successfully generate the assembly plan, validate the assembly tools, and generate moving paths for fixture design and applications. The VE is intuitive and sufficient to support fixture planning, as well as other virtual design and manufacturing tasks.

Die gängige Methodik zum Konzipieren automatisierter Montagesysteme umfasst die Planung der Montage und die physische Entwicklung der technischen Gesamtlösung. Zur Abbildung der konkreten Aufgabe werden standardisierte Symbole in einem Ablaufplan miteinander verknüpft. Die Hauptaufgabe des Konstrukteurs ist die Auswahl und die Zusammenstellung einer optimalen Konfiguration der Funktionsträger sowie deren Implementierung in einer Gesamtlösung unter Berücksichtigung der vorgegebenen Randbedingungen. Das Problem ist der fehlende Informationsgehalt der bisher eingesetzten Handhabungssymbole und Symbole zur Ermittlung der Funktionsträger zur Beschreibung der Montage- und Handhabungsplanung sowie die fehlende Vorgehensweise zur Auswahl der Funktionsträger aus den verschiedenen Varianten nach minimaler Taktzeit und Gesamtanschaffungskosten. Zur Realisierung eines effizienten Montageplanungssystems leitet sich daher die Zielstellung ab, den Informationsgehalt der standardisierten Symbole zu erweitern und mit logischen Schnittstellen für eine automatisierte Verknüpfung in der Funktionsfolge auszustatten. Diese neuen Symbole beinhalten die Definition der Funktionen sowie alle Randbedingungen und Parameter zur eindeutigen Beschreibung der Handhabungsaufgabe. Mithilfe dieser Parameter werden Anforderungslisten erstellt und nach passenden Anlagenkomponenten gesucht. Zur Auswahl der optimalen Komponenten des Montagesystems wird das lineare Optimierungsproblem hinsichtlich der Kombination aus Taktzeit und Gesamtanschaffungskosten gelöst. / The common methodology for designing automated assembly systems involves the assembly planning and the physical development of overall technical solution. To illustrate the concrete task, standardized symbols are connected together in a flowchart. The designer's main task is the selection and the composition of an optimal configuration of the functional carriers as well as their implementation in an overall solution in consideration of the predetermined boundary conditions. One problem is the lack of information content of the previously used handling symbols and the symbols for determining the functional carriers, which describe the assembly and handling planning. The other is the insufficient methods for selecting the functional carriers from the different variants based on minimum cycle time and total acquisition cost. In order to realize an efficient assembly planning system, the objective is therefore to expand the information content of the standardized symbols and equip them with logical interfaces for automated connection in the functional sequence. These new symbols contain the definition of the functions as well as all boundary conditions and parameters for the unambiguous description of the handling task. These parameters are utilised to create requirement lists and search for suitable plant components. In order to select the optimal components of the assembly system, the linear optimization problem regarding the combination of cycle time and total acquisition costs is solved.