| Tool management is often described as all the activities required to ensure the right tool is at the right machine at the right time. This work concentrates on the problem of scheduling and allocating tools in a Flexible Manufacturing System (FMS). Two approaches are developed and evaluated.;The first approach is based on a Petri net machine. The system shows the feasibility of dynamic tool allocation in an FMS but pinpoints a potential problem arising from frequent access to external databases.;A second tool management system was developed using an object-oriented programming environment. To reduce access to external databases and improve the response of the system, all computations are performed on local images of frequently used information obtained from the external databases. Also, different scheduling heuristics were evaluated.;The tool management system developed integrates procedural and rule-based modes of computation. A heuristic of least commitment where irreversible decisions are delayed until unavoidable as to keep the most alternatives open is implemented. The heuristic was found to result in "good" tool allocation, especially in a dynamic environment where production plans may change, for example following a tool breakage. |
