This paper deals with models for flow management problems in flexible assembly systems (FASs). The system consists of a set of machines that must perform the assembly of a number of parts, possibly of different types. Each part type requires a set of operations; the precedence relations among the operations are specified by an assembly tree. Machines are provided with limited-capacity tool magazines and a finite buffer for holding parts. Each machine can be tooled to perform only a particular subset of the operations required by the whole process. One problem is that of finding a feasible assignment of operations to machines and a feasible schedule of the subassemblies in order to minimize the completion time of all of the parts. In this paper, the problem is analysed as a case of pipelined assembly, i.e., when the FAS is characterized by a serial transportation system (flow line) and there exist a dominating path in the assembly tree. We present polynomial-time dynamic programming algorithms for solving the problem for both single-type and multi-type production.>

The authors deal with the problem of part flow management in a class of assembly systems characterized by a serial transportation system connecting the workstations. The system assembles a number of identical units, each requiring a set of operations. Each operation is performed by a workstation and each workstation can perform any operation. The problem consists of assigning the operations to the workstations to maximize some productivity index of the system. Usually, a tree-like precedence relationship exists among the operations (assembly tree). The problem is analyzed for the case in which a dominating path on the assembly tree exists. A polynomial time dynamic programming algorithm is presented for the optimal assignment of operations to workstations.>

Some optimization models for the problem of tool management in flexible manufacturing cells are presented. The cell considered consists of two machines (working centers) in charge of executing a set of part programs. The tools required by the machining operations are located in a central tool magazine and are moved to the machines by a tool handling system consisting of two shuttles and one robot. The robot picks and places the tools from/in the magazine; each shuttle exchanges the tools with the robot and with the machine. The problem is to synchronize the robot and shuttle moves in order to maximize the cell productivity (minimize the machines' idle time). Two different models are proposed for the situation in which a configuration of tools in the magazine is given and in which a budget for tool purchasing is fixed.>

The problem of part routing and scheduling in flexible manufacturing systems is considered with the goal of increasing the throughput. The flexible system considered is strongly characterized by the inclusion of assembly among the manufacturing operations to be performed on a mix of part batches. In particular, the logic structure of some basic decision problems is indicated through a set of combinatorial models. Two basic assembly problems characterized by batches of large and small size, respectively, are analyzed.>

In this paper a program for generating the model of industrial robots in a symbolic form is presented. The program, called DYMIR, derives the motion equations of robots here considered as a chain of rigid bodies connected by suitable single degree-of-freedom (DOF) joints. This is transparent to the user and allows the symbolic calculation of dynamical models until twelve DOF and may take into account elasticity and transmission losses at the joints.