Abstract: This paper presents modeling and optimization of two NP-hard problems in flexible manufacturing system (FMS), part type selection problem and loading problem. Due to the complexity and extent of the problems, the paper was split into two parts. The first part of the papers has discussed the modeling of the problems and showed how the real coded genetic algorithms (RCGA) can be applied to solve the problems. This second part discusses the effectiveness of the RCGA which uses an array of real numbers as chromosome representation. The novel proposed chromosome representation produces only feasible solutions which minimize a computational time needed by GA to push its population toward feasible search space or repair infeasible chromosomes. The proposed RCGA improves the FMS performance by considering two objectives, maximizing system throughput and maintaining the balance of the system (minimizing system unbalance). The resulted objective values are compared to the optimum values produced by branch-and-bound method. The experiments show that the proposed RCGA could reach near optimum solutions in a reasonable amount of time.
Abstract: In this paper, a particle swarm optimization (PSO)
algorithm is proposed to solve machine loading problem in flexible
manufacturing system (FMS), with bicriterion objectives of
minimizing system unbalance and maximizing system throughput in
the occurrence of technological constraints such as available
machining time and tool slots. A mathematical model is used to
select machines, assign operations and the required tools. The
performance of the PSO is tested by using 10 sample dataset and the
results are compared with the heuristics reported in the literature. The
results support that the proposed PSO is comparable with the
algorithms reported in the literature.
Abstract: In this paper is study the possibility of successfully
implementing of hollow roller concept in order to minimize inertial
mass of the large bearings, with major results in diminution of the
material consumption, increasing of power efficiency (in wind power
station area), increasing of the durability and life duration of the large
bearings systems, noise reduction in working, resistance to
vibrations, an important diminution of losses by abrasion and
reduction of the working temperature. In this purpose was developed
an original solution through which are reduced mass, inertial forces
and moments of large bearings by using of hollow rollers. The
research was made by using the method of finite element analysis
applied on software type Solidworks - Nastran. Also, is study the
possibility of rapidly changing the manufacturing system of solid and
hollow cylindrical rollers.