A generic model of manufacturing flexibility based on system control hierarchies

Models of manufacturing flexibility have become centred on highly automated systems. These fail to account for the flexibility that is characteristic of many small, human-centred manufacturing operations or in systems based on hybrid automation. This paper presents a generic framework that models flexibility in terms of the underlying capability of a manufacturing system and its control systems, human and machine. In this model, manufacturing versatility, the ability to change, is realized through the application of automatic control to the inherent capability of the system. Flexibility defined as the ability to cope with the uncertainty of change, extends versatility through the application of intelligent control. This process generates new knowledge about the system and its environment. The system learns by applying this knowledge and consequently the autonomic response of the system is dynamically improved. The model is hierarchical, accounting for capability, versatility and flexibility at various levels of manufacturing system, from the operator-machine level up to a whole organization. The efficacy of the model is demonstrated in a study of a semi-manual assembly cell in a small manufacturing company