The authors discuss a hierarchical control structure from the viewpoints of the degree of information resolution and the fuzziness of the knowledge base at various levels of the hierarchy. In particular, the concept of fuzzy resolution is addressed. The specific control system considered is a workcell for automated mechanical processing of fish. Qualitatively, the required information resolution decreases and fuzziness of the knowledge base increases with the hierarchical level of the system. Correspondingly, the fuzzy resolution will decrease. Also, since the quantity of data increases with resolution, and, furthermore, the duration of event cycles is generally longer at high levels, the bandwidth of information and control will decrease with the hierarchical level. These considerations are equally applicable to control, sensing, and organizational functions within the hierarchical structure.
展开▼
