Production Planning and Control Structure for Automated Manufacturing Systems

Abstract

The previous chapters have indicated some important characteristics of production planning and control systems. The first is that the problem of production planning and control for batch manufacturing is tremendously complex; a wide variety of interrelationships exists within a typical manufacturing system. This problem can be approached by using a hierarchy of control where major aggregate decisions are made at the highest levels and these decisions are gradually broken down into more detail as they pass through to the lower levels. The top levels of the hierarchy are therefore concerned with broad aspects of decision making, ensuring that the manufacturing system is globally achieving the desired objectives. Little detail is used at these higher levels but instead, such entities as aggregate production rates and capacities are used. The time periods considered tend to be longer at these higher levels, decreasing as the hierarchy is descended; where time periods measured in years may be used at the highest levels, the time periods may only be minutes at the lower levels. Overall, therefore, the characteristic complexity of the production planning and control task for manufacturing systems can be approached via hierarchical planning and control. As we descend the hierarchy the level of detail increases, whereas the time period considered decreases.