Knowledge-Based Process Planning

We provide a brief discussion of knowledge-based process planning. A knowledge based system refers to a computer program that can store knowledge of a particular domain and use that knowledge to solve problems from that domain in an intelligent way (Hayes-Ruth, 1983). In a knowledge-based process planning system we use a computer to simulate the decision process of a human expert. Usually, human process planners develop process planning based on their experience, knowledge, and inference. A computer, to some extent, can also be used to perform these functions. By capturing this process through the use of a knowledge-based system, the proper process plan may be developed. In a knowledge-based system, two major problems need to be solved: the knowledge representation and the inference mechanism. The knowledge representation is a scheme by which a real-world problem can be represented in such a way that the computer can manipulate the information. For example, to define a part, we need to define whether there is a hole in it. Given that there is a hole, we next have to define the attributes of the hole, such as the type of hole, the length, and the diameter.

The reason for this is that the computer is not capable of reading the design from blueprints or databases as humans are. The inference mechanism is the way in which the computer finds the solution. One approach is based on IF-THEN structured knowledge. For example, IF there is a hole, THEN a drill may be used. Through this type of knowledge, the computer can infer what operations are needed. Once the operations are known, it is easy to calculate other details and the process plan can be developed. Other aspects of a knowledge-based system include the interface, which contains the user interface, the interface with the computer-aided design (CAD) database, and the inquiry facility, which explains why a decision is made.