Integration of humans and computers in the operation and control of flexible manufacturing systems

The comparative abilities and limitations of humans and computers in the operation and control of flexible manufacturing systems (FMS) are reviewed and a table emphasizing the allocation of functions between humans and computers in an FMS is produced. A case study is presented to illustrate the effectiveness of the allocation of functions.     

Development of a knowledge-based decision support system for diagnosing malfunctions of advanced production equipment

This paper presents a case study documenting the development of an expert system for diagnosing the malfunctions of a machine used by the NEC Corporation to mount chips on integrated circuit boards. Development of the expert system was justified by the inability of operators to efficiently diagnose many malfunctions of the chip-mounting machine, the associated cost of production delays, and the disruption incurred when experts were forced to leave unrelated tasks to help operators troubleshoot malfunctions. The first step in development of the expert system was to elicit and organize the machine designer's knowledge. This process resulted in a hierarchical classification of malfunction symptoms and causes, a set of 15 flow diagrams documenting the designer's troubleshooting procedures for particular malfunction symptoms, and a matrix documenting design information. The flow diagrams were translated into a large logic network diagram, which was directly translated into a set of 94 rules. An additional set of 270 rules were derived from the design matrix. The resulting 364 rules were then implemented in an expert system using the KES shell. On-site validation revealed that 92% of the chip-mounting machine's malfunctions occurring in 1988-1989 were successfully diagnosed by the expert system. Future directions of this research will be oriented toward the development of a general purpose expert system capable of diagnosing the malfunctions of other similar production equipment.     

Selection of industrial operators The one-hole test

The one-bole test was developed to provide a situation in which unlike that in the Purdue peghoard and similar teste, the reach, grasp, move and position elements were consistent and their rate of improvement measurable. Results support the hypothesis tlmt measurements of rate of learning or of performance after 600 cycles of practice have a higher concurrent and predictive validity of production output than measurements of initial performance on the test. The one-hole test has a mean predictive validity of 0-75 (N = 228) between test scores and rate of learning in the training school; and a mean concurrent validity of 0-66 [N = 307) between test scores and mean production performance of experienced operators. Norms (N = 1422), reliabilities (W=158) and correlation of the one-hole test scores with anthropometric measurements, personality, intelligence, age and other manual dexterity tests are discussed.     

Improvements in physiological performance as a function of practice∗

As a result of the limitations inherent in the present technique of estimating work standards, the concept of utilizing psychological and physiological indices instead of time alone in establishing predetermined work standards is evaluated in an exploratory study.

Experiments were conducted on 15 male subjects on a transport and position type repetitive task. The operation was performed single-handedly and with simultaneous motions for over 1000 cycles per subject per condition. Results indicate that :

(1)Physiological performance improved with practice of the designated manual task.

(2)The energy expenditure per cycle for the preferred and non-preferred hand motions is not significantly different from that required in simultaneous motions.

(3)The indication that energy expenditure of simultaneous hand motions is not significantly different from that of single-hand motions supports the classical claims, put forth by neurophysiologists, that the sum of the individual time elements does not equal the time of the whole motion patterns. This encourages the possibility of being able to establish predetermined work standards using physiological indices instead of time.     

An experimental study of human decision-making in computer-based scheduling of flexible manufacturing system

This paper describes a study which explores human decision-making abilities in scheduling and dispatching of a flexible manufacturing system (FMS) An experiment is described, using an FMS, in which subjects make scheduling and dispatching decisions using a real-time interactive computer-simulation based system. The experimental results demonstrate that human decision-making is superior to general dispatching rules. An explanation of these results and an analysis of subjects' behaviour is presented in the light of information obtained from verbal protocol data     

The application of cognitive simulation techniques to work measurement and methods analysis of production control tasks

The implementation of flexible control in production and manufacturing operations has resulted in jobs largely consisting of cognitive tasks in which performance is determined by worker goals, knowledge, and transient task-related conditions. As has been the case for traditional jobs that are characterized by predictable and/or repetitive operations, jobs that emphasize cognitive tasks also require examination. This paper presents cognitive simulation as a promising tool for work measurement and methods analysis of the cognitive tasks found within such jobs. Levels of performance, taxonomies of tasks, and the sequencing of elemental tasks are discussed from this perspective. It is noted that existing techniques for developing cognitive simulations have important similarities to the knowledge acquisition methods used to develop expert systems. Several representative techniques and their application are then discussed in terms of their potential value to work measurement and methods analysis.