Skill evaluation of human operators

The skills of humans performing tasks can be evaluated using Fitts' law, which is described by a straight line in the coordinate system of execution time and task difficulty index. The inverse of the slope of the straight line is called the execution capacity of a human. The aforementioned variables can be calculated from experimental data collected for a task. Experimental data were collected in the task in which a peg attached to the hand of an exoskeleton guided by a human arm was placed into a hole. Indeed, we have determined the mean and standard deviations for individual performances and also for the performances of a group of individuals. Thus, the numerical values calculated to describe the skills of an individual form a basis for comparison of the skills of the individuals. Since Fitts' law is a geometric one-dimensional approach to skill evaluation, it is difficult to apply when the task performance is characterized by two or more variables. Our study introduces a never probabilistic skill index to evaluate skills of operators performing tasks characterized by two or more variables. The probabilistic skill index provides a broader basis for the skill evaluations of the individuals. Moreover, the skills of the individuals performing tasks can be compared objectively by using the probabilistic skill index introduced.