Weibull Distribution: User Performance Analyses for Telerobotics System Interface

When aiming to improve interfaces for remote devices, methods are required for assessing them and comparing the effect of changes. Distributions provide a means of summarizing data and a model that produces a particular distribution is known, so that if the data is found to match a known distribution a useful model is available for interpreting the data. This paper presents the analysis using the Weibull distribution to evaluate the user performance of the prototype telerobotics user interface. This prototype was deployed for public testing at an exhibition in the CSIRO Discovery Centre, Canberra, Australia, over three months. An investigation of operator requests to three models of telerobotics control from a total of 6139 total user sessions was found to fit Weibull distributions. All of the devices offered operators the opportunity to manipulate wooden blocks through the application with three model controls. Usage patterns were quite different on the different control models, but operator behavior could be characterized by the two parameters of the Weibull distribution. One of the parameters, the shape parameter, was found to be nearly invariant so the comparison could be reduced to the scale parameter. This meant interfaces can be compared with a single value calculated from automatically captured data during use of the interface.