usability evaluation
This was to evaluate whether the perceptual information analyzed from task analysis was sufficient for the designated tasks in this study. The ten subjects included five males and five females (mean age 32.1, SD=5.2) who were asked to perform the tasks and then determined subjectively the difficulty level for performing the subtasks within the tasks. A seven-level Likert scale was used to measure the difficulty level of each subtask in this study, with 1 for quite difficult and 7 for quite easy. All subjects have had experience using vacuum cleaners. In addition to rating the difficulty level, the subjects were also asked to write down the reasons for any difficulties that they encountered after completing the tasks. Thus, whether adequate perceptual information was provided for completing the tasks was immediately evaluated.