Testing methodology and procedure
Besides the strict performance measurement, i.e. required time and number of errors, other factors, such as user acceptance, mental workload and learning style influence were to be evaluated. Before the actual experiment started, we assumed that the learning style of users might be in relationship with the performance they obtained in the training process. The VARK questionnaire that provided users with a profile of their learning preferences was used. The preferences were divided into four categories: Visual, Aural, Read/Write and Kinaesthetic.
To measure the mental workload that users ‘suffer’ in doing the assembly task while using wearable technology, the NASA TLX test was chosen. NASA TLX is a subjective tool to assess mental workload on operators working with human-machine systems.
In all cases the workers had to complete a usability questionnaire consisting of both close-end and open-ended questions. As at Skoda, the Wizard of Oz was used to simulate all interaction modalities.
- One user during the second experiment
The 20 workers that took part in the second experiment had to perform 4 new assembly tasks supported by the platform: At the first time, the information explaining the task was presented on a large monitor near the platform; the other three times, the task was explained by presenting the information on a HMD. The intention was to compare the performance and acceptance of three different HMDs, each of them based on different techniques, namely, Carl Zeiss’ binocular lookaround HMD, Carl Zeiss’ see-through HMD and Microoptical VI monocular look-around, as well as the use of a big monitor near the working place.
To this aim, we measure the number of errors, time expended and finally the subjective opinion of the participants through a questionnaire.
