Study results

In the last two months our main focus was on analyzing the data that we collected with our FlexIRob system during the user study on physical human robot interaction at Harting. We were able to evaluate the questionnaire and got first insights about the perception of our system by potential co-workers.

Descriptive evaluation

We had 45 users, 16 male and 29 female, belonging to the working units 'cage assembly', 'mechanical processing', 'die casting', 'internal part production', 'machine assembly', and 'prefabrication'. Most of them were working for 1 to 33 years at Harting (M = 11.36 years, SD = 9.78 years, Min = 1, Max = 33). The participants' mother tongue distributes over German (77,8%), Russian (11,1%), Turkish (6,7%) and Greek(2,2 %). Concerning their highest level of education, almost a half of the participants declared the receipt of a certificate of secondary education (CSE) or a general CSE (Haupt- oder Realschulabschluss), ca. 13% received a vocational or university-entrance diploma, and the remaining participants finished a vocational education (Berufsausbildung).

Answering the questions raised

As reported earlier, we conducted the study to answer questions concerning the perception and manageability of the FlexIRob system. In particular: Is such a physical MMI actually intuitive? For all users? Is it comfortable? How exhausting is the work with the robot arm?  Is the reconguration of the robot practicable? How well and how fast can it be done?  What are the characteristics of the training data provided by the naive users of the system?

The results are very convincing. First of all, the users felt not threatened by the robot and perceived it to be reliable, which is an important fact regarding the applicability in future industrial co-worker scenarios. Concerning the physical interaction, they stated that the robot was easy and comfortable to handle as well as the operation of the robot to be self-explanatory. Additionally, they felt the system to give helpful feedback during the collaboration. 

Evaluation concerning assisted vs. not-assisted wire-loop game

As reported earlier, we divided the participants into two groups during the wire-loop game: One group (group A) was assisted by the robot that respects the constraints of the environment and the other one (group N) not. Each joint of the robot arm needs to be controlled manually. Our motivation was to evaluate the new control mode, i.e. whether solving the wire-loop game was easier for participants of group A or not. Again, the results are promising. First of all, we can report that there is a significant difference in the perceived simplicity of operating the robot arm. The participants of group A appraised the operation easier than the ones from group N. Second, group A declared the settings of the robot to be significant more appropriate than group N. Finally, we could detect a marginal significant effect on the handling of the robot arm during the interaction. Participants of group A felt the handling more comfortable than the ones from group N.

A first analysis of the trajectories taught-in during the wire-loop game shows differences in the duration and the smoothness of the trajectories between the two groups. The assisted group is significant faster in teaching a trajectory than the not-assisted group. Group A also produces much smoother and more comparable trajectories than group N.