## 3 Results and Discussion
[42], who identified safety as a requirement in this context in which workers and cobots collaborate, sharing a task and workspace, and having targets to achieve. _Relationship_ was identified as a positive element of the experiences run by [PERSON] et al. [39], specifically through adequate features that assure acceptable communication between a user and a cobot. [PERSON] et al. [16] further emphasized relationship as a UX goal, by mentioning fellowship and sympathy as means to create a bond between both parts. [PERSON] and [PERSON] [40] pointed out the social aspects of a relationship and the need to develop multiple relationships as implications to be considered when designing cobots, to enrich the social environment of the organizations and provide the required social cues for coordinated actions. [PERSON] et al. [41] referred to the principle of secondary action, which does not contribute to a defined purpose but adds to the lifelikeness of a cobot, and so to the building of a relationship with it. The _Usability_ category was extensively present in the study by [PERSON] and [PERSON] [38], which contemplated development goals, such as mobile robot cells, use of machine vision, utilization of artificial intelligence, new kinds of user interfaces, utilization of other sensors, programming methods, and mobility. [PERSON] et al. [42] also identified usability as a requirement to consider cobots's adoption and acceptance. When [PERSON] et al. [37] referred to physical effortlessness, that could be linked with usability, as it concern a physical aspect of a task performed in a collaborative setting. Following the same logic, arcing, one of the principles of the study of [PERSON] et al. [41], can be seen as linked to this category, by addressing the trajectory of the interaction. _Inspiration_ was defined by [PERSON] et al. [16] as a UX goal that relates to feeling motivated and challenged, making the collaboration as fluent as possible. [PERSON] et al. [37] mentioned the feature of mental effortlessness, which can contribute to this goal of inspiration. [PERSON] et al. [41] studied how making a cobot more appealing, manipulating its characteristics such as physical appearance, posture and gaze, can elicit interest and engagement with it, i.e., inspiration. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Reference** & **Safety** & **Relationship** & **Usability** & **Inspiration** & **Flexibility** & **Efficiency** & **Accomplishment** & **Score (Study)** \\ \hline
[38] & + & 0 & + & 0 & 0 & + & 0 & 3 \\
[39] & + & + & 0 & 0 & 0 & + & 0 & 3 \\
[16] & + & + & 0 & + & 0 & 0 & + & 4 \\
[42] & + & 0 & + & 0 & + & + & 0 & 4 \\
[37] & + & 0 & + & + & + & 0 & + & 5 \\
[40] & 0 & + & 0 & 0 & 0 & 0 & 1 \\
[41] & 0 & + & + & + & 0 & 0 & 0 & 3 \\
**Score (item)** & 5 & 4 & 4 & 3 & 3 & 3 & 2 & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: UX goals for the designing of cobots derived from the systematic literature review. The UX goal of _Flexibility_ was acknowledged by both [PERSON] et al. [42] and [PERSON] et al. [37], which can be leveraged by the human-robot collaboration models. [PERSON] et al. [39] pointed out the flexibility of material handling devices as a development need, which also integrates the present category. In the _Efficiency_ category, [PERSON] and [PERSON] [38] enumerated the following need for cobots development: new ways of allocating work between human workers and cobots; developing performance; and comprehensive solutions taking advantage of the best of robots and humans. Similarly, [PERSON] et al. [39] and [PERSON] et al. [42] identified this goal in their research, which could refer, for instance, to increasing precision and speed. [PERSON] et al. [16] nominated the feeling of success derived from HRC as the UX goal Accomplishment, integrating aspects as confidence, enthusiasm, and pride. The study from [PERSON] et al. [37] also refers to this goal as one of its features, by evaluating the perceived success of an HRC architecture.