# UX in AR-Supported Industrial Human-Robot Collaborative Tasks: A Systematic Review
## 4 Discussion on Review Results  
From the current analysis, a substantial lack of structured methods to design user-centered AR applications for HRI have emerged. Despite several attempts in other various contexts (tourism, mobile application games, etc. [24; 25; 26; 27; 28]), UX-driven methodology are poorly adopted in HRI, and this led to the design of interfaces which are far from real users' needs. On this base, the authors believe that it is crucial to promote UX-driven design processes to develop successful AR interfaces, especially for collaborative tasks involving humans and robots, to fully support the O4.0. Only the adoption of a proper HCD framework allows considering the real needs of the operators in a specific context of use, focusing not only on safety and ergonomics issues, but on the overall UX aspects (e.g., usability, intuitiveness, satisfaction, cognitive load, and emotional response) with the final aim to have a renovated human-robot relationship where both subjects are actively participating and transmitting knowledge to the equivalent counterpart, according to a win-win approach. For these purposes, the review results suggest defining a structured UX-driven process to design AR interfaces for HRI tasks. The review represents a nonlinear and iterative process aiming at assisting the AR interface designer in implementing a valuable communication with robots, during the execution of HRI tasks. As depicted in Figure 4, the process must be made up of three main steps:  
1. Requirements Gathering;
2. AR Interface Design and Prototyping;
3. UX Assessment. The process starts with the need to define a new AR interface for collaborative tasks, and brings to the interface definition, before the AR interface development. Such a process goes a step further with respect to a few recent studies [10,34]. The first step to be investigated consists of requirement gathering from user research. It is a vital part of any UX-driven processes because it is the act of understanding the users and their needs, making sense of who the user is, what he/she wants, and how he/she will perform a certain task. It mainly consists of a deep, accurate user analysis based on the context research to be carried out in a not invasive way using a set of UX design techniques. The most suitable techniques for user understanding are user observation, focus groups, and interviews [66]. User observation consists of observing users in their natural environment without affecting their normal behaviors and performance, with the aim to understand the users' needs and widely used when users belong to specific categories. It can also be done using video analysis, but in some industrial contexts video recording is not always possible. Such analysis is frequently combined with focus groups or interviews, which can provide a deeper insight about the users' habits and behaviors since they actively involve users to collect, in different ways, qualitative data about their  
Figure 4: The need of a UX-driven process for AR interface design to support HRI tasks. needs, expectations, or fears. The mixed approach combining different techniques is very useful since it allows combining quantitative and qualitative data. After that, the list of executed tasks can be easily defined, reporting also the actors involved for each task (e.g., humans, robots) and the time span. These actions finally led to the definition of design specifications considering functional, technical, and safety aspects. A different set of UX design techniques can be validly adopted, from user scenarios and personas to experience maps, as proposed by [10]. User scenarios are stories to show how users might act to achieve a goal in a system or environment. They are valuable aids for designers to visualize aspects of their solutions which users might appreciate most in their contexts of use and with their unique needs and motivations. Personas represent the target users by a set of probable users and flesh out their experiences to reflect realistic situations.