# Enabling Technologies for Operator 4.0: A Survey
## 4 IoT-Based Solutions to Support Operator Activities
\begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Operator 4.0** & **Feedback** & **Technologies** & **Examples** \\ \hline Analytical operator & Report/potential danger & Smart glasses, smartphones, tablets and personal displays & Big data-based development of a manufacturing process [145]. \\ \hline Augmented operator & Each possible feedback & Smart glasses & AR for tractor manufacturing [146]. Smart glasses [23, 26]. \\ \hline Collaborative operator & Waiting for interaction/technical problem & Smart glasses, smartphones, tablets, personal displays, headsets and smartwatches & Collaborative operator workspace [147]. \\ \hline Healthy operator & Need rest & Smart glasses, smartphones, tablets, personal displays and headsets & Measurement of physiological parameters [148, 149]. Security issues [150]. \\ \hline Smarter operator & Answer to a question & Smart glasses, smartphones, tablets, personal displays and headsets & Chatbot [151] and AI provide support to operators [152]. \\ \hline Social operator & Emergency & Smart glasses, smartphones, tablets, personal displays and headsets & Facebook-based product avatar [40] and Social Manufacturing (SocialM) [53]. \\ \hline  & Optimal route/targeting/training & Smart glasses, tablets and smartphones & Navigation [153, 154] and targeting [154, 155, 156]. \\ \multirow{2}{*}{Super-strength operator} & Force feedback on a hand or whole arm & Smart gloves and special exoskeletons & HaptX[157, 158], VRgluv[159] and ABLEProject [41, 160] are such technologies. \\ \cline{2-2}  & Danger indicator & Smart glasses and speakers & Safety and risk management (related to exoskeleton technology) [161]. \\ \hline Virtual operator & Collision/weight/pressure & Smart clothes/smart gloves & VR technology in prototyping and testing [162]. This kind of technology becomes more efficient with every wearable feedback device (e.g., smart gloves [163]) that use (secondary) human senses directly. \\ \hline \end{tabular}
\end{table} 
Table 6: Feedback technologies for Operator 4.0 solutions. distribute 20,000 packages (9000 orders), leading to a 25% increase in the efficiency of the operators and a reduction in errors of 40%. Quality and reliability are critical in aerospace manufacturing. Boeing and Model-Based Instructions (MBI) from Iowa State University support the work of the operators. The first solution was designed to show the instructions for the workers. The installation of the desktop MBI was static, and there were numerous situations when the operator could not see them during the assembly process. The tablet MBI used the same instructions as the desktop MBI, but it was mounted on a mobile arm. The tablet AR was the same tablet that provided the tablet MBI solution; however, the operator could see the real world on the display of the tablet, and the software added virtual elements into the video stream. It was observed that the AR technology yielded the best solutions with regard to first-time quality, speed and worker efficiency out of these three solutions [164; 165]. These benefits are in accordance with what was observed in the introduction of general Industry 4.0 solutions [166]. The examination of 385 published applications shows that the most common benefits of Industry 4.0 are the enhanced efficiency (47%), prevention of errors (33%), reduction of cost (33%), employee support (32%) and minimization of lead time (31%). It is worth noting that the importance of communication (31%), human-machine interfaces (25%) and sensor technology (11%) were also highlighted. The review concerning examples of applications showed clearly that the Operator 4.0 concept works in practice, and the following advantages were observed: (1) elimination of classical paper-based administration; (2) operators can use their arms freely and receive real-time feedback about the manufacturing process; (3) the duration of training of workers decreases; and (4) the efficiency of production increases and the number of errors decreases simultaneously in all cases.