## 5 Production Impacts of Exoskeletons in Manufacturing, Especially \"Time Management\"
### Exoskeleton \"Wear/Unwear\" Times Experiments and Evaluation  
In this paragraph, the \"wear/unwear\" times for commercial exoskeletons are presented. A method for establishing and evaluating times for all three different types of passive exoskeletons (overhead, bending and sitting support) is developed. Therefore, six different devices of diverse manufacturers were chosen to perform experiments, as follows: (a) 2x overhead exoskeleton: Exo1 and Exo2; (b) 2x bending exoskeleton: Exo3 and Exo4; and (c) 1x sitting exoskeleton: Exo5 in 2 different versions.  
Before the kick-off for the experiments, the exoskeleton was adjusted initially to an optimum for each individual worker. This initial adjustment time is not captured and counted, as in serial operation each worker wears his own exoskeleton and therefore the settings were previously personalized.  
Methodologically, first of all, the wear/unwear process was captured with a camera device. The goal was to analyze the particular movements and tasks on the basis of MTM-1 (methods-time measurement) and thereby, to achieve a valid assessment of time management. It became apparent that the setup process was too detailed and diverse to be depicted sufficiently by this method. Therefore, the decision to implement an assessment following the REFA (Reichsausschuss fur Arbeitszeitermittlung--Reich Committee for Labour Studies) method was made. For the perspective of work-condition regulations, a measurement of the voluntary workers' performance level is not legitimate. Enough beforehand training confirms this hypothesis of 100% performance level [37].  
For this purpose, the test person first picked up the exoskeleton from a tripod. After taking it off the holder, the test person wore the exoskeleton, paused for a short moment in order to signalize the end of the wearing process, subsequently removed the exoskeleton and hung it up properly in its initial tripod. Without another break, once again, a wear/unwear cycle was started. Every exoskeleton was taken thorugh the weared/unweared cycle ten times. The performance of every test person was captured on a video device. A digital signal started and stopped the test. The intermediate results (wearing starts and unwearing starts) were documented on a form. Deviations, for example, resulting from mistakes or twisted straps, were recorded as well. The related table forms, based on validated methods following [38], were used for the measurement process. The respective start of the diverse partial tasks (each wear/unwear) of a whole cycle was documented and enhanced by eventually interfering disturbances of different types. Likewise, the performance level of each partial task was documented at all times (here, 100%, as mentioned before). To simplify the following statistical evaluation, the results were digitalized after 10 cycles of experiments. For evaluation purposes, each time value, \(\mathfrak{t}_{i}\), between the partial tasks of each cycle was determined separately. Each cycle's total time was determined through the addition of times within one cycle. The different results are shown in Table 2.  
In conclusion, the times for wear/unwear were determined via time observation methods used while performing experiments. Depending on the exoskeleton needed, wear/unwear time is between 20.3 and 87 s.