###### Abstract  
Although the actual use of delivery robots like UGVs and UAVs has not yet been generalized, they are also used for additional purposes like fun and enjoyment in some limited areas such as tourist destinations. In this study, an optimal algorithm is proposed that operates a delivery service through an integrated system of UGVs and UAVs at certain tourism destination. It is assumed that both UGVs and UAVs or only one means could be used depending on the type of goods delivered and the topographical characteristics. The mathematical model-based optimization technique is applied to generate the delivery service route of both UGVs and UAVs that can maximize total customer satisfaction. The developed mathematical model is solved through CPLEX and genetic algorithm, and the results are compared by dividing into case 1 in which UAVs move freely and case 2 in which UAVs can move only in a limited path since there is a risk of accidental falling when moving. As a result, when UAVs move freely, the total customer satisfaction is higher while the total complete time increases. However, it is suggested that an appropriate operation policy should be determined considering the risk of accidental falling. U 20221212039620222120103962022121203962022121212212122121221212212212212212221222222222222222222222222222  
As social distancing has become routine due to the COVID-19 pandemic, people have been unable to visit restaurants to eat but order their food by using food delivery applications. In the meantime, many people who have lost their jobs have entered the food delivery business, but as the demand for non-face-to-face food delivery increases, many attempts are being made to utilize delivery robots. The use of UGVs or unmanned aerial vehicles (UAVs) is generally considered as a candidate for delivery robots, and UGVs have already been recognized for their utility as logistics robots [5]. In the case of UGVs, many applications and success cases have been reported for transport in a closed environment, but lots of studies for practical use are being conducted because of the high complexity of using them as a delivery robot in an open environment. In the case of UAVs, they are free to several problems that recognizing the obstacles and so on because they can move through the sky. However, more efforts are needed for practical use because they can endanger people or objects on the ground due to the possibility of the accidental fall of transported object or the UAVs themselves. Nevertheless, since the advantages of delivery robots using UGVs and UAVs are clear, many studies are being conducted for practical use, and lots of companies are actually making various attempts [6]. There are still limitations to providing a satisfied customer service through robots as well as delivery robots. However, in the tourism field, a service using robots is being presented on a trial basis due to the additional purposes such as fun and enjoyment. Recently, guide robots that can provide airport usage information to tourists are easily found at airports in many countries, and hotels often use delivery robots for customer service, such as room service [3]. In particular, the customer can have a special experience through the services providing by robots. Therefore, the 'Henn-na Hotel' in Japan proposed a check-in service and luggage storage service using robots even though the service itself is a little bit incomplete as shown at Figure 1[7]. Currently, there may be some possible problems in active introduction of service robots because there is still a limit to provide services through it, but robots can be considered as an alternative to solve the fundamental problem of the tourism sector such as the labor shortage. In this study, considering this situation, it is tried to develop an optimal algorithm for an integration system of both UGVs and UAVs to provide delivery services at certain tourist destinations such as beaches or riverside parks.