## 1 Introduction
Nevertheless, the work related to the implementation of the system of preventive maintenance of pumps is based on the recommendations of collection and processing of big data and the implementation of special models and calculation complexes to assess the service life and technical condition of pumping equipment [15]. All information is collected and transmitted to the users or specialists who operate this equipment for processing. The potential problems in implementing predictive analytics systems are associated with the lack of a tool that can clearly recognize a possible dangerous situation for the equipment at the right time or indicate the cause of a situation [16; 17]. For example, [18] states that maintenance technicians were largely not using field maintenance data because of problems with data availability and reliability. It is said that technicians spend 12+% of their total maintenance time on each piece of equipment requesting and searching for information. However, these activities can be alleviated by providing proper computing support and implementing a tool that will provide the right information support for oil pump maintenance. The authors of the present work propose using an augmented reality system as such a tool. Today, the world lives in the age of digitalization [19; 20]. Digital technologies are being introduced everywhere and affect all sectors and areas of human activity [21; 22]. According to the authors, one of the digital technologies most suitable for pump maintenance tasks is augmented reality technology. By matching real objects with virtual ones, the augmented reality system can become the main support for technicians when making decisions [23; 24]. The use of an augmented reality system in equipment maintenance is not a new thing. Such systems are used, developed, and presented in various studies. For instance, Ref. [25] provides an overview of the current state of AR in maintenance and the most important technical limitations based on a systematic literature review. The results of the study show the areas where there are still shortcomings. As an example, traceability methods are indicated as the main problem in the way of implementing AR technologies in the industry. Because of their imperfection, it is difficult to compare real and virtual objects. The authors of [26] considered the application of augmented reality for creating an integrated object management system in the oil industry. The authors suggest combining two technologies in the present paper: augmented reality [27] and dynamic simulation [28,29]. This will make it possible to evaluate the effectiveness of their collaborative use in the maintenance of pumping equipment and to form recommendations for the development, implementation, and collaboration of these technologies. In a way, the dynamic modeling system works on the principle of a digital twin [30,31]. However, it is essential to point out that the digital twin is a rather complex concept as it comprises different functionalities. For example, a numerical simulation system [32] is used to solve local target tasks (e.g., determination of the pump shaft impeller load and blade movement). For this purpose, this system uses a pump/pump motor numerical simulation system. However, if it is necessary to extend the functionality and determine changes in the technological parameters over time (e.g., changes in the flow rate of raw materials flowing through the pipeline, temperature, and other regime parameters that characterize a particular technological process), then the numerical simulation system is not appropriate for solving this problem. In this case, dynamic modeling [33] is a more preferable tool. To achieve this goal, the Methods and Materials section will present ways of connecting the dynamic model and the augmented reality system, and the methodology for conducting experiments and testing and evaluating the effectiveness of the system will be given.