# A Study on Design and Control of the Multi-Station Multi-Container Transportation System
## 1 Introduction  
When transporting and distributing products in warehouses, factories, buildings, or hospitals, the problem of allocating space in a congested area with a reasonable cost has led to the need for an automatic transportation system (ATS). This ATS needs to operate efficiently in the limited spaces and also meet the current precision machining and manufacturing capabilities in Vietnam. To ensure automation and flexibility in product distribution, the authors propose a multi-station ATS with the feature of redirecting products to transport them to the exact stations. There are some automated transportation systems in the world, but these system are unsuitable to apply in Vietnam. However, these systems are also referenced in this section. Vietnam needs a localized product, which saves costs and is convenient for future maintenance. With the proposed concept of an MSMC ATS, many options have been explored, which are the pneumatic tube system (PTS) [1, 2], the Telelift rail-based system [3], and the SwarmRail overhead robot system [4]. However, these options are still not suitableand feasible when applied widely on a large scale in many areas in the country because of the following objective limitations: [PERSON] et al., in [1], indicated that the PTS has an incredible average speed of 5 m/s, but it is typically used for specimen delivery and their load capacity is not significant. Furthermore, [PERSON] et al., in [2], mentioned several disadvantages when using the pneumatic capsule pipeline system, such as the inability to carry special delivery parcels due to the size limitation of the carriers, as each container can carry about only five pounds. Moreover, the inability to dispatch between intermediate stations is significant. Therefore, the continuous transmission between any two points and to railroad companies without other handling is unachievable. Another concept is the Telelift multi-station rail-type transport system, which is described in [3] by [PERSON] et al. This advanced system consists of container trucks that can travel independently along electrical railway lines between stations. Such a rail-type system ensures a significant degree of flexibility and automation, but the current precision manufacturing capability in many local regions, and also the investment cost of the investors, is not enough to meet the requirements. Regarding the rail-type multi-station transportation system, [PERSON] et al., in [4], proposed an overhead robot system called SwarmRail. This system involves multiple robots moving along an overhead rail grid for indoor transportation. The significant advantage of the SwarmRail system is that the mobile robot units can change the direction at an intersection of the rail grid without the need for tracking switches or other active parts. Therefore, many mobile units can operate independently in parallel and with a variety of different paths, which enhances flexibility to the overall operation. However, the complexity of this system is beyond the ability to manufacture and while still ensuring a reasonable cost. In addition, automated guided vehicle (AGV) systems are also considered, but they are unsuitable when applied to confined spaces with crowded situations, such as hospitals or office buildings, and they may also change the layout of the present building. In this paper, the design of a multi-station ATS is described. This ATS is more feasible, flexible, and easy to fabricate at a reasonable cost, and at the same time, integrated with the line switching feature as referred to the rail-based system in [3]. The purpose of this proposed system is to perform the transportation to improve the productivity and mobility of many factories, hospitals, and warehouses. This multi-station ATS would also ensure that countries, which still have a manufacturing industry with many limitations, can still achieve it independently.