# Self-Assembly at a Macroscale Using Aerodynamics  
[PERSON]  
1 School of Mechanical and Energy Engineering, Ningbo Tech University, Ningbo 315100, China; [EMAIL_ADDRESS] (Y.L. ); [EMAIL_ADDRESS] (X.J. ); [EMAIL_ADDRESS] (Q.N.) [PERSON]  
2 Ningbo Innovation Center, State Key Laboratory of Fluid Power and Mechatronic Systems, School of Mechanical Engineering, Zhejiang University, Ningbo 315100, China; [EMAIL_ADDRESS] (Y.C. ); [EMAIL_ADDRESS] (C.L. ); shangfang  
particles. For example, in biological systems, self-assembly construction exists in cellular division as the body's ability to grow and repair. Various elements in the system compete and cooperate with a high efficiency, higher-order structures are built, the effect of various resources is maximized, and their functionality emerges autonomously [21]. The essence of the mechanical assembly structure is also a high-level complex functional structure formed through the interaction of local energy, materials, and information. Well-designed assembly product systems are normally nonlinear and complex with a certain organization. With the improvement of product complexity, the organization will be strengthened usually. As a result, the orderly evolution rule needs to be explored, and the \"optimization\" and \"emergence\" mechanism contained in self-assembly is the exact endogenous internal force that is needed to solve the collaborative order problem of complex systems. The majority of related research has been conducted at a microscale in order to explore the molecule assemble method. However, at a larger scale, especially in the mechanical assembly field, [PERSON] et al. conducted a limited amount of research [22], where molecular self-assembly through tangible physical models was demonstrated in 2007. The geometry and material components were based on various molecular structures, such as the tobacco plant virus, ferritin protein, and catechol dioxygenase enzyme [23]. In 2012, a container was designed to tumble the units inside, and it was discovered that units could be self-assembled into structures at a furniture scale [24]. In 2014, formations of crystal growth were imitated in a fluid environment. In the same year, research called the \"self-assembly chair\" was conducted in fluid environments to demonstrate the process of irregular asymmetric components. Other research, such as \"aerial balloon assembly\", investigated the possibility of large-scale self-assembly in aerial environments by using lightweight structures. Self-replicating spheres explored the processes of growth and division through the agitation of simple spherical units in 2015 [23]. It has been proposed that a self-assembly system must include four components: parts for assembly, links for connection, a container for accommodation, and the target for the final assembly goal [21]. Furthermore, the driving energy of the assembled system needs to be calculated: too much driving energy will cause the links to break; however, too little driving energy will not allow the parts to move together and be pinned to each other [25]. Although some researchers have already conducted self-assembly experiments at a microscale, a macroscale self-assembly method is still required. Compared with the research mentioned above, it is still of great significance to design a macroscale self-assembly device with the ability to control the environmental variables. Moreover, the purpose of previous research was to realize a self-assembly process of a specific structure; however, in this paper, the self-assembly device introduced is not limited to this--it also represents the \"optimization\" and \"emergence\" mechanism by experiments. In this research, the designed experimental device is more suitable for laboratory circumstances, and the whole device can easily fit onto a normal desk. The designed pneumatic self-assembly device controls the airflow force as the driving implement. The parts for assembly are divided into two groups: parts of the directed assembly experiment and parts of the indirect assembly experiment.