# Using a Cable-Driven Parallel Robot with Applications in 3D Concrete Printing
## 1 Introduction  
Currently, the technology of rapid prototyping, 3D printing, machining with CNC machines, factory automation with robots, and monitoring and control over the internet is being widely applied to reduce production and labor costs, as well as to increase productivity and consistency [1, 2, 3, 4, 5]. Meanwhile, the traditional construction field has been slow to integrate modern technologies into its processes. In developed countries, the traditional concrete mixing and casting method of building parts at the construction site has been replaced by being prefabricated in a factory and then transferred to the construction site for assembly. This allows for a specialization construction process and shortens the construction times, increasing the quality and stability of the building. However, this option is not suitable for single houses with different designs; the size of the prefabricated parts is also limited due to transport problems. Additive manufacturing (AM)--an appropriate name to describe the technologies that build objects by adding layer-upon-layer of material, such as plastic, metal, concrete, combined with the assistance of computers for the calculation, design, and simulation of the structure--optimizes the shape design and distributes the material appropriately so that the structure meets the technical requirements with the lowest amount of material. When applying 3D printing technology in construction, we can save the costs of the concrete form work and mold installation time, thus shortening the projectimplementation time. Many fast prototype printers (3D printers) can work continuously, thereby project costs can be significantly reduced. By adopting 3D printing techniques in the construction industry, it is possible to reduce labor and construction time, improve quality, and reduce the environmental impact and health of workers. The construction 3D printing technology for building a layer-by-layer construction [1] is known as additive manufacturing (AM). [PERSON] et al. [2] investigated the additive manufacturing processes in construction and reviewed large-scale additive manufacturing processes that have been applied in the construction and architecture sectors for concrete printing, based on the principle of automatic material extrusion. In that paper, the wet properties of the material were considered, as it had a great influence on the product's success. The paper also proposed several new criteria for the classification of specific parameters of this process. Three processes were considered for different applications and materials, including the D-Shape process--uses a powder deposition process, which was selectively hardened using a binder; Concrete Printing--based on the extrusion of cement mortar; and Contour Crafting--build large-scale objects with a smooth surface finish by the layered printing method based on the printing process with a towel. The authors have analyzed the Concrete Printing procedure in detail, showing many advantages, such as being responsive to a design with complex profiles, achieving a high accuracy, and saving a lot of labor costs. It is difficult to do with conventional construction processes. Different materials can be used for 3D printing, with equipment sizes range from small to large, corresponding to many types of products such as statues, houses, vehicles, and boats. Some structures have been studied and used for large 3D printing, such as cartesian structures, serial robots, and cable parallel robots, as shown in several studies. [PERSON] et al. [3] proposed a 3D printing system that employs two mobile robots with industrial robots printing concurrently a large, one-piece structure; the system consists of two 6-axis industrial robots with a reach of 0.9 m and repeatability accuracy of 0.02 mm, placed on two holonomic mobile robots; two printing nozzles also was designed and attached to the robots, connected with a pump.