An automatic piping algorithm including elbows and bends

Nowadays, the pipe arrangement has been enabled to be more efficient and economical by development and spread of CAD (Computer-Aided Design). However, it is difficult to design a piping layout automatically because there are many regulations and functional design rules which must be satisfied. The authors propose an automatic routing method for simple pipes including elbows and bends. In a practical design of a piping layout, there are many bends connecting straight eccentric pipes which have gaps within the pipes' diameter. However, no precedence automatic piping algorithm has been taken into account pipelines with such bends. The proposed method finds piping routes making use of not only elbows but the bends in order to minimize costs of the path connecting start point to goal point, while avoiding obstacles such as structures, equipments and the other circuits. In this approach, the authors regard the piping route design problem as a routing problem in a directed and weighted graph. Note that the nodes in the proposed graph have state variables not only locations but directions of the pipes. This graph can easily express the bends as simple edges, and then the routing algorithm can easily handle the bends. In addition, the presented method has specifications that the sizes of each cell, which is generated by decomposing of a free space, are not restricted within the diameter of the pipe. The routing algorithm uses Dijkstra's method to provide candidate paths. The efficiency of the proposed method is demonstrated through several experiments