An Alignment Object Detection Method for Automatically Erecting Precast Components

Abstract

In the context of intelligent construction, the alignment of precast components is the key to the automated erection of precast components. This can be divided into preliminary and precise alignment. The alignment process depends on alignment objects on site. The preliminary alignment is based on the control surface, while the precise alignment is based on exact control elements. Traditionally, this requires manual operations and communications to determine alignment objects, thus leading to low efficiency and being prone to accidents. To address this issue, taking the typical sleeve-rebar connection during the erection of precast structural components as an example, this research proposes an alignment object detection method based on computer vision. Firstly, an automatic generation algorithm for the hoisting control surface is established by combining image processing and a precast component model database. Then, an automatic extraction and matching algorithm is proposed to match the extracted control elements (i.e., sleeve centers and rebar contours). Finally, two experiments are conducted to verify the feasibility of the alignment object detection method. It is found that the proposed method can extract the basic alignment information for the automated erection of precast components.