## 4 Methodology
### Semantic Map Creation from BIM  
A robot's operating software should internally maintain a map, which is an internal representation of its operating environment. From the map, the robot can retrieve geometric  
Figure 1: Overall framework. Figure 2: AMCL localization errors (**a**) due to the interpretation of the sofa front as a wall and (**b**) doors being mistakenly recognized as a contiguous wall. and semantic information required for task planning and execution. In cases of AMCL localization, the map should provide the geometric information of the environment (as shown in the 2D AMCL map in Figure 2a) and key coordinates, such as the initial location and target destination. In addition to the structural elements, our study incorporates dynamic non-structural elements, such as doors and furniture, in order to represent the environment with details sufficient for robot operations. For example, the static door element modeled in BIM (Figure 3a) describes a door with a static solid model with annotations showing possible door swings. However, as shown in Figure 3b, the main body of the door needs to be described as a dynamically movable element that can interact with a robot. In order to overcome the limitation, our study describes a building in a URDF format to describe static and dynamic elements within the robot operating environment. The URDF is a format that is commonly used for precise description of the dynamic actions of robot parts. A URDF file expresses a robot with its subparts as links and joints that describe the relationship between links. We utilized the IFC-URDF convertor from our previous work [43] to generate a URDF building model from a BIM model. Ref. [43] provides technical details about the BIM-URDF conversion used in this study. There are four major steps required for the generation of a dynamic URDF building model. **Step 1. BIM-based building model creation**: This first step is a traditional process to model a 3D BIM model that contains project information, including geometric information of individual building elements and properties of the building elements. This process can use commercially available BIM authoring tools. **Step 2. Conversion of building element information using IFC-URDF converter**: This step converts the information about individual building elements to a ROS-compliant URDF format. This is done to describe both the static and dynamic aspects of building elements required for robot operations. Ref. [43] created the IFC-URDF converter that generates URDF files from an IFC file. The conversion first extracts shapes of static elements, such as walls and floors, from an IFC file and generates one URDF file. This URDF file describes static building elements as links connected with fixed joints. Using fixed joints, the one congregate object combining all static elements remains static during robot operations. However, elements with dynamic behaviors, such as doors and windows, are expressed in a different way. After extracting geometric information of the dynamic elements, the relationship between their hosting element links and the dynamic joints are specified to define their possible motions. As shown in Figure 3c, doors are connected to walls with revolute joints that allow door swings around the door hinges when a robot attempts to open the door. Moreover, any other project information required for robot task planning  
Figure 3: URDF building model creation for semantic localization of (**a**) conventional static door element in BIM, (**b**) dynamic door element with joint control, (**c**) 3D URDF building model with static and dynamic building elements, and (**d**) part of the URDF building file presenting dynamic building elements. can be stored separately in other formats, such as XML, which a robot can parse. As a result, step 2 generates one URDF file for all static building elements, a URDF file for each dynamic element, and multiple XML files for other project information that are combined in step 3. **Step 3.