# Path Planning Strategy for Implementing a Machine Control System in Grader Operations
## 1 Introduction  
The current construction industry is experiencing a shortage of new labor inflow and skilled workers due to a declining population [1]. This causes problems in terms of productivity, safety, and quality within the construction sector. This phenomenon is common across many countries, and efforts are being made to enhance the competitiveness of the construction industry to address these pressing issues. Recently, with the advent of 4 th Industrial Revolution technologies, the concept of smart construction was introduced. It aims to enhance productivity, efficiency, and safety by integrating digital technologies and automation systems into the construction industry. Smart construction leverages various advanced technologies to transform processes such as planning, design, construction, and maintenance, and is regarded as a valuable solution to the challenges confronting the construction industry. Earthwork is essential in most construction projects [2; 3; 4] and can account for as little as 20% to over 30% of the total cost depending on the type of construction [5; 6]. Owing to the high dependency on construction equipment in earthworks compared to other construction trades [7], the productivity of tasks relies heavily on the skill level of equipment operators. Therefore, optimizing the efficiency of large machinery such as dump trucks and dozers is crucial [8; 9; 10; 11]. Effective management of earthworks is vital not only for maintaining the overall project schedule but also for cost control and quality assurance [12]. Given the impact of earthworks on the entire construction process, the efficient management of earthworks is a significant challenge for improving the overall efficiency and competitiveness of the construction industry. To address this challenge, countries around the world are focusing on the efficient operation of construction equipment, with considerable efforts directed towards the development of MG (machine guidance) and MC (machine control) equipment, especially for earthwork machinery. MG/MC are technologies that precisely guide and control construction equipment. The MG uses geographic positioning technology to measure the location and direction of the equipment, providing real-timeattribute information necessary for earthworks [13]. Based on this information, the equipment operator manually controls the machinery to perform the tasks [14]. MC goes a step further by directly controlling the machine or its blade without the need for operator intervention [15]. This MC technology can significantly enhance precision, efficiency, and safety in earthworks, while also contributing to cost savings [16]. One of the key components of MC (machine control) technology is the task path generation function. This function creates an optimal work path for the construction equipment, which is essential for the precise and efficient operation of machinery. It is necessary to generate appropriate work paths that suit the type of construction equipment and the nature of the task. The generated path must be the one that the construction equipment can follow, and it should enhance the efficiency, precision, and safety of the equipment. Figure 1 illustrates the smart earthwork process. First, drones are used to scan the site and create a point cloud, which is then processed to convert it into a terrain model. By incorporating the terrain model and design information, a 3D target model is completed. Based on the generated 3D target model, the specifications of the construction equipment, and the tasks to be performed, the work path is automatically generated. The information related to the generated work path is transmitted to the MC equipment, which then performs the assigned tasks using the provided information. This study focused on developing an algorithm to automatically generate work paths within a smart earthwork process.