Path Planning of the Turning Back of an Autonomous Large-Scale Six-Wheeled Dump Truck for Loading/Leaving Sediment Based on Backhoe Work

There is an urgent need to automate earthmoving activities for large-scale six-wheeled dump trucks using retrofitted sensors and driving robots. A dump truck stops at a loading position with its bed facing the backhoe to fill the bed with sediment quickly. It also stops with its bed facing the leaving position. Therefore, it is necessary to plan ahead to safely and accurately enter and exit those working positions. However, existing path planners did not generate a path with a turning point that is suitable for large-scale six-wheeled dump truck loading sediment. In this paper, we propose an online pathplanning method with the following main features. First, a path is planned to move the dump truck forward and/or backward to the working position to load and/or leave sediment. Second, when a new working position is designated, a path from the turning position to the new goal position is automatically established. We verified the proposed method using a simulator of the dump truck (3.5 m × 11 m), showing that it is possible to properly account for the turning radius of the dump truck. The result reveals that it is possible to replan with a working position shift of 4.8 m or 33° from a 25 m distance and that the time required for replanning can be shortened to ≤ 7.56 s. We also confirmed that the large-scale autonomous dump truck can automatically stop at the loading position in cooperation with a humanoperated backhoe 10 out of 10 times with a stopping accuracy of 0.57 m and 5.29°.