Side-to-side 3D coverage path planning approach for agricultural robots to minimize skip/overlap areas between swaths

Automated path planning is important for the automation and optimization of field operations. It can provide the waypoints required for guidance, navigation and control of agricultural robots and autonomous tractors throughout the execution of these field operations. In agriculture, field operations are usually repeated in the same field and from year to year as well, therefore, it should be carried out in a manner that minimizes environmental impact and cost taking into account the topographic land features. Current 3D terrain field coverage path planning algorithms are simply 2D coverage path planning projected into 3D through field terrain. When projecting 2D coverage plan into its 3D counterpart through field terrain, the actual distance between adjacent paths on the topographic surface increases, and there might be skips between adjacent paths on the slopes. In addition, when the machine rolls on slopes the effective width of the implement decreases by a similar amount to double this error and complicates the problem. In this paper, a numerical approach to estimate the total skip and/or overlap areas is developed and applied to determine the optimum driving angle which minimizes this impact. Also, a novel side-to-side 3D coverage path planning approach which ensures zero-skips regardless of the topographical nature of the field terrain is developed. The approaches developed in this paper are tested and validated using a typical field of a tailored terrain and then applied to two real experimental fields of uneven terrain nature. The proposed approaches illustrated that a significant percentage of uncovered area could be saved and used if appropriate driving angle is chosen and if a side-to-side 3D coverage is used.