Terrain-Constrained Coverage Planning with Connector-Risk Pre-Evaluation for Hilly Farmland Harvesters

Abstract

Coverage planning on hilly farmland must reconcile terrain traversability, harvested area, path efficiency, and curvature-constrained turning. This paper presents a deterministic multi-direction method with two coupled mechanisms: direction-dependent decomposition of digital elevation model (DEM) gradients into longitudinal and cross-slope components, and pre-assessment of non-working connectors before sweep-direction selection. Parallel swaths are clipped by the field, directional slope mask, and exact simulated obstacle footprints; Dubins connectors are then generated and audited at their instantaneous headings. Experiments use eight fields containing real elevation measurements and three harvester configurations. Relative to fixed 0°, mean working cross-slope violation decreases from 16.87% to 0.003%, with a 0.46% pathlength increase. Relative to Fields2Cover 2.1.0, it decreases from 18.46% to 0.003%, while path length increases by 11.90% and exact whole-field coverage decreases from 97.70% to 93.08%. Connector pre-assessment reduces connector violation from 18.61% to 12.50% relative to its ablation, but does not guarantee a fully feasible continuous route. The results quantify the safetyefficiency trade-off without claiming real-vehicle validation.