Dynamic-weighing grain mass flow sensing for reliable in-field yield monitoring in combine harvesters.

The accuracy of on-board yield monitoring for combine harvesters is limited by the difficulty of acquiring high-fidelity mass flow signals and achieving reliable cumulative integration under complex vibration and varying operating conditions. To address this challenge, this study developed a weighing-based on-board yield monitoring system (DW-ORMS), in which a flow-collecting weighing-type grain mass flow sensor (C-GMFS) served as the core sensing unit. The C-GMFS enables stable weighing observation in confined installation spaces through mechanical decoupling and a single force-transmission path. At the system level, a state-aware gating strategy and trusted update mechanism were introduced to improve the reliability of output and cumulative mass estimation during unsteady operating phases. Based on field-measured disturbance characteristics, a parameterized disturbance model was established and used to identify the valid operating window and fix the gating parameter range. Simulation results showed that the proposed method achieved band-limited interference suppression of Aband ≥17.73 dB under strong disturbances while maintaining trend fidelity of PRRtrend ≥41.73% and low processing delay. Field harvesting experiments were conducted at working speeds of 2-8 km·h-¹. The cumulative strip mass showed excellent agreement with manual weighing references, with R²=0.973 and RMSE = 0.84 kg, and the strip-level mass closure error remained within CE ≤ 5% (N = 35). No monotonic drift in error was observed across working-speed groups. These results demonstrate that the DW-ORMS provides a deployable and traceable solution for high-confidence on-board yield monitoring of combine harvesters under unsteady field conditions.