Development of an Autofollow Row Control System for a Mechanized Harvesting Test Bench for Underground Crops

To solve problems such as the low quality and efficiency of mechanized harvesting for underground crops in China, this study developed an autofollow row control system for a mechanized harvesting test bench for underground crops. A closed-loop fixed dual-threshold dead-zone PD (proportional differential) algorithm was developed to control the corrective displacement of the excavating mechanism. The backlash, dead-zone width, proportional gain constant, and differential gain constant of the control system were determined as ±70 mm, 180 mm, 700, and 15, respectively, according to previous statistical analysis of underground crop production data, design calculations, simulations, and debugging. The test bench simulation experiments indicated that the missed excavation rate and breakage rate were significantly lower than those of a conventional harvester without an autofollow row control system. At a plant spacing of 40 cm, off-centerline distance of 6 cm, and forward speed of 0.7 m s-1, the average values of the missed excavation rate and breakage rate for the autofollow row harvester were 2.29% and 3.58%, respectively. This research can provide a technical reference for mechanized autofollow row harvesting of underground crops.HighlightsAn autofollow row control system for a mechanized harvesting test bench for underground crops was developed to improve harvesting quality and efficiency.A series of test bench experiments was conducted to determine the optimal parameter combination.A closed-loop fixed dual-threshold dead-zone PD algorithm was developed to control the corrective displacement of the excavating mechanism.The appropriate parameters (dead-zone threshold, dead-zone width, proportional coefficient, and differential coefficient) were determined.Harvesting quality improved significantly by using the developed autofollow row control system. Keywords: Autofollow row, Excavating harvest, Fixed dual-threshold dead-zone PD algorithm, Underground crops.