Development and performance evaluation of an automatic section control system for corn precision planters

•A mathematical model for calculating real-time coordinates of the seed tube egress point of each row unit was developed.•Key algorithms for improving the storage and retrieval efficiency and performance of the automatic section control system were proposed.•Experiments results demonstrated that the designed control system can effectively reduce overlap-planted area. Overlap- planted area (OPA) tends to appear when large precision planters with more row units were employed in planting corn for the operator would typically need to drive the planter into the already planted area and decide when to stop planting to ensure complete coverage. This will lead to an increase in the cost of seeds and potential yield losses. In this paper, an automatic section control (ASC) system for corn precision planters was proposed to address above problems, the working principle of the system is to build a database of planted areas (DAPA) by collecting coordinates of the planted area during planting, and constantly query whether the coordinates of the seed tube egress point (STC) of each row unit is in DAPA, finally control the start-stop state of the corresponding brushless DC motors (BLDCM) according to the query results. A mathematical model calculating STC of each row unit in real-time according to coordinates acquired by GPS receivers is established. In addition, the system adopts controller area network (CAN) bus distributed control mode, which makes independent control of the row unit possible and offers good extensibility. Algorithms including Geohash algorithm, algorithm of discarding the same prefix, and dynamic trie data structure for improving the efficiency and performance of the ASC systems were proposed. Laboratory experiments were conducted at five Geohash string quantities (7410, 37040, 74070, 111110, and 148,150 Geohash strings), the results demonstrate that the proposed algorithms have high efficiency and are basically not affected by the increase of DAPA scale: time consumed (t) of retrieving and inserting a Geohash string from the dynamic trie is less than 36.51 ms and 62.99 ms, respectively, and there is no significant difference in t under various Geohash string quantities (P greater than 0.05). Field experiments were conducted at three positioning frequencies (fGPS) (2, 5, and 10 Hz) and three field shape complexity (pa) (0.08, 0.10, and 0.12). The results showed that the dp value could be decreased immensely when the ASC function was turned on: under