Design Method and Experimental Study of a Rice Transplanting Mechanism with Three Planting Arms Constrained by Differential Noncircular Gear Trains

Abstract

HighlightsThe fuzzy transplanting requirements were transformed into optimization targets.A transplanting mechanism constrained by differential noncircular gear trains was designed.The optimal software design of the transplanting mechanism was developed.The designed transplanting mechanism realized the trajectory and attitude required for rice transplanting.Abstract. The transplanting mechanism is the core working part of a rice transplanter, and its working cycle includes the stages of picking, transporting, planting, and returning. Aimed at the problems of poor working precision, poor trajectory and attitude, and low operating efficiency of the existing transplanting mechanism of rice transplanters, a transplanting mechanism with three planting arms constrained by differential noncircular gear trains was designed to avoid the side gap accumulation caused by unequal multistage speed transmission. The movement of the 2R open-chain mechanism was constrained by a differential noncircular gear train so that the connecting rod could realize the trajectory and attitude required for rice transplanting. Based on the unequal speed transmission of differential noncircular gear trains, a kinematic model of the transplanting mechanism with three planting arms was established, and the optimal software design of the transplanting mechanism was developed in a visual programming environment. Based on the agronomic requirements for rice transplanting, the optimization design targets of the transplanting mechanism were customized, the functional relationship between the optimization targets and parameters was established, and the optimization targets were embedded into the optimal software design. Through parameter optimization, a set of mechanism parameters meeting the requirements of the trajectory and attitude for rice transplanting were obtained, and the structural design of the transplanting mechanism was completed. Virtual simulation experiments and bench experiments with the transplanting mechanism with three planting arms constrained by differential noncircular gear trains showed that the transplanting mechanism accurately realized the trajectory and attitude required for rice transplanting. Keywords: 2R open-chain mechanism, Differential gear, Noncircular gear, Rice transplanter, Transplanting mechanism.