Modelling and simulation of the dynamic performance of a no-till seeding assembly with a semi-active damper

Abstract

In no-till seeding, one of the biggest challenges to achieve a reliable seed germination and an even plant field emergence is an extreme variation in the desired seeding depth. This is caused by the inadequate response of the seeder motion dynamics to harsh soil conditions and to high operating speeds. In order to assess and optimise the dynamic response of a no-till seeder, mathematical models were developed for simulating the vertical motion of a coulter assembly. The models included the dynamics of the coulter assembly, with the packer wheel as a passive system, and a semi-active MR (magnetorheological) damper system, which was considered to be located in-between the coulter and the packer wheel. The developed model of the coulter assembly dynamics was validated based on a correlation between the simulated and the measured impact forces and pitch angles. A root-mean-squared (RMS) error resulted from the correlation have increased from 6.84% at the lower speed of 10kmh−1 to 14.5% at the higher speed of 15kmh−1 for the impact forces, from 8.1% at the lower speed of 10kmh−1 to 13.1% at the higher speed of 15kmh−1 for the pitch angle. Conversely, there was a fall in the correlation coefficient from 0.699 to 0.681 for the impact forces and from 0.942 to 0.684 for the pitch angle between the lower speed of 10kmh−1 and the higher speed of 15kmh−1, respectively. Furthermore, all three applied hysteresis models, such as Bingham, Dahl and Bounc-Wen model, for the semi-active MR damper system behaviour demonstrated significant improvements over the passive system model. Among the models, the Bouc-Wen model produced more adequacy of the MR damper behaviour with the highest reduction of 54.1%, 63.3% and 41.2% in the amplitude of the impact forces and 52.3%, 58.2% and 38.1% in the amplitude of the pitch angles at the speeds of 10kmh−1, 12kmh−1 and 15kmh−1, respectively.