Design and experiment of bionic stubble breaking-deep loosening combined tillage machine

Under the conditions of straw returning operation, there are three major technical bottlenecks in the Phaeozem region of northeast China, namely low stubble breaking rate, poor tillage depth consistency, and high fuel consumption. In this research, a bionic stubble-deep loosening combined tillage machine (BSD) was designed through bionic prototype analysis, coupled bionic analysis, coupled bionic design, theoretical analysis and application of intelligent control techniques. It consists of a bionic stubble breaking device and a bionic self-excited vibratory deep loosening device. Based on the unique biting pattern of locust mouthparts on maize rootstocks, the bionic stubble breaking device adopted a new multi-segment serrated bionic structure and a symmetrical rotational motion, which could significantly increase the stubble breaking rate (p<0.05) and reduce the resistance to stubble breaking operations (p<0.05). Based on the unique biology of the hare's paws, toes and nails, the bionic self-excited vibration deep loosening device adopted a new series-parallel composite bionic elastic system and an intelligent tilling depth control system with a fuzzy algorithm, which significantly improved the tilling depth consistency (p<0.05). The operational performance of the BSD was verified at different operating speeds through comparative experiments and reveals the mechanism of its excellent performance through theoretical analysis. The final experiment results showed that, at the same operating speed, the BSD improved the stubble breaking rate by 9.62% and 10.67%, reduced the stubble breaking torque by 28 N.m and 33 N.m, reduced the tillage depth coefficient of variation by 12.73% and 13.48%, and reduced the specific fuel consumption by 36 g/km.h and 40 g/km.h compared to the two most common models. The operating performance of the three kinds of machines will decrease with the increase of operating speed, and the BSD has the least decrease.