Authors

Abstract

During the tillage of two-way ploughing equipment in rocky and barren soil, due to hard objects such as stones, the plough and the key working parts such as plough column are deformed and broken, thereby reducing the reliability and service life of machines and tools. As such, an anti-overload automatic obstacle avoidance mechanism for two-way ploughing is developed. The maximum obstacle avoidance height is 40 cm, and the obstacle avoidance angle α is designed. The rotation range is 4.6 ~51.5°, and the effective compression stroke of the spring after pre-tightening is 39.34 mm. The motion equation and quasi-static force equation of the mechanism are established. The plowing resistance in the equilibrium state is 9.74 KN, and the required spring preload is 9.75 KN. Under the safety factor of 1.3, different spring elastic coefficients change with the rotation angle of the mechanism. The virtual prototype simulation model of the anti-overload automatic obstacle avoidance mechanism is established. The simulation results show that the mechanism can effectively perform the obstacle avoidance action. Bench test verifies that the mechanism can avoid obstacles according to the predetermined load. The field test shows that the stability coefficient of the ploughing depth of the mechanism is less than 8%. The results can effectively realize the obstacle avoidance function and ensure the farming quality, and provide an efficient and reliable anti-overload obstacle avoidance structure and parameter basis for the rocky land.

Abstract in Chinese

针对当前双向犁耕装备在多石贫瘠土壤耕作过程中，石块等坚硬物体使犁体以及犁柱等关键工作部件产生变形、断裂，降低了机具可靠性和使用寿命等问题，研制了双向犁耕防过载自动避障机构，对过载保护自动避障机构的结构和关键参数进行了设计，设计最大避障高度为40cm，避障转角α 转动范围为4.6°~51.5°，弹簧预紧后的有效压缩行程为39.34mm。分别建立了机构运动方程和准静态受力方程，得到平衡状态下犁耕阻力9.74KN对应所需的弹簧预紧力为9.75KN，为提高机构可靠性设置安全系数为1.3，分析了不同弹簧弹性系数随机构转角α的变化曲线。通过台架试验验证了机构能按照预定载荷进行避障动作，进行了田间试验，根据响应曲面设计法中Box-Behnken Design原理，试验结果表明，对耕深稳定性变异系数影响的贡献率由大到小依次为：耕速、耕深和弹簧弹性系数。机构耕深稳定性变异系数均小于8%，能有效实现避障功能并能保证耕作质量，为多石地提供了高效可靠的防过载避障结构和参数依据。