油菜旋耕移栽联合作业机穴距电液比例控制系统研究

Electro-hydraulic Proportional Control System of Hole Distance for Rape Seedling Rotary Tillage Combined Transplanter

油菜旋耕移栽联合作业机以拖拉机为动力,由于拖拉机动力输出为定值,故栽植速度不能随拖拉机前进速度而变化,导致栽植穴距不稳定。针对上述问题设计了穴距控制系统,以STM32为主控制器,通过地轮测速编码器检测前进速度,通过电液比例液压系统实时调节驱动栽植系统的液压马达转速,从而实现栽植速度与前进速度的实时匹配。穴距控制系统台架试验表明:液压马达转速与地轮转速变化趋势一致,滞后时间在600 ms内,左右两个移栽单元的液压马达同步性好,转速平均误差为0.7%。将穴距电液控制系统安装于油菜旋耕移栽联合作业机上,并进行了整机田间试验,4种理论穴距(150、160、170、180 mm)、4种作业速度(2、3、4、5 km/h)的对比试验表明:穴距稳定性好,理论穴距、作业速度均对穴距一致性变异系数影响显著,其中理论穴距影响最显著,在穴距160 mm和4种作业速度下,穴距一致性变异系数均能保持较小值,说明160 mm为最佳穴距。

The rape rotary tillage combined transplanter takes the tractor as power.As the PTO of tractor is fixed value,the planting speed of rape combined transplanter cannot change with the forward speed of tractor,which leads to the instability of the planting hole distance.A hole distance control system was designed,which was based on STM32 controller.The forward speed of tractor was detected by a ground wheel speed encoder.The speed of the hydraulic drive motor was adjusted by the electric proportional hydraulic system in real time.Generally,the real time matching of planting speed and forward speed was realized.The bench test of hole distance control system was developed.The test result showed that the hydraulic motor speed was consistent with the change trend of ground wheel speed,and the delay time was within 600 ms.Moreover,the hydraulic drive motor of the left and right two transplanting units had excellent synchronization,and the average speed error was 0.7%.The electro-hydraulic control system of hole distance was installed on the rape combined transplanter.Comparative field tests were conducted for four theoretical hole distances(150 mm,160 mm,170 mm,180 mm)and four operating speeds(2 km/h,3 km/h,4 km/h and 5 km/h).The test result indicated that the transplanter had terrific hole distance stability.The primary and secondary factors affecting the consistency coefficient of variation were theoretical hole distance and forward speed.Theoretical hole distance had the most significant effect on the consistency of hole distance.When the hole distance was 160 mm,the consistency coefficient of variation of hole distance at different forward speed can keep a small value,which indicated that the hole distance of 160 mm was the most ideal hole distance.