针对甘蔗收割机在田间作业时,地形起伏变化影响切割刀盘刀片入土切割的深度,造成甘蔗根茬高度变化、根茬破头等问题,设计了一种基于AT89S52单片机的刀盘高度浮动控制系统.采用超声波测距雷达测量刀盘刀片最前端位置以及对应切割刀盘刀片最前端处垄间地形变化情况,在单片机内部对测量值进行中位值滤波处理后作为刀盘调整的参考值,对电液换向阀输出控制信号调整刀尖位置,实现切割刀盘高度随地形变化.为验证该系统的工作性能,在4GDL-132型甘蔗收割机样机上进行了试验,试验结果表明,设置刀尖与地面距离标准值为17.5 cm,允许波动范围± 2 cm,在20 m长、± 5°坡度变化的路面行驶时,刀尖与地面距离平均值为17.49 cm.试验结果证明,切割刀盘浮动控制系统能基本实现刀盘浮动控制,刀尖轨迹曲线与地面的轨迹曲线相同.%When sugarcane harvesters are operating in the field,the ups and downs of the ridge might affect the height of stubbles,and might even cause stubbles damages. In order to solve this problem, this paper designed a control system based on AT89S52 MCU. This control system can locate both the most front-end of Basecutter tip and the variation of ridge terrain under the most front-end of Basecutter tip by ultrasonic ranging radars. In the MCU, there is a median filter program which processes the measurement value to use as the parameters of Basecutter discs adjustment. If it needs to be adjusted, MCU outputts signals to control the electro-hydraulic valve through a relay and achieved Basecutter discs moving following the terrain changes. The system was tested on a 4GDL-132 billet harvester pro-totype in order to verify its performance. The test showed that driving 20 m on the ground with ± 5° slope changes,the average distance between the tip and the ground was 17.49 cm, in the case of 17.5 cm setting height difference with ± 2 cm fluctuation range. The test proved that the control sys-tem could adjust Basecutter tip position automatically obtain the same curve of Basecutter tip as that of the ground.
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