果树对靶喷雾机柔性喷臂控制设计及试验

由于生态环境问题日益严峻,农药喷雾必然是朝着低污染、高精度、智能化与安全化的趋势发展。现有的对靶喷雾机虽然可以针对有无靶标植株进行喷药,但其喷雾架通常是固定不变的,难以同时适用于不同靶标植株。为此,提出喷臂变形以使中心喷头对准靶标植株树冠中心的柔性喷雾架方案,通过安装在拖拉机侧面的激光测距传感器对靶标植株进行距离探测,采用安装在喷臂上的角度传感器对柔性喷雾架的形状进行实时检测。根据上述检测结果,通过程序内部运算,获得控制量,驱动电推杆对喷雾架进行形状调整,同时由安装在十字架上的超声波传感器对喷雾架下的靶标植株进行实时的识别探测,并设计了一种能同时满足不同靶标植株形状的对靶喷雾控制机构。为了减小调节时间和由于机构抖动造成的系统误动作,在喷臂调节算法的基础上增加了调整死区。通过试验分析,喷雾架可以根据拖拉机侧面与靶标植株树干的距离进行柔性对靶调节,喷雾架最大的调节时间为5.8s,满足对靶喷雾的实时性要求。

Design and Experiment of the Control of Flexible Spray Arm on Orchard Targeted Spray Device

Because of the increasingly serious ecological environment , agricultural spray is definitely on the trend toward low pollution , high precision , intellectualization and safety .Prevention and control of orchard plant diseases and insect pests is the most essential and time-consuming job .According to statistic , the spray of the fruit tree would need at least 8-15 times in a year of growing period and this job will occupy 30%of the orchard workload .The traditional method of spray used in our country is continuous spray and this method has one obvious shortcomings :the fruit trees in the orchard is not planted continuously and there is row spacing between two trees .When the spray device moves to the row spacing between two trees , the spray can not be deposited on the tree efficiently and this will cause invalid spray .Via the detec-tion technique , can the spray device distinguish the existence of the targeted plants .These technique will change the con-tinuous spray into the discontinuous spray .Although the available targeted spray device can do the spray job based on the existence of the targeted plants , the spray frame is always fixed and it is hard to apply to different targeted plants .In or-der to solve this problem , this article has put forward a scheme that adjusting the position of the central nozzle to align the center of the crown of the targeted plant by deformation of the spray frame .The distance between the targeted plant and the right side of the tractor is measured by the laser sensor installed on the tractor .The shape of the flexible spray frame is detected by the inclinometer installed on the spray arm .Base on the detection result above , the controlled variable is acquired through the operation of the internal program and the electromotive handspikes are motivated to adjust the spray frame .In order to reduce the adjusting time and the mechanical vibration , the PD regulation algorithm is used in the con-trol of the diagonal arm and the soft star and stop regulation algorithm is used in the control of the horizontal arm .In the same time , the ultrasonic sensor installed on the cross is used to detect the targeted plant below the spray frame .A targe-ted spray device is designed to apply to different targeted plants .This device is consisted of the spray arm unit , the de-tection unit , the spray unit and the control unit .The spray arm unit is consisted of the diagonal arm , the horizontal unit and the telescopic boom .The detection unit is consisted of the laser distance measuring sensor , the inclinometer and the ultrasonic sensor .The spray unit is consisted of five nozzles hanged in the horizontal arm .The control unit is consisted of two mega-16 system board .The regulated dead zone is added on the basis of the adjusting algorithm of the spray arm . Through the analysis of the experiment , the spray frame can do the flexible targeted deformation according to the distance between the right side of the tractor and the targeted plants .The maximum adjusting time of the spray frame is 5 .8 s and it fulfills the real-time demand of the targeted spray .