【作者】 耿爱军；

【导师】 张晓辉；

【作者基本信息】 山东农业大学 ， 农业机械化工程， 2011， 博士

【摘要】 自动化、智能化的综合作业机械是目前国际农机发展趋势,是发展高效节本农业的有效途径。世界农业发达国家在采用了高度自动化的作业机械后不仅提高了工作效率,降低了作业成本,而且还提高了其农产品在国际市场场上数量和价格的相对优势。目前,我国农机化已经进入了一个快速发展机遇期。而在我国烟草种植业中,烟草打顶和抑芽剂施药技术落后,烟草打顶工作全部由人工完成(工作效率为0.133 hm~2/h);烟草打顶后的抹杈、抑芽剂喷施也全部由人工逐步完成(工作效率仅为0.033 hm~2/h),生产效率低。国内尚未开展烟草打顶、抑芽剂喷施联合作业机的研究,也未见对烟草仿形打顶、抑芽剂对靶喷施技术研究的报道。针对这一现状,在借鉴国内外打顶机械研究现状的基础上,研制了智能烟草打顶机,对其关键技术进行了理论分析和试验研究。研究的主要内容包括:(1)对烟草打顶期茎秆的力学特性进行了试验研究。分析了烟草茎秆抗弯弹性模量随烟草茎秆含水率的变化规律,并对数据曲线进行了拟合,建立了烟草茎秆弹性模量——含水率的数学模型;利用非保守系统的哈密顿原理,建立了单自由度系统下变截面烟草茎秆在集中力作用下的运动方程;对打顶部位的烟茎进行了切割试验,分析了烟草茎秆直径、刀片安装角、切割速度对最大切割力和单位切割力的影响。(2)从理论上分析了烟草打顶过程,建立了切割力计算公式;并对打顶时烟草茎秆的变形和刀片受力进行了分析,研究了切割力各组成部分的计算方法,为烟草打顶机切割器参数计算提供了理论依据,同时也为其它机械切割器参数计算方法提供了思路。(3)研究设计了抑芽剂自动对靶喷施系统。设计了曲柄滑块机构,该机构主要由曲柄、滑块、滑轨、喷管、行程开关等组成;建立了曲柄滑块机构的虚拟样机模型,对其输出特性曲线进行了分析;并分析了曲柄滑块机构中各因素对施药效果的影响。根据试验的目的要求,拟定了双因素和多因素正交试验方案,分析了各因素对施药准确性的影响程度,得到了其最佳试验组合。(4)设计了对靶施药自动控制系统。主要有单片机系统、测速模块、烟草茎秆检测模块、电磁阀控制模块、步进电机控制模块等组成。测速模块可实现对机组行进速度的实时监测,烟草茎秆检测模块检测到烟草茎秆信号时,单片机系统一方面控制电磁阀通电开启,实施喷药,另一方面根据测定的机组行进速度和喷药时间控制步进电机的转速和转角,使喷药过程中喷管对准烟草茎秆或处于烟草茎秆周围,实现对靶施药。喷药结束,步进电机反转直到触到行程开关,行程开关有信号时步进电机停止,等待下一次工作信号。(5)针对曲柄滑块结构中滑块运动速度是非匀速、导致施药过程喷管与烟草茎秆存在位置偏置的弊端,设计了卷轴对靶施药系统。该系统将曲柄滑块结构中的曲柄连秆换成了卷轴和钢丝绳,步进电机匀速转动时,滑块作匀速平移运动,速度大小与进机组行进速度相同、方向相反,使喷药过程中喷管始终对准烟草茎秆。模拟喷药试验结果显示:原抑芽剂施药系统小车速度0.3m/s时,收集药量占每次喷量的63.68%,小车速度0.5m/s时,收集药量占每次喷量的43.47%,而卷轴对靶施药系统小车速度0.3m/s时,收集药量占每次喷量的84.51%,小车速度0.5m/s时,收集药量占每次喷量的77.68%,明显提高了有效施药率。更多还原

【Abstract】 Automatic, intellectualized comprehensive machinery is trend of currently international agricultural development, and it is the effective ways of developing efficient and investment–reducing agriculture. Countries of adopting the automatized machinery not only improve the work efficiency, reduce the work cost, but also improve its relative advantage of agricultural products in the international market on the quantity and the price.At present, agricultural mechanization has entered a rapid development period in China. But the technology of tobacco topping and Restrain-germinating fall behind. The working of tobacco topping is all acomplished by manpower(work efficiency is 0.133 hm~2/h) and then the working of disbuding and Restrain-germinating drug spraying are also entirely completed by handwork gradually (work efficiency only is 0.133 hm~2/h). the productivity is very low. Research of comprehensive machinery which can accomplish tobacco topping and Restrain-germinating drug spraying is not beginning, and report about technology of tobacco shape-following topping and Restrain-germinating drug spraying on target are not seen in China. In this situation, the intellectualized tobacco topping machine was developed, theoretical analysis and experimental research of its pivotal technology were done. The main contents include:(1)The mechanics characteristic experiment of the tobaccostalk was researched and the relationship between modulus of anti-bending elasticity and moisture content of the tobaccostalk was analyzed, the curve was fitted for experimentaldata, the mathematical model of modulus of elasticity of the tobacco stalk-the water ratio was established; used Hamilton’s principle of the non-conservative system and The motion equation of the variable-section stalk impacted by Concentrated force in Single-degree-of-freedom system used Hamilton’s principle of the non-conservative system; The cutting experiment for tobaccostalk topping position was done, the relationships were analyzed between the maximum force ,unit cutting force and the stalk diameter, blade fixed angle.(2) The toping process was analyzed theoretically and the calculation formula of the cutting force was established. the stalk deformation and the force impacting on the blade were analyzed and the calculating methods for factors of the cutting force were discussed, which provided basis in theory for the cut parameter of the tobacco topping machine and also provide a way for cut parameter of the other machine.(3) the spraying system on target was researched and the slider-crank mechanism was designed. It include the crank, the slider, the sliding rail, the effuser, the position switch etc. The virtual prototyping model for the slider-crank mechanism was established and its output characteristic curves were analyzed. The spraying results affected by the factors of the slider-crank mechanism was also analyzed. According to the purpose and the requirement of the experiment, the scheme of double factors and multi-factor orthogonal experiment was determined , and the influence to accuracy of each factor was analyzed, The best combination of experiment was obtained.(4) the automatic controlling spraying system on target was designed. It composed of SCM system, speed measuring module, tobaccostalk detecting module, Electromagnetic valve -controlled module , step motor-controlled module etc. The speed measuring module could realize the speed of machine real-time. When the tobaccostalk detecting module detected the signals of the stalk, on the one hand the SCM system controlled the Electromagnetic valve openning to spray, on the other hand the SCM system controlled the palstanceand the rotated angle according to the moving velocity and each time of machine,which made nozzle aim at or near to the tobaccostalk, so spraying on target was realized. Spraying was over,end, stepp motor reversalled until it touched the position switch, when position travel switch showed a signal ,the stepp motor stopped, waiting for the next work signal(5) On account of the slider moving non-uniformly which caused the nozzle and tobaccostalk exist position deviation in spraying process. So the scroll spraying system on target was designed. It changed the crank and rocker of the slider-crank mechanism to scroll and steel wire. When the step motor rotated on uniform velocity, The slider did uniformly and translational motion, its speed is same of machine and its moving orientation was opposite to machine,which made the nozzle always aim at the tobaccostalk. The simulating spraying experiment result showed when the speed of machine was 0.3 m/s in the original spraying system, the collecting solution was 63.68% of each spraying. When the speed of machine was 0.5 m/s, the collecting solution was 43.47% of each spraying. In the scroll mechanism spraying system on target, when the speed of machine was 0.3 m/s, the collecting solution was 84.51% of each spraying. When the speed of machine was 0.5 m/s, the collecting solution was 77.68% of each spraying, the effective spraying was improved obviously.更多还原