基于作物需求的设施二氧化碳智能调控技术研发

发布时间：2018-01-30 16:36

本文关键词： 设施环境二氧化碳无线传感网络智能调控均匀补施　出处：《西北农林科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：二氧化碳是作物光合作用暗反应过程中的重要物质,但设施环境中二氧化碳变化趋势与作物实际需求呈负相关关系。传统设施环境二氧化碳调控多限于单因子阈值方式,无法根据作物实际需求进行调控,导致作物光合速率相对较低;且在二氧化碳调控均匀性方面研究较少,导致设施二氧化碳调控空间浓度分布不均。针对上述问题,本文提出基于作物需求的设施二氧化碳智能调控方法,融合小波神经网络的粒子群寻优算法,构建设施作物二氧化碳调控模型,设计以无线传感器网络为基础的智能监控设备,根据流体力学相关原理,设计开孔大小不同的气体导输管道,系统实现设施环境二氧化碳动态调控的目的,满足按需、精准、均匀调控的需求。二氧化碳智能调控系统的成功研发,对于完善设施小环境全方位智能调控起到了重要的补充作用。本文主要研究内容包括:(1)建立了作物光合速率模型,构建了设施二氧化碳调控模型。通过构建设施番茄二氧化碳响应试验,获取不同温度、光照、二氧化碳梯度下的光合速率试验数据,通过应用小波神经网络算法,建立光合速率预测模型,预测模型的相关系数为0.99,预测输出的平均绝对误差小于0.8;根据建立的光合速率模型,在不同温度、光照条件下,通过粒子群算法对光合速率进行极值寻优,获取对应二氧化碳饱和点,建立了二氧化碳调控模型,通过模型值与理论值进行对比,得出两者之间的相关系数大于0.954左右,相对误差小于4%,可证明构建的调控模型精度较高。(2)构建基于无线传感器网络的设施二氧化碳调控系统。根据不同节点在网络架构中功能的差异,调控系统分为主控、监测、补施3个模块。系统硬件开发主要包括电源模块、外接传感器、模块间通信电路等原理图、PCB设计,从而完成信息采集,获取以及交互等硬件平台搭建;系统软件开发主要包括基于Linux工控机底层驱动与上层处理软件的编程,以及基于ZigBee无线传感器网络的二次软件编程,从而完成实现基于无线传感器网络的设施环境的监测、处理以及二氧化碳浓度控制功能。(3)二氧化碳调控精准性、均匀性及有效性等功能与性能验证。根据流体力学相关理论分析,依据不同压强、相对深度等条件,结合气体射流理论,计算管道相对深度与开孔大小之间的关系,设计不同开孔大小的补施管道,保证各出气孔瞬时流量相同。通过部署整套系统并进行试验测试分析,结果表明,系统二氧化碳调控误差小于3.5%,系统补施均匀性变异系数小于3%;通过对照试验,验证二氧化碳调控系统对作物实际光合速率效果的影响,试验表明,二氧化碳调控区域作物光合速率得到了相对提升。系统较好地满足了设施环境二氧化碳调控需求。
[Abstract]:Carbon dioxide is an important substance in the dark reaction of crop photosynthesis. But the change trend of carbon dioxide in facility environment is negatively related to the actual demand of crops. The traditional regulation of carbon dioxide in facility environment is limited to single factor threshold mode and can not be adjusted according to the actual demand of crops. The photosynthetic rate of crops is relatively low; And there is little research on the uniformity of carbon dioxide regulation, which leads to the uneven distribution of the spatial concentration of carbon dioxide in facilities. In view of the above problems, this paper proposes an intelligent control method of facility carbon dioxide based on crop demand. Combining the particle swarm optimization algorithm of wavelet neural network, constructing the carbon dioxide regulation model of facility crops, designing intelligent monitoring equipment based on wireless sensor network, according to the relevant principles of fluid dynamics. Design the gas pipeline with different opening sizes, realize the purpose of dynamic control of carbon dioxide in the facility environment, meet the demand of demand, precision and uniform control. The successful research and development of carbon dioxide intelligent control system. It plays an important role in improving the comprehensive intelligent control of facilities and small environment. The main research contents in this paper include the establishment of crop photosynthesis rate model. The greenhouse carbon dioxide regulation model was constructed, and the photosynthetic rate test data under different temperature, light and carbon dioxide gradient were obtained by constructing the greenhouse tomato carbon dioxide response test. The prediction model of photosynthetic rate is established by using wavelet neural network algorithm. The correlation coefficient of prediction model is 0.99, and the average absolute error of prediction output is less than 0.8. According to the established photosynthetic rate model, under different temperature and light conditions, the particle swarm optimization algorithm was used to optimize the photosynthetic rate, the saturation point of carbon dioxide was obtained, and the carbon dioxide regulation model was established. By comparing the model value with the theoretical value, the correlation coefficient is greater than 0.954 and the relative error is less than 4%. It can be proved that the precision of the proposed model is high. (2) constructing the facility carbon dioxide control system based on wireless sensor network. According to the different functions of different nodes in the network architecture, the control system is divided into main control. The hardware development of the system mainly includes the PCB design of power supply module, external sensor, communication circuit between modules and so on, so as to complete the information collection. Acquisition and interactive hardware platform construction; The software development of the system mainly includes the programming based on the bottom driver and the upper processing software of the Linux industrial control computer, and the secondary software programming based on the ZigBee wireless sensor network. In order to achieve the wireless sensor network based on the facility environment monitoring, processing and carbon dioxide concentration control function. According to the theory of fluid mechanics, according to the different pressure, relative depth and other conditions, combined with the theory of gas jet. The relationship between the relative depth of pipeline and the size of the hole is calculated, and the filling pipeline with different opening sizes is designed to ensure the same instantaneous flow rate of each pore. The results show that the system is deployed and tested and analyzed. The systematic carbon dioxide control error was less than 3.5, and the coefficient of variation of systematic supplementation uniformity was less than 3. The effect of carbon dioxide control system on the actual photosynthetic rate of crops was verified by a controlled experiment. The photosynthetic rate of crops in the region regulated by carbon dioxide has been relatively improved, and the system can meet the demand of carbon dioxide regulation in the greenhouse environment.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212.9;TN929.5;S316

【相似文献】