为了找出多旋翼无人机喷洒农药时影响农药沉积的因素及其影响程度,提高雾滴在靶标上的沉积水平,并通过试验制定相应的试验方法和规范,在单因素试验的基础上,采用Box-Benhnken的中心组合试验设计理论对施药机具的喷雾参数进行研究.以飞...为了找出多旋翼无人机喷洒农药时影响农药沉积的因素及其影响程度,提高雾滴在靶标上的沉积水平,并通过试验制定相应的试验方法和规范,在单因素试验的基础上,采用Box-Benhnken的中心组合试验设计理论对施药机具的喷雾参数进行研究.以飞行高度、飞行速度、喷头流量等工作参数为影响因素,以雾滴在靶标上的沉积水平为目标函数,建立雾滴沉积水平的二次多项式数学模型,并分析模型的有效性与因子间的交互作用.利用Design-Expert 8.0.5软件的回归分析法和响应面分析法对模型进行优化分析,得到施药机最优喷洒参数组合.结果表明,对雾滴沉积水平影响大小依次为飞行高度、飞行速度、喷头流量;最优喷洒参数组合为飞行高度2.0 m,飞行速度3.7m·s^(-1),喷头流量430 m L·min^(-1),此条件下的雾滴在靶标上的最大沉积水平为68.69%,且与模型预测值相比相对误差为±5%以内.展开更多
空中加油吊仓多采用"涵道式冲压空气涡轮"(Ducted Ram Air Turbine,以下简称DRAT)作为动力装置。空气涡轮性能的优劣直接影响DRAT的工作性能。为了对吊仓飞行高度以及飞行表速对空气涡轮性能影响进行研究,找到减少涡轮流动损...空中加油吊仓多采用"涵道式冲压空气涡轮"(Ducted Ram Air Turbine,以下简称DRAT)作为动力装置。空气涡轮性能的优劣直接影响DRAT的工作性能。为了对吊仓飞行高度以及飞行表速对空气涡轮性能影响进行研究,找到减少涡轮流动损失,提高系统的输出功率和效率的方法。采用NUMECA软件对涡轮流动进行叶轮机械数值仿真,对涡轮飞行包线内性能变化进行分析,得到了涡轮在飞行包线内的最小功率点和对应的最小功率,并通过对空气涡轮性能分析,建立一套关于空气涡轮性能的可行和实用的数值仿真方法。展开更多
A novel pressure and vacuum continuous control system,which adopts a hybrid pump as pressure and vacuum source,is presented.The mathematical model of the system is developed.The theoretical simulation and analysis on ...A novel pressure and vacuum continuous control system,which adopts a hybrid pump as pressure and vacuum source,is presented.The mathematical model of the system is developed.The theoretical simulation and analysis on the system are implemented in order to study the relationships among the characteristics,parameters and working points of the system.The experimental investigations on the system characteristics are presented with the adoption ofa fuzzy-PID controller.The simulation and experimental results indicate that the pressure and vacuum continuous control system based on hybrid pump has good dynamic and static performance,strong robustness and satisfactory adaptability to various system parameters.According to the results,system can successfully gain high accuracy and fast response signal.Also,the mathematical model of system is also testified by the experimental results.展开更多
文摘为了找出多旋翼无人机喷洒农药时影响农药沉积的因素及其影响程度,提高雾滴在靶标上的沉积水平,并通过试验制定相应的试验方法和规范,在单因素试验的基础上,采用Box-Benhnken的中心组合试验设计理论对施药机具的喷雾参数进行研究.以飞行高度、飞行速度、喷头流量等工作参数为影响因素,以雾滴在靶标上的沉积水平为目标函数,建立雾滴沉积水平的二次多项式数学模型,并分析模型的有效性与因子间的交互作用.利用Design-Expert 8.0.5软件的回归分析法和响应面分析法对模型进行优化分析,得到施药机最优喷洒参数组合.结果表明,对雾滴沉积水平影响大小依次为飞行高度、飞行速度、喷头流量;最优喷洒参数组合为飞行高度2.0 m,飞行速度3.7m·s^(-1),喷头流量430 m L·min^(-1),此条件下的雾滴在靶标上的最大沉积水平为68.69%,且与模型预测值相比相对误差为±5%以内.
文摘空中加油吊仓多采用"涵道式冲压空气涡轮"(Ducted Ram Air Turbine,以下简称DRAT)作为动力装置。空气涡轮性能的优劣直接影响DRAT的工作性能。为了对吊仓飞行高度以及飞行表速对空气涡轮性能影响进行研究,找到减少涡轮流动损失,提高系统的输出功率和效率的方法。采用NUMECA软件对涡轮流动进行叶轮机械数值仿真,对涡轮飞行包线内性能变化进行分析,得到了涡轮在飞行包线内的最小功率点和对应的最小功率,并通过对空气涡轮性能分析,建立一套关于空气涡轮性能的可行和实用的数值仿真方法。
基金This project is supported by National Natural Science Foundation of China(No.50675075).
文摘A novel pressure and vacuum continuous control system,which adopts a hybrid pump as pressure and vacuum source,is presented.The mathematical model of the system is developed.The theoretical simulation and analysis on the system are implemented in order to study the relationships among the characteristics,parameters and working points of the system.The experimental investigations on the system characteristics are presented with the adoption ofa fuzzy-PID controller.The simulation and experimental results indicate that the pressure and vacuum continuous control system based on hybrid pump has good dynamic and static performance,strong robustness and satisfactory adaptability to various system parameters.According to the results,system can successfully gain high accuracy and fast response signal.Also,the mathematical model of system is also testified by the experimental results.
