变雨强人工模拟降雨自动控制系统设计与试验

针对变雨强降雨的室内人工模拟,通过分析降雨执行器件性能参数,建立了模拟雨强和流量频率、流量频率和执行器调节电压之间的线性关系,设计了基于供水流量调节的人工降雨控制系统.通过分析信号采集设备性能参数和电动执行器的电压-机械灵敏度,提出基于LabVIWE语言的变时间步长自动控制算法,用于人工降雨系统中模拟降雨雨强的渐变控制.电动执行器的电压-机械灵敏度为0.2 mm/V;供水流量频率的最小控制精度为7 Hz;雨强的最小控制精度为0.053 mm/min.试验结果显示,设计雨强和模拟雨强的相对误差在4%以下;降雨的重现性、稳定性在0.98以上;降雨空间分布的均匀性在0.97以上;渐变降雨的线性相关系数在75%以上.

Design and test of automatic control system of artificially simulating rainfall with variable intensity

For artificially simulating rainfall with variable intensity in laboratory, a linear relation be- tween the simulated rainfall intensity and the frequency of flow rate, and that between the frequency and the regulating voltage of electric actuator were established through analyzing the performance parameters of the actuator; subsequently, an automatic control system for such a simulation was designed based on the flow rate regulation of water supply. An automatic control algorithm with variable time-step was pro- posed based on the LabVIEW language and then applied into gradation control on the water supply in the artificial rainfall system by analyzing the performance parameters of signal acquisition equipment and the voltage-mechanical sensitivity of electric actuator. The voltage-mechanical sensitivity of electric actuator was 0.2 mm/V, and the minimum control accuracies of frequency of water supply flow rate and rainfall intensity were 7 Hz and 0. 053 mm/min, respectively. The experimental results indicated that the rela- tive error between the rainfall intensity achieved and the designed one is less than 4% ; the fidelity and the stability of simulated rainfall intensity is above 0.98 ; the spatial homogeneity coefficient of rainfall intensity is above 0.97 ; the linear correlation coefficient of rainfall intensity is above 0.75.