营养液组份检测与控制系统的设计与实现

将动态矩阵控制引入营养液组份控制领域，并提出一种“模型改造”的方法：将激励信号引入非自衡对象，使其变为一阶稳定系统．试验结果表明：动态矩阵控制可以将营养液中的各组份浓度控制在设定值．

The Design and Implementation for Nutrient Solution Components

To solve the problem of recirculating nutrient solution process, the design and implementation of the measurement and control of a nutrient solution components are introduced. The ion density of nutrient solution is measured by Ion Selective Electrode, which has high impedance. For this reason, operation amplifiers with high imput impedance are applied. A novel method for model improvement is presented for the integrating plant : an extra signal is introduced to the integrating plant, which stablizes the system. The predictive control scheme is: Firstly, considering the absorbing of the crop as disturb, the unit step response of the reformed model is obtained. Secondly, the future output is computed. At Last, the volume of dense nutrient solution which will add to the primary nutrient solution was computed. The control results showed that the algorithm was effective: the nutrient solution components were well controlled. The error is less than 10%. Furthermore, this system can reject disturbances. The application of this system is benefitial to agriculture automation in China.