温室温度约束模型预测控制研究

Constrained Predictive Control Model for Greenhouse Temperature

【目的】针对温室温度控制中模型参数不确定、系统时滞和调控设备的物理限制问题,研究温室温度约束模型预测控制(MPC)。【方法】采用系统辨识的方法,建立一个包含室外气候条件和室内调控设备的温室温度控制模型,以天窗开度和作物生长温度要求为约束条件,基于MPC方法对温室内天窗通风的降温过程进行控制。【结果】建立的温室温度控制系统ARX模型(扩展的自回归模型)3步预测输出和实测值的拟合度为94.53%,基于该模型的温室温度约束MPC夜间和白天实现温度控制的均方根误差(RMSB)分别为0.38和4.6℃,温室内温度可以按照设定值实现平稳准确的变化。【结论】该方法适用于温室温度控制,具有较好的应用价值。

[ Objective ] The constrained predictive control model presented aims at the problems in green-house temperature control, such as uncertain parameters,time delays and physical limitation of the regulate fa-cilities. [ Method ] The model of greenhouse temperature control was set up by system identification. This mod-el included not only the external weather conditions but also the inside regulation and control facility. Thegreenhouse roof ventilation cooling processes were controlled based on MPC method with the constraints of roofvent opening and temperature requirements for the crop growth. [ Result ] It was showed that from the simula-tion experiment, the fit was 94.53% between the 3 step predictive output of the ARX model and the measureddata. The root - mean - square error of greenhouse temperature control was 0.38°C in the night and 4.6°C inthe daytime by the constrained MPC method. The internal temperature changed smoothly and accurately ac-cording to the set points. [ Conclusion ] This method was suitable for the greenhouse temperature control and ofgood application value.