温室温度分层递阶控制系统的设计与仿真

作物生长周期为小时级，温室温度变化为分钟级，两者响应时间尺度相差较大.针对这种双时间尺度特性，提出了一种温室温度分层递阶控制系统的设计方法.系统具体分为作物层和环境层.在作物层，根据奇异摄动理论获取解耦的低阶模型，设计优化控制器以求取温室温度设定值，使生产净成本达到最小，并将设定值传递给环境层；在环境层，设计模糊控制器以有效跟踪设定值.最后，对该控制系统进行了仿真验证，结果表明各层控制器均可有效发挥作用，控制效果良好. 

Design and Simulation of Greenhouse Temperature Hierarchical Control System

For greenhouse crop system, significant differences in response times exist. Crop dry matter production responds rather slowly to the changes in the environmental conditions while the greenhouse temperature responds relatively fast. For this reason, a greenhouse temperature hierarchical control system was proposed. The hierarchical system was designed with two layers, including the crop layer and the climate layer. First, in the crop layer, a decoupled lower order model was established based on the theory of singularly perturbed systems. The controller was handled by means of an optimal control approach to achieve temperature set points, minimize the net cost according to objective function. Then, a fuzzy controller in the climate layer was designed to cope with the problem of tracking set points obtained from the crop layer. At last, the designed hierarchical control system was tested in Matlab. The simulation results show that both the crop and climate layer controllers can work well with better control performance.