根据茶叶物料烘焙时具有迟滞、大惯性和非线性的特点,采用传统PID控制时温度控制精度不高,超调量较大,鲁棒性差。设计了一种基于动态矩阵控制的茶叶烘干机,烘干机采用多层隧道式,上加热方式,加热元件为电加热远红外辐射板,运用DMC-PID串级温度控制系统,前级的DMC算法提高温度控制系统的动态响应能力与鲁棒性;后级PID算法提高系统的抗干扰性能。对样机进行绿茶烘焙试验,试验表明,采用PID温度控制系统时烘干机超调量为10.5%,而采用DMC–PID串级温度控制其超调量为5.9%。DMC-PID可显著提高茶叶烘干机的温度控制精度及成茶品质。

According to the characteristics of delay, inertia and nonlinearity in the baking of tea materials, the low accuracy of temperature control, large overshoot and poor robustness of traditional PID control largely limited relative application. A tea drying machine was designed based on DMC-PID control in this paper. The drying machine adopted multi-layer tunnel with the infrared radiation plate heating element above the conveyor belt. The DMC-PID cascade temperature control system was also used. The first DMC algorithm improved the robustness and capability of the dynamic temperature control system and the second PID algorithm improved the anti-jamming performance simultaneously. The green tea baking experiment on the prototype was carried out. The results showed that when the PID temperature control system was adopted, the overshoot of the dryer became 10.5%. When the DMC PID cascade temperature control was used,the overshoot was 5.9%. DMC-PID control could improve the temperature control precision and tea quality of the tea dryer.