关键词: 番茄种植, 昼夜温差, 温度积分, 变论域模糊控制, 控制算法

Abstract: In order to control accurately the temperature in tomato grown greenhouse in northern China, this study put forward the intelligent temperature control strategy, according to temperature characteristics for each period of tomato growth in greenhouse, using accumulated temperature theory and variable universe fuzzy control theory. Through accumulated temperature method to calculate temperature thresholds, this paper made it adapt to the dynamic changes in external environment, and solved the difficult problem in traditional fuzzy control method by the variable universe fuzzy control theory, due to its structural parameters of relative fixation, yet not applying to high-precision control. Thus, the stability and system response time were greatly enhanced, and the control error was reduced. The simulation results showed that compared to the PID control scheme, this method had a 54.17% and 75% improvement in response time and overshoot aspect. Compared with the traditional fuzzy control scheme, this methods in response time and overshoot aspect had 35.29% and 55.56% improvement. The actual effect of the test showed that compared with the existing control strategies, both in daytime and nighttime, this control strategy could make the average indoor temperature closer to the desired temperature value, and at the same time save nearly 10% energy consumption, thus effectively improved the energy utilization rate.

Key words: tomato cultivation, temperature difference between day and night, temperature integral, variable universe fuzzy control, control algorithm