Analysis of temperature control system for strawberry greenhouse based on Smith predictive fuzzy PID

Abstract

Temperature is one of the key environmental factors in greenhouses. Its temperature control system has problems such as time delay, strong nonlinearity, prolonged response time, and large overshoot. Traditional PID control cannot meet the requirements. Aiming at this problem, a Smith predictive fuzzy PID control method was designed, which adds the Smith predictor to the loop system, predicts the performance of the object, feeds it back into the regulator, reduces the overregulation amount, eliminates the adverse impact of time delay on the controlled system, and simulates it through MATLAB/Simulink. The test results show that compared with traditional PID algorithm and fuzzy PID algorithm, Smith predictive fuzzy PID control that the time required to reach stable temperature was shortened by 23.07%, the overshoot is 0, and the recovery time after temperature change was shortened by 36.84 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">%</sup> , the maximum peak change after the interference signal was 4.71%, and the vibration amplitude was the smallest. Therefore, compared with traditional PID algorithm and fuzzy PID algorithm, Smith predictive fuzzy PID control has superiority in temperature control of strawberry greenhouse.