Using the Smith PSO-Fuzzy PID Model to Control Electrical Conductivity of Nutrient Solution of Precision Fertilization

Abstract

【Background and objective】 Precision irrigation and fertilization not only improve crop yield and quality but also reduce the environmental footprint of agriculture. How to control precise irrigation and fertilization at large scales is a key to achieving this goal. The objective of this paper is to propose such a methodology. 【Method】 The method is based on a multi-channel water and fertilizer integration device. It consists of seven parts: an industrial aluminum profile frame, a main pipeline system, a fertilizer suction system, a fertilizer mixing system, a detection system, a control system, and a fertilization system. Based on the PSO optimized Fuzzy PID, a Smith control system (Smith PSO-Fuzzy PID) for water and fertilizer application is constructed. Taking EC of the nutrient solution being 2 mS/cm as the control target, the proposed method is compared with the traditional PID, and the fuzzy PID (Fuzzy PID). 【Result】 The steady-state time and the overshoot calculated by the proposed method are 47 s and 4.83%, respectively; the EC of the nutrient solution calculated by the proposed method is in the range of 1.987~2.080 mS/cm, very close to the targeted value. 【Conclusion】 Compared with traditional PID and Fuzzy PID, the proposed method for controlling water and fertilizer application has the advantages of fast response and high precision.

Keywords

• smith
• pso
• fuzzy pid control
• water and fertilizer integration