Soil moisture regulation of agro-hydrological systems using zone model predictive control

• Published in: Computers and electronics in agriculture Vol. 154; pp. 239 - 247
• Main Authors: Mao, Yawen, Liu, Su, Nahar, Jannatun, Liu, Jinfeng, Ding, Feng
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-11-2018; Elsevier BV
• Subjects: Agriculture; Computer simulation; Control methods; Control systems design; Hydrologic modeling; Hydrology; Identification methods; Irrigation; Mathematical models; Moisture; Moisture content; Parameter identification; Predictive control; Soil layers; Soil moisture; Soils
• ISSN: 0168-1699; 1872-7107
• DOI: 10.1016/j.compag.2018.09.011

•A method to identify a linear parameter varying model between irrigation amount and root zone soil moisture.•An approach to design state and disturbance observers based on the LPV model.•A zone model predictive control with asymmetric zone tracking cost.•Extensive simulations that demonstrate the efficiency of the proposed methods in water conservation.
In this paper, we consider input-output model identification and zone model predictive control of agro-hydrological systems. Specifically, we consider an agro-hydrological system with homogeneous soil layers to illustrate the proposed model identification and predictive control methods. The primary control objective is to maintain the soil moisture at the center of the root zone within a target zone. A secondary control objective is to reduce the total amount of water used in irrigation. First, a linear parameter varying (LPV) model for controller design purpose is identified. Then, based on the LPV model, a zone model predictive control (MPC) is designed, which uses asymmetric zone tracking penalties to reduce irrigation amount under weather uncertainties while maintaining the soil moisture within the target zone. The simulation results show that the LPV model provides satisfactory approximation of the process dynamics, and the designed zone MPC is suitable for irrigation of the agro-hydrological system.