*2.2. Equipment System Components*

The formation of the manure spreading command equipment is exhibited in Figure 1. During fertilization, the chief command pattern, with the host computer as the main control unit, was used to control the open–shut the solenoid valve (Proportional solenoid valve, Shanghai Kaiweixi Co., Shanghai, China). An angular speed sensor (Analog output, Beijing Tianyuhengchuang Co., Beijing, China) was used to collect the wheel speed and convert it into the vehicle driving speed. The instantaneous flow rate of liquid manure was collected

through the flowmeter as input data. The controller output the current signal to the solenoid valve after algorithm conversion. The solenoid valve was used to control valve opening, and the output of the system was the liquid manure flow. Then, the real–time data collected with the fluid meter were coupled back to the regulator, through which the closed–loop negative feedback control was realized.

**Figure 1.** Structure diagram of fertilizer throwing control device: 1: tractor; 2: angular speed sensor; 3: pump; 4: liquid manure storage tank; 5: electric proportional valve; 6: flow meter; 7: liquid level meter; 8: monitoring and control by computer; 9: distributor; 10: sprinkler pipe.
