## 2 Materials and Methods
### Seeding Spacing Test Method  
To analyze the stability of the dynamic compensation system for seeding position, stability tests were conducted on longitudinal and transverse grain spacing. For this experiment, the maize seed variety used was Zhengdan 958, and the seed spacing was set at 30 cm. The conveyor speed was set to 1.67 m/s to maintain consistent flow, and the time interval between the falling of two seeds was no less than 400 ms. The seeding spacing test method involved using a measuring tape to determine the distance between the centers of two adjacent seeds, both longitudinally and transversely. The collected data were then analyzed, with the mean value, standard deviation, and coefficient of variation calculated to quantify the stability of the seeding spacing. This process was repeated multiple times to obtain sufficient data for analysis. Additionally, the falling interval time of the two seeds is  
\[t=\frac{d}{v} \tag{6}\]  
where \(t\) is the falling interval time of 2 seeds, s; \(d\) is seeding grain distance, m; \(v\) is the running speed of conveyor belt, m/s. According to Formula (6), the falling interval time of 2 seeds is 0.18 s, and the seed metering device rotation speed is  
\[r=\frac{60}{nt} \tag{7}\]  
Figure 4: Simulation model of fuzzy PID control for servo motor.  
where \(r\) is the rotation speed of the seed metering device, r/min; \(n\) is the seed holes of the seed metering device; \(t\) is the time between the falling of 2 seeds, s.  
According to Formula (7), the speed of the seed metering device is 30 r/min. In field conditions, corn platters experience vibration due to uneven ground during the seeding process. To simulate such conditions, researchers conducted experiments using a six-degree-of-freedom platform and applied three different disturbance signals: a sine wave disturbance signal with an amplitude of 10 mm, a random disturbance signal with an amplitude of 6.2 mm, and a combination of random disturbance signal and sine wave disturbance signal with an amplitude of 15.7 mm.  
To prevent corn seeds from bouncing, the conveyor belt was sprayed with high-viscosity hydraulic oil before starting the conveyor and seed metering device. For each experiment, the disturbance signals were applied, and the setup was repeated three times.  
In the experiment, as illustrated in Figure 5a, eleven consecutive corn seeds were selected after each sowing test, and the distance between adjacent seeds was measured to obtain ten measured values of corn seeding distance. Four sets of longitudinal grain distance deviation data were obtained under different conditions: no disturbance signal, random disturbance signal, sine wave disturbance signal, and random disturbance signal plus sine wave disturbance signal.  
Additionally, Figure 5b shows that a laser transmitter was used to emit a reference line along the first and 11 th seeds of each test, and the distance from the second seed to the reference line was measured continuously for 10 seeds. Three sets of transverse grain distance data were obtained under different disturbance signals: random disturbance signal, sine wave disturbance signal, and random disturbance signal plus sine wave disturbance signal.