# Design and Testing of an Intelligent Control System for Maize Picking Harvest
## 3 Experimental Testing and Analysis of the Developed System
### Experimental Tests and Results
#### 3.2.2 Field Experiment of System  
Before a harvest, the operator first adjusts the working parameters to empirical values based on personal experience. The initial rotational speed of the pulling rollers was set to approximately 1200 r/min, the header height was set to 500 mm in low cutting mode, and the harvesting was conducted at an operating speed of 7 km/h. Figure 10a shows the regulation process of the corresponding outputs when the maize picking loss rate was high, and the two red circles respectively indicate the first and second deceleration of the rotational speed of the pulling rollers. The ears of maize were harvested after approximately 5 s. At the beginning of the harvest, the excessively high rotational speed of the pulling rollers and operating speed caused the ears to bounce higher. The greater impact force caused more ears to be broken, and the maize plants were jammed on the header. The maize picking loss sensor shows a larger equivalent value for the maize picking loss, which means that the maize picking loss rate was high. At this time, the controller sent a flow reduction control command to the proportional valves to decrease the rotational speed of the pulling rollers according to the received  
Figure 9: Automatic adjustment of pulling rollers under no load.  
m maize picking loss rate and formulated control strategy. The rotational speed of the pulling rollers was adjusted twice and was reduced to approximately 1100 r/min. The operating speed was reduced from approximately 7 to 6 km/h. This significantly reduced the popping height of the ears, and the header was no longer congested. Thus, the maize picking loss rate was reduced to the allowable range. In order to calibrate the maize picking loss sensor and verify the validity of the intelligent control system, the maize picking loss rate was determined manually through statistics after the maize was harvested. The manually measured maize picking loss rate was 1.676%, and the acceptable loss rate in China is <4% (ear harvesting), which satisfies maize harvesting requirements.  
Before the second experiment, the initial rotational speed of the pulling rollers was set to approximately 900 r/min, and the header height was set at 500 mm. The maize was picked at an operating speed of 5 km/h. Figure 10b shows the regulation process of the corresponding outputs, and the two red circles respectively indicate the first and second increase in the rotational speed of the pulling rollers. In the early stages of the harvest, the slow feeding of maize plants at the header was caused by the low rotational speed of the pulling rollers and the low operating speed. Although the maize picking loss rate was within the allowable range, the maize harvest efficiency was low. Thus, the controller issued a flow increase control command to proportional valves to increase the rotational speed of the pulling rollers. The rotational speed of pulling rollers was adjusted to approximately  
Figure 10: Automatic adjustment of pulling rollers under a load. (**a**) Regulation process of the corresponding outputs when the maize picking loss rate was high. (**b**) Regulation process of the corresponding outputs when the maize picking loss rate was in the allowable range.  
1050 r/min, and the operating speed was increased to 6 km/h. During this time, the maize picking loss rate did not exceed the allowable range, and the harvest efficiency improved. After the maize was harvested, the maize picking loss rate was determined manually through statistics. The manually measured maize picking loss rate was 1.386%, which satisfies maize harvesting requirements.