High-accuracy velocity control is required for maintaining precision and efficiency in farm operations involving automated agricultural machinery. The velocity of agricultural machinery undergoes variation because of the disturbances on a farm. Moreover, during operations in the agricultural field, agricultural machinery is required to pull equipment or trailers. In this paper, a design method of velocity control based on gain-scheduled H_∞ control is proposed to deal with these disturbances and variations in weight. Furthermore, we implemented the proposed control law on an unmanned ground vehicle. The results of the experiments showed that the proposed method is effective in dealing with these disturbances and variations in weight, and thus, it can be applied to general mobile agricultural machinery.

View full abstract

We studied the physical properties of spray liquid droplets generated as a result of air-assisted electrostatic spraying with an aim to improve the pesticide adherence performance demonstrated in a crop community by providing air-assistance from behind the spray nozzle for the control of pests in a greenhouse, plant factory, etc. In the course of this study, we used an electrostatic spraying system equipped with an annular electrode in a wind tunnel in order to examine the relationship between the air-assisted wind speed, the diameter of spray liquid droplets, the spray nozzle height, spray distance, the electrode voltage, the distribution of precipitation of spray liquid droplets, the specific charge of liquid droplets, etc. As a consequence, we identified the increase in the volume of spray liquid droplets reaching the object by horizontally spraying the liquid in an air-assisted manner through the use of a hollow conical spray nozzle and found out that the specific charge of liquid droplets measured at the 100cm spray distance was approx. 8 times greater than when no air-assisted electrostatic spraying was conducted.

View full abstract