Experiments were conducted to reduce the towing resistance of a disk type slurry injector unit for the purpose of increasing working speed and reducing fuel consumption. Three thicknesses and three diameters of solid disks were used in the experiments. The horizontal and vertical forces acting on a disk and gauge wheels were measured at 20, 40 and 60mm cutting depths. The towing resistance was reduced when the thickness of an injector disk was thinner or the diameter was larger. As the cutting depth of a disk increased, the upward vertical force applied by the soil to the disk increased, and the vertical force supported by the wheels decreased. This phenomenon is important in analyzing the generation of the resistance.

We developed a no-till soybean chisel seeder for attachment to tractors. Chisels were modified to a boot shape to avoid straw entanglement and placed in a zig-zag pattern. The machine first digs a drainage furrow 100 to 150mm deep in each row. To reduce the influence of soil mass on sowing and emergence, seeds are sown 50mm laterally from the furrow. We also refined a commercial soil coverer. Field experiments showed that the seeder was efficient in fields with a wheat straw length of 130mm or less and had a sowing accuracy and emergence rate comparable to those of commercial seeders. The tractor should be at least 2t and 30 to 40kW for 5-rows seeding.

We developed a collecting robot and a storage device for tomato clusters. The collecting robot receives a tomato cluster as it is unloaded from the conveyor of a harvesting robot. When the conveyor of the collecting robot is filled with tomato clusters, the robot proceeds to the shipping room. Next, the tomato clusters on the conveyor of the collecting robot are unloaded on the conveyor of the storage device. In our experiment, the collecting robot could collect and unload the fruits without committing a fault. In addition, the processes of collecting, transportation, and unloading caused no damage to the tomatoes. However, to operate the harvesting system efficiently in a large-scale greenhouse, it is necessary to use multiple collecting robots.

A method for making an instruction manual of cleaning the inside of a combine harvester by including the knowledge of practiced workers was developed. In the method, first, experienced workers’ knowledge is gathered by workers’ interviews with watching videos of them performing cleaning tasks. Second, the gathered knowledge is arranged in a chart. Finally, the knowledge is translated into written text with accompanying figures and photographs. To demonstrate the level of cleaning precision on account of the developed method, we made a new cleaning-instruction manual according to this developed method, and examined the residual grain after the combine harvester was cleaned according to the cleaning manual produced. As a result, the quantity of residual grain decreased to 3-5g from 54-60g by workers referring to the newly produced cleaning manual.

We developed an arm-raising work assistance tool and evaluated its ability to mitigate effects of working load during grape cultivation. The tool comprises a hip belt, armrests, and connectors linking them. This tool supports the arms when held at any height, while keeping the wearer’s elbows pulled in. When performing berry thinning by using the tool, %MVC of the deltoid muscle was found to reduce by about 30% to 80% without reducing the efficiency. Seven of eight workers reported that the use of the tool made their work easier to perform.