Fieldkaihatsu Co Ltd (Utsunomiya City) developed a method to control the height of weeds by using an autonomous robot to periodically step on them on the premises of a solar power plant.
A patent for the method was granted to the company Nov 2, 2018.
Fieldkaihatsu considers it possible to commercialize the autonomous robot and plans to release it as "Grapress" in March 2019. The expected price of the robot is ¥800,000 (approx US$7,050, excluding tax).
Grapress adjusts the height of weeds at about 10cm by stepping on grasses at a certain interval while autonomously moving on the premises of a solar power plant. According to botanical knowledge, when plants are contacted or cut, they emit ethylene, which is a hormone related to the suppression of growth. Because of this function, the heights of grass and weeds in a park become low in areas on which people often walk, Fieldkaihatsu said.
Thus far, when the robot is used to mechanically apply a weight to weeds four times a day, their growth was suppressed by up to 75%, Fieldkaihatsu said.
Equipped with a proximity sensor, the robot can autonomously move in space surrounded by fences and run on routes designated by wires, etc. By discriminating humans from plants with an ultrasonic sensor, it automatically stops in front of a human and moves backward/makes a turn. Also, even when it goes out of a designated area due to external factors such as stones and mud, it can automatically return to the designated route.