The National Agricultural Research Center (NARC) of Japan has engaged in a robotic project that fully mechanized rice production with a global positioning system (GPS) capability that can painstakingly transplant rice using sensors and computers which can be independent from human activities or the use of human labor.
The transplanting machine can make an accurate plan and direction on where to transplant around a six inch long rice seedlings. The rice seedlings are grown over two weeks on a long mat, using hydroponics culture system.
The long mat containing the seedlings is unrolled from the machine, and each seedling is sown into the soil, six in a row each time. Twenty rolls of mats weighing a total of two hundred eighty kilograms (280 kgs.) are needed to cover a one hectare area. The transplant robotic machine is estimated to cost a farmer for acquisition cost around sixty thousand US dollars (US$ 60,000).
However, the technology is still under evaluation at present. But once proven ready for commercialization, price of the equipment may decrease to accommodate especially the farmers in developing nations where the traditional old methods of rice production are still prevalent.
Mass production of the same can lower the price or cost of the technology. A Controller Area Network (CAN) bus is set up to oversea the activities of the rice transplanter through its Equipment Control Unit (ECU), where all the sensors, motors and a main computer are all connected.
Prior to the transplanting operation of the machine, the four corners of the field and the travel path have to be plotted. During transplanting, the main computer controls actions to minimize the deviation from the desired travel path in accordance to position and direction data.
The travel speed of the transplant robotic machine can be revised from the main computer in order to make any adjustments from the deviations of transplanter’s path. The main computer commands the robotic to stop at the end o a field, lifts and turns it to the next path. As observed, deviations from the planned path is at ten centimeters.
To measure direction and inclination of the machine, an Inertia Measuring Unit (IMU) that has fiber optic gyro sensors and accelerator is used. The NARC is actually on a six row transplanter that already exists in Japan. Ninety nine percent of rice farms in Japan are already mechanized and even rice transplanting is reportedly in practice by one hundred percent of Japanese farms.
Apparently, Japan’s average rice yield is six metric tons per hectare compared to the developing countries of three and a half metric tons only per hectare. Transplanting maximizes land use and cuts weed presence. Japan has its own mechanized rice planter since 1966 yet, but it was dependent with human labor pushing the transplanter while the farm worker’s feet are on knee deep on the ground.
With the present GPS system, Japan’s rice production may be fully mechanized from land preparation to harvest time. The NARC has proposed that in order to be cost efficient in producing this farm equipment technology, it has to compact the system by combining the sensors and computer segments on a rice transplanter, combine harvester, fertilizer and a tractor segments are shared as the first stage of their plan.
In the next stage, they are planning to develop an autonomous combine harvester using the Controller Area Network (CAN) bus to share with GPS receiver, IMU and a main computer attached to the rice planter.
