In recent years, wet rice farming that does not use chemical herbicides has come in demand owing to the diversified consumer needs, preference for pesticide-free produce, and need to reduce the environmental load. In this paper, we propose a “weeding robot” that can navigate autonomously while weeding a paddy field. The weeding robot removes the weeds by churning up the soil and inhibits the growth of the weeds by blocking-off sunlight. It has two wheels, whose rotational speed is controlled by pulse width modulation (PWM) signals. Moreover, it has capacitive touch sensors to detect the rice plants and an azimuth sensor used when turning. To demonstrate its effect in wet rice culture, we conduct a navigation experiment using the proposed weeding robot in two types of paddy field: conventional and sparse planting. The experiment results demonstrate that the proposed weeding robot is effective in its herbicidal effect, promoting the rice seedling growth and increasing the crop yield.

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