Zigbee-assisted mobile robot gardener

With an aging population and recent change in traditional industries, automatic agricultural production has become inevitable in intensive agriculture. Agriculture in every country has gradually developed in terms of low-cost technical development and transformed to tourism type of orchard or greenhouse. Thus, the development of autonomous mobile robot gardener to assist farmers has become quite important. In this study, the prototype semi-autonomous mobile robot gardener is proposed to meet the requirement for spraying in the greenhouse. A robot designed with three wheels and driven by front-wheels whose speed difference controls the moving direction of the robot. The sensors including wide-angle laser rangefinder (LRF), single-point LRF, ultrasonic, and Hall-rotary encoders are equipped in the robot. The ARM-based controller serves as the main core processor to proceed with the behavior of mobile robot gardener. The initial tests are conducted in miniature greenhouse. The operation area is divided into multiple regions in the greenhouse. The internal map information, the location of soil moisture sensor modules (including Zigbee sensors), and mobile robot gardener moving path are known a priori. When the particular task within the region requires assistance, the robot moves on to the region and performs spraying task. The robot is equipped with Zigbee transceiver/receiver module to receive spraying task messages from the soil moisture sensor modules. While all task flags are confirmed by the robot, the control and decision-making program are performed under the known location information of the robot. The robot will move towards the selected path (the edge of planting bed) and finally will arrive at designated region. When the spraying work is completed, the robot stays on original operation point and waits for the next task command. The proposed mobile robot gardener can be applied for unmanned management of greenhouse in the future.