Development of an individual weed treatment system using a robotic arm

Abstract

A robotic weed control system was developed to mechanically cut a targeted weedapart while applying a minute amount of chemical to the cutting surface of the weed. The developedsystem consisted of an USB video camera, robotic arm with a duel weed control mechanism endeffector, soil pads, and artificial weeds contained in an aluminum structure. A modified excessivegreenmethod provided a good threshold image, and noise was well filtered out using continuity ofpixel property, comparing the gray level of the pixel in the threshold image over neighboring pixels.The center coordinates of the detected objects in the image were determined by using the geologicalmoment. The use of the objects geological moment obtained from the image was used to successfully determine the center of the objects with Total Error (TE) ranging from 0.0 to 0.3 cm.Inverse kinematics of the arm were solved with the given center coordinates of the weeds, andsolving given inverse kinematics obtained an angle set of the arm joints moving the end effector tothe desired point. A program written in Visual Basic was used for both image analysis and the controlof the robotic arm. The robotic arm has a recommended workspace of 11 to 14 cm in longitudinaldirection (X) with 6 to 3 cm in the horizontal direction (Y) from the world origin. The developedrobotic weed control system has an 83 % rate of success in the image area; however, a success rateof 100 % was observed within the recommended workspace. The dual-mechanism end effectorshowed potential for controlling weeds using both mechanisms; the mechanical weed control layer ofthe end effector showed feasibility to remove the top portion of the targeted weed, and the chemicalinsertion mechanism of the end effector provided an acceptable chemical applicability to a target.