Design,development, and field evaluation of a rubber tapping robot

Modern robotics has made great strides in the field of agricultural harvesting. In the field of rubber tapping, however, there are still significant challenges to be faced. As one of the few agricultural harvesting areas primarily manual, rubber tapping requires precise control of the knife in the forest's unstructured environment at night. This paper presents the design of a rubber cutting robot for natural rubber plantations. An upgraded spatial spiral trajectory is established by analyzing the trunk and manual rubber cutting trajectories for the operation of a six-axis tandem robot arm. A compact binocular stereo vision system achieved the initial perception of the parameters required for the cutting trajectory. Besides, an integrated end-effector was developed to enable further precise perception of the cutting trajectory and cutting operations. The system was tested in the field at a rubber plantation in Hainan Province. The upgraded trajectory's adaptability and the accuracy and efficiency of the starting point positioning algorithm were verified. The operational performance of the complete system was evaluated to help guide future improvements. The error of the start point locating is 1.0 $\pm$ 0.1 mm, and the execution time is 17.01 $\pm$ 3.65 s. The bark consumption—cutting depth setting of (2.0 and 5.0 mm) is more appropriate for the rubber tapping robot. Then the accuracy of chip thickness and chip width is about 1.73 $\pm$ 0.28 mm, and 5.07 $\pm$ 0.13 mm, respectively. Furthermore, the accuracy of chip weight is 1.99 $\pm$ 0.24 mm. The average operating time of the whole tapping operation is 80 $\pm$ 5 s. Future work will include improvements in system stiffness and robustness. This study demonstrates the potential of applying industrial robotics to the field of latex harvesting. Robotics may be a future development towards mechanized rubber tapping.