Development of UAV autonomous lifting and transportation equipment for mountain bananas

Lifting and transportation equipment can greatly contribute to the harvesting of mountain bananas in the agricultural industry. However, some challenges still remain during post-harvest transportation, such as high labor intensity and cost, easy damage to fruits, and safety accidents. In this study, an Unmanned aerial vehicle (UAV) autonomous lifting and transportation equipment was designed to harvest the mountain bananas. The autonomous grasping and unloading of banana shafts were realized during the lifting and transportation. Manual participation was effectively reduced to ensure the safety of operators. The grasping mechanism, lifting gear, guide mechanism, and connecting parts were designed, according to the measured morphological features of the mountain banana. The specific needs were fully met by the postharvest transportation of mountain bananas. A three-dimensional model of the equipment was established using SOLIDWORKS software. The communication system of the upper and lower machines was also built. The key components of lifting and transportation equipment were simulated and theoretically calculated, using the explicit dynamics and magnetostatic analysis of ANSYS Workbench software. The parameters of an electromagnet and steering gear were determined to meet the requirements. The simulation highlighted that the better performance of equipment was achieved for subsequent testing. A laboratory experiment was then carried out to validate the efficacy of the equipment. The success rates of lifting and transportation were 92.59%, 96%, and 88.89%, respectively. The average time of grasping and unloading was 63.8 and 20.8 s, respectively. The effectiveness of equipment was verified to transport the mountain bananas. Furthermore, the field experiment UAV was carried out on the lifting and transportation equipment. The success rate of lifting and transportation was 83.33%, the total time of grasping and unloading was 90.8 s, and the average speed of lifting and transportation was 0.99 m/s, which was more than three times that of manual carrying speed (0.17~ 0.33 m/s). Because the banana bunch was suspended under the equipment without contacting with other objects, there was no damage to the fruit finger, indicating the better quality of the fruits during transportation. Nevertheless, the equipment produced a large lateral swing on the positioning and grasping of the banana shaft, due mainly to the strong wind field under the UAV. Therefore, there were some differences between the field test and the indoor experiment, but the expected performance was achieved anyway. The structure can be further optimized to improve the success rate of lifting and transportation of the equipment for less operation time. In conclusion, the equipment can fully meet the operational requirements for the autonomous lifting and transportation of mountain bananas by UAV. Overall, these findings can provide a strong reference for efficient, low-loss, and safe unmanned lifting and transportation equipment. A reliable and efficient solution can be offered for autonomous lifting and transportation in the banana industry towards sustainable growth and productivity.