Bio-inspired soft pneumatic gripper for agriculture harvesting

For agricultural harvesting, handling fruits and vegetables are important processes which need a flexible but firm grip with dexterity. Due to the existing limitations of standard traditional grippers, a diverse range of soft grippers has been developed utilising elastomer, silicon, flexible plastic material etc. The manufacturing process includes mainly moulding or 3D printing and is actuated by pneumatic/ hydraulic drives, tendon drives or electrical signals. Still, there is a gap in the current market of soft grippers in terms of creating the required holding force with flexibility and bending to handle delicate foods. To overcome these existing limitations, a bio-inspired soft gripper is developed from 3D printing using Ninjaflex material. The proposed pneumatic controlled gripper is integrated with a hair-like fine structure and DIP-inspired feature to provide better grip to surfaces along with electrostatic attraction and suction. A comprehensive FEA simulation has been performed on material selection to find lower stress, longer lifespan, and higher bending capacity. Three basic tests are conducted to evaluate its performance: static friction, block force and radius of curvature. Besides, a simple grasping experiment is also conducted for holding tomatoes and coffee cups. Considering these results, the developed gripper has the potential to be acceptable in the current agricultural industry for handling objects.

1. WWF-UK.: Hidden waste: The scale and impact of food waste in primary production.WWF. Available at: https://www.wwf.org.uk/our-reports/hidden-waste (2022).
2. Rose, D.C. and Bhattacharya, M.: Adoption of autonomous robots in the soft fruit sector:Grower perspectives in the UK. Smart Agricultural Technology 3, p.100118 (2023).
3. Nasini, L., & Proietti, P.: Olive harvesting. The Extra‐Virgin Olive Oil Handbook. John Wiley & Sons, pp. 87-105 (2014).
4. Dimeas, F., Sako, D. V., Moulianitis, V. C., & Aspragathos, N. A.: Design and fuzzy control of a robotic gripper for efficient strawberry harvesting. Robotica 33(5), 1085-1098 (2015).
5. Muscato, G., Prestifilippo, M., Abbate, N., & Rizzuto, I.: A prototype of an orange picking robot: past history, the new robot and experimental results. Industrial Robot: An International Journal 32(2), 128-138 (2005).
6. Birglen, L., & Schlicht, T.: A statistical review of industrial robotic grippers. Robotics and Computer-Integrated Manufacturing 49, 88-97 (2018).
7. Mazzolai, B., Mondini, A., Del Dottore, E., Margheri, L., Carpi, F., Suzumori, K., ... & Lendlein, A.: Roadmap on soft robotics: multifunctionality, adaptability and growth without
borders. Multifunctional Materials 5(3), 032001 (2022).
8. Polygerinos, P., Correll, N., Morin, S. A., Mosadegh, B., Onal, C. D., Petersen, K., ... & Shepherd, R. F.: Soft robotics: Review of fluid‐driven intrinsically soft devices; manufacturing, sensing, control, and applications in human‐robot interaction. Advanced Engineering Materials 19(12), 1700016 (2017).
9. Hayashi, S., Shigematsu, K., Yamamoto, S., Kobayashi, K., Kohno, Y., Kamata, J., & Kurita, M.: Evaluation of a strawberry-harvesting robot in a field test. Biosystems engineering 105(2), 160-171 (2010).
10. Yaguchi, H., Nagahama, K., Hasegawa, T., & Inaba, M.: Development of an autonomous tomato harvesting robot with rotational plucking gripper. In: IEEE/RSJ international conference on intelligent robots and systems, pp. 652-657. IEEE, Daejeon, Sotuh Korea (2016).
11. Birrell, S., Hughes, J., Cai, J. Y., & Iida, F.: A field‐tested robotic harvesting system for iceberg lettuce. Journal of Field Robotics 37(2), 225-245 (2020).
12. Galley, A., Knopf, G. K., & Kashkoush, M.: Pneumatic hyperelastic actuators for grasping curved organic objects. Actuators 8(4), p. 76 (2019).
13. Gafer, A., Heymans, D., Prattichizzo, D., & Salvietti, G.: The quad-spatula gripper: A novel soft-rigid gripper for food handling. In: 2020 3rd IEEE International Conference on Soft Robotics, pp. 39-45. IEEE, New Haven, CT, USA (2020).
14. Wang, Z., Or, K., & Hirai, S.: A dual-mode soft gripper for food packaging. Robotics and Autonomous Systems 125, 103427 (2020).
15. Lee, J. H., Chung, Y. S., & Rodrigue, H.: Long shape memory alloy tendon-based soft robotic actuators and implementation as a soft gripper. Scientific reports 9(1), 11251 (2019).
16. Hu, W., Mutlu, R., Li, W., & Alici, G. (2018). A structural optimisation method for a soft pneumatic actuator. robotics, 7(2), 24.
17. Hegde, C., Su, J., Tan, J. M. R., He, K., Chen, X., & Magdassi, S.: Sensing in soft robotics. ACS nano 17(16), 15277-15307 (2023).
18. Walker, J., Zidek, T., Harbel, C., Yoon, S., Strickland, F. S., Kumar, S., & Shin, M.: Soft robotics: A review of recent developments of pneumatic soft actuators. Actuators 9(1), p. 3 (2020).
19. Youn, J. H., Jeong, S. M., Hwang, G., Kim, H., Hyeon, K., Park, J., & Kyung, K. U.: Dielectric elastomer actuator for soft robotics applications and challenges. Applied Sciences 10(2), 640 (2020).
20. Plante, J. S., & Dubowsky, S.: On the performance mechanisms of dielectric elastomer actuators. Sensors and Actuators A: Physical 137(1), 96-109 (2007).
21. Tawk, C., Gillett, A., in het Panhuis, M., Spinks, G. M., & Alici, G.: A 3D-printed omnipurpose soft gripper. IEEE Transactions on Robotics 35(5), 1268-1275 (2019).
22. Venter, D., & Dirven, S.: Self morphing soft-robotic gripper for handling and manipulation of delicate produce in horticultural applications. In: 24th International Conference on Mechatronics and Machine Vision in Practice, pp. 1-6. IEEE, Auckland, New Zealand (2017).
23. Yirmibeşoğlu, O. D., Oshiro, T., Olson, G., Palmer, C., & Mengüç, Y.: Evaluation of 3D printed soft robots in radiation environments and comparison with molded counterparts. Frontiers in Robotics and AI 6, 40 (2019).
24. Ranasinghe, H. N., Kawshan, C., Himaruwan, S., Kulasekera, A. L., & Dassanayake, P.: Soft pneumatic grippers for reducing fruit damage during strawberry harvesting. In: 2022 Moratuwa Engineering Research Conference, pp. 1-6. IEEE, Moratuwa, Sri Lanka (2022).
25. Alici, G., Canty, T., Mutlu, R., Hu, W., & Sencadas, V.: Modeling and experimental evaluation of bending behavior of soft pneumatic actuators made of discrete actuation chambers. Soft robotics 5(1), 24-35 (2018).
26. Jahanbakhshi, A., Rasooli Sharabiani, V., Heidarbeigi, K., Kaveh, M., & Taghinezhad, E.: Evaluation of engineering properties for waste control of tomato during harvesting and postharvesting. Food science & nutrition 7(4), 1473-1481 (2019).
27. Rasmussen, M. H., Holler, K. R., Baio, J. E., Jaye, C., Fischer, D. A., Gorb, S. N., & Weidner, T.: Evidence that gecko setae are coated with an ordered nanometre-thin lipid film. Biology Letters 18(7), 20220093 (2022).
28. Stojiljković, D., Milošević, M., Ristić-Durrant, D., Nikolić, V., Pavlović, N. T., Ćirić, I., & Ivačko, N.: Simulation, analysis, and experimentation of the compliant finger as a part of hand-compliant mechanism development. Applied Sciences 13(4), 2490 (2023).