Supplementary material for the article: Soft robotic grippers for crop handling or harvesting: A review

Nowadays, harvesting delicate and high-value fruits, vegetables and edible fungi requires a large input of manual human labor. The relatively low wages and many health problems the workforce faces make this profession increasingly unpopular. Meanwhile, robotic systems that selectively harvest crops are being developed. Whilst the moving platform, manipulator, and recognition systems of such robots are studied the past few decades, research on the gripping end of such robots is only recently growing. This study analyses the state-of-the-art of soft grippers for crop handling and harvesting, reporting their quantitative and qualitative characteristics. Seventy-eight grippers are retrieved from the academic literature and compared with each other in terms of their design and reported performance, more specifically grasping and detachment methods, materials used, type of actuators and sensors employed, and the control of the gripping procedure. In addition, the identified grippers are classified into 13 distinct soft grasping technology categories. Moreover, the retrieved papers are analyzed with respect to their publication date and country of origin to observe the recent growth in the field. Furthermore, a subset of soft grippers is identified that was tested on the task of selectively harvesting crops, where grip and detachment success rates and plant and crop damage are compared.

如今，采收精细且高附加值的水果、蔬菜与食用菌（edible fungi）需要投入大量人力劳动。劳动力薪资相对偏低且面临诸多健康问题，使得该职业的受欢迎度日益走低。与此同时，具备作物选择性采收功能的机器人系统正处于研发阶段。尽管在过去数十年间，学界已针对此类机器人的移动平台、操纵装置与识别系统开展了大量研究，但针对其夹持末端的相关研究直至近年才逐渐兴起。本研究针对用于作物搬运与采收的柔性夹持器（soft gripper）的当前最先进技术水平展开分析，梳理并报告其定量与定性特征。研究从学术文献中检索得到78款柔性夹持器，并从设计维度与已报道的性能表现展开对比分析，具体涵盖抓取与脱离方式、所用材料、所采用的执行器与传感器类型，以及夹持流程的控制方式。此外，本次研究将所识别出的柔性夹持器划分为13个不同的柔性抓取技术类别。同时，研究还针对检索到的论文的发表年份与原产国进行分析，以观察该领域近年的发展态势。此外，研究还锁定了一组针对选择性采收作物任务开展测试的柔性夹持器子样本，并对比了其抓取与脱离成功率，以及对植株与作物造成的损伤情况。