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.

当前，高附加值精细果蔬与食用菌的采收作业仍需投入大量人力劳动。由于从业者薪资偏低且面临多种健康困扰，该职业的吸引力正持续下滑。与此同时，具备作物选择性采收能力的机器人系统正逐步研发。尽管近几十年来，此类机器人的移动平台、机械臂与识别系统已得到充分研究，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 grippers）的当前技术前沿展开分析，系统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，并从设计方案、已报道的性能指标（具体涵盖抓取与脱离方式、所用材料、执行器与传感器类型，以及夹持流程的控制策略）等维度开展横向对比。此外，本次纳入分析的柔性夹持器被划分为13个独立的柔性抓取技术类别。进一步地，本研究还按文献的发表年份与原产国进行统计分析，以观察该领域近年来的发展态势。此外，本研究还筛选出一批针对选择性采收作物任务开展实测的柔性夹持器，并对其抓取与脱离成功率、对植株及作物造成的损伤情况展开对比分析。