This article proposes a two-finger-based micrograsping system with high compliant borosilicate 3.3 glass probes and the corresponding sensing and control algorithms, which enables the orientation manipulation of microparts in three-dimensional (3-D) space. Compared with the existing research, the novelty of this article relies on three aspects: 1) the end-effector of the microgripper is designed to be with high compliance so that the squeeze force exerted on microparts can be more accurately regulated and the proposed microgripper is capable of manipulating fragile microparts; 2) the micrograsping system is endowed the capability to fully manipulate microparts' orientation without recurring to auxiliary probes or rotary stages; and 3) the vibration characteristic of the grasping arm is investigated as cantilever beam for gasping stability analysis and squeeze force maintaining. In specific, taking spherical microparts with dimensions in the range from tens to hundreds of micrometers as target, the grasping system configuration, and the contact model between the probe and the microparts are first presented. Afterward, kinematics-based motion control strategy for position adjustment and orientation manipulation of microparts is clarified. Then, squeeze force regulation strategy is proposed, including adhesive force evaluation, vision-based squeeze force estimation, and the micropart releasing method. Finally, the vibration characteristic of the grasping arm is investigated as cantilever beam for grasping stability analysis and the squeeze force maintaining. The reliability and availability of the proposed micrograsping system is validated by well-designed experiments.

中文翻译：

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一种新型的基于双探头的微抓取系统，可实现灵巧的 3-D 方向调整


本文提出了一种基于两指的微抓取系统，具有高顺应性硼硅酸盐 3.3 玻璃探针以及相应的传感和控制算法，可实现三维 (3-D) 空间中微型零件的方向操纵。与现有研究相比，本文的新颖性在于三个方面：1）微夹具的末端执行器设计为具有高柔顺性，从而可以更精确地调节施加在微型零件上的挤压力，并且所提出的微夹具是能够操纵脆弱的微型零件； 2) 显微抓取系统能够完全操纵微型零件的方向，而无需重复使用辅助探头或旋转台； 3）研究抓臂作为悬臂梁的振动特性，进行喘振稳定性分析和挤压力维持。具体而言，首先以尺寸在数十至数百微米范围内的球形微型零件为目标，提出了抓取系统的配置以及探针与微型零件之间的接触模型。随后，阐明了基于运动学的微型零件位置调整和方向操纵的运动控制策略。然后，提出了挤压力调节策略，包括粘附力评估、基于视觉的挤压力估计和微零件释放方法。最后，研究了悬臂梁抓取臂的振动特性，以进行抓取稳定性分析和挤压力维持。所提出的微抓取系统的可靠性和可用性通过精心设计的实验得到验证。