Modeling and Prototyping of an Underactuated Gripper Exploiting Joint Compliance and Modularity
Modeling and Prototyping of an Underactuated Gripper Exploiting Joint Compliance and Modularity
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DOI：
10.1109/lra.2018.2845906
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发表时间：
2018-10-01
影响因子：
5.2
通讯作者：
Prattichizzo, Domenico
中科院分区：
文献类型：
--
作者：
Hussain, Irfan;Renda, Federico;Prattichizzo, Domenico
在这项研究中，我们根据螺钉理论提出了软机器人手指的有效数学表示。然后，我们展示了如何在设计阶段利用模型及其主要特性，并提出了一个具有模块化结构的肌腱驱动的握力的应用，其中定义了关节刚度值以获得所需的等效刚度并在指尖操纵运动。刚度通过抓地力的柔性部分的分布对于表征其整体行为至关重要：引入的数学模型使握把设计师能够分析特定特性，例如，指尖的所需轨迹，所需的整体僵硬，分布，分布接触力等的被动接头刚度的影响，反之亦然，评估关节刚度值允许获得所需的特性。可以通过调节制造过程中的三维印刷参数和材料特性来获得具有不同刚度值的关节。可以设计具有相同机械结构的模块化抓地力，但是不同的行为，即不同的指尖轨迹，等效的指尖刚度椭圆形等。抓地力模块可以轻松组装并分配，并分配，并保持相同的基础，以使它们适应不同的基础。任务。提出的模型和设计准则是可以针对特定问题进行优化的软抓手方向的第一步。
In this study, we present an efficient mathematical representation of soft robotic fingers based on screw theory. Then, we show how the model and its main properties can be exploited in the design phase, and we present an application for an underactuated tendon-driven gripper with a modular structure, in which the joint stiffness values are defined to obtain the desired equivalent stiffness and kinematics manipulability at the fingertips. A distribution of stiffness through the flexible parts of the gripper is fundamental to characterize its overall behavior: The introduced mathematical model enables the gripper designer to analyze how a specific property, e.g., a desired trajectory of the fingertips, a desired overall stiffness, a distribution of contact force, etc., is influenced by the stiffness of its passive joints, and vice-versa evaluating the joint stiffness values allowing to get a desired properties. Joints with different stiffness values can be obtained by regulating three-dimensional-printing parameters and material properties in the manufacturing process. It is possible to design modular grippers with the same mechanical structure, but different behaviours, i.e., different fingertip trajectories, equivalent fingertip stiffness ellipsoids etc. Gripper modules can be easily assembled and dis-assembled, maintaining the same base, to adapt them to different tasks. The presented model and design guidelines are a first step in the direction of soft grippers that can be optimized for a specific problem.