Highly Articulated Tube Mechanism With Variable Stiffness and Shape Restoration Using a Pneumatic Actuator
Highly Articulated Tube Mechanism With Variable Stiffness and Shape Restoration Using a Pneumatic Actuator
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使用气动执行器具有可变刚度和形状恢复的高度铰接管机构
DOI：
10.1109/lra.2022.3147246
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发表时间：
2022
影响因子：
5.2
通讯作者：
Tadokoro Satoshi
中科院分区：
文献类型：
--
作者：
Onda Issei;Tadakuma Kenjiro;Watanabe Masahiro;Abe Kazuki;Watanabe Tetsuyou;Konyo Masashi;Tadokoro Satoshi
近年来，软机器人研究的重点是控制机器人结构刚度的机构。有几种类型的变刚度机构可以通过改变摩擦力来改变这种结构的刚度。其中负压法是对袋内填充的颗粒或层施加负压，使其相互接触，增加刚度。然而，使用负压方法可以实现的最大驱动压力为0.1 MPa，这限制了刚度。在这项研究中，我们设计了一种新的流体驱动机构，通过气动人造肌肉的正加压来改变刚度。所提出的结构由空心珠和内部肌肉组成，可以通过施加压力时产生的收缩力来保持任意关节角度。我们测量了当内压力和内管片直径改变时，在俯仰方向上由于摩擦产生的扭矩。我们证实，在任何内径下，实测扭矩值与理论扭矩值之间的误差在20%以内。此外，由于气动人造肌肉被封闭在结构内部，当施加压力时可能会产生驱动效应。我们测量了当阀瓣开度比和阀瓣内径改变时，这种效应的恢复角和恢复力。我们证实了通过改变单个橡胶管的流量可以改变形状恢复特性的功能。我们的方法将有助于在软机器人应用中使用正加压设计有效的强化机制。未来，我们将设计一种任意改变轴向段距离的张紧机构，并研究段距离改变时的保持力矩、恢复角和力。
Recently, soft robotics research has focused on mechanisms to control the stiffness of robot structures. There are several types of variable stiffness mechanisms that can change the stiffness of such structures by altering friction force. Among these, the negative-pressurization method applies negative pressure to the particles or layers that are filled inside a bag so that they contact each other and increase stiffness. However, the maximum driving pressure that can be achieved using the negative-pressurization method is 0.1 MPa, which limits the stiffness. In this study, we devised a new fluid-driven mechanism that can change the stiffness through positive pressurization using pneumatic artificial muscles. The proposed structure constructed with hollow beads and inner muscles can hold arbitrary joint angles by the contraction force generated when a pressure is applied. We measured the torque in the pitch direction due to friction when the internal pressure and inner segment diameter were changed. We confirmed that the error between the measured and theoretical torque value was within a 20% at any inner diameter. Also, since a pneumatic artificial muscle is enclosed inside the structure, an actuation effect can occur when the pressure is applied. We measured the restoring angle and force of this effect when the valve opening ratio and inner segment diameter were changed. We confirmed the function that can change the shape restoration characteristics by changing the flow rate with a single rubber tube. Our approach will help design effective stiffening mechanisms using positive pressurization in soft robotics applications. In future, we will design a tensioner mechanism for arbitrarily changing the distance of segments in the axial direction, and we will investigate the holding torque, restoring angle and force when the distance of the segments is changed.