Kinematics and Stiffness Modeling of Soft Robot With a Concentric Backbone
Kinematics and Stiffness Modeling of Soft Robot With a Concentric Backbone
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DOI：
10.1115/1.4055860
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发表时间：
2022-10
期刊：
影响因子：
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通讯作者：
Q. Xiao;Mishek Musa;I. Godage;Hao Su;Yue Chen
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文献类型：
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作者：
Q. Xiao;Mishek Musa;I. Godage;Hao Su;Yue Chen
软机器人可以承受大的弹性变形，并适应复杂的形状。然而，由于制造材料（硅树脂或橡胶）的固有顺应性，它们缺乏承受外部载荷的结构强度。在本文中，我们提出了一种新的刚度调制方法，控制机器人的刚度的需求，而不会永久地影响固有的符合弹性体。受同心管机器人的启发，这种方法使用镍钛合金管作为骨干，它可以滑入和滑出软机器人身体，以实现机器人姿势或刚度调制。为了验证所提出的想法，我们制作了肌腱驱动同心管（TDCT）软机器人和Cosserat杆理论的基础上开发的模型。通过改变关节空间的肌腱输入和任务空间的外部接触力，该模型在不同的情况下进行了验证。实验结果表明，该模型能够估计TDCT软体机器人的形状，平均均方根误差（RMSE）为0.90~mm，平均尖端误差为1.49~ mm。仿真研究表明，镍钛合金主干的插入可以增强TDCT软体机器人的运动工作空间，并使其柔度降低57.7%。两个案例研究（对象操作和软腹腔镜光动力治疗），以证明所提出的设计的潜在应用。
Soft robots can undergo large elastic deformations and adapt to complex shapes. However, they lack the structural strength to withstand external loads due to the intrinsic compliance of fabrication materials (silicone or rubber). In this paper, we present a novel stiffness modulation approach that controls the robot's stiffness on-demand without permanently affecting the intrinsic compliance of the elastomeric body. Inspired by concentric tube robots, this approach uses a Nitinol tube as the backbone, which can be slid in and out of the soft robot body to achieve robot pose or stiffness modulation. To validate the proposed idea, we fabricated a tendon-driven concentric tube (TDCT) soft robot and developed the model based on Cosserat rod theory. The model is validated in different scenarios by varying the joint-space tendon input and task-space external contact force. Experimental results indicate that the model is capable of estimating the shape of the TDCT soft robot with an average root mean square error (RMSE) of 0.90~mm and an average tip error of 1.49~mm. Simulation studies demonstrate that the Nitinol backbone insertion can enhance the kinematic workspace and reduce the compliance of the TDCT soft robot by 57.7%. Two case studies (object manipulation and soft laparoscopic photodynamic therapy) are presented to demonstrate the potential application of the proposed design.