Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System, Yanshan University, Qinhuangdao, 066004, People's Republic of China.
Key Laboratory of Advanced Forging & Stamping Technology and Science (Yanshan University), Ministry of Education of China, Qinhuangdao, 066004, People's Republic of China.
Bioinspir Biomim. 2022 Jun 21;17(4). doi: 10.1088/1748-3190/ac72e0.
How to further improve the dexterity of continuum robots so that they can quickly change their structural size like flexible biological organs is a key challenge in the field of robotics. To tackle this dexterity challenge, this paper proposes a soft-rigid coupled bioinspired elephant trunk robot with variable diameter, which is enabled by combining a soft motion mechanism with a novel rigid variable-diameter mechanism (double pyramid deployable mechanism). The integration of these two mechanisms has produced three significant beneficial effects: (i) The coexistence of multi-degree-of-freedom motion capability and variable size function greatly improves the dexterity of the elephant trunk robot. (ii) The motion refinement can be improved by structural amplification, making up for the low resolution of soft actuators. (iii) Its stiffness can be increased by enlarging its diameter, while its reachable workspace can be increased by decreasing its diameter. Thus, the elephant trunk robot can optimize its performance when facing different tasks by opening and closing the rigid variable-diameter mechanism. Further, we established a kinematic model of the elephant trunk robot by the structure discretization method and the principle of mechanism equivalence, and experimentally verified its reasonableness. The demonstration experiments show that the elephant trunk robot has good flexibility. This work provides a new variable diameter configuration for continuum robots, and presents a method of how to analyze the kinematics of continuum mechanisms using rigid mechanism theory.
如何进一步提高连续体机器人的灵活性，使其能够像灵活的生物器官一样快速改变结构尺寸，是机器人领域的一个关键挑战。为了解决这一灵活性挑战，本文提出了一种具有可变直径的软刚耦合仿生象鼻机器人，它通过将软运动机构与新颖的刚性可变直径机构（双金字塔可展开机构）相结合来实现。这两种机制的集成产生了三个显著的有益效果：（i）多自由度运动能力和可变尺寸功能的共存极大地提高了象鼻机器人的灵活性。（ii）通过结构放大可以提高运动精度，弥补软执行器分辨率低的问题。（iii）可以通过增大直径来增加其刚度，通过减小直径来增加其可达工作空间。因此，象鼻机器人可以通过打开和关闭刚性可变直径机构来优化其在面对不同任务时的性能。进一步地，我们通过结构离散化方法和机构等效原理建立了象鼻机器人的运动学模型，并通过实验验证了其合理性。演示实验表明，象鼻机器人具有良好的灵活性。这项工作为连续体机器人提供了一种新的变径配置，并提出了一种如何使用刚性机构理论分析连续体机构运动学的方法。
